Occurrence and Haematology of Canine Tick-Borne Protozoa in Dhaka City, Bangladesh.

Dogs, being companion animals, serve a variety of economic, social and cultural purposes. However, diseases caused by the tick-borne protozoans are drawing attention globally due to their zoonotic transmission. In this context, the present study aimed to observe the occurrence of tick-borne protozoan infections as well as some selective haematological parameters of stray dogs in Dhaka city, Bangladesh. A total of 160 dogs from various places were selected randomly and examined for both tick and protozoan infection. Only one species of hard tick, Rhipicephalus sanguineus, was identified, where 49 (30.62%) among the study population were found to be infested with this tick. Ticks ranging from 1-16 were removed from dogs, where most of the ticks were collected from the neck and chest regions (P < 0.001). On the other hand, examinations of blood smears confirmed three protozoan species (Babesia canis, Babesia gibsoni and Hepatozoon spp.) comprising 23.13% of the overall infection. Among the protozoan species, B. canis (11.88%) was the most prevalent protozoan. Subsequently, only 10.81% of the infected samples showed multiple infections. In both cases, females were more infected than males. Among the haematological parameters, the RBC counts, haemoglobin and PCV of all infected dogs were significantly lower (P < 0.001) compared to the non-infected group. Moreover, the eosinophils of the infected groups showed higher values (11.00 % and 12.70% for protozoa and ticks, respectively) than the normal range, indicating parasitic infections. Therefore, these results suggest the necessity of frequent blood examinations to enhance animals' welfare and disease prevention.