Ehrlichia canis, E. chaffeensis and Anaplasma phagocytophila are the tick-borne pathogens of ehrlichiosis in both human and dogs. E. canis causes disease mainly for canine host, and E. chaffeensis and A. phagocytophila cause the majority of apparent diseases in humans. The number of stray dogs in Bangkok have been increasing and caused public health problems.

Objectives

The purpose was to evaluate the infection rate of E. canis, E. chaffeensis and A. phagocytophila in stray dogs in Bangkok.

Methods

Canine sera were taken from 100 stray dogs in Bangkok. The antibody titers against each agent were examined by immunofluorescence assay. The titers of 1:20 or higher were thought to be positive.

Results

Positive rates against E.canis, E. chaffennsis and A. phagocytophila were 22, 22 and 11 %, respectively. Although most of dogs showed higher titers against E. canis than other 2 agents, 4 dogs showed higher titers against E. chaffeensis than that of E. canis. The antibody titers against A. phagoocytophila were relatively lower than those of Ehrlichia species.

Conclusion

E. canis seemed a main agent that infects dogs in Thailand. It is suggested that other Ehrlichia species related to E. chaffeensis may also infect on stray dogs in Thailand.