Novel incidental finding of Hepatozoon canis infection in two dogs of the same household in Trinidad, West Indies

A five-year old mixed breed bitch was presented to the veterinary clinic in lateral recumbency with a history of anorexia and muscle hyperaesthesia. Examination of the blood smear of this animal revealed the presence of Hepatozoon spp. gamonts in the neutrophils and monocytes with a parasitaemia level of approximately 2%. Complete blood count (CBC) revealed a neutrophilia, and a normocytic normochromic non-regenerative anaemia which were consistent with Hepatozoon spp. infections. Diagnosis was confirmed by polymerase chain reaction (PCR) amplification of the 18S rRNA gene followed by DNA sequencing of the amplicon. Although the other dog in the household appeared asymptomatic, Hepatozoon canis infection was confirmed by both microscopic examination of blood smear and PCR. Both dogs were infested with Rhipicephalus sanguineus ticks. Phylogenetic analysis revealed that the H. canis sequences from these two dogs were similar to those from Venezuela and St Kitts but not Brazil. This is the first reported case of Hepatozoon canis infections in dogs in Trinidad that were confirmed by molecular techniques.