A longitudinal study of Japanese encephalitis in suburban Bangkok, Thailand.

A one-year study of Japanese encephalitis (JE) in a small focus of transmission was conducted in suburban Bangkok in 1985. Monthly data were collected on weather, vector density, sentinel pig and chick JE antibody seroconversions, and epidemiology as related to human JE cases. The primary vector species were found to be Culex gelidus and Culex tritaeniorhynchus; from which one isolate each was obtained in March and June, respectively. Pig JE antibody seroconversion peaked in April (the hottest month), with secondary peaks following in July and December. Chick seroconversions were found only in June and July. Human cases (7) in the primary focus occurred from May-July, and started 2 months following the finding of the first JEV isolate in mosquitoes and 1 month following mass JEV seroconversion in pigs. Overall, the attack rate in the focus (0.83/10(5] was greater than 4 times that of the rest of Bangkok (0.19/10(5]. Attack rates were highest in 0-9 and 10-19 year-old groups, respectively. Indications are that JEV is transmitted to humans in Bangkok at least 10 out of 12 months per year, but that cases are concentrated in the May to July period.

Anti-rabies virus IgM in serum and cerebrospinal fluid from rabid dogs.

An anti-rabies IgM antibody capture radio immunoassay was used to test serum and cerebrospinal fluid from 37 dogs held in quarantine for suspicion of rabies. Rabies was confirmed in dogs that died by mouse inoculation and subsequent examination of mouse brains by fluorescent antibody technique to detect rabies antigen. The mean counts per minute (CPM) of iodinated anti-rabies gamma globulin coupled IgM rabies antibody in CSF and serum from rabid dogs were significantly higher than in CSF and serum from non-rabid dogs. Mean CPM from rabid dogs was greater in CSF than in sera, in contrast with non-rabid dogs, from which mean cpm was higher in sera than CSF, suggesting that antibody may have been synthesized in the CSF. To evaluate this test further, a dog was infected by rabies virus, and serial serum and CSF specimens were collected until the time of death. IgM anti-rabies antibody developed in the CSF and serum 29 days following infection, and rose just before the dog died of rabies on day 34. The rabies MAC RIA is potentially useful as a diagnostic method in quarantined dogs with rabies-like illness. Perhaps more importantly, it may be applied to better understand the immunopathogenicity of rabies.

Blood value changes in flavivirus-inoculated Macaca fascicularis monkeys.

Blood values were analysed in eighteen cynomolgus monkeys on pre-and post-neurovirulence testing of dengue-2 and yellow fever vaccine viruses, dengue-2 parental and Japanese encephalitis viruses. Certain changes between blood chemistry, hematology and serology were observed and briefly discussed.