Epidemiology and characterization of leptospirosis at an urban and provincial site in Thailand.

Patients with FUOs at the Children's Hospital in Bangkok and the Chao Phya Abhai Bhu Bejhr Hospital in Prachinburi were screened for leptospirosis by blood and urine culture in addition to microagglutination testing of their serum. Animal populations in urban and periurban areas of Bangkok were surveyed for evidence of leptospira infection. Three rural sites near the Prachinburi Provincial Hospital were also surveyed. The rodents' and domestic animals' blood, urine, and/or kidney cell samples were cultured for leptospira. Sera from these animals were also tested for leptospira antibody. The bataviae serovar was the most commonly detected leptospiral agent in both man and animals. Presenting symptoms varied with age with children showing primarily fever, vomiting, headache, abdominal and generalized muscle pain and diarrhea whereas adults had fever, headache, anorexia, muscle pain and constipation. Blood samples from patients suspected of having leptospirosis were tested for antibody by the MAT and cultured in EMJH media. The following serogroups were identified: bataviae, autumanalis, javanica, hebdomadis, and pyrogens. Leptospirosis incidence in humans was much higher in the rainy/flooding year of 1983 compared to the relatively dry year of 1984. Results of our animal surveillance studies indicate that in addition to rats, which have previously been mentioned, dogs, bandicoots, cattle and pigs could be the source of human leptospirosis infection in both urban and provincial locations in Thailand.

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.

Serologic evidence of Hantaan-like virus in rodents and man in Thailand.

A serologic survey was conducted to determine the presence of antibody to Hantavirus in rodents in Thailand. Sera from over 300 rodents were tested by an immunofluorescent antibody method. Bandicota indica, a field rodent, was found to have a high incidence of infection (20-24%) in 2 locations. A Hantavirus was isolated from lung samples of B. indica. When sera were tested from humans living in Kanchanaburi and several locations in Bangkok, those people living in close proximity to the infected B. indica had greater than 30% prevalence of positive antibody titers.

Doxycycline prophylaxis for experimental leptospira infection in non-human primates and hamsters.

Doxycycline was effective as a chemoprophylactic agent for experimental Leptospira infection in non-human primates and hamsters. Monkeys injected intraperitoneally with Leptospira bataviae, and receiving only diluent as treatment developed a leptospiremia during the first week and later leptospires were cultured from the cerebrospinal fluid and urine. Monkeys treated daily with oral doxycycline for 10 days beginning one day before infection had a shortened period of detectable leptospiremia, and organisms were never detected in the cerebrospinal fluid or urine. Even an oral dose of doxycycline 2 hours before infection and on day 7 prevented the later infection of the cerebrospinal fluid and urine. In hamsters, doxycycline treatment prevented deaths from acute Leptospira infection and when hamsters were treated daily for 4 or more days, renal infection was prevented. The results of animal studies, the susceptibility of LC0475 and the five other isolates to doxycycline in vitro, and lack of evidence for antibiotic resistance in culture suggests this antibiotic may be useful as a prophylactic drug for high risk groups and an effective treatment for leptospirosis in Thailand.