Clinical observation of dogs serologically positive for the potentially zoonotic Ehrlichia Canis in the Philippines

Abstract

Canine Ehrlichiosis is a disease with worldwide distribution caused by the potentially zoonotic Ehrlichia canis, a Gram negative intra-cellular pathogen transmitted by the Rhipicephalus sanguineus tick. Most studies have reported the epidemiological distribution of E. canis, but information on the clinical signs and hematological values were limited and retrospectively gathered. The present study endeavored to prospectively document the clinical profile of dogs that were serologically positive for E. canis in the Philippines. A total of 68 canine patients presented at the Makati Dog and Cat Hospital, Manila, Philippines were investigated. Inclusion criteria were history or presence of tick infestation, anemia, and/or thrombocytopenia. Blood samples were collected in EDTA tubes, and plasma samples were tested for E. canis using a commercial serological test kit. Clinical signs were recorded, and complete blood counts (CBC) were performed. Results revealed that 86.7% (59) were found serologically positive for E. canis. Most seropositive dogs had tick infestation, inappetence, and lethargy. Thrombocytopenia and anemia accompanied with normal WBC counts were the common hematologic findings. Statistical analyses revealed no significant differences in the hematological values of seropositive and seronegative dogs. Also, from the clinical signs, only lethargy was found to be significantly correlated with seropositivity (p value = 0.026). This study documents the clinical profile of dogs that were serologically positive for E. canis infection in the Philippines. Results are very useful to clinical practitioners who usually rely on clinical signs, CBC and commercial test kits for the diagnosis of Canine Ehrlichiosis