Stray dogs and rabies in Bangkok, Thailand Songsri Kasempimolporn Queen Saovabha Memorial Institute, Bangkok, Thailand

Estimated dog population and vaccine coverage in Bangkok, Thailand Data were compiled by The Bangkok Metropolitan Administration and the Bureau of National Statistics Dog population 1992 1999 2006 House dogs 358,936 523,230 823,504 No. vaccinated 240,786 452,034 753,478 (67%) (86%) (91%) Stray dogs 40,019 110,584 ? No.vaccinated ?? ?? ??

Human deaths from rabies, 1997-2006 Year Bangkok*/Thailand 1997 7/58 1998 4/57 1999 7/68 2000 6/50 2001 8/37 2002 0/30 2003 3/21 2004 0/19 2005 3/20 2006 1/25 * Bitten by dogs located in Bangkok

Sources of rabies transmitted to man, 2002-2005 Dog 81% Not recorded 9% Mongoose 5% Rabbit 5% 2003 Dog 93% Not recorded 7% 2002 Not recorded 5% Dog 95% 2004 Dog 70% Not recorded 20% Monkey 5% Cat 5% 2005

Rabies virus N gene was digested with enzyme DdeI or HinfI Study of molecular epidemiology of rabies virus that is prevalent among dogs in Bangkok A B Rabies virus N gene was digested with enzyme DdeI or HinfI

Canine rabies virus M I II Hf Type I: DdI-HfI Type II: DdII-HfII Type III: DdIII-HfI Type IV: DdIV-HfI Type V: DdIV-HfIII

Dog Cat

Stray dogs in Bangkok, Thailand: Rabies virus infection and rabies antibody prevalence

Saliva sample collection was done with a total of 3,314 dogs seen for surgical sterilization during 12/2003-6/2004

Detection of rabies virus in dog saliva Screening test: The latex agglutination test (Kasempimolporn et al. J Clin Microbiol 2000;38:3098-99) Confirmatory test: RT-PCR with nested primers

Blood sample collection

Determination of rabies antibody in dog serum Enzyme-linked immunosorbent assay (ELISA) - A minimum value of 0.5 IU/ml of neutralizing antibodies should be attained to demonstrate seroconversion in humans, and we used the same for the dogs. - An estimated true prevalence of antibodies among stray dogs was calculated using the Rogan-Gladen-estimator and the confidence interval (CI) was set at 95% (Grenier and Gardner, Prev Vet Med 2000;45:43-59)

Latex agglutination test

Detection of rabies virus RNA in saliva specimen by RT-PCR 524 bp DNA Ladder 100 bp + ve Control - ve Control Dog saliva The prevalence of rabies virus infection among stray dogs investigated was 0.03% (1 of 3,314)

Central Bangkok Bangkok’s outskirts Seroprevalence of rabies antibodies among stray dogs, based on an ELISA cut-off level of 0.5 EU/ml Central Bangkok Bangkok’s outskirts No. tested No. positive Adjusted seroprevalence No. teested No. positive Adjusted seroprevalence % 95% CI % 95%CI 1,208 887 86 76-96 2,106 933 49 41-57 The overall seroprevalence of rabies antibody among stray dogs in Bangkok was 62% (95%CI 54-70%)

Map of Bangkok depicting the 50 districts Map of Bangkok depicting the 50 districts. Shaded surface areas represent the districts in which the antibody seroprevalence among stray dogs reached 70%

Conclusions Rabies infection is still prevalent in Bangkok Low vaccination coverage and ineffective management of stray dogs are the most likely reasons for the dog rabies elimination program’s lack of success

Thank you