ECOHEALTH APPROACHES IN PREVENTION OF EMERGING AND

RE-EMERGING ZOONOTIC DISEASES IN SOUTHERN VIETNAM: A

RETROSPECTIVE STUDY 2008-2011

Van Cao1, Le Hong Phong3, Solenne Costard4, Tran Cong Kha1, Dang Trinh Minh Anh1, Nguyen Quoc Huy1, Duong Nguyen Khang2, Nguyen Ngoc Thuy2,

Nguyen Van Khanh2, Nguyen Truc Ha3, Ma. Lucila Lapar4, Gilbert, Jeffrey4 and Mai Van Hiep3

1Pasteur Institute, Ho Chi Minh City, 2 Nong Lam University, 3Department of Animal Health, 4International Livestock Research Intitute

Overview

• Among 1,500 pathogens causing diseases in humans, 60% causative agents originate from animals2,3,4. Approximately 200 diseases

are classified as emerging infectious disease (EID), with 75% of these being zoonoses5.

• Developing countries – especially Southeast Asian countries, are continually encountering emerging strange, and re-emerging

diseases of which causative agents are of animal origin1. Rapid climate change and economic growth in this region are considered as

the leading cause in the emergence, or re-emergence of dangerous infectious diseases. Such disease include A/H5N1 avian flu,

rabies, Streptococcus suis, Leptospira, Japanese encephalitis B and PRRS.

• To assess the influence of zoonoses to human health, environmental and socio-economic issues, the EcoZD project in Vietnam

focuses on investigating the prevalence of selected diseases, most likely to be transmitted from animals in Vietnam. Research results

will contribute a basis for “hot spots” selection for PRA and cross-sectional study at a later stage.

Materials and Methods

Research sites: Locations selected for research were Binh Phuoc and Tien Giang province, the representatives of socio-economic, husbandry and disease models for highland and lowland provinces

in the southern region.

Results – Discussion

Conclusion

Since data collection was almost entirely based on case reports, incidence of zoonotic diseases and its transmission between humans and animals could be underestimated. Some zoonoses were newly

included in the regular monitoring, such as Japanese Encephalitis (JE) and Streptococcus suis. It is necessary to conduct cross-sectional studies as well as further research on animals and humans to obtain

a better picture of the circulating zoonoses in the region. The results nonetheless provided useful empirical evidence on that were combined with other hypothesized risk factors in the selection of ‘hot

spots’ and ‘cold spots’ for selected EIDs in the target study areas.

EcoZD Ecosystem Approaches to the Better Management

of Zoonotic Emerging Infectious Diseases

in the Southeast Asia Region

Binh Phuoc Tien Giang

Area (km2) 6,874.4 2,484.2

Population (people) 952,460 1,805,171

Population density

(people/km2) 130 675

Approach and data collection: Information of the diseases and outbreaks in livestock and poultry in the area were collected from

routine surveillance data at district veterinary stations. Epidemiological investigations on the prevalence of morbidity of one of the

six diseases from 1/2008 to 31/12/2011 in Tien Giang and Binh Phuoc provinces were collected based on annual monitoring data

stored at provincial preventive health centers according to the surveys.

• For avian influenza A/H5N1: From late 2003 to September 2012, there are more than 2,664 poultry-related outbreaks in Vietnam [OIE 2012].. Despite large-scale vaccination, the A/H5N1 virus still

caused sporadic poultry outbreaks in Tien Giang province. The incidence rate was 0.27/100,000 poultry per year while, with only one human death case, human rate is extremely low. There were no

reported cases or outbreak in Binh Phuoc province during the study period. According to the WHO, there were 61 deaths among 123 cases infected with A/H5N1 avian flu in Vietnam, with an average

mortality rate of 49.6%. In southern Vietnam – there were 30 cases of A/H5N1 infection, with 26 deaths (mortality rate 86.67%) from 2004 to 2011..

• For rabies, no cases of rabid dogs were reported in Tien Giang and only 1 case in Binh Phuoc. One of the difficulties in collecting data on animals was that residents did not report to the veterinary

centers or consider the possibility of rabies when the animal died. Therefore, this result may not accurately reflect actual situations. In humans, only 1 case of death from rabies was recognized in Binh

Phuoc (2011), and no deaths due to rabies were reported in Tien Giang. The incidence of dog bites, accumulated through the total-anti-rabies vaccine shots given, varied from 173.8/100,000 to

890.3/100,000 people/year in Binh Phuoc and Tien Giang respectively. According to the result of an epidemiological study of rabies in 25 provinces and cites across northern Vietnm between 2000–

2009, the average rate of prophylaxy was 194 people/100,000 population per year, mortality due to rabies was 34 people/year, the deaths were concentrated in mountainous areas, with 89.3% of these

deaths occuring in unvaccinated individuals.

• S. suis and PRRS: according to the Department of Animal Health, the incidence of S. suis in pigs in Tien Giang and Binh Phuoc are 6.3/100,000 and 1.72/100,000/year respectively. The incidence of

PRRS virus (porcine Reproductive and Respiratory Syndrome) in Tien Giang and Binh Phuoc is 295.5/100,000 and 187.2/100,000 pigs/year respectively. PRRS virus is considered as having an

association with S. suis. Human infection due to swine S. suis has been included in the monitoring system of the Department of Preventive Medicine since March 2011. There were 6 human S. suis

infection cases in Tien Giang province (incidence rate 0.33/100,000 population), and none in Binh Phuoc with zero deaths were recorded.

• For Japanese Encephalitis (JE), no data available for swine JE during 2008-2011. Data from independent studies in a number of southern provinces in the period of 2000-2001 reflected the rate of

encephalitis virus infection in pigs of 60.3%. In humans, according to the statistical results from samples sent to the Pasteur Institute in Ho Chi Minh City from 2008 to 2011, Binh Phuoc province

recorded average incidence of 0.73/100.000 people, with no cases of death recorded. Tien Giang province is yet to recognize cases of infection or death due to JE.

• For Leptospirosis, the incidence of Leptospirosis in pigs in Tien Giang and Binh Phuoc are 1.04/100.000 and 13/100.000 pigs/year respectively. In humans, there was little research of Leptospiral disease

conducted for the region.

Acknowledgements

We thank sub-Departments of Animal Health and Departments of Preventive Medicine in Tien

Giang and Binh Phuoc for data extraction, Mai Van Nam, Le Thi Lien, Nguyen Thi Yen Nhi,

Nguyen Van Khoa, Le Ha Tam Duong (PIHCMC) for their efficacious help in data analysis,

Andrew (ILRI) help in editing and formatting the poster.

This research was supported by International Livestock Research Institute (ILRI)

References

1. Coker RJ, Hunter BM, Rudge JW, Liverani M, Hanvoravongchai P. 2001. Emerging infectious diseases in southeast Asia: Regional challenges to control. The

lancet 37:599-609.

2. Taylor LH, Latham SM, Woolhouse ME. 2001. Risk factors for human disease emergence. Philos Trans R Soc Lond B Biol Sci 356:983–9.

3. Woolhouse ME, Gowtage-Sequeria S. 2005. Host range and emerging and reemerging pathogens. Emerg Infect Dis 11:1842–7.

4. Woolhouse ME, Taylor LH, Haydon DT. 2001. Population biology of multihost pathogens. Science 292:1109–12.

5. World Health Organization. 2011. Managing zoonotic public health risks at the human-animal-environment interface. Available from:

http://www.who.int/foodsafety/about/Flyer_zoonoses.pdf

6. Dapartment of Preventive Medicine. Statistical Yearbook of Vietnam 2009, 2010, 2011. Statistic Publishing House, Hanoi, Viet nam