CLINICAL DISEASE ASSOCIATED WITH ANAPLASMA PHAGOCYTOPHILUM INFECTION IN CAPTIVE PRZEWALSKI'S HORSES (EQUUS FERUS PRZEWALSKII)

Abstract

Anaplasma phagocytophilum is a tick-borne pathogen of domestic horses and the causative agent of equine granulocytic anaplasmosis. This case series describes three confirmed cases of clinical anaplasmosis, and a fourth case of presumptive anaplasmosis in Przewalski's horses ( Equus ferus przewalskii) housed at the Smithsonian Conservation Biology Institute from 2008 to 2014. Clinical signs varied among individuals with affected horses exhibiting lethargy, weakness, pyrexia, hypophagia, reluctance to move, or ataxia. Anaplasmosis cases were confirmed with a combination of identification of neutrophilic inclusions (morulae) on peripheral blood smear, positive polymerase chain reaction (PCR) testing of whole blood, or convalescent titers. All animals recovered after antimicrobial therapy with oxytetracycline. Diagnosis should be made by a combination of clinical signs plus identification of morulae or positive A. phagocytophilum PCR. Treatment is curative using oxytetracyline intramuscularly or intravenously followed by daily therapy with oxytetracyline or minocycline for 14-30 days. The authors recommend that A. phagocytophilum infection be included on any differential list for Przewalski's horses presenting with fever or ataxia within or near an enzootic area.

Role of Zoo-Housed Animals in the Ecology of Ticks and Tick-Borne Pathogens—A Review

“…and Aponomma spp. [23,26,28,31,127,128]. Various, and often nonspecific, clinical symptoms are associated with Rickettsiales infections in animals (anorexia, depression, dehydration, fever, lethargy, lymphadenopathy and ataxia) [23,26,28,129].…”

“…[23,26,28,31,127,128]. Various, and often nonspecific, clinical symptoms are associated with Rickettsiales infections in animals (anorexia, depression, dehydration, fever, lethargy, lymphadenopathy and ataxia) [23,26,28,129]. Acute infections with bacteria from the Anaplasmataceae family (Anaplasma, Ehrlichia) can be detected using blood smears, showing a characteristic "morulae" (mulberry-shaped microcolonies) located in the host cell cytoplasm [26,28,128].…”

“…In the USA, several cases were also reported for anaplasmosis (A. phagocytophilum), in four captive Przewalski's horses (E. przewalskii) from Virginia [26]. E. chaffeensis was found in five ring-tailed lemurs (Lemur catta) and one ruffed lemur (Varecia variegate rubra) in the Duke Lemur Center in North Carolina (USA; [28]).…”

“…Indeed, several indigenous tick species have been reported in the areas of zoos, wildlife parks or farms worldwide. In the United States of America (USA) and Canada, Ixodes pacificus [23], Ixodes scapularis [24][25][26], Amblyomma americanum, Rhipicephalus sanguineus and Dermacentor variabilis [25,27,28] have been reported to exist in such captive exotic animal facilities. In Southern America, Brazilian zoo-animal infection cases have been connected to the following tick species of the Amblyomma and Rhipicephalus genera: A. dubitatum, A. calcaratum, A. aureolatum, A. sculptum or R. sanguineus in Southeastern regions of Brazil [21].…”

Türkiye’de Atlarda anti-Anaplasma phagocytophilum Antikorlarının İlk Tespiti

“…Also, infections of A. phagocytophilum have been reported in neighbouring countries of Turkey such as Greece [17] , Bulgaria [18] and Iran [19] . Many available studies conducted on A. phagocytophilum infection on horses were present [20][21][22][23][24][25] . In Turkey, although studies conducted on A. phagocytophilum including a wide variety of animal species such as cattle, sheep, dog, mice, besides human [26][27][28][29][30][31][32] were exist, but there is no report about equine anaplasmosis.…”