Epidemiology of human rabies in Thailand, B.E.2546-2550 (2003-2007 AD).

In Thailand, rabies remains an important zoonotic disease due to its lethality in humans. Although the numbers of human rabies cases have been steadily decreasing over the past ten years, the epidemiological situation has started to change. Assessment of human rabies was based on the national infectious disease surveillance system from B.E. 2546-2550. There were 106 cumulative cases distributed in all four regions of Thailand. The highest mortality rates were found in the Central and Southern regions. Dogs were the main reservoir with the highest percentage found in puppies younger than 3 months (45%). Most of the causal dogs, and 61% of the dogs with owners had not received Rabies vaccination each year. The data strongly revealed that most of the human rabies cases did not receive rabies vaccine after the animal contact or bite. Prevention and control strategies should focus especially on the regions and provinces which had the highest number of cases, or on those regions which continue to have incident cases each year. It is also essential to set up a better control of the animal population which can potentially infect humans.

Prevalence of rabies virus and Hantaan virus infections in commensal rodents and shrews trapped in Bangkok.

Five hundred rodents and shrews (Rattus norvegicus: 458, Rattus rattus: 28, Rattus exulans: 5, Mus musculus: 4 and Suncus murine: 5) trapped from the fresh food markets around Bangkok area were investigated for rabies virus and Hantaan virus infections. No rabies viral antigens in the animals' brains were detected by direct immunofluorescence. On the other hand, antibodies to Hantaan virus were demonstrated in the sera of 7 (1.53%) R. norvegicus caught in various markets using a particle agglutination technique. Further determination of the viral genome in rat lung tissue was performed by reverse transcriptase-polymerase chain reaction (RT-PCR) and nested PCR, 3 (0.66%) out of 7 were positive. HindIII and HifI restriction enzyme analyses showed the pattern of the Hantaan virus genome in 2 samples and that of the Seoul virus genome in the other. The results of the present study suggest that rodents from Bangkok's fresh food markets did not carry rabies. Thus, getting rid of rabies in dogs or cats in the Bangkok area may be easier than anticipated because there are no sources of asymptomatic reservoirs. This may result in the low incidence of rabies patients observed in Bangkok. On the contrary, the presence of antibodies and the Hantaan virus genome and Seoul virus genome in R. norvegicus will definitely provide evidence for physicians to be aware of hemorrhagic fever with renal syndrome (HFRS) and other clinical settings of Hantaan/Seoul virus disease in patients with a history of having contact with rats or their excreta.

Reduced regimen of plasma derived hepatitis B vaccine.

The antibody response after vaccination by reduced regimen of plasma derived hepatitis B vaccine (Hevac B) was studied. The vaccines were 48 medical student, who were seronegative for HBV markers. The vaccination schedule was at 0, 1 and 6 months, whereas the recommended schedule for this vaccine is at 0, 1, 2, 12 months. Anti-HBs and anti-HBc were measured at 1, 2, 7 months after the first dose. The seroconversion rate of anti-HBs were 14.9, 62.2, 84.6% and GMT (geometric mean titer) were 24.3, 128.4, 8037.3 mlU/ml respectively. No serious side effect was recorded. Six vaccines, who were seronegative after the third dose of vaccination, received another additional dose at 1 year after first dose. Blood testing performed 1 month after such booster dose showed seroconversion in 5 of 6 vaccinees.