Research article

Transmission dynamics of rabies virus in Thailand: Implications for disease control

Jessada Denduangboripant¹ , Supaporn Wacharapluesadee² , Boonlert Lumlertdacha³ , Nipada Ruankaew⁴ , Wirongrong Hoonsuwan⁵ , Apirom Puanghat ⁶ and Thiravat Hemachudha⁷

¹  Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand

²  Molecular Biology Laboratory for Neurological Diseases, Chulalongkorn University Hospital, Bangkok, Thailand

³  Queen Saovabha Memorial Institute, Thai Red Cross Society, Bangkok, Thailand

⁴  Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand

⁵  Department of Livestock Development, Ministry of Agriculture, Bangkok, Thailand

⁶  Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand

⁷  Molecular Biology Laboratory for Neurological Diseases, Chulalongkorn University Hospital, Bangkok, Thailand

author email corresponding author email

BMC Infectious Diseases 2005, 5:52doi:10.1186/1471-2334-5-52

Published:	29 June 2005

Abstract

Background

In Thailand, rabies remains a neglected disease with authorities continuing to rely on human death statistics while ignoring the financial burden resulting from an enormous increase in post-exposure prophylaxis. Past attempts to conduct a mass dog vaccination and sterilization program have been limited to Bangkok city and have not been successful. We have used molecular epidemiology to define geographic localization of rabies virus phylogroups and their pattern of spread in Thailand.

Methods

We analyzed 239 nucleoprotein gene sequences from animal and human brain samples collected from all over Thailand between 1998 and 2002. We then reconstructed a phylogenetic tree correlating these data with geographical information.

Results

All sequences formed a monophyletic tree of 2 distinct phylogroups, TH1 and TH2. Three subgroups were identified in the TH1 subgroup and were distributed in the middle region of the country. Eight subgroups of TH2 viruses were identified widely distributed throughout the country overlapping the TH1 territory. There was a correlation between human-dependent transportation routes and the distribution of virus.

Conclusion

Inter-regional migration paths of the viruses might be correlated with translocation of dogs associated with humans. Interconnecting factors between human socioeconomic and population density might determine the transmission dynamics of virus in a rural-to-urban polarity. The presence of 2 or more rabies virus groups in a location might be indicative of a gene flow, reflecting a translocation of dogs within such region and adjacent areas. Different approaches may be required for rabies control based on the homo- or heterogeneity of the virus. Areas containing homogeneous virus populations should be targeted first. Control of dog movement associated with humans is essential.