a1 Department of Applied Immunology, National Institute of Health, 10–35, Kamiosaki, 2-chome, Shinagawaku, Tokyo 141, Japan
a2 Asaka Laboratories, Fuji Photo Film Co. Ltd, Japan
a3 Department of Microbiology, Nippon Medical School, Japan
a4 Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
A total of 270 serum samples collected in Chiang Mai province were examined for antibodies against leptospira using the microscopic agglutination test (MAT). Four of 40 serum specimens from patients who visited the hospital with the common cold, were positive with a titre of 20. Twelve (10·4%) of the 115 samples in the Doi Saket district showed a positive reaction. Only 2 of 115 sera of school children in Chiang Mai city had antibodies.
Specific serovars detected were Leptospira hebdomadis (5), L. australis (3), L. icterohaemorrhagiae (2), L. bataviae (2), and one each of L. canicola, L. javanica and L. pyrogenes. One case of mixed infection with L. hebdomadis and L. javanica, and L. auhnnnalis and L. australis were observed.
(Accepted August 19 1986)