[Investigation of B. canis infection in China].

Twelve thousand nine hundreds and forty-nine dogs, 1,676 peoples and 2,255 animals of 15 species were detected for B. canis infection in 23 provinces and cities in China. Positive rates of dogs in various provinces were different (0.3-42.7%). The positive rates of dogs in south China were more higher than north. A positive rate of female was higher than male (2:1). Positive rate of young dogs (below 1 year old) was lower than older. There was no different of the positive rates among the age groups (more than 2 years old). 166 B. canis strains were isolated from spleen, lymph nodes and liver in 644 dogs. On the basis of two dyes sensitivity of B. canis isolated from China could divide into two types: one was resistant to both dyes, the other was resistant to thionine, but sensitive to basic fuchsin. Eight serological methods were used in the investigation. R-SAT and R-RBPT were more sensitive than the others. The positive rate of culture B. canis was 50%, when the dogs were selected for isolation at 1:80 titer. The positive rate of B. canis was 80%, when the dogs were selected for isolation at 1:320 titer.