Hepatozoon canis is a tick-borne protozoan that has been reported in dogs worldwide. H. canis has the higher prevalence in stray dogs since they have more chances to approach tick vectors in the environment than in-house dogs. Increasing number of stray dogs in Bangkok has caused a rising rate of transmission of tick-borne diseases between in-house and stray dogs.

Objectives

This objective of this study was to investigate the current infection rate of hepatozoonosis that ranges in severity from an asymptomatic infection in apparently health dogs, to a life-threatening disease.

Methods

Blood was collected from 308 stray dogs from 30 districts of Bangkok from October 2001 to September 2002. The blood was used and analyzed by 18S rRNA gene of H. canis.

Results

Using polymerase chain reaction, H. canis was identified in 11.36 % (35 out of 308) of the animal examined compared to 2.59 % by microscopic examination. Prevalence of canine hepatozoonosis was 36.67 % (11 out of 30 districts) of Bangkok area examined. This corresponds to the high number of Rhipicephalus sanguineus, which were also found to be abundant in these dogs.

Conclusion

Stray dogs might serve as potential carriers of hepatozoonosis to domestic pet dogs.