Contents lists available at ScienceDirect Veterinary Parasitology: Regional Studies and Reports journal homepage: www.elsevier.com/locate/vprsr Case report Novel incidental finding of Hepatozoon canis infection in two dogs of the same household in Trinidad, West Indies Candice Sant ⁎ , Karla C. Georges, Patricia Pow-Brown School of Veterinary Medicine, Faculty of Medical Sciences, The University of the West Indies, St. Augustine Campus, Eric Williams Medical Sciences Complex, Mt. Hope, Trinidad and Tobago ARTICLE INFO Keywords: Hepatozoon infections Ticks Canine Phylogenetic tree Trinidad ABSTRACT 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 micro- scopic 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. 1. Introduction Hepatozoon spp. are haemoprotozoan parasites of birds, reptiles and mammals which belong to the family Hepatozoidae (Forlano et al., 2007). Hepatozoon canis and H. americanum are two species that infect dogs (Forlano et al., 2007; Ivanov and Tsachev, 2008). H. canis infec- tions occur when mature oocysts contained within the definitive host, the brown dog tick, Rhipicephalus sanguineus, are ingested by the dog. Infections may also be transmitted transplacentally from an infected dam to the foetus (Forlano et al., 2007; Amoli et al., 2012). Potential vectors of canine hepatozoonosis include Amblyomma ovale, Rhipice- phalus turanicus, Rhipicephalus spp. II and Haemaphysalis spp. (Forlano et al., 2007; Ivanov and Tsachev, 2008; Giannelli et al., 2013; Latrofa et al., 2014). The parasite produces gamonts in the peripheral blood and schizonts in the lungs, heart, skeletal muscle, liver, spleen and lymph nodes (Ivanov and Tsachev, 2008; Amoli et al., 2012). The life cycle of H. canis is approximately 81 days with meronts observed in the bone marrow of the dog 13 days post inoculation and gamonts in the peripheral blood 28 days after infection (Baneth, 2011). The level of parasitaemia in H. canis infections is usually low with < 5% parasitaemia reported in most cases. The severity of the disease is thought to be proportional to the level of parasitaemia of the host (Ivanov and Tsachev, 2008). Cases involving low parasitaemias of H. canis are usually asymptomatic, however, clinical signs such as fever, weight loss, lethargy, pale mucous membranes, cachexia, paralysis, hind limb weakness, muscle hyperaesthesia and anorexia are observed in cases with high parasitaemias (Ivanov and Tsachev, 2008; Baneth, 2011; Chhabra et al., 2013). Diagnosis can be made by observation of gamonts in the cytoplasm of neutrophils or monocytes in peripheral blood or buffy coat smears (Amoli et al., 2012). The gamonts appear as a clear oblong capsule with a faintly staining nucleus within the cytoplasm of the neutrophil or monocyte. The parasite can also deform the cell membrane of the in- fected white blood cell (WBC) (Vincent-Johnson et al., 1997). However, diagnosis by microscopic examination of the blood smear is not reliable as the level of parasitaemia may be low or intermittent resulting in a low number of circulating gamonts in the blood (Amoli et al., 2012). Other more sensitive diagnostic tests for Hepatozoon infections include immunofluorescence antibody test (IFAT), enzyme linked immunoassay (ELISA) and conventional and real time polymerase chain reaction (PCR) (Baneth, 2011). Common conventional PCR primers used to di- agnose Hepatozoon infections target the 18S rRNA gene (Inokuma et al., 2002; Forlano et al., 2007; Aktas et al., 2015). H. canis infections have been reported in the Caribbean region. Reports have been documented in Aruba (Vilar et al., 2005), Grenada (Yabsley et al., 2008), St Kitts (Kelly et al., 2013; Loftis et al., 2013) and http://dx.doi.org/10.1016/j.vprsr.2017.06.003 Received 6 March 2017; Received in revised form 18 April 2017; Accepted 3 June 2017 ⁎ Corresponding author. E-mail address: Candice.Sant@sta.uwi.edu (C. Sant). Veterinary Parasitology: Regional Studies and Reports 9 (2017) 98–103 Available online 08 June 2017 2405-9390/ © 2017 Elsevier B.V. All rights reserved. MARK