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NSW Arbovirus Surveillance Program, 2005-2006

Institute for Clinical Pathology & Medical Research 1

EEXXEECCUUTTIIVVEE OOVVEERRVVIIEEWW • For the 2005-2006 season, the NSW Arbovirus Surveillance Program: (i) Monitored

mosquito vector populations and undertook surveillance of arbovirus activity through virus isolation on the NSW western slopes and plains, north coast region and metropolitan Sydney. (ii) Monitored flavivirus transmission through the testing of sentinel chickens across inland NSW. The majority of sites operated between November and May.

• The dry conditions during the three previous seasons abated during the winter and

spring of 2005 for the inland with above average rainfall. By early 2006 much of the inland had become exceptionally dry. The coastal strip mostly had below average rainfall, although the far north coast had extremely heavy precipitation during late January, which coincided with the spring tides. By mid autumn, conditions along the entire coast had become very dry and cool.

• For the inland, the above average rainfall early in the season resulted in some very

large collections with over 10,000 mosquitoes per trap. Arbovirus activity was intense; there were 61 virus isolates (8 RRV, 49 SINV, 1 KOKV & 3 unknowns) and 477 case notifications including 419 RRV and 58 BFV, close to double the average. The onset of the dry summer halted the RRV epidemic with the epidemic peak being almost two months earlier than that of previous years. There were no seroconversions to MVEV or KUNV in the sentinel chickens.

• Along the coast, the relatively dry conditions meant that freshwater breeding

mosquito numbers were low, however breeding of the saltmarsh mosquito, Aedes vigilax, was extensive and overall mosquito numbers were much higher than normal. There was intense arboviral activity, with 73 isolates (28 BFV, 15 RRV, 1 SINV, 5 EHV, 22 STRV & 2 unknowns). Aedes vigilax yielded 50 isolates (22 BFV, 12 RRV, 3 EHV & 13 STRV), Aedes procax yielded 12 (5 BFV, 1 RRV, 1 EHV & 5 STRV) and other isolates were from freshwater and brackish water breeding mosquitoes.

• Barmah Forest virus (BFV) continued to be active along the north coast for the sixth

season running, with a new record high of 614 cases for the state. This is now the largest documented outbreak of BFV in Australia. As previously, most notifications occurred within the Mid North Coast AHS (166 cases), although activity extended to the Hunter (163 cases) and Northern Rivers AHSs (143). These regions produced almost 77% of all BFV reports for NSW. RRV was also intensely active, with 730 cases for the coast, over double the average and the second highest number for the coast since reporting began. The Northern Rivers AHS had the highest case number (276), followed by the Hunter (172) and Mid North Coast (157).

• For the Sydney trapping locations, fewer mosquito collections were undertaken this

season. Human notifications from the region were almost double the average (179 in total), and included 119 RRV, 20 BFV and 40 ‘other’.

• The NSW Arbovirus Surveillance Web Site http://www.arbovirus.health.nsw.gov.au/

continued to expand and now has over 169MB of information with 1,290+ pages.



TTAABBLLEE OOFF CCOONNTTEENNTTSS

EEXXEECCUUTTIIVVEE OOVVEERRVVIIEEWW _____________________________________________ 1 IINNTTRROODDUUCCTTIIOONN ____________________________________________________ 3 MMEETTHHOODDSS _________________________________________________________ 3

Background ______________________________________________________ 3

MMOONNIITTOORRIINNGG LLOOCCAATTIIOONNSS ___________________________________________ 5 WWEEAATTHHEERR DDAATTAA ___________________________________________________ 5

MVEV Predictive Models ____________________________________________ 6

MMOOSSQQUUIITTOO MMOONNIITTOORRIINNGG ____________________________________________ 7 Methods _________________________________________________________ 7 Results __________________________________________________________ 8

Inland _______________________________________________________________ 8 Coastal ______________________________________________________________ 8 Metropolitan Sydney____________________________________________________ 8

AARRBBOOVVIIRRUUSS IISSOOLLAATTIIOONNSS FFRROOMM MMOOSSQQUUIITTOOEESS _________________________ 9 Methods _________________________________________________________ 9 Results _________________________________________________________ 11

SSEENNTTIINNEELL CCHHIICCKKEENN PPRROOGGRRAAMM _____________________________________ 11 HHUUMMAANN NNOOTTIIFFIICCAATTIIOONNSS____________________________________________ 12 DDIISSCCUUSSSSIIOONN______________________________________________________ 12 TTHHEE NNEEWW SSOOUUTTHH WWAALLEESS AARRBBOOVVIIRRUUSS SSUURRVVEEIILLLLAANNCCEE WWEEBB SSIITTEE ________ 19 Appendix 1. LLOOCCAATTIIOONN--BBYY--LLOOCCAATTIIOONN SSUUMMMMAARRYY ______________________ 20

Inland Locations __________________________________________________ 20 Coastal Locations _________________________________________________ 21 Sydney Locations _________________________________________________ 23

AAppppeennddiixx 22.. MMEEDDIIAA RREELLEEAASSEESS ______________________________________ 24 Media Release – NSW Health, 10 February 2006 ________________________ 24 Media Release – Port Stephens Council, 10 February 2006 ________________ 25 Media Release – Hunter New England AHS, 10 February 2006 _____________ 26 Media Release – Hunter New England AHS, 3 March 2006 ________________ 27

Appendix 3. TTHHEE MMOOSSQQUUIITTOOEESS ______________________________________ 28 AAppppeennddiixx 44.. TTHHEE VVIIRRUUSSEESS __________________________________________ 29 AACCKKNNOOWWLLEEDDGGMMEENNTTSS _____________________________________________ 31 RREEFFEERREENNCCEESS_____________________________________________________ 32



NNSSWW AARRBBOOVVIIRRUUSS SSUURRVVEEIILLLLAANNCCEE AANNDD MMOOSSQQUUIITTOO MMOONNIITTOORRIINNGG PPRROOGGRRAAMM 22000055--22000066

IINNTTRROODDUUCCTTIIOONN The aim of the Program is to provide an early warning of the presence of Murray Valley encephalitis virus (MVEV) and Kunjin (KUNV) viruses in the state, in an effort to reduce the potential for human disease. In addition, the Program compiles and analyses mosquito and alphavirus, especially Ross River (RRV) and Barmah Forest (BFV) viruses, data collected over a number of successive years. This will provide a solid base to determine the underlying causes of the seasonal fluctuations in arbovirus activity and the relative abundance of the mosquito vector species with the potential to affect the well being of human communities. This information can then be used as a basis for modifying existing local and regional vector control programs, and creation of new ones. MMEETTHHOODDSS Background Arbovirus activity within NSW has been defined by the geography of the state, and three broad virogeographical zones are evident: the inland, the tablelands and the coastal strip (Doggett 2004, Doggett and Russell 2005). Within these zones, there are different environmental influences (e.g. irrigation provides a major source of water for mosquito breeding inland, while saltmarshes along the coast are highly productive), different mosquito vectors, different viral reservoir hosts and different mosquito borne viruses (e.g. MVEV and KUNV occur only in the inland, while BFV is active mainly on the coast). As a consequence, arboviral disease epidemiology often can be vastly different and thus the surveillance program is tailored around these variables. Arbovirus surveillance can be divided into two categories: those methods that attempt to predict activity and those that demonstrate viral transmission. Predictive methods include the monitoring of weather patterns, the long-term recording of mosquito abundance, and the isolation of virus from vectors. Monitoring of rainfall patterns, be it short term with rainfall or longer term with the Southern Oscillation, is critical as rainfall is one of the major environmental factors that influences mosquito abundance; in general, with more rain comes higher mosquito numbers. The long-term recording of mosquito abundance can establish baseline mosquito levels for a location (i.e. determine what are ‘normal’ populations), and this allows the rapid recognition of unusual mosquito activity. The isolation of virus from mosquito vectors can provide the first indication of which arboviruses are circulating in an area. This may lead to the early recognition of potential outbreaks and be a sign of the disease risks for the community. Virus isolation can also identify new viral incursions, lead to the recognition of new virus genotypes and identify new vectors. Information from vector monitoring can also reinforce and strengthen health warnings of potential arbovirus activity. Methods that demonstrate arboviral transmission include the monitoring of suitable sentinel animals (such as chickens) for the presence of antibodies to particular viruses



(e.g. MVEV and KUNV within NSW), and the recording of human cases of disease. Sentinel animals can be placed into potential ‘hotspots’ of virus activity and, as they are continuously exposed to mosquito bites, can indicate activity in a region before human cases are reported. Seroconversions in sentinel flocks provide evidence that the level of virus in mosquito populations is high enough for transmission to occur. The monitoring of human cases of arboviral infection has little direct value for surveillance, as by the time the virus activity is detected in the human population, often not much can be done to control the viral transmission. Via the other methodologies, the aim of the surveillance program is to recognise both potential and actual virus activity before it impacts greatly on the human population so that appropriate preventive measures can be implemented. The recording of human infections does, however, provide important epidemiological data and can indicate locations where surveillance should occur. These methods of surveillance are listed in order; generally, with more rainfall comes more mosquito production. The higher the mosquito production, the greater the probability of enzootic virus activity in the mosquito/host population. The higher the proportion of virus infected hosts and mosquitoes, the greater the probability of transmission and thus the higher the risk to the human population. The NSW Arbovirus Surveillance and Mosquito Monitoring Program undertakes the first four methods of arbovirus surveillance and the results for the 2005-2006 season follow.

Fig 1. Mosquito trapping locations and Sentinel Chicken sites, 2005-2006.



MMOONNIITTOORRIINNGG LLOOCCAATTIIOONNSS http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/location/locations.htm For 2005-2006, mosquito-trapping sites were operated at 6 inland, 8 coastal and 5 Sydney locations (Fig 1). Chicken sentinel flocks were located at 6 locations. WWEEAATTHHEERR DDAATTAA http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/climate/climate.htm

Mosquito abundance is dictated principally by rainfall patterns and irrigation practices in inland regions, while in coastal regions tidal inundation along with rainfall is important. Temperature and/or day-length are often critical in determining the initiation and duration of mosquito activity for species in temperate zones. Hence, the monitoring of environmental parameters, especially rainfall, is a crucial component of the Program. The conditions leading up to the season of 2003-2004 were of very low precipitation. These dry conditions were not alleviated during the second half of 2004 for much of the state. The third quarter (i.e. Jul-Sep 2004) of 2004 had average rainfall (Figure 2), and while the last quarter of the year saw some heavy rainfall along the coast, much of the inland stayed relatively dry (Figure 3). The first quarter of 2005 saw a worsening of the drought situation in the northwest inland, with some areas experiencing record low rainfall (Figure 4). These dry conditions extended to the Murray region by the second quarter of 2005 (Figure 5), although pockets in the north received some good rainfall. Some above average rainfall was recorded along the mid-north coast during January, otherwise the coastal strip remained relatively dry during early 2005. The conditions leading up to the season of 2003-2004 were of very low precipitation. These dry conditions were not alleviated during the second half of 2004 for much of the state. The third quarter (i.e. Jul-Sep 2004) of 2004 had average rainfall (Figure 2), and while the last quarter of the year saw some heavy rainfall along the coast, much of the inland stayed relatively dry (Figure 3). The first quarter of 2005 saw a worsening of the drought situation in the northwest inland, with some areas experiencing record low rainfall (Figure 4). These dry conditions extended to the Murray region by the second quarter of 2005 (Figure 5), although pockets in the north received some good rainfall. Some above average rainfall was recorded along the mid-north coast during January, otherwise the coastal strip remained relatively dry during early 2005.

Figures 2-5. Australian Rainfall deciles for the 3 month periods, Jul-Sep 2005, Oct-Dec 2005, Jan-Mar 2006 & Apr-Jun 2006. The stronger the red, the drier the conditions. Conversely, the stronger the blue, the wetter the conditions. Modifed from the Australian Bureau of Meterology, 2006.



The dry conditions over the last three seasons abated during the winter and spring months of 2005 for the inland, where rainfall was above average, particularly in the south west, although it was becoming dry again in the northwest by late 2005 (Figures 2&3). By the start of 2006 much of the inland was again experiencing dry conditions and many areas were soon to become ‘drought declared’ (Figures 4&5). Rainfall along the coastal strip was variable and mostly below average. This was particularly the case during the late summer along the mid-north to south coast, although the far north coast had extremely heavy rainfall in the last week of January, which coincided with a spring tide. By mid autumn, conditions had become very dry, with rainfall below average overall and very much below average for the mid north coast (Figure 5). As per the previous season, temperatures were well above average for 2005-2006, particularly in December & January. For the latter month, some areas of the western inland experienced temperatures of up to five degrees above average. By April, conditions had cooled across the state, were down to two degrees below normal, and remained so through to June. MVEV Predictive Models Two models have been developed for the prediction of MVEV outbreaks in southeastern Australia; the Forbes’ (1978) and Nicholls’ (1986) models. Forbes associated rainfall patterns with the 1974 and previous MVEV epidemics, and discussed rainfall in terms of 'decile' values. A decile is a ranking based on historical values. The lowest 10% of all rainfall values constitute decile 1, the next 10% make up decile 2, and so on to the highest 10% of rainfall constituting decile 10. The higher the decile, the greater the rainfall.

Figure 6. The SO by seasons prior to MVEV active years, according to Nicholls (1986), updated up to Winter 2006. The black bars represent the pre-MVEV active seasons. The yellow arrows indicate the respective SO values relevant to the 2005-2006 season.



Forbes' hypothesis refers to rainfall levels in the catchment basins of the main river systems of eastern Australia. These include: • The Darling River system, • The Lachlan, Murrumbidgee & Murray River systems, • The Northern Rivers (that lead to the Gulf of Carpentaria), and • The North Lake Eyre system. The hypothesis states that if rainfall levels in these four catchment basins are equal to or greater than decile 7 for either the last quarter of the previous year (eg. October- December 2004) or the first quarter of the current year (January-March 2005) and the last quarter of the current year (October-December 2005), then a MVEV outbreak is probable. Rainfall was not above decile 7 for all the catchment basins for the last quarter of 2004, the first quarter of 2005 or the last quarter of 2005. Thus, the hypothesis was not satisfied for the 2005-2006 season. As rainfall was only above decile 7 in one of the catchments for the first quarter of 2006, the hypothesis would suggest that an MVEV outbreak in southeastern Australia would be unlikely for the 2006-2007 season. Nicholls’ hypothesis uses the Southern Oscillation (SO) as a tool to indicate a possible MVEV epidemic. He noted a correlation between past outbreaks of MVEV and the SO (as measured by atmospheric pressures at Darwin in mm) for the autumn, winter and spring period prior to a disease outbreak. For the autumn, winter and spring periods of 2005, the SO values of 1010.47mm, 1012.93mm and 1010.20mm respectively (indicated on Figure 6 by the yellow arrows), were outside the range of values for the same period of past MVEV outbreak years (Figure 6). Likewise, the summer 2005–2006 SO value of 1006.63mm was higher than that experienced during MVEV years. Currently, the autumn and winter Nicholls’ values for 2006 are 1008.50mm and 1014.10mm, respectively, and while the autumn figure is in the range of past MVEV outbreak years, the winter value is not. MMOOSSQQUUIITTOO MMOONNIITTOORRIINNGG Methods Mosquitoes were collected overnight in dry-ice baited Encephalitis Vector Surveillance type traps. They were then sent live in cool, humid Eskies via overnight couriers to the Department of Medical Entomology, Institute of Clinical Pathology and Medical Research (ICPMR), Westmead for identification and processing for arbovirus isolation. The mosquitoes were identified via taxonomic keys and illustrations according to Russell (1993, 1996), Dobrotworsky (1965) and Lee et al. (1980 – 1989). A brief description of the main mosquito species for NSW appears in Appendix 3. It was reported in the 2000-2001 Annual Report of the New South Wales Arbovirus Surveillance & Mosquito Monitoring Program (Doggett et al. 2001), that the mosquito genus Aedes had undergone taxonomic revisions and many species had been given the generic name of ‘Ochlerotatus’. This genus has since been used in the Annual Reports; however, most specialist scientific journals have recently reverted to ‘Aedes’, pending further scientific taxonomic clarification; hence the use of ‘Aedes’ in this report. Note that the genus ‘Verrallina’, which was also formerly in Aedes, has not reverted.



Mosquito abundances are best described in relative terms, and in keeping with the terminology from previous reports, mosquito numbers are depicted as: • 'low' (1,000 per trap), and • ‘extreme’ (>10,000 per trap). All mosquito monitoring results (with comments on the collections) were placed on the NSW Arbovirus Surveillance Web site, and generally were available within 1-2 days of receiving the sample into the laboratory. Access to each location's result is from: http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/results/results.htm. Results Overall, 209,359 mosquitoes representing 54 species were collected in NSW during the 2005-2006 season. This total is close to double that of the previous season. Culex annulirostris and Anopheles annulipes were the most abundant and most important of the inland mosquito species during the summer months, whereas Aedes vigilax, Culex annulirostris, Culex sitiens, Coquillettidia linealis and Aedes notoscriptus were the most numerous species on the coast. A full summary of the results on a location-by-location basis is included in Appendix 1 and the complete mosquito monitoring results are available on the NSW Arbovirus Surveillance web site. Inland The solid spring rainfall meant that mosquito numbers were well up during December to early January across the inland. The total of 102,045 mosquitoes trapped, comprising 22 species, was almost five times that of the previous season. Culex annulirostris was the dominant species yielded at most sites and comprised 65.1% of the total inland collections. Anopheles annulipes (25.9%) was the next most common species. Coastal The overall mosquito collections were higher in abundance than the previous two seasons and one of the largest collections for the coast to date. In total, 94,503 mosquitoes comprising 46 species were collected from coastal NSW. The most common species collected were Aedes vigilax (61.2% of the total coastal mosquitoes trapped), Coquillettidia linealis (10.5%), Aedes notoscriptus (6.0%), Culex annulirostris (5.7%), Aedes procax (4.5%) and Culex sitiens (4.3%). Metropolitan Sydney Mosquito collections from Sydney were considerably lower than the previous season, due mainly to fewer collections being undertaken. A total of 12,991 mosquitoes, comprising 27 species, was collected from metropolitan Sydney. Aedes vigilax (42.5% of the total Sydney mosquitoes trapped) was the most common species followed by Aedes notoscriptus (26.8%), Culex annulirostris (8.5%) and Coquillettidia linealis (7.5%).



AARRBBOOVVIIRRUUSS IISSOOLLAATTIIOONNSS FFRROOMM MMOOSSQQUUIITTOOEESS http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/about/methods.htm Methods Viral isolation methods were as per earlier annual reports (Doggett et al., 1999a, 2001). Assays were used to identify any suspected viral isolate, and can identify the alphaviruses - BFV, RRV and Sindbis (SINV), and the flaviviruses - MVEV, KUNV, Alfuy (ALFV), Edge Hill (EHV), Kokobera (KOKV) and Stratford (STRV). Any isolate that was not identified by the assays was labelled as 'unknown'. A short description of the various viruses and their clinical significance is detailed in Appendix 4. Positive results were sent to Dr Jeremy McAnulty, Director, Communicable Diseases Branch, NSW Health, to the relevant Public Health Unit, and posted on the NSW Arbovirus Surveillance Web Site (under ‘Mosquito/Chicken Results’) and under each locations’ surveillance results.

Table 1. Arbovirus isolates from inland locations, 2005-2006.

Virus LOCATION - Site Date Mosquito Species RRV SINV KOKV Virus?

TOT

MENINDEE - Pump Stn 13-Dec-05 Culex quinquefasciatus 1 1 GRIFFITH - Willbriggie 20-Dec-05 Aedes theobaldi 1 1 GRIFFITH - Willbriggie 20-Dec-05 Culex annulirostris 5 5 GRIFFITH - Hanwood 10-Jan-06 Culex annulirostris 2 2 LEETON - Farm 347 11-Jan-06 Culex annulirostris 4 4

GRIFFITH - Willbriggie 17-Jan-06 Culex annulirostris 2 2 GRIFFITH - Hanwood 17-Jan-06 Culex annulirostris 2 2 LEETON - Farm 347 18-Jan-06 Culex annulirostris 4 4

ALBURY - Sewage TP 24-Jan-06 Culex annulirostris 1 1 GRIFFITH - Hanwood 24-Jan-06 Culex annulirostris 15 1 16 GRIFFITH - Willbriggie 24-Jan-06 Culex annulirostris 7 7 LEETON - Farm 347 24-Jan-06 Culex annulirostris 3 3

GRIFFITH - Hanwood 31-Jan-06 Culex annulirostris 2 2 LEETON - Almond Rd 1-Feb-06 Culex annulirostris 1 1 LEETON - Farm 347 1-Feb-06 Culex annulirostris 3 3 LEETON - Farm 347 14-Feb-06 Culex annulirostris 1 1

GRIFFITH - Willbriggie 15-Feb-06 Anopheles annulipes 1 1 GRIFFITH - Willbriggie 15-Feb-06 Culex annulirostris 2 2 GRIFFITH - Willbriggie 22-Feb-06 Culex annulirostris 1 1 GRIFFITH - Willbriggie 8-Mar-06 Culex annulirostris 1 1 GRIFFITH - Hanwood 15-Mar-06 Culex annulirostris 1 1

TOTAL 8 49 1 3 61 RRV = Ross River virus, SINV = Sindbis virus, KOKV = Kokobera virus, Virus? = unknown (not MVEV, KUNV, EHV, STRV, KOKV, RRV, BFV or SINV)



Table 2. Arbovirus isolates from coastal locations, 2005-2006.

Virus LOCATION - Site Date Mosquito Species BFV RRV SINV EHV STRV Virus?TOT

PORT STEPHENS - Karuah 24-Jan-06 Aedes vigilax 1 1 PORT STEPHENS - Saltash 24-Jan-06 Aedes vigilax 1 1

PORT STEPHENS - Heatherbrae 31-Jan-06 Aedes procax 2 1 3 PORT STEPHENS - Heatherbrae 31-Jan-06 Aedes vigilax 2 2 PORT STEPHENS - Heatherbrae 7-Feb-06 Aedes vigilax 2 2

PORT STEPHENS - Karuah 7-Feb-06 Aedes vigilax 3 1 4 PORT STEPHENS - Lakeside 7-Feb-06 Aedes vigilax 1 1

PORT STEPHENS - Heatherbrae 14-Feb-06 Aedes procax 1 1 PORT STEPHENS - Lakeside 14-Feb-06 Aedes vigilax 2 2 PORT STEPHENS - Saltash 14-Feb-06 Aedes procax 1 1 NEWCASTLE - Tomago* 16-Feb-06 Aedes vigilax 1 1

LAKE MACQUARIE - Dora Ck* 16-Feb-06 Aedes procax 1 1 LAKE MACQUARIE - Dora Ck* 16-Feb-06 Aedes vigilax 1 1 LAKE MACQUARIE - Dora Ck* 21-Feb-06 Aedes procax 1 1 2 LAKE MACQUARIE - Dora Ck* 21-Feb-06 Aedes vigilax 4 1 5 LAKE MACQUARIE - Teralba* 21-Feb-06 Aedes vigilax 2 1 1 4

LAKE MACQUARIE - Five Is Rd* 21-Feb-06 Aedes vigilax 2 2 PORT MACQUARIE - Partridge

Ck 21-Feb-06 Verrallina funerea 1 1

PORT STEPHENS - Heatherbrae 21-Feb-06 Aedes procax 1 1 2 PORT STEPHENS - Heatherbrae 21-Feb-06 Aedes vigilax 1 4 3 8 PORT STEPHENS - Heatherbrae 21-Feb-06 Culex sitiens 1 1

PORT STEPHENS - Saltash 21-Feb-06 Coquillettidia linealis 1 1 WYONG - Halekulani 24-Feb-06 Aedes vigilax 1 1 2

PORT MACQUARIE - Partridge Ck 28-Feb-06 Culex annulirostris 1 1

PORT STEPHENS - Heatherbrae 28-Feb-06 Aedes vigilax 1 1 PORT STEPHENS - Karuah 28-Feb-06 Aedes procax 1 1 PORT STEPHENS - Karuah 28-Feb-06 Aedes vigilax 1 1

PORT STEPHENS - Heatherbrae 8-Mar-06 Aedes vigilax 1 1 PORT STEPHENS - Heatherbrae 8-Mar-06 Culex annulirostris 1 1

PORT STEPHENS - Karuah 8-Mar-06 Aedes vigilax 1 1 LAKE MACQUARIE - Dora Ck* 13-Mar-06 Aedes alternans 1 1 LAKE MACQUARIE - Belmont* 13-Mar-06 Aedes notoscriptus 1 1

LAKE MACQUARIE - Muddy Lk* 13-Mar-06 Aedes vigilax 1 1 LAKE MACQUARIE - Stingaree* 13-Mar-06 Aedes alternans 1 1 LAKE MACQUARIE - Stingaree* 13-Mar-06 Aedes procax 1 1 LAKE MACQUARIE - Stingaree* 13-Mar-06 Aedes vigilax 1 1 2 LAKE MACQUARIE - Teralba* 13-Mar-06 Aedes vigilax 1 1

PORT STEPHENS - Heatherbrae 14-Mar-06 Aedes vigilax 1 1 1 PORT STEPHENS - Karuah 14-Mar-06 Aedes vigilax 1 1 BALLINA - Lennox Heads 16-Mar-06 Cq. variegata 1 1

LAKE MACQUARIE - Belmont* 4-Apr-06 Aedes aculeatus 1 1 LAKE MACQUARIE - Dora Ck* 4-Apr-06 Aedes vigilax 1 1

LAKE MACQUARIE - Stingaree* 4-Apr-06 Aedes vigilax 1 1 PORT STEPHENS - Gan Gan 6-Apr-06 Aedes vigilax 1 1

WYONG - Ourimbah 6-Apr-06 Aedes notoscriptus 1 1 TOTAL 28 15 1 5 22 2 73

BFV = Barmah Forest virus, RRV = Ross River virus, SINV = Sindbis virus, EHV = Edge Hill virus, STRV = Stratford virus, Virus? = unknown (not MVEV, KUNV, EHV, STRV, KOKV, RRV, BFV or SINV) *This location is not currently part of the NSW Arbovirus Surveillance Program, however the data is included as



this provides valuable information on virus activity for the mid-north coast. Results http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/results/virusisolates.htm From the mosquitoes processed, there were 134 viral isolates; 61 from the inland and 73 from the coastal locations. These are listed in Tables 1 & 2 above. SSEENNTTIINNEELL CCHHIICCKKEENN PPRROOGGRRAAMM http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/about/chickenmethods.htm Location of flocks The 2005-2006 season began on October 18th 2005 with the first bleed and ended on April 30th 2006 with the last. For 2005-2006, six flocks each containing 15 Isa Brown pullets were deployed at Bourke, Griffith, Lake Cargelligo, Leeton, Macquarie Marshes and Menindee (Figure 1). Methods The NSW Chicken Sentinel Program was approved by the WSAHS Animal Ethics committee. This approval requires that the chicken handlers undergo training to ensure the chickens are cared for appropriately and that blood sampling is conducted in a manner that minimises trauma to the chickens. The chickens are cared for and bled by local council staff and members of the public. Laboratory staff, under the supervision of a veterinarian, are responsible for training the chicken handlers. A veterinarian (usually the Director of Animal Care at Westmead) must inspect all new flock locations prior to deployment to ensure animal housing is adequate. Existing flocks are inspected approximately every two years. The health of each flock is reported weekly, and is independently monitored by the Animal Ethics Committee via the Director of Animal Care. Full details of the bleeding method and laboratory testing regimen were detailed in the 2003-2004 NSW Arbovirus Surveillance Program Annual Report (Doggett et al. 2004). Results are disseminated via email to the relevant government groups as determined by NSW Health and are placed on the NSW Arbovirus Surveillance website. Confirmed positives are notified by telephone to NSW Health and Communicable Diseases Network, Australia. Results The season began with 90 pullets and only three deaths were recorded for the entire season. A total of 133 samples were received from the six flocks in NSW over the six-month period in 2005-2006. This represented 266 ELISA tests (excluding controls and quality assurance samples), with each specimen being tested for MVEV and KUNV antibodies. There were no seroconversions to MVEV or KUNV. Likewise, no cases of MVEV or KUNV disease were detected in humans in NSW, Vic or SA in 2005-2006.



HHUUMMAANN NNOOTTIIFFIICCAATTIIOONNSS http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/human/human.htm Table 3 contains the number of laboratory notifications of human RRV and BFV disease by former Area Health Service (AHS) for NSW. The former AHSs data were used, rather than the current, to allow for a comparison of notification trends over time. Note that these are laboratory notifications based on a single IgM positive specimen, and may not always represent infections from this season, as IgM can persist for long periods. The total number of notifications for the period July 2005 to June 2006 was 1,937 and included 614 BFV, 1,268 RRV and 55 ‘other’ arboviral notifications. This was the highest number of notifications since reporting began in 1991 and more than double the previous eleven season average of 967. The coastal region accounted for 1,266 (67%) of the BFV and RRV notifications, which was also more than double the average (630) for the previous eleven seasons (Table 4). The 477 notifications (25%) from the inland were well above the previous eleven year seasonal average of 267. Within the Sydney region there were 139 cases reported, again above the eleven season average of 70. The Northern Area Health Service received the highest number of notifications (425) with the Hunter having 339 and Mid North Coast 320. Combined, these three areas accounted for 56% of all the arbovirus notifications for the state.

Table 3. Arbovirus disease notifications according to former Area Health Service, July 2005 - June 2006.

Month CS NS WS WE SW CC HU IL SE NR MN NE MA MW FW GM SA TotalRRV 7 28 11 26 19 55 172 45 28 276 157 80 73 74 36 156 28 1268BFV 4 7 0 2 2 37 163 16 5 143 166 17 5 3 4 29 11 614

Other 6 13 4 3 1 1 4 0 13 6 0 0 0 0 1 2 0 55 Total 17 48 15 31 22 93 339 61 46 425 320 97 78 77 41 187 39 1937

CS = Central Sydney, NS = Northern Sydney, WS = Western Sydney, WE = Wentworth, SW = South Western Sydney, CC = Central Coast, HU = Hunter, IL = Illawarra, SE = South Eastern Sydney, NR = Northern Rivers, MN = Mid North Coast, NE = New England, MA = Macquarie, MW = Mid Western, FW = Far Western, GM = Greater Murray, SA = Southern Area.

DDIISSCCUUSSSSIIOONN The Inland. The solid spring rainfall meant that mosquito numbers were well up and above average during December and early January, with one collection at Griffith of over 11,000 mosquitoes, and another at Leeton that yielded over 12,500. With the higher mosquito numbers, arbovirus activity soon followed; there was a series of RRV isolates (Table 1) and subsequent human cases, which prompted media warnings by NSW Health during mid February (the Media Release is in Appendix 2). The 419 notifications of RRV from the inland (Table 4) were almost 1.7 times that of the previous eleven season average of 248.



Table 4. Notifications of BFV & RRV disease per virogeographic regions of NSW, per season from 1994-1995 to 2005-2006 (after Doggett 2004 & Doggett & Russell 2005).

BFV RRV Season

Coastal Cases1

Inland Cases2 Sydney

3 Total Coastal Cases1 Inland Cases2 Sydney

3 Total

94/95 233 8 7 248 163 45 14 222 95/96 141 9 3 153 399 511 32 942 96/97 155 19 16 190 731 566 250 1547 97/98 103 14 2 119 162 129 41 332 98/99 208 26 8 242 575 522 117 1214 99/00 158 22 6 186 359 341 43 743 00/01 367 18 3 388 432 218 115 765 01/02 371 14 11 396 135 73 6 214 02/03 407 21 6 434 395 57 10 462 03/04 303 26 6 335 417 176 41 634 04/05 394 33 9 436 327 87 23 437 05/06 536 58 20 614 730 419 119 1268 Total 3376 268 97 3741 4825 3144 811 8780 Ave4 258 19 17 284 372 248 63 683

1Represents the former Area Health Services of CC, HUN, ILL, MNC, NR and SA. 2Represents the former Area Health Services of FW, GM, MAC, MW and NE. 3Represents the former Area Health Services of CS, NS, SES, SWS, WEN and WS. 4This is the eleven season average from 1994-1995 to 2004-2005.

Figure 7. Seasonal notifications of RRV disease for the inland region. The blue line represents notifications for 2005-2006, while the brown line is the previous ten season average. Note that the date represents virus acquisition, i.e. when the patient was bitten by the viraemic mosquito (after Doggett & Russell 2005).



With the onset of the hot dry summer in early 2006, mosquito numbers notably declined by late January and had become well below average. The number of isolates also dropped, with only seven yielded after mid February and none of RRV. The sudden halt to the mosquito season was fortuitous and prevented a continuation of human cases. This meant that the epidemic curved was skewed to the left with peak activity occurring almost two months earlier than normal (Figure 7). Sindbis was also active across the inland with some 49 isolates, although it is not known if there were any human cases. The vast majority of the isolates were from Culex annulirostris. There were no seroconversions to MVEV or KUNV in the sentinel chickens, and no human case of either virus was reported. The Coast. The relatively dry conditions meant that freshwater breeding mosquito numbers were lower than that of previous years. Despite this, the spring tides led to some very large populations of Aedes vigilax, which meant that the overall mosquito number for the region was one of the largest to date. An indication of the relative bias towards the saltmarsh mosquito Aedes vigilax this season can be seen when compared to recent years. For 2005-2006 Aedes vigilax comprised 61.2% of the collections, for 2004-2005 this was 31.3% and for 2003-2004 it was 45%. The one area that did receive considerable rainfall was the far north coast and, as this coincided with the January spring tide, it was expected that human notifications would be considerably greater than usual. The increased mosquito numbers was followed by extremely intense arbovirus activity. The 73 isolates (including 28 BFV & 15 RRV) represents the second biggest year in terms of arboviral isolations from mosquitoes, and the 1,266 human notifications (730 RRV & 536 BFV) represents the largest ever epidemic of mosquito borne disease from the coast since reporting began. The 730 cases of RRV was the second highest recorded to date; only one behind the previous record of 731 for 1996-1997, and the 536 BFV notifications were well up on the previous high of 407 for 2002-2003 (Table 4).

Table 5. Notifications of BFV & RRV by Statistical Local Area for north coast NSW during 2005-2006 with >10 notifications/disease.

SLA BFV RRV Total SLA BFV RRV Total

Byron 38 65 103 Nambucca 26 23 49 Hastings 49 46 95 Greater Taree 27 22 49 Lismore 25 57 82 Great Lakes 27 16 43 Kempsey 46 33 79 Maclean 18 18 36 Gosford 27 39 66 Maitland 14 16 30 Ballina 20 42 62 Newcastle 19 21 30 Lake Macquarie 29 34 63 Bellingen 23 15 28 Coffs Harbour 22 37 59 Wyong 10 16 26 Tweed 13 45 58 Richmond River 8 15 23 Port Stephens 28 28 56

Not surprisingly, with the combination of high tides and rain, the Northern Rivers AHS produced the highest number of notifications with 425 cases (276 RRV & 143 BFV). A



breakdown of the cases by Statistical Local Area (Table 5) indicates that the focus of disease activity occurred within the Byron SLA, with almost 25% of the cases within the Northern Rivers AHS; this was followed by Lismore with almost 20% and Ballina with 15% of regional cases. Like the inland, the elevated arboviral activity prompted health warnings, with several issued during February and March (Appendix 2). As per the arboviral activity across the inland, the lack of late summer rainfall, along with the cool autumn, meant that the coastal season ended earlier that usual. In fact, the peak in RRV notifications occurred almost two months earlier than normal (Figure 8), while for BFV the peak was earlier by almost one month (figure not shown). With the raised populations of Aedes vigilax, it was to be expected that most of the isolates would be from this species (including 22 BFV, 12 RRV, 3 EHV & 13 STRV);

however, a range of other species produced arboviruses, including the freshwater mosquitoes Aedes procax (5 BFV, 1 RRV, 1 EHV & 5 STRV), Aedes notoscriptus (2 STRV), Aedes alternans (1 EHV, 1STRV), Aedes aculeatus (1 STRV), Coquillettidia variegata (1 SINV) and Culex annulirostris (1 BFV), and the brackish water Culex sitiens (1 RRV) and Verrallina funerea (1 RRV). The range of species yielding isolates and the different habitats they represent, demonstrated the complex nature of arboviral ecology within coastal regions and the difficulty in predicting the risk of transmission to humans. The BFV activity for 2005-2006 was the sixth consecutive annual outbreak for the north coast. This season the activity was again concentrated on the Mid North coast region with the highest case loads in the Hastings (49 notifications) and Kempsey (46) areas. Activity was, however, quite widespread, with many cases in the far north of the state and considerable activity to the south, even to Gosford (Figure 14). It is of interest to

Figure 8. Seasonal notifications of RRV disease for the coastal region. The blue line represents notifications for 2005-2006, while the brown line is the previous ten season average. Note that the date represents virus acquisition, i.e. when the patient was bitten by the viraemic mosquito (after Doggett & Russell 2005).



compare the 2005-06 activity with that of previous seasons. In 2000-2001, activity was mainly confined to the Kempsey region on the mid north coast and followed upon heavy flooding as a result of record rainfall, along with high spring tides (Figure 9). The 2001-2002 activity was more diffuse along the coast, with the first ever cases being reported in western Sydney, and it is thought that this outbreak may have had a greater involvement of freshwater vectors (Figure 10). For 2002-2003, the far north coast had most activity, although the mid north coast had 136 cases (Figure 11), and this was the largest recorded outbreak of BFV in Australia to date. For the 2003-2004 season the mid north coast was again the most active BFV region (Figure 12). During 2004-2005, the outbreak again focused on the mid-north coast especially around Port Macquarie (Figure 13). The north coast of NSW continues to be the region which is responsible for the majority of human notifications. Combining the Mid North Coast and the Northern Rivers AHSs, there were 309 BFV cases and 433 RRV. The total (739) represented almost 40% of all BFV/RRV reports from the state for the 2005-2006 season, and over the last six seasons, these AHSs have accounted for close to 53% of all the state wide BFV/RRV disease notifications (Table 5).

Figures 9-14. BFV notifications for the NSW North Coast. Fig 9. List of Statistical Local Areas (SLA), the name in the bracket is the largest urban centre for the area, if that name is different to the SLA name, along with BFV notifications for 2000-2001. Fig 10. BFV notifications for 2001-2002. Fig 11. BFV notifications for 2002-2003. Fig 12. BFV notifications for 2003-2004. Fig 13. BFV notifications for 2004-2005. Fig 14. BFV notifications for 2005-2006. Note that the numbers on Figs. 11 & 13 indicate the number of BFV disease cases when >51 were reported.



Table 6. Notifications of BFV & RRV disease from the Northern Rivers & Mid North Coast AHSs, over the last five mosquito seasons.

Virus 2000-01 2001-02 2002-03 2003-04 2004-05 2005-06 Total BFV 307 250 350 274 337 309 1827 RRV 215 82 347 305 230 430 1609 Total 522 332 697 579 567 739 3436 NSW Total 1161 711 901 988 873 1882 6516

A closer examination of the human notifications since the 1994-1995 season by SLA, reveals that the top ten in terms of notifications are all within the north coast of NSW (a total of 4,261 cases over this period) and a further seven are in the top 21 (5,349 cases in total). The Hastings area, with 653 notifications rates the number one ‘hot spot’ for arbovirus activity in NSW. Why this should be so is unknown, although the region does comprise numerous and diverse waterways, with many native animals that may act as viral reservoir and amplifying hosts. Table 7. Notifications of RRV & BFV by Statistical Local Area for 1994-1995 to 2005-

2006, for areas with total notifications of over 200 and includes the ranking*.

Statistical Local Area RRV

RRV Rank BFV

BFV Rank Total

Total Rank

Hastings 297 2 353 1 653 1 Tweed 339 1 166 5 505 2 Byron 286 3 203 3 495 3

Kempsey 207 8 248 2 465 4 Port Stephens 265 5 113 13 396 5

Lismore 216 7 154 8 385 6 Greater Taree 170 13 167 4 354 7

Lake Macquarie 269 4 65 17 355 8 Coffs Harbour 167 14 137 9 327 9 Great Lakes 146 19 154 7 326 10 Eurobodalla 139 20 156 6 321 11 Shoalhaven 196 11 92 15 314 12

Ballina 166 16 104 14 300 13 Griffith 246 6 19 29 300 14 Gosford 199 10 46 19 274 15 Maclean 124 22 114 12 272 16

Nambucca 103 27 119 11 260 17 Walgett 201 9 21 27 258 18

Bellingen 93 29 124 10 256 19 Newcastle 163 17 46 20 246 20

Wyong 184 12 24 26 246 21 *Data from the NSW Notifiable Diseases Database, courtesy Mr Mark Bartlett. Following a growing incidence of mosquito borne disease and an increasing awareness about mosquitoes within the Hunter region, a group of local Councils formed a committee to address these mounting concerns. An outcome of the committee was the document ‘Living with Mosquitoes in the Lower Hunter and Mid North Coast’ (http://www.hnehealth.nsw.gov.au/hneph/LivingWithMosquitos.htm). One of the key recommendations within this awareness plan was that steps should be taken to fill gaps



in knowledge of regional mosquito fauna (Webb and Russell 2005). The document highlighted Lake Macquarie, in particular Dora Creek and Teralba, as areas of particular interest. In fact the Lake Macquarie area had the eighth highest total of arboviral notifications for any Statistical Local Area within NSW (Table 7), the fourth highest in terms of RRV cases and a growing incidence of BFV disease; however, historically, this activity has never been investigated. Following the recommendation, a mosquito and arbovirus survey was undertaken in the Lake Macquarie region for the first time. A total of five study sites was selected, adult trapping occurred on four occasions (16th & 21th February, 13th March and 4th April 2006), and the spatial abundance of pest and vector mosquitoes was documented. During the sampling period the total rainfall was below the long term average; however, despite this, mosquitoes were particularly abundant and close to 15,000 adult mosquitoes were trapped (Webb and Russell 2006). This included 26 species belonging to 7 genera including many known vectors and pest species. The most common were Aedes vigilax (61.0% of total mosquitoes collected), Culex annulirostris (10.0%), Aedes procax (9.4%), Coquillettidia linealis (3.9%) and Aedes notoscriptus (4.8%). There was also heavy arbovirus activity during this period, with some 26 isolates recovered, including 11 BFV, 1 RRV, 3 EHV and 11 STRV (Table 7). A range of saltwater and freshwater mosquitoes yielded isolates, including 18 from Aedes vigilax (10 BFV, 1 RRV, 1 EHV & 6 STRV), 4 from Aedes procax (1 BFV, 1 EHV & 2 STRV), 2 from Aedes alternans (1 EHV & 1 STRV), and one each from Aedes aculeatus (1 STRV) and Aedes notoscriptus (1 STRV).

Table 8. Arbovirus isolates from Lake Macquarie, 2005-2006.

Virus Site Date Mosquito Species BFV RRV EHV STRV TOT

Dora Ck 16-Feb-06 Aedes procax 1 1 Dora Ck 16-Feb-06 Aedes vigilax 1 1 Dora Ck 21-Feb-06 Aedes procax 1 1 2 Dora Ck 21-Feb-06 Aedes vigilax 4 1 5 Teralba 21-Feb-06 Aedes vigilax 2 1 1 4

Five Is Rd 21-Feb-06 Aedes vigilax 2 2 Dora Ck 13-Mar-06 Aedes alternans 1 1 Belmont 13-Mar-06 Aedes notoscriptus 1 1

Muddy Lk 13-Mar-06 Aedes vigilax 1 1 Stingaree 13-Mar-06 Aedes alternans 1 1 Stingaree 13-Mar-06 Aedes procax 1 1 Stingaree 13-Mar-06 Aedes vigilax 1 1 2 Teralba 13-Mar-06 Aedes vigilax 1 1 Belmont 4-Apr-06 Aedes aculeatus 1 1 Dora Ck 4-Apr-06 Aedes vigilax 1 1

Stingaree 4-Apr-06 Aedes vigilax 1 1 TOTAL 11 1 3 11 26

Despite the few adult mosquito collections, the overall number of isolates was very high, especially for BFV. Not surprisingly, this season had the most number of BFV case notifications for the area to date (29), and this was almost double that of the previous peak (16 in 2001/02). The detection of substantial BFV activity from February prompted



health warnings from the local Public Health Unit, and one of these media releases is detailed in Appendix 2. Due to the high mosquito numbers for various species, the heavy history of human morbidity in the area and the recent arbovirus activity, the report of Webb & Russell recommended the inclusion of routine surveillance trap sites in the coming seasons. For the south coast, there was again no monitoring of mosquito populations or virus activity, however human case notifications (27 BFV & 73 RRV) were well up on previous seasonal records. Sydney. In Sydney, mosquito collections were not as frequent this season and, of those sites that did trap, mosquito numbers were around to be average although often ‘high’ in number. Human notifications were well up; of the 179 cases recorded this season from Sydney, the 20 BFV cases was a record high for the region and the 119 RRV represented the second highest number of cases (plus there were 40 ‘others’). The Statistical Local Areas that produced the most cases included Sutherland (13 RRV & 3 BFV), Hawkesbury (12 RRV & 1 BFV), Blue Mountains (7 RRV), Hornsby (7 RRV), Baulkham Hills (6 RRV), Campbelltown (6 RRV), Penrith (6 RRV) and Warringah (6 RRV). How many of these cases were locally acquired has yet to be determined. TTHHEE NNEEWW SSOOUUTTHH WWAALLEESS AARRBBOOVVIIRRUUSS SSUURRVVEEIILLLLAANNCCEE WWEEBB SSIITTEE http://www.arbovirus.health.nsw.gov.au/ The NSW Arbovirus Surveillance web site was established in early 1999 to facilitate the rapid dissemination of surveillance results (Doggett et al., 1999b). An additional important function is to provide information on mosquitoes and the arboviruses they transmit. Over the last year, the site has continued to grow to the current size of 169MB, and has 1,290+ pages of information. Added to the site since the last annual report includes:

• Archived data for the 2005-2006 season, • Weekly rainfall summaries, • Monthly rainfall summaries, with long-term averages, • Monthly rainfall and temperatures maps, • Monthly SOI updates.



Appendix 1. LLOOCCAATTIIOONN--BBYY--LLOOCCAATTIIOONN SSUUMMMMAARRYY http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/results/results.htm Inland Locations Albury: collections from the Sewage Treatment Works site were consistently ‘high’ from mid-December through until the end of January and thereafter ‘low’. ‘Low’ numbers were continually collected at the Water Pump Station. There was one isolate of Ross River virus, from Culex annulirostris trapped at the Sewage Treatment on 24/Jan/2006. Bourke: eight collections were made this season with collections mostly being from ‘medium’ to ‘high’, and the largest numbers were in late January. There were no viral isolates, or any seroconversion to MVEV or KUNV in the sentinel chickens. Condobolin: four mosquito collections were undertaken, with mostly ‘high’ numbers trapped. There were no viral isolates from the trapped mosquitoes. Griffith: mosquito numbers were well up this season compared to recent years, especially during early January, with one ‘extreme’ collection of 11,775 mosquitoes from Hanwood. By late January, numbers had declined and were well below average for the remainder of the season. There were 43 arboviral isolates from Griffith, including 6 RRV, 34 SINV and 3 unknowns. Full details are in the summary table below.

Table 9. Arbovirus isolates from Griffith, 2005-2006.

Virus Site Date Mosquito Species RRV SINV Virus?

TOT

Willbriggie 20-Dec-05 Aedes theobaldi 1 1 Willbriggie 20-Dec-05 Culex annulirostris 5 5 Hanwood 10-Jan-06 Culex annulirostris 2 2 Willbriggie 17-Jan-06 Culex annulirostris 2 2 Hanwood 17-Jan-06 Culex annulirostris 2 2 Hanwood 24-Jan-06 Culex annulirostris 15 1 16 Willbriggie 24-Jan-06 Culex annulirostris 7 7 Hanwood 31-Jan-06 Culex annulirostris 2 2 Willbriggie 15-Feb-06 Anopheles annulipes 1 1 Willbriggie 15-Feb-06 Culex annulirostris 2 2 Willbriggie 22-Feb-06 Culex annulirostris 1 1 Willbriggie 8-Mar-06 Culex annulirostris 1 1 Hanwood 15-Mar-06 Culex annulirostris 1 1

TOTAL 6 34 3 43 Lake Cargelligo: no mosquito collections were undertaken this season, and there were no seroconversions to MVEV or KUNV in the sentinel chickens. Leeton: like Griffith, Leeton also had mosquito numbers that were much higher than previous years during the mid part of the season, with one ‘extreme’ collection of 12,577 in mid-January at Farm 347. Thereafter at this site, numbers remained ‘very high’ until the 3rd week of March. There were 16 isolates from Leeton, including 15 SINV and 1



KOKV. Full details in order of date of isolation are; 4 SINV (Site, Mosquito Species, Collection Date; Farm 347, Culex annulirostris, 11/Jan/2006), 4 SINV (Farm 347, Culex annulirostris, 18/Jan/2006), 3 SINV (Farm 347, Culex annulirostris, 24/Jan/2006), 1 KOKV (Almond Rd, Culex annulirostris, 1/Feb/2006), 3 SINV (Farm 347, Culex annulirostris, 1/Feb/2006), and 1 SINV (Farm 347, Culex annulirostris, 14/Feb/2006). There were no seroconversions to MVEV or KUNV in the sentinel chickens. Macquarie Marshes: there were no mosquito collections undertaken this year. There were no seroconversions to MVEV or KUNV in the sentinel chickens. Menindee: mosquito numbers were mostly ‘low’ with only two ‘medium’ collections. There was one isolate of RRV from Culex quinquefasciatus trapped on 13/Dec/2005. There were seroconversions to MVEV or KUNV in the sentinel chickens. Wanaaring: there were no mosquito collections nor any sentinel chickens operated this season. Coastal Locations Ballina: no trapping was undertaken at the North Creek Road site, because permission for access was not granted to the Council. Mosquito numbers were below average and mainly ‘low’ to ‘medium’ up until late January and thereafter continually ‘high’ until May. Aedes multiplex, Coquillettidia variegata, Coquillettidia linealis and Aedes vigilax were the dominant species at this site. One SINV was isolated at Lennox Heads from Coquillettidia variegata trapped on 16/Mar/2006. Gosford: two sites at Gosford were again monitored this year: Empire Bay and Killcare Heights. For Empire Bay, mosquito numbers were mostly ‘low’ to ‘medium’ until mid January, followed by a series of ‘high’ collections until March, with ‘low’ densities thereafter. Numbers were considerably higher at Killcare Heights and, at least ‘high’ until April, with one ‘very high’ collection from the first week of March. These collections were strongly dominated by Aedes vigilax. No viruses were isolated from the mosquitoes. Port Macquarie: The sites within Port Macquarie itself produced mostly ‘high’ numbers. Lord Street was strongly dominated by Coquillettidia linealis, while Partridge Creek consistently yielded higher numbers, with a range of species being trapped. The Wauchope trap had mainly ‘medium’ collections, with the main species being Aedes notoscriptus. The Crescent Head location produced mostly ‘low’ numbers as did the Bellingen site, which was only trapped for six weeks. There were two isolates this season, one BFV from Partridge Creek from Culex annulirostris trapped on 28/Feb/2006 and one RRV from the same site from Verrallina funerea trapped on 21/Feb/2006. Port Stephens: as usual, the collections varied substantially in mosquito abundance and species composition between the sites, which reflects the diverse mosquito breeding habitats within the region. For example, some trapping sites are near freshwater habitats, while others are near saltmarsh environments. Gan Gan had mostly ‘high’ collections through January to mid February, with large numbers of Aedes vigilax following the spring tides. Mosquitoes were more abundant at Saltash and numbers



were ‘high’ throughout most of the season, with one ‘very high’ collection in mid January and the peaks were associated with Aedes vigilax breeding. Medowie collections went through several peaks and troughs, with ‘very high’ collections dominated by Aedes vigilax following spring tides. Karuah consistently produced ‘very high’ numbers through January and February, heavily dominated by Aedes vigilax. As usual, Heatherbrae continued to trap the most mosquitoes for any site within NSW, and mosquito numbers tended to be ‘very high’ from early December to late March, with one collection of over 8,000 mosquitoes in mid March. Aedes vigilax was the most common species trapped at Heatherbrae, although freshwater species including Culex annulirostris, Culex orbostiensis, Coquillettidia linealis and Aedes procax were also trapped in ‘high’ numbers. A new site at Lakeside yielded many ‘high’ collections (and two ‘very high’), and was also dominated by Aedes vigilax. There were 39 arboviral isolates from Port Stephens, including 15BFV, 13RRV, 2EHV, 8 STRV and 2 unknowns. Full details are in the summary table below.

Table 10. Arbovirus isolates from Port Stephens, 2005-2006.

Virus Site Date Mosquito SpeciesBFV RRV EHV STRV Virus?

TOT

Karuah 24-Jan-06 Aedes vigilax 1 1 Saltash 24-Jan-06 Aedes vigilax 1 1

Heatherbrae 31-Jan-06 Aedes procax 2 1 3 Heatherbrae 31-Jan-06 Aedes vigilax 2 2 Heatherbrae 7-Feb-06 Aedes vigilax 2 2

Karuah 7-Feb-06 Aedes vigilax 3 1 4 Lakeside 7-Feb-06 Aedes vigilax 1 1

Heatherbrae 14-Feb-06 Aedes procax 1 1 Lakeside 14-Feb-06 Aedes vigilax 2 2 Saltash 14-Feb-06 Aedes procax 1 1

Heatherbrae 21-Feb-06 Aedes procax 1 1 2 Heatherbrae 21-Feb-06 Aedes vigilax 1 4 3 8 Heatherbrae 21-Feb-06 Culex sitiens 1 1

Saltash 21-Feb-06 Coquillettidia linealis 1 1 Heatherbrae 28-Feb-06 Aedes vigilax 1 1

Karuah 28-Feb-06 Aedes procax 1 1 Karuah 28-Feb-06 Aedes vigilax 1 1

Heatherbrae 8-Mar-06 Aedes vigilax 1 1 Heatherbrae 8-Mar-06 Culex annulirostris 1 1

Karuah 8-Mar-06 Aedes vigilax 1 1 Heatherbrae 14-Mar-06 Aedes vigilax 1 1 1

Karuah 14-Mar-06 Aedes vigilax 1 1 Gan Gan 6-Apr-06 Aedes vigilax 1 1

TOTAL 15 13 2 8 2 39 Tweed Heads: all but one collection was ‘low’ from Piggabeen Road, while Beltana Road consistently yielded greater mosquito densities with several ‘high’ collections. These tended to be dominated by Culex sitiens. No virus isolation was undertaken. Wyong: there were two sites where trapping was undertaken: Ourimbah and Halekulani. The former collection produced mainly ‘low’ to ‘medium’ numbers dominated by Aedes notoscriptus. While for Halekulani, there were several ‘high’ collections early in the season, and this trap was dominated by Coquillettidia linealis and Culex annulirostris.



There were two isolates this season, one of RRV from Aedes vigilax collected at Halekulani on 24/Feb/2006 and one of STRV from Aedes notoscriptus trapped at Ourimbah on 6/Apr/2006. Sydney Locations Baulkham Hills: this site, which produced large numbers of mosquitoes during the previous season, was trapped only intermittently. Despite this, many of the collections were ‘high’ in number, and dominated by Coquillettidia linealis and Culex annulirostris. No viruses were isolated. Blue Mountains: No mosquito collections were made this season. Concord: mosquito numbers were mostly ‘low’ throughout the season, with one ‘high’ collection from Powell’s Creek during mid-February that was dominated by Aedes vigilax. No virus isolation was undertaken. Hawkesbury: only six trapping nights were conducted this season, producing mostly ‘low’ collections. Virus isolation was undertaken but no isolates were yielded. Parramatta: the ongoing mosquito management program at Homebush continued to ensure that mosquito numbers did not reach ‘very high’ levels in Parramatta (or Concord and Ryde) this season. Due to its close proximity to saltmarsh habitat, the George Kendall Reserve site (as always) was the most productive site, with consistently ‘high’ numbers dominated by Aedes vigilax. The only other site that had numbers ‘medium’ or higher was Eric Primrose Reserve, which had two ‘high’ collections during early March. Virus isolation was undertaken but no isolates were yielded. Penrith: no mosquito collections were made this season. Ryde: the majority of the trapping yielded ‘low’ to ‘medium’ mosquito densities, although there were several ‘high’ collections from Wharf Road through January and one of 947 mosquitoes in March, dominated by Aedes vigilax. Lambert Park produced a series of ‘high’ collections with large numbers of Aedes notoscriptus being trapped. Other sites also had some ‘high’ collections, which were associated with Aedes vigilax breeding. Only the Lambert Park collections were processed for viruses and none were isolated.



AAppppeennddiixx 22.. MMEEDDIIAA RREELLEEAASSEESS

Media Release – NSW Health, 10 February 2006

Ross River virus cases rise in rural NSW

A dramatic increase in Ross River Virus cases in NSW, mostly in rural areas, has prompted NSW Health to issue a healthwarning to people to protect themselves against infection.

In recent weeks, NSW has experienced a significant rise in the number of Ross River Virus infections, with 167 casesreported last month - an increase of 133 cases compared to the same month last year and an increase of 68 cases on theprevious month.

The majority of cases are from rural NSW with the Greater Southern Area reporting 53 cases, Greater Western with 49cases and the Hunter New England region reporting 31.

NSW Health Director Communicable Diseases, Dr Jeremy McAnulty, advises that the best way to prevent infection is toavoid being bitten by mosquitoes, which spread the disease.

"Ross River Virus is spread by mosquitoes that feed on animals that have the infection," Dr McAnulty said.

"The virus is not fatal but it can cause persistent and debilitating symptoms such as aches and pains in joints, fever, chills,headache and sometimes a rash. The rash usually disappears after seven to 10 days."

Dr McAnulty suggested a possible reason for this sudden peak in cases could be recent rains and warmer weather across thestate.

"Higher levels of rain in the affected areas may have contributed to a rise in mosquito breading, causing an increase in mosquito bites and Ross River Virus infections. The warmer weather and holidays also mean that people tend to spend moretime outside and become exposed," Dr McAnulty said.

"There is no specific treatment for Ross River Virus so prevention depends on avoiding mosquito bites, especially in the summer and autumn months when infections peak," Dr McAnulty said.

Dr McAnulty's advice for avoiding mosquito bites includes:

When outside wear loose fitting, light coloured clothes that cover your arms and legs.

Use an insect repellent that contains the chemical DEET or picaridin.

Avoid being outside unprotected before dawn and after dusk.

Fit fly screens to all windows and doors and keep them in good repair.

If mosquitoes are inside, use a knockdown insecticide in bedrooms half an hour before going to bed according toinstructions.

Ensure that there are no pools of water around the home where mosquitos can breed, for example, undrained potplants, blocked gutters and old tyres.

When camping, make sure your tent has fly screens that are in good condition.

Number of Ross River Virus Cases onset in January 2006, NSW

Greater Southern Area Health Service

53

Greater Western Area Health Service 49

Hunter New England Health 31

North Coast Area Health Service 12

South Eastern Sydney/Illawarra Health 15

Northern Sydney Central Coast Health 4

Sydney South West Area Health Service 2

Sydney West Area Health Service 1

Total cases in NSW 167



Media Release – Port Stephens Council, 10 February 2006

Increased risk of Ross River and Barmah Forest viruses in Port Stephens area

Council has issued an alert to Port Stephens residents and visitors about an increased risk of catching the Ross River and Barmah Forest viruses through mosquitoes. Environmental Services Manager Bruce Petersen said a number of mosquitoes trapped in Salt Ash and Heatherbrae had tested positive for the viruses. “Tests undertaken by Westmead Hospital as part of our ongoing mosquito monitoring program have indicated the presence of these viruses which, while not fatal, can be quite incapacitating.” “People who have caught the viruses complain of flu-like symptoms and severe joint pain which can persist for a number of weeks, months or even years. “It is essential that people take appropriate steps to protect themselves including: • Avoiding breeding areas where possible

• Avoiding outside activity around dusk and dawn – when mosquitoes are most active

• Wearing loose fitting, light-coloured clothing that covers the legs and arms

• Applying insect repellent that contains the chemical diethyl toulamide (DEET) on any

exposed skin

• Ensuring doors and windows are fitted with good quality insect screens.”

Mr Petersen said council had been working closely with Hunter New England Health, the Premiers Department and other agencies to develop a regional approach to minimising the impact of mosquitoes. “Mosquitoes can travel many kilometers and are therefore almost impossible to control or eradicate.” “We abandoned the outdated process of ‘fogging’ a couple of years ago because it was only effective in still air and impacted negatively on the environment by killing other insects. “As an alternative, council has taken a proactive approach to monitoring virus levels and educating people about the risks and encouraging them to avoid getting bitten in the first place.



Media Release – Hunter New England AHS, 10 February 2006

Risk of Ross River and Barmah Forest viruses

Hunter New England Population Health has issued an alert to people in the Hunter New England Area due to a dramatic increase in Ross River Virus cases in NSW, particularly in rural areas.

During the past month there has also been a significant increase in Barmah Forest Virus cases, particularly in the coastal areas of Hunter New England. This week, Ross River and Barmah Forest viruses were also detected in salt-marsh mosquitoes captured as part of our ongoing mosquito monitoring program in the Port Stephens area.

Hunter New England Public Health Physician, Dr David Durrheim, advises that the best way to prevent infection is to avoid being bitten by mosquitoes, which spread Ross River and Barmah Forest disease. “These viruses are spread by mosquitoes that feed on animals that have the infection,” Dr Durrheim said. “Although the illness caused by the viruses is not fatal, it can cause persistent and debilitating symptoms such as aches and pains in joints, fever, chills, headache and sometimes a rash. The rash usually disappears after seven to 10 days.” “Higher levels of rain in the affected areas may have contributed to a rise in mosquito breading, causing an increase in mosquito bites and infections. The warmer weather and holidays also mean that people tend to spend more time outside and become exposed,” Dr Durrheim said. “As there is no specific treatment for Barmah Forest or Ross River Virus, prevention depends on avoiding mosquito bites, especially in the summer and autumn months when infections peak,” Dr Durrheim said. Methods for avoiding mosquito bites include:

• Avoiding being outside unprotected before dawn and after dusk. • Avoiding known high risk breeding sites, including marsh areas. • When outside wearing loose fitting, light coloured clothes that cover arms and legs. • Using an insect repellent that contains the chemical DEET or picaridin on exposed skin. • Fitting fly screens to all windows and doors and keeping these in good repair. • If mosquitoes are inside, using a knockdown insecticide in bedrooms half an hour before

going to bed according to instructions. • Ensure that there are no pools of water around the home where mosquitos can breed, for

example, undrained pot plants, blocked gutters and old tyres.

A fact sheet and current data on the number of Ross River Virus infections in NSW is available on the NSW Health website at http://www.health.nsw.gov.au



Media Release – Hunter New England AHS, 3 March 2006

Risk from Barmah Forest virus in Lake Macquarie area

Hunter New England Population Health has issued an alert to people in the Lake Macquarie area after the detection of Barmah Forest virus in mosquitoes at Dora Creek and Teralba on the western side of the lake.

Hunter New England Public Health physician, Dr David Durrheim said that mosquito numbers are on the increase following the recent wet weather and king tides in January and February.

“The presence of the virus at this time of the year is not unusual, however, it has been isolated from eight separate mosquito samples across this area by the Department of Medical Entomology, ICPMR, which suggests that infected mosquitoes are widespread,” Dr Durrheim said.

There have been seven confirmed human cases of Barmah Forest virus notified from the Lake Macquarie and Greater Newcastle area in 2006.

This is more than the reported cases for January and February during the past five years.

Dr Durrheim said that the best way to prevent infection is to avoid being bitten by mosquitoes, which spread the disease.

“These viruses are spread by mosquitoes that feed on animals that have the infection,” Dr Durrheim said.

“Although the illness is not fatal, it can cause persistent and debilitating symptoms such as aches and pains in joints, fever, chills, headache and sometimes a rash. The rash usually disappears after seven to 10 days.”

“As there is no specific treatment for Barmah Forest virus, prevention depends on avoiding mosquito bites, especially in the summer and autumn months when infections peak,” Dr Durrheim said.

Methods for avoiding mosquito bites include:

• Avoiding being outside unprotected before dawn and after dusk.

• Avoiding known high risk breeding sites, including marsh areas.

• When outside wearing loose fitting, light coloured clothes that cover arms and legs.

• Using an insect repellent that contains the chemical DEET or picaridin on exposed skin.

• Fitting fly screens to all windows and doors and keeping these in good repair.

• If mosquitoes are inside, using a knockdown insecticide in bedrooms half an hour before going to bed according to instructions.

• Ensure that there are no pools of water around the home where mosquitos can breed, for example, undrained pot plants, blocked gutters and old tyres.



Appendix 3. TTHHEE MMOOSSQQUUIITTOOEESS The following briefly details the main mosquito species collected in NSW.

The Common Domestic Mosquito, Aedes notoscriptus.

A common species that breed in a variety of natural and artificial containers around the home. It is the main vector of dog heartworm and laboratory studies shows it be an excellent transmitter both of RRV and BFV.

The Northern Saltmarsh Mosquito, Aedes vigilax.

The most important species along coastal NSW. This species breeds on the mud flats behind saltmarshes and can be extremely abundant and a series nuisance biter. It is the main vector for RRV and BFV along the coast.

The Common Australian Anopheline, Anopheles annulipes.

A mosquito collected throughout NSW, although is most abundant in the irrigated region of the Murrumbidgee where it can be collected in the 1000’s. Despite its abundance, it is not thought to be a serious disease vector.

The Common Marsh Mosquito, Coquillettidia linealis.

Found throughout NSW but especially in areas with freshwater marshes such as the Port Stephens area. Both BFV & RRV have been isolated from this species and is probably involved in some transmission.

The Common Banded Mosquito, Culex annulirostris.

The species is common in the NSW inland regions that have intense irrigation. This species is highly efficient at transmitting most viruses and is responsible for the spreading of most of the arboviruses to humans inland.

The Brown House Mosquito, Culex quinquefasciatus.

A common species throughout Australia and tends to breed in polluted ground pools. While this species is an important nuisance biter, it appears to be a poor vector of most of the arboviruses.



AAppppeennddiixx 44.. TTHHEE VVIIRRUUSSEESS Alphaviruses Barmah Forest virus (BFV): disease from this virus is clinically similar to that of RRV disease although BFV disease tends to be associated with a more florid rash and a shorter duration of clinical severity. This is an emerging disease and is increasingly becoming more common in NSW, with around 3-400 cases annually. Despite being first isolated from an inland region, cases of BFV disease tend occur mainly in coastal regions. The main vector in NSW is Aedes vigilax although other species are involved. Ross River virus (RRV): this virus causes RRV disease and is the most common arbovirus affecting humans in NSW and Australia. For the state, there are around 700 cases per season. A wide variety of symptoms may occur from rashes with fevers, to arthritis that can last from months to occasionally years. The virus occurs in both inland and coastal rural regions. The main vectors are Culex annulirostris (inland) and Aedes vigilax (coast), although other species are undoubtedly involved in the transmission of the virus. Sindbis virus (SINV): this is an extremely widespread virus throughout the world and occurs in all mainland states of Australia. In contrast with Africa and Europe where outbreaks have been reported, disease from SINV is relatively uncommon; only 24 cases were notified in NSW from Jul/1995-Jun/2003 (Doggett 2004). Symptoms of disease include fever and rash. Birds are the main host, although other animals can be infected such as macropods, cattle, dogs and humans. The virus has been isolated from many mosquito species, but most notably Culex annulirostris in south eastern Australia. Flaviruses Alfuy virus (ALFV): no clinical disease has been associated with this virus and it has not been isolated from south-eastern Australia. Edge Hill virus (EHV): a single case of presumptive infection with EHV has been described, with symptoms including myalgia, arthralgia and muscle fatigue. Aedes vigilax has yielded most of the EHV isolates in south east Australia, although it has been isolated from several other mosquito species. The vertebrate hosts may be wallabies and bandicoots, however studies are limited. Kokobera virus (KOKV): only three cases of illness associated with KOKV infection have been reported and all were from south east Australia. Symptoms included mild fever, aches and pains in the joints, and severe headaches and lethargy. Symptoms were still being reported by the patients five months after onset. Culex annulirostris appears to be the principal vector. Kunjin virus (KUNV): disease from this virus is uncommon, with only two cases were notified from 1995-2003 (Doggett 2004). Activity is confined to the inland region of NSW where it is detected every few years. Culex annulirostris appears to be the main vector.



Murray Valley Encephalitis (MVEV): activity of this virus is rare in south-eastern Australia and the last clinical cases of MVEV disease occurred in 1974. The virus occurs only in inland regions of the state and the last major activity was in the summer/spring of 2001, although no human cases were reported. Symptoms are variable, from mild to severe with permanent impaired neurological functions, to sometimes fatal. Culex annulirostris is the main vector. Stratford virus (STRV): there have been very few documented symptomatic patients, only three described to date and symptoms included fever, arthritis and lethargy. The virus has mostly been isolated from coastal NSW, particularly from the saltmarsh mosquito, Aedes vigilax, although recent isolates from the Sydney metropolitan area include Aedes notoscriptus and Aedes procax.



AACCKKNNOOWWLLEEDDGGMMEENNTTSS This project is funded and supported by the Environmental Health Branch of NSW Health. The following are acknowledged for their efforts in the Arbovirus Program: Glenis Lloyd (Environmental Health Branch, NSW Health, Gladesville); Tony Kolbe (Centre for Public Health, Albury); Dr Jeanine Liddle & Peter Tissen (Mid Western NSW Public Health Unit, Bathurst); Bill Balding (Far West Population Health Unit, Broken Hill); Dr Peter Lewis, Sam Curtis, John James, Adam McEwan (Central Coast Public Health Unit, Gosford); Kerryn Allen, Paul Corben and David Basso (Mid-North Coast Public Health Unit), Christine Robertson, Greg Bell, K. Taylor, Charles Rablin (New England Public Health Unit, Tamworth); Geoff Sullivan (Northern Rivers Institute of Health and Research, Lismore); Tony Brown (Macquarie Centre for Population Health, Dubbo); Helen Ptolomy (Wentworth Population Health Unit, Kingswood); Bhram Deo & Lauriston Muirhead (Albury City Council); Graham Plumb, Kerri Watts, Rachael Currie, Mary & Don Apps, Janice & Bill McMillan (Ballina Shire Council, Ballina); Lisa Kennedy (Baulkham Hills Shire Council), Grant Ashley (Bellingen); Graham Liehr (Blue Mountains City Council); Linda George (Bourke Shire Council); Colleen Allen (Crescent Head); David Sanders & Pauline Porter (Griffith Shire Council, Griffith); Dianne Tierney, Edward White, Andrea Horan & Christine Mitchell (Hawkesbury Council); John Reberger (Lake Cargelligo); Ben Lang (Leeton Shire Council, Leeton); the McLellan family (especially Linda) (Macquarie Marshes); Ivan Cowie (Menindee); Mike Randall & Haley Lloyd (Parramatta Council); Belinda Comer & Kelly Demattia (Penrith City Council); Cheyne Flanagan & Thor Aaso (Port Macquarie); Graeme Pritchard, Bruce Peterson, & Leigh Ernst (Port Stephens Shire Council, Raymond Terrace); Gith Striid (Ryde Council); Clive Easton (Tweed Shire Council, Murwillumbah). The chicken handlers included; David Sanders (Griffith), Ivan Cowie (Menindee), Linda George (Bourke), Ben Lang (Leeton), Linda McLellan (Macquarie Marshes) & John Reberger (Lake Cargelligo). The laboratory staff within CIDM are acknowledged including; Jennifer Goder and Sue Howard. Dr Cameron Webb provided information on the ‘Living with Mosquitoes in the Lower Hunter and Mid North Coast’ document and the results of the mosquito surveys at Lake Macquarie. Human case numbers and epidemiological information were obtained through the NSW Health Department and the NSW Notifiable Diseases Database with the assistance of Mr Mark Bartlett. The input of Dr Ross Mathews, Director of Animal Care, Westmead Hospital in the implementation & continuation of the chicken surveillance program is greatly appreciated. We are grateful to the Arbovirus Laboratory, Department of Microbiology, University of Western Australia, particularly Dr Annette Broom & Dr Cheryl Johansen, for the supply of monoclonal antibodies for antigen detection. Our apologies to anyone inadvertently omitted.



RREEFFEERREENNCCEESS Bureau of Meteorology, Australia. (2006). Rainfall Maps. http://www.bom.gov.au/cgi-bin/climate/rainmaps.cgi, accessed 17Aug/2006. Dobrotworsky N.V. (1965). The Mosquitoes of Victoria. Melbourne University Press, Carlton. Doggett S.L., Russell R.C., Clancy J., Haniotis J. and Cloonan M.J. (1999a). Barmah Forest virus epidemic on the south coast of New South Wales, Australia, 1994-1995: Viruses, Vectors, Human Cases, and Environmental Factors. Journal of Medical Entomology, 36: 861-868. Doggett S., Russell R. and Dwyer D. (1999b). NSW Arbovirus Surveillance Web Site. NSW Public Health Bulletin, 10: 7. Doggett S. (2004). Population health aspects of mosquito-borne disease in New South Wales. NSW Public Health Bulletin, 15: 193-199. Doggett S., Clancy J., Haniotis J., Russell R.C., Hueston L., Marchetti M. and Dwyer D. (2001). The New South Wales Arbovirus Surveillance & Mosquito Monitoring Program. 2000 – 2001 Annual Report. Department of Medical Entomology, Westmead. 27pp. Doggett S., Clancy J., Haniotis J., Russell R.C., Hueston L., Marchetti M. and Dwyer D. (2004). The New South Wales Arbovirus Surveillance & Mosquito Monitoring Program. 2003 – 2004 Annual Report. Department of Medical Entomology, Westmead. 23pp. Doggett S.L. and Russell R.C. (2005). The epidemiology of Ross River and Barmah Forest viruses in New South Wales. Arbovirus Research in Australia, 9: 86-100. Forbes J.A. (1978). Murray Valley encephalitis 1974 - also the epidemic variance since 1914 and predisposing rainfall patterns. Australasian Medical Publishing Co., Glebe. 20pp. Lee D.J., Hicks M.M., Griffiths M., Russell R.C., Geary M. and Marks E.N. (1980 – 1989). The Culicidae of the Australian Region. Vols. 1 - 11. Australian Government Publishing Service, Canberra. Nicholls N. (1986). A method for predicting Murray Valley encephalitis in southeast Australia using the Southern Oscillation. Australian Journal of Experimental Biology and Medical Science, 64: 587-94. Russell R.C. (1993). Mosquitoes and mosquito-borne disease in southeastern Australia. Department of Medical Entomology, Westmead, NSW, 310pp. Russell R.C. (1996). A Colour Photo Atlas of Mosquitoes of Southeastern Australia. Department of Medical Entomology, Westmead, NSW, 193pp. Webb C.A. and Russell R.C. (2005). Living with Mosquitos. Department of Medical Entomology, Westmead. 72pp. This can be downloaded for free from: www.hnehealth.nsw.gov.au/hneph/LivingWithMosquitoes/LivingWithMosquitosInTheLowerHunterAndMidNorthCoastRegionOfNSW.pdf Webb C.A. and Russell R.C. (2005). Mosquito Population & Arbovirus Survey: Lake Macquarie, NSW. A report for Lake Macquarie City Council. Department of Medical Entomology, Westmead. 44pp.

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