A Case Report: a Dog with Acute Onset of Hepatozoon canis Infection

Abstract

ABSTRACT. We present a clinical overview of a dog with acute onset of Hepatozoon canis infection. A stray female beagle dog of unknown age was referred to Kagoshima University showing anemia. Blood tests revealed the presence of anemia, thrombocytopenia, hyperproteinemia, polyclonal gammopathy, hypoalbuminemia, and elevated creatine kinase and alkaline phosphatase activities. In addition, capsule-like organisms were detected in the cytoplasm of approximately 50% of neutrophils in blood smears. H. canis infection was confirmed by polymerase chain reaction and DNA sequencing analyses. Amplified DNA fragments revealed 100% identity to the 18S ribosomal RNA gene of H. canis. The clinical symptoms improved after the administration of antibiotics. Hepatozoonosis in dogs is rare, but veterinarians should be alert to its possible acute onset. Hepatozoon is a genus of protozoa belonging to phylum Apicomplexa. Dogs are known to be susceptible to infection by both Hepatozoon canis and H. americanum, but only the former has been confirmed in Japan [3,10,[15][16][17][18][19]21]. Hepatozoon parasites are transmitted by ticks, and the infection becomes established after the ingestion of infected ticks [4]. Ingested parasites enter the blood or lymphatic vessels through the intestinal mucosa and reach the bone marrow. Most H. canis infected dogs show clinical latency, and several factors, such as co-infection with other infectious agents and immunosuppression, are thought to be important factors promoting the acute onset of hepatozoonosis [2,4,6,9,20]. A few reports have described the acute onset of H. canis infection and its epidemiological distribution in Japan [10,[15][16][17][18][19]. The clinical symptoms associated with severe H. canis infection are anemia, fever, lethargy and weight loss [5]. Ataxia and lameness are also sometimes observed in Hepatozoon-infected dogs, due to the development of osteomyelitis. Characteristic hematological abnormalities in H. canis infection include non-regenerative anemia, thrombocytopenia, neutrophilia, hyperproteinemia, hypoalbuminemia, polyclonal gammopathy, and increased serum creatine kinase (CK) and alkaline phosphatase (ALP) concentrations [5][6][7]. The detection of capsule-like gamonts in the cytoplasm of neutrophils in blood smears is helpful for diagnosing hepatozoonosis. Other diagnostic techniques, such as polymerase chain reaction (PCR) for Hepatozoonderived genomic DNA or enzyme linked immunosorbent assay for anti-Hepatozoon antibodies, are also potentially useful [8,10,11] A stray female beagle dog of unknown age was cared for by a temporary owner in the suburbs of Kagoshima, Japan. The owner took her to a private veterinary hospital for a health check. Severe dehydration, numerous ticks on the skin and pale mucus membranes were detected by physical examination (day 1). Fecal examination revealed roundworm, whipworm and tapeworm infections. Blood examination demonstrated the presence of anemia [packed cell volume (PCV), 17%], leukocytosis (44,900/l) and mild thrombocytopen...

Occurrence of Hepatozoon sp. in dogs in the urban area originating from a municipality in southeastern Brazil

“…Symptoms may vary from asymptomatic cases (70-80% of infected animals) to grave and potentially fatal signs (Mundim et al, 2002;Baneth et al, 2003) such as intermittent or persistent fever, muscle hyperesthesia, lethargy, difficulties of locomotion, eye and nose discharge, diarrhea -sometimes bloody, anemia, weight loss and terminal anorexia (Allen et al, 2008;Mundim et al, 2008;Little et al, 2009;Sakuma et al, 2009).…”

Epidemiological Survey of Tick-Borne Protozoal Infection in Iriomote Cats and Tsushima Leopard Cats in Japan

“…In addition, there may be an influence of infectious diseases other than H. felis on host susceptibility. Acute onset of hepatozoonosis in domestic dogs is often observed in cases of co-infection with organisms, such as Babesia, internal parasites, Dirofilaria and others [10,21,23]. Since little is currently known about infectious diseases in Japanese wildcats, a wide range of potential pathogens should be evaluated to determine their contribution to the development of Hepatozoon parasitemia in these animals.…”

Failure of combination therapy with imidocarb dipropionate and toltrazuril to clear Hepatozoon canis infection in dogs

“…The clinical symptoms associated with severe H. canis infection (HCI) are fever, emaciation, anorexia, weight loss, pale mucous membranes and lymphadenopathy (Craig 1990;Baneth and Weigler, 1997;Gavazza et al 2003;Mundim et al 2008). Ataxia and lameness are also sometimes observed in Hepatozooninfected dogs due to the development of osteomyelitis (Sakuma et al 2009). The values of haemato-biochemical parameters vary widely.…”