dengue outbreak in a hilly state of arunachal pradesh in northeast

Research ArticleDengue Outbreak in a Hilly State of Arunachal Pradesh inNortheast India

Siraj A Khan Prafulla Dutta Rashmee Topno Monika Soni and Jagadish Mahanta

Entomology and Filariasis Division Regional Medical Research Centre (ICMR) NE Region PO Box 105 Dibrugarh Assam India

Correspondence should be addressed to Siraj A Khan sirajkhanicmrgmailcom

Received 31 August 2013 Accepted 22 October 2013 Published 21 January 2014

Academic Editors K Ikuta and A Manzin

Copyright copy 2014 Siraj A Khan et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Dengue has been reported from plains as well as hilly regions of India including some parts of Northeast India In July-August 2012outbreak of fever with unknown origin (FUO) indicative of Dengue was reported in Pasighat East Siang district of ArunachalPradesh (AP) state Serum samples (n = 164) collected from patients from Health Training and Research Centre General HospitalPasighat were tested for NS1 antigen and IgM antibodies NS1-positive samples were analyzed by RT-PCR assay and entomologicalsurveys were carried out The majority of suspected cases reported NS1 antigen positivity Females and young adults were mostlyaffected The majority of the amplified NS1-positive samples showed Dengue serotype 3 infection Aedes (Stegomyia) albopictusknown as semiurban breeding mosquitoes was the only potential vector species identified from the affected areas of Pasighatwhich single handedly contributed to the outbreakThus the present work identifies Dengue as an emerging arboviral infection inhilly state of AP along with a looming risk of its spread to neighbouring areas

1 Introduction

Dengue is a mosquito-borne viral disease of global publichealth concern More than 100 countries in Africa AmericaEasternMediterranean Southeast Asia andWestern Asia areaffected The disease poses a threat to more than 18 billionpeople in the tropics and subtropical region infecting about100 million people every year [1] According toWorld HealthOrganization (WHO) Dengue is the fastest spreading tropi-cal disease and represents a pandemic threat [2] Dengue viralinfection may be asymptomatic or may give rise to undiffer-entiated fever with or without other associated clinical mani-festations namely Dengue fever (DF) Dengue hemorrhagicfever (DHF) or Dengue shock syndrome (DSS) [3] Dengueis caused by Dengue virus (DENV) that comprises of fourserotypes (DENV 1ndash4) DENV is a single-stranded positivesense RNA enveloped virus belonging to genus Flavivirusunder family Flaviviridae Dengue transmission in humans iscaused by Aedes (Stegomyia) aegypti (Linnaeus) and Aedes(Stegomyia) albopictus (Skuse) mosquito species [4]

In India Denguewas first reported in 1945 [5]Thereafterat a gap of 18 years in 1963-1964 an initial epidemic of DFwas reported on the Eastern Coast of India The disease

spread northwards and reached Delhi and Kanpur in 1967and 1968 respectively Simultaneously it also involved thesouthern part of the country and gradually the entire coun-try was involved with widespread epidemics followed byendemichyperendemic prevalence Rapid growths of pop-ulation and urbanisation compounded by change in climatehave contributed significantly towards the increase in cases ofDFDHF in India [4 6] Dengue is no more an urban areainfection but it is extending to rural areas also [7]The diseasehas recently spread to hilly regions like Nilgiris and Car-damom hills as well 20 serologically positive patients werereported fromCoimbatore located at an altitude of 411metres(m) above mean sea level (MSL) on the eastern slopes ofNilgiri Hills in 1998 [8]

In the northeast region (NER) of India serological surveyconducted during 1963 revealed Dengue activity in the Lohitdistrict of Arunachal Pradesh (AP) and Darrang districtof Assam [9 10] Subsequently another report of Dengue(DENV-2) in Assam and Nagaland appeared during thenineties [10ndash12] During 2009ndash2011 a study carried out byDutta et al (2012) reported 143 laboratory confirmed casesbelonging to Assam (82) Meghalaya (35) Nagaland (15)Manipur (8) and AP (3) [13]

Hindawi Publishing Corporatione Scientific World JournalVolume 2014 Article ID 584093 6 pageshttpdxdoiorg1011552014584093

2 The Scientific World Journal

In the present study we report Dengue outbreak inPasighat a hill station located at an altitude of 155mMSL (lat-itude 2807∘ N longitude 9533∘E) situated in the East Siangdistrict of AP The outbreak was confirmed by serologicalclinical and molecular evidence

2 Materials and Methods

21 The Outbreak Study During the months of July-August2012 suspected cases of fever of unknown origin (FUO)were reported from Pasighat AP India The case definitionsof suspected Dengue infection were based on guidelines ofCenters for Disease Control and Prevention (CDC) Theclinical descriptions include fever and two or more of the fol-lowing headache retroorbital pain myalgia arthralgia rashhemorrhagic manifestations or leucopenia A total of 164probable patients from hospitalisedOut Patient Department(OPD) at Health Training and Research Centre GeneralHospital Pasighat conforming to the above mentioned casedefinition were recorded Serum samples collected fromthe patients were transported under cold conditions to theRegional Medical Research Centre (RMRC) ICMR NERegion Dibrugarh India for laboratory investigations Thenonresearch activity was a part of public health response tooutbreak investigation and thus did not require a review ofInstitutional Ethics Committee of RMRC ICMR Dibrugarh

22 Serological Diagnosis All serum samples were tested forpresence of Dengue viral nonstructural 1 (NS1) antigen byusing Platelia Dengue NS1 kits (Bio-Rad USA) The sampleswere also tested for Dengue specific immunoglobulin M(IgM) antibody by using IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) kits procuredfrom the National Institute of Virology (NIV) Pune IndiaNS1-positive sampleswere also tested for IgGusingDENGUEIgG capture ELISA (Panbio Australia) All tests were carriedout according to manufacturerrsquos instructions

23 Molecular Typing Dengue NS1-positive serum sampleswere subjected to detect Dengue specific RNA by two-step reverse transcriptase polymerase chain reaction (RT-PCR) assay based on Harris et al 1998 [14] Viral RNAwas extracted using QIAamp viral RNA mini kit (QiagenGermany) Complementary DNA (cDNA) was synthesisedusing cDNA synthesis kit (Fermentas USA) PCRwas carriedout using primer pairs amplifying capsid region according toLanciotti et al 1992 [15] using cDNA as template AmplifiedPCRproducts were visualized in 2 agarose gel electrophore-sis

24 Follow-Up Survey of Dengue Affected Areas and VectorMonitoring Following laboratory confirmation of Dengueoutbreak an entomological survey was undertaken to iden-tify the vector(s) involved in order to devise vector controland disease containment strategies As part of mosquitosurveillance program solid waste containers namely bam-boo stumps metal and plastic wares cans flower pots dis-carded automobile tyres and so forth whichever could hold

Table 1 Clinical characteristics of Dengue-positive cases

Clinical features Percentage frequencyFever 105 (981)Headache 100 (934)Myalgia 87 (813)Arthralgia 56 (523)Vomiting 46 (429)Vertigo 44 (411)Retroorbital pain 30 (280)Itching eruption 28 (261)Loose motion 20 (186)Cough 20 (186)Pain in abdomen 20 (186)Rashes 18 (168)Hypotension 18 (168)Sore throat 17 (158)Irritability 7 (65)Nausea 4 (37)Dysuria 3 (28)

rain water or were used for water storage were searched forimmature stages (larvae and pupae) ofmosquitoes Immaturemosquitoes were link reared and on emergence to adultswere identified using standard mosquito identification keys[16] Adult mosquitoes were screened for virus detectionaccording to the above mentioned protocol Fifty-six adultmosquitoes of Aedes species were collected from indoors andscrape yards

3 Results

31 Serological Findings Out of 164 samples 107 (652)were found to be Dengue positive Ninety-eight (915) NS1positives 5 (46) IgM positives and 4 (37) both NS1 andIgM positives were detected To test the recency of outbreak87 NS1-positive samples were tested for IgG antibodies and 5positives were detected (6) One sample was positive for allthe tests NS1 IgM and IgG Four samples were both NS1 andIgG positive but IgM negative Clinical profiles for all pos-itive cases are summarized in Table 1 The common clinicalpresentations were fever (981) headache (934) myalgia(813) arthralgia (523) vertigo (411) and retroorbitalpain (280) Female patients comprised 672of the positivecases The positive patients were from all age groups (range9ndash70 years) with a median age of 28 years 467 of the casesbelonged to the young adult age group (18ndash30 years)

32Molecular Typing of Dengue Serotypes Eighty-nine of the98 NS1-positive samples were processed for Dengue-specifictwo-step RT-PCR assay PCR amplificationwas detected in 35samples (393) of which 27 (77) were Dengue serotype 3Seven (20) samples were coinfected by serotypes 1 and 3whereas 1 (3) sample had coinfection of serotype 2 and 3Thus serotype 3 was the predominant serotype circulatingduring the outbreak

The Scientific World Journal 3

NIndia

Pasighat location of Dengue outbreak in AP state India

92∘09984000998400998400E

30∘09984000998400998400N

28∘09984000998400998400N28

∘09984000998400998400N

94∘09984000998400998400E 96

∘09984000998400998400E

92∘09984000998400998400E 94

∘09984000998400998400E 96

∘09984000998400998400E

Figure 1 Pasighat location of Dengue outbreak in AP state India

33 Vector Surveillance Following confirmation of Dengueoutbreak an entomological survey was carried out in thePasighat area Only A albopictus mosquitoes were caughtduring the survey both in immature as well as adult collec-tions All the mosquitoes screened for Dengue virus werePCR negativeThemost common habitats forAedes breedingwere discarded automobile tyres mostly stored in the openin tyre repairing shops and solid waste scrape dump yardsin the vicinity of the market area bamboo stumps in theresidential localities as well as in the extensive bamboo plan-tations adjoining the humanhabitations and discarded plasticcontainers around houses having container index values of571 428 and 285 respectively Breteau Index (BI) forA albopictus was estimated as 750

4 Discussion

Thepresent paper reportsDengue outbreak fromPasighat hillstation (Figure 1) East Siang district of AP The East Siangdistrict had never reported any Dengue infection earlier

It was observed that the majority of Dengue cases weredetected by the presence of viral NS1 antigen compared toIgM antibodies in patientrsquos sera Therefore it is known thatearly detection of Dengue cases by NS1 assay helps in diag-nostic detection and confirmation of cases [17] Viral antigendetection is particularly useful during the first five days ofillness with NS1 assays that are significantly more sensitivefor primary than secondary Dengue infection [18ndash20] Sixpercent of NS1-positive samples were also IgG positiveThesepatients provided serological evidence of previous exposureIt might also be possible that IgG positivity in these patientscould be due to early development of IgG response at the endof first week of acute Dengue infection rather than previousexposure to another Dengue serotypeinfection One patientpositive for all NS1 IgM and IgG was probably in the latestage of either a primary or a secondary infection and might

have been infectious for mosquitoes [21] Clinical presen-tations of Dengue-positive cases showed that fever was themost common presenting symptom as it was also observedin other studies [22] Other common symptoms found wereheadache [23] musculo-skeletal symptoms (arthralgia andmyalgia) [24] retroorbital pain and itching [25] Thus it canbe stated that supporting clinical symptoms along with earlydetection of viral NS1 antigen can help to speedup diagnosisof Dengue cases

DF is typically known as a childhood disease and is animportant cause of paediatric hospitalisation in SoutheastAsia [26] However in India all age groups have been affectedby DF [27] In an outbreak in Delhi during 2003 dengue-positives in the adult group outnumbered those of childrenalthough the difference in the number of positive cases wasnot significant compared to pediatric age group [28] Inanother outbreak in Malaysia during 2006-2007 it wasobserved that the majority of the cases were adults in the 21to 25 years and gt35 years old age groups with mean per-centages of 205 and 23 respectively This trend is similarin most dengue endemic countries in Southeast Asia Withthis changing demography it is possible that there are featuresof severe dengue leading to death that could be differentfrom those seen in children [29] In the present study itwas observed that the maximum cases were in the youngadult age group similar observations were also found inother studies [30] Female cases were more than malesthis observation tallied with another study carried out inKolkata India in 2010 [31]The vectormosquitoes (Aedes sp)are mainly domestic and peridomestic in nature and femaleshouse wives have a greater chance of exposure to mosquitobites

For molecular typing of NS1-positive samples RT-PCRassay was carried out It was observed that only 393 of thecases showed molecular amplification among NS1-positivecases It can be stated that in early detection NS1 antigen


detection appeared to be better than RT-PCR In a studyDENV NS1 antigen detection in travelers upon arrival atairports in Taiwan was important in detection of 19 RTPCR-negative travelers who would have been labeled DENVnegative [32] Furthermore inMalaysia 42 of 55 patientswitha diagnosis of acuteDenguewere positive forNS1 but negativeby both RT-PCR and virus isolation [33] In India during pastDengue epidemics all four serotypes were found to circulatebut type 2was themost predominant typeHowever in recenttrends epidemiology of Dengue infection is changing inIndia with predominance of serotype 3 [34] In our study alsoserotype 3 was the major serotype circulating Among the 35PCR-positive samples monotypic infections of type 3 wereobserved in 27 (77) samples

In entomological survey among the potential Denguevectors only A albopictus was found The species has beenimplicated as an efficient potential vector of epidemicDengue[35] although it is believed to be a less efficient vector ofarboviruses than A aegypti the major reported vector ofDengue However A albopictus adapts better than A aegyptiin temperate climate and outbreaks may be caused by thisspecies of mosquitoes in temperate regions and also in areaswhere A aegypti is not present [36] But outbreaks caused byA albopictus are usually smaller and mild in nature In spiteof being considered as a less efficient vector its notoriety withregard to spread of dengue infection is increasing due to arapid change in its overall distribution In recent decade Aalbopictus has been the vector in outbreaks in different areasof the world namely China [37] Hawaii [38] and Mauritius[39] The region of Pasighat experiences a temperate climatewarm summers and winters are moderately cold [40] Abun-dance of A albopictus from the area supported the role ofthe species in the Dengue outbreak A Breteau index lowerthan 5 denotes a low risk whereas an index value greaterthan 50 indicates a high risk of Dengue transmission [41]We recorded a BI of 75 which made the area vulnerable toa high risk of Dengue transmission However none of themosquitoes could be incriminated for the presence ofDengueviral RNAA albopictus is a mosquito of semiurban area [10]This mosquito was observed in Pasighat a semiurban townDengue is a disease of urban areas where solid wastes airconditioners air coolers flower pots and so forth are themajor contributors in the growth of A aegypti the principalurban vector of Dengue On the contrary Pasighat beinga semiurban town surrounded by lash green vegetationincluding bamboo plantations was devoid of A aegypti Inthis township located at an elevation of 155 MSL bambooplantations were found to be the major contributors support-ing the breeding of A albopictus mosquitoes This species ofmosquitoes single-handedly caused the Dengue outbreakMature bamboos are cut just at around internode havingample space for collection of rain water The people wereeducated to cut the bamboo at the node or fill the already cutbamboo stamp with soil so as just to avoid water collectionThe decline in breeding of A albopictus was noticeable infour-week time

Moreover insecticide spraying public health education(including community source reduction) and probably onsetof dry winter seasonmay have contributed to the culmination

of the outbreak Though Dengue is widely endemic in manyparts of the world there were no reports of Dengue casesfrom Pasighat region of the state However after the presentoutbreak the disease has to be recognized as an emergingpublic health problem in the state A albopictus seemed to bethe lone vector species responsible for the virus transmissionPublic awareness activities combinedwith efforts to eliminatethe identified risk factors for vector breeding could beinstrumental in prevention of further outbreaks in the future

5 Conclusions

The recent outbreak has established Dengue as an arboviraldisease in the AP state NE India of public concern Femalesand young adult groups weremore affectedMolecular typingelucidated type 3 as the major circulating serotype Entomo-logical surveys conducted in the area during the outbreakhave shown the presence of only one potential vector speciesnamely A albopictus the mosquito of semiurban areasIdentification of etiological agent timely intervention andpublic awareness led to a prompt reduction in the intensity ofoutbreak Information education and communication (IEC)activities combined with efforts towards vector breedingsource reduction would go a long way in prevention of spreadof the disease

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to acknowledge health authoritiesof Health Training and Research Centre General HospitalPasighat for their immense assistance during outbreak inves-tigations Technical assistance received from Mr P K Doloiand critical scrutiny of paper byDr P Chowdhury are humblyacknowledged Ms Rashmee Topno is supported by theICMR SRF Fellowship Programme

References

[1] World Health Organization (WHO) and the Special Pro-gramme for Research and Training in Tropical Diseases(TDR) ldquoDengue guidelines for diagnosis treatment preven-tion and controlrdquo 2009 httpwhqlibdocwhointpublications20099789241547871 engpdf

[2] S Nebehay ldquoDengue is fastest-spreading tropical diseaseWHOsaysrdquo 2013 httpwwwreuterscomarticle20130116health-tropical-idUSL6N0AKCPB20130116

[3] World Health Organization (WHO) ldquoClinical diagnosis chap-ter 2rdquo httpwwwwhointcsrresourcespublicationsdengue012-23pdf

[4] NGupta S Srivastava A Jain andUC Chatuvedi ldquoDengue inIndiardquo Indian Journal of Medical Research vol 136 pp 373ndash3902012


[5] A B Sabin ldquoResearch on dengue during world war IIrdquo TheAmerican Journal of Tropical Medicine and Hygiene vol 1 no 1pp 30ndash50 1952

[6] U Raheel M Faheem M N Riaz et al ldquoDengue fever in theIndian subcontinent an overviewrdquo Journal of Infection in Devel-oping Countries vol 5 no 4 pp 239ndash247 2011

[7] P M Ukey S A Bondade P V Paunipagar R M Powar and SL Akulwar ldquoStudy of seroprevalence of dengue fever in centralIndiardquo Indian Journal of Community Medicine vol 35 no 4 pp517ndash519 2010

[8] N L Kalra and C Prasittisuk ldquoSporadic prevalence of DFDHFin the Nilgiri and Cardamom hills of Western Ghats in SouthIndia is it a seeding from sylvatic dengue cyclemdasha hypothesisrdquoDengue Bulletin vol 28 pp 44ndash50 2004

[9] F M Rodrigues and C N Dandawate ldquoArthropod-borneviruses in north-eastern India a serological survey of Arun-achal Pradesh and northern Assamrdquo Indian Journal of MedicalResearch vol 65 no 4 pp 453ndash465 1977

[10] P Dutta and J Mahanta ldquoPotential vectors of dengue and theprofile of dengue in the north-eastern region of India an epi-demiological perspectiverdquoDengue Bulletin vol 30 pp 234ndash2422006

[11] H C Barua and J Mahanta ldquoSerological evidence of Den-2 activity in Assam and Nagalandrdquo Journal of CommunicableDiseases vol 28 no 1 pp 56ndash58 1996

[12] T Sankari S L Hoti T B Singh and J Shanmugavel ldquoOut-break of dengue serotype-2 (DENV-2) of cambodian origin inManipur India-association withmeteorological factorsrdquo IndianJournal of Medical Research vol 136 pp 649ndash655 2012

[13] P Dutta S A Khan J Borah and J Mahanta ldquoDemographicand clinical features of patients with Dengue in NortheasternRegion of India a retrospective cross-sectional study during2009ndash2011rdquo Journal of Virology and Microbiology vol 2012 11pages 2012

[14] E Harris T G Roberts L Smith et al ldquoTyping of dengueviruses in clinical specimens and mosquitoes by single-tubemultiplex reverse transcriptase PCRrdquo Journal of Clinical Micro-biology vol 36 no 9 pp 2634ndash2639 1998

[15] R S Lanciotti C H Calisher D J Gubler G-J Chang andA V Vorndam ldquoRapid detection and typing of dengue virusesfromclinical samples by using reverse transcriptase-polymerasechain reactionrdquo Journal of Clinical Microbiology vol 30 no 3pp 545ndash551 1992

[16] L M Rueda ldquoPictorial keys for the identification of mosquitoes(Diptera Culicidae) associated with Dengue virus transmis-sionrdquo Zootaxa vol 78 pp 239ndash241 2004

[17] S Datta and CWattal ldquoDengue NS1 antigen detection a usefultool in early diagnosis of dengue virus infectionrdquo Indian Journalof Medical Microbiology vol 28 no 2 pp 107ndash110 2010

[18] P Dussart L Petit B Labeau et al ldquoEvaluation of two newcommercial tests for the diagnosis of acute dengue virusinfection using NS1 antigen detection in human serumrdquo PLoSNeglected Tropical Diseases vol 2 no 8 article e280 2008

[19] M D R Q Lima R M R Nogueira H G Schatzmayr andF B dos Santos ldquoComparison of three commercially availabledengue NS1 antigen capture assays for acute diagnosis ofDengue in Brazilrdquo PLoS Neglected Tropical Diseases vol 6 no 7article e738 2010

[20] V Tricou H T T Vu N V N Quynh et al ldquoComparison oftwo dengue NS1 rapid tests for sensitivity specificity and rela-tionship to viraemia and antibody responsesrdquo BMC InfectiousDiseases vol 10 article 142 2010

[21] S C Arya N Agarwal S C Parikh and S Agarwal ldquoSimul-taneous detection of dengue NS1 antigen IgM plus IgG andplatelet enumeration during an outbreakrdquo Sultan Qaboos Uni-versity Medical Journal vol 11 no 4 pp 470ndash476 2011

[22] A Kumar C R Rao V Pandit S Shetty C Bammigatti and CM Samarasinghe ldquoClinical manifestations and trend of denguecases admitted in a tertiary care hospital Udupi District Kar-natakardquo Indian Journal of Community Medicine vol 35 no 3pp 386ndash390 2010

[23] T Jelinek N Muhlberger G Harms et al ldquoEpidemiology andclinical features of imported dengue fever in Europe sentinelsurveillance data from TropNetEuroprdquo Clinical Infectious Dis-eases vol 35 no 9 pp 1047ndash1052 2002

[24] M G Guzman G P Kouri J Bravo et al ldquoDengue haemor-rhagic fever in Cuba II Clinical investigationsrdquo Transactions ofthe Royal Society of TropicalMedicine andHygiene vol 78 no 2pp 239ndash241 1984

[25] D Priyadarshini R R Gadia A Tripathy et al ldquoClinicalfindings and pro-inflammatory cytokines in dengue patients inWestern India a facility-based studyrdquo PLoS ONE vol 5 no 1Article ID e8709 2010

[26] DGuha-Sapir andB Schimmer ldquoDengue fever newparadigmsfor a changing epidemiologyrdquo Emerging Themes in Epidemiol-ogy vol 2 2005

[27] C Prasittisuk A G Andjaparidze and V Kumar ldquoCurrentstatus of denguedengue haemorrhagic fever in WHO South-East Asia Regionrdquo Dengue Bulletin vol 22 pp 1ndash123 1998

[28] A Chakravarti and R Kumaria ldquoEco-epidemiological analysisof dengue infection during an outbreak of dengue fever IndiardquoVirology Journal vol 2 article 32 2005

[29] S S Sam S F S Omar B T Teoh J A Jamil and S AbuBakarldquoReview of dengue hemorrhagic fever fatal cases seen amongadults a retrospective studyrdquo PLOS Neglected Tropical Diseasesvol 7 article e2194 2013

[30] P Gurugama P Garg J Perera A Wijewickrama and SSeneviratne ldquoDengue viral infectionsrdquo Indian Journal of Der-matology vol 55 no 1 pp 68ndash78 2010

[31] A Sarkar D Taraphdar and S Chatterjee ldquoMolecular typing ofdengue virus circulating in Kolkata India in 2010rdquo Journal ofTropical Medicine vol 2012 Article ID 960329 5 pages 2012

[32] P-Y Shu C-F Yang J-F Kao et al ldquoApplication of the denguevirus NS1 antigen rapid test for on-site detection of importeddengue cases at airportsrdquoClinical and Vaccine Immunology vol16 no 4 pp 589ndash591 2009

[33] S Zainah A H A Wahab M Mariam et al ldquoPerformance ofa commercial rapid dengue NS1 antigen immunochromatogra-phy test with reference to dengue NS1 antigen-capture ELISArdquoJournal of Virological Methods vol 155 no 2 pp 157ndash160 2009

[34] E Gupta L Dar G Kapoor and S Broor ldquoThe changingepidemiology of dengue in Delhi Indiardquo Virology Journal vol3 article 92 2006

[35] Centers for Disease control and Prevention (CDC) ldquoInforma-tion on Aedes albopictusrdquo httpwwwcdcgovncidoddvbidarboralbopic newhtm

[36] G Rezza ldquoAedes albopictus and the reemergence of DenguerdquoBMC Public Health vol 12 no 1 article 72 2012

[37] G Xu H Dong N Shi et al ldquoAn outbreak of dengue virusserotype 1 infection in Cixi Ningbo Peoplersquos Republic of China2004 associated with a traveler fromThailand and high densityof Aedes albopictusrdquoAmerican Journal of Tropical Medicine andHygiene vol 76 no 6 pp 1182ndash1188 2007


[38] P V Effler L Pang P Kitsutani et al ldquoDengue fever Hawaii2001-2002rdquo Emerging Infectious Diseases vol 11 no 5 pp 742ndash749 2005

[39] M I Issack V N Pursem T M S Barkham L-C Ng MInoue and S S Manraj ldquoReemergence of dengue inMauritiusrdquoEmerging Infectious Diseases vol 16 no 4 pp 716ndash718 2010

[40] ldquoPasighat weatherrdquo httpwwwmustseeindiacomPasighat-weather

[41] T Seyler P Sakdapolrak S Sanjeevi Prasad and R DhanrajldquoA chikungunya outbreak in the metropolis of Chennai India2006rdquo Journal of Environmental Health vol 74 no 6 pp 8ndash132012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Genetics Research International


Advances in

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Nucleic AcidsJournal of

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Stem CellsInternational



Enzyme Research



Microbiology


In the present study we report Dengue outbreak inPasighat a hill station located at an altitude of 155mMSL (lat-itude 2807∘ N longitude 9533∘E) situated in the East Siangdistrict of AP The outbreak was confirmed by serologicalclinical and molecular evidence

2 Materials and Methods

21 The Outbreak Study During the months of July-August2012 suspected cases of fever of unknown origin (FUO)were reported from Pasighat AP India The case definitionsof suspected Dengue infection were based on guidelines ofCenters for Disease Control and Prevention (CDC) Theclinical descriptions include fever and two or more of the fol-lowing headache retroorbital pain myalgia arthralgia rashhemorrhagic manifestations or leucopenia A total of 164probable patients from hospitalisedOut Patient Department(OPD) at Health Training and Research Centre GeneralHospital Pasighat conforming to the above mentioned casedefinition were recorded Serum samples collected fromthe patients were transported under cold conditions to theRegional Medical Research Centre (RMRC) ICMR NERegion Dibrugarh India for laboratory investigations Thenonresearch activity was a part of public health response tooutbreak investigation and thus did not require a review ofInstitutional Ethics Committee of RMRC ICMR Dibrugarh

22 Serological Diagnosis All serum samples were tested forpresence of Dengue viral nonstructural 1 (NS1) antigen byusing Platelia Dengue NS1 kits (Bio-Rad USA) The sampleswere also tested for Dengue specific immunoglobulin M(IgM) antibody by using IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) kits procuredfrom the National Institute of Virology (NIV) Pune IndiaNS1-positive sampleswere also tested for IgGusingDENGUEIgG capture ELISA (Panbio Australia) All tests were carriedout according to manufacturerrsquos instructions

23 Molecular Typing Dengue NS1-positive serum sampleswere subjected to detect Dengue specific RNA by two-step reverse transcriptase polymerase chain reaction (RT-PCR) assay based on Harris et al 1998 [14] Viral RNAwas extracted using QIAamp viral RNA mini kit (QiagenGermany) Complementary DNA (cDNA) was synthesisedusing cDNA synthesis kit (Fermentas USA) PCRwas carriedout using primer pairs amplifying capsid region according toLanciotti et al 1992 [15] using cDNA as template AmplifiedPCRproducts were visualized in 2 agarose gel electrophore-sis

24 Follow-Up Survey of Dengue Affected Areas and VectorMonitoring Following laboratory confirmation of Dengueoutbreak an entomological survey was undertaken to iden-tify the vector(s) involved in order to devise vector controland disease containment strategies As part of mosquitosurveillance program solid waste containers namely bam-boo stumps metal and plastic wares cans flower pots dis-carded automobile tyres and so forth whichever could hold

Table 1 Clinical characteristics of Dengue-positive cases

Clinical features Percentage frequencyFever 105 (981)Headache 100 (934)Myalgia 87 (813)Arthralgia 56 (523)Vomiting 46 (429)Vertigo 44 (411)Retroorbital pain 30 (280)Itching eruption 28 (261)Loose motion 20 (186)Cough 20 (186)Pain in abdomen 20 (186)Rashes 18 (168)Hypotension 18 (168)Sore throat 17 (158)Irritability 7 (65)Nausea 4 (37)Dysuria 3 (28)

rain water or were used for water storage were searched forimmature stages (larvae and pupae) ofmosquitoes Immaturemosquitoes were link reared and on emergence to adultswere identified using standard mosquito identification keys[16] Adult mosquitoes were screened for virus detectionaccording to the above mentioned protocol Fifty-six adultmosquitoes of Aedes species were collected from indoors andscrape yards

3 Results

31 Serological Findings Out of 164 samples 107 (652)were found to be Dengue positive Ninety-eight (915) NS1positives 5 (46) IgM positives and 4 (37) both NS1 andIgM positives were detected To test the recency of outbreak87 NS1-positive samples were tested for IgG antibodies and 5positives were detected (6) One sample was positive for allthe tests NS1 IgM and IgG Four samples were both NS1 andIgG positive but IgM negative Clinical profiles for all pos-itive cases are summarized in Table 1 The common clinicalpresentations were fever (981) headache (934) myalgia(813) arthralgia (523) vertigo (411) and retroorbitalpain (280) Female patients comprised 672of the positivecases The positive patients were from all age groups (range9ndash70 years) with a median age of 28 years 467 of the casesbelonged to the young adult age group (18ndash30 years)

32Molecular Typing of Dengue Serotypes Eighty-nine of the98 NS1-positive samples were processed for Dengue-specifictwo-step RT-PCR assay PCR amplificationwas detected in 35samples (393) of which 27 (77) were Dengue serotype 3Seven (20) samples were coinfected by serotypes 1 and 3whereas 1 (3) sample had coinfection of serotype 2 and 3Thus serotype 3 was the predominant serotype circulatingduring the outbreak


NIndia


92∘09984000998400998400E

30∘09984000998400998400N

28∘09984000998400998400N28

∘09984000998400998400N

94∘09984000998400998400E 96

∘09984000998400998400E

92∘09984000998400998400E 94

∘09984000998400998400E 96

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4 Discussion











5 Conclusions




Acknowledgments


References



















































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology


NIndia


92∘09984000998400998400E

30∘09984000998400998400N

28∘09984000998400998400N28

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92∘09984000998400998400E 94

∘09984000998400998400E 96

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4 Discussion











5 Conclusions




Acknowledgments


References



















































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology






5 Conclusions




Acknowledgments


References



















































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology















































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology

dengue outbreak in a hilly state of arunachal pradesh in northeast

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