Theileriosis in six dogs in South Africa and its potential clinical significance

Abstract

Theileriosis is a tick-borne disease caused by a piroplasma of the genus Theileria that can causeanaemia and thrombocytopenia. Its clinical importance for dogs’ remains poorly understood,as only some develop clinical signs. In this study, physical and laboratory findings, treatment and outcomes of six client-owned diseased dogs presented at the Onderstepoort Veterinary Academic Hospital are described retrospectively. In the dogs, Theileria species (n = 4)and Theileria equi (n = 2) were detected by a polymerase chain reaction (PCR)-reverse blothybridisation assay in blood samples, whilst PCR for Babesia, Anaplasma and Ehrlichia were negative. The most common physical findings were pale mucous membranes (five out of six dogs), bleeding tendencies (five out of six dogs) and lethargy (three out of six dogs). All dogs were thrombocytopenic [median 59.5 x 109/L (range 13–199)] and five out of six dogs were anaemic [median haematocrit 18% (range 5–32)]. Bone marrow core biopsies performed in two dogs showed myelofibrosis. Theileriosis was treated with imidocarb dipropionate and the suspected secondary immune-mediated haematological disorders with prednisolone and azathioprine. Five dogs achieved clinical cure and post-treatment PCR performed in three out of five dogs confirmed absence of circulating parasitaemia. An immune-mediated response to Theileria species is thought to result in anaemia and/or thrombocytopenia in diseased dogs with theileriosis. A bleeding tendency, most likely secondary to thrombocytopenia and/or thrombocytopathy, was the most significant clinical finding in these cases. The link between thrombocytopenia, anaemia and myelofibrosis in theileriosis requires further investigation and theileriosis should be considered a differential diagnosis for dogs presenting with anaemia and/or thrombocytopenia in endemic tick-borne disease areas.

Molecular Detection ofTheileriaspp. in Livestock on Five Caribbean Islands

“…On the other hand, T. equi is a well-recognized cause of equine piroplasmosis [ 25 ], an important disease of horses which has been recognized and studied in the Caribbean [ 14 – 16 ]. The organism has also been found in dogs in Spain [ 26 ], South Africa [ 27 ], and Nigeria [ 28 ] with some having clinical signs that responded to appropriate treatment [ 29 ]. Our finding that T. equi also occurs in domestic ruminants further expands the host range of the organism.…”

ACVIM consensus statement on the diagnosis of immune‐mediated hemolytic anemia in dogs and cats

“…Overall, 66 manuscripts were reviewed . The IME values were calculated for 27 infectious agents or types of infection (Figures ), but could not be calculated for many infectious agents either because of the way data were summarized (eg, the number of individual patients with IMHA and an infection could not be discerned) or because an individual patient with IMHA had >1 comorbidity (Supporting Information S2).…”

“…A retrospective case series of dogs naturally infected with Theileria spp. developed IMHA . Dogs were treated with combined immunosuppression and imidocarb dipropionate.…”

“…Borrelia spp., hemotropic Mycoplasma spp., Bartonella spp., and Leishmania infantum ), non‐vector‐borne protozoal pathogens (including Neospora caninum ), and other bacterial infections induce IMHA was negligible to low (Figure ), or could not be quantified based on how results were reported (Supporting Information S5). For some of these organisms, such as Leishmania spp., D. immitis , and Bartonella spp., Coombs' test‐positive anemia is observed commonly with infection . Therefore, from a clinical perspective, it is still important to eliminate infection with these agents in a dog in which IMHA is a differential diagnosis.…”

Tick-borne Diseases (Borreliosis, Anaplasmosis, Babesiosis) in German and Austrian Dogs: Status quo and Review of Distribution, Transmission, Clinical Findings, Diagnostics and Prophylaxis

“…Babesia species (DNA detection by means of conventional PCR technique) were detected in 2.4 % of these samples (Hirsch and Pantchev 2008). However, canine babesiosis is increasingly endemic in both Germany (Barutzki et al 2007) and Switzerland Table 3 Current Babesia / Theileria species in the dog (small forms): at least five genetically different species (according to Zahler et al 2000a,b;Beck et al 2009;Irwin 2009;Birkenheuer 2012;Falkenö et al 2013;Najm et al 2014;Duscher et al 2014;Gallusova et al 2014;Rosa et al 2014;Baneth et al 2015;Farkas et al 2015). (Schaarschmidt et al 2013).…”