Background: Tick-borne bacteria, Anaplasma platys and Ehrlichia canis are well recognized as the etiology of anemia and thrombocytopenia in dogs. The clinical signs of anaplasmosis and ehrlichiosis range from asymptomatic to severe symptoms. There are insufficient studies about epidemiological surveys of these blood parasites, also the association of infections with the hematological study.

Aim: This study aimed to screen A. platys and E. canis in naturally infected dogs and the effects of the infection on the levels of packed cell volume (PCV) and platelet count.

Materials and Methods: A total of 68 blood samples were collected from free-roaming dogs at Nong Kung Sri district, Kalasin Province, Thailand, and examined for A. platys and E. canis infection by polymerase chain reaction (PCR) and measured PCV levels and platelet count.

Results: Using nested PCR, 42.65% of dogs were infected with one or two pathogens. The molecular detection of anaplasmosis and ehrlichiosis in this population was 29.4% (95% confidence interval [CI]: 18.98-41.71) and 25% (95% CI: 14.4-35.3), respectively. Coinfection occurred at 11.8% (95% CI: 5.22-21.87). Infection with E. canis and coinfection showed significant association with PCV levels (p<0.05) while A. platys infection showed no statistical relationship. Infection with A. platys, E. canis, and coinfection had a non-significant correlation with platelet count (p>0.05).

Conclusion: This study provides data of anaplasmosis and ehrlichiosis in free-roaming dogs which indicated that these zoonotic diseases are widespread and require for disease frequency determination, especially in Kalasin Province of Thailand where data of tick-borne infections in dogs have not been reported.

Keywords: packed cell volume, platelet count, Thailand, tick-borne pathogens.

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