Fatal heartwater in a captive sitatunga

Natural Ehrlichia ruminantium infection in two captive Arabian tahrs (Arabitragus jayakari) in Oman

This study was investigated the cause of death of two captive adult Arabian tahrs (Arabitragus jayakari) died within 2-3 days after onset of fever and neurologic signs in a private farm in northern Batinah Region of Oman. Blood counting revealed leukocytosis attributed to neutrophilia and serum chemistry showed hypoproteinemia, increased creatine kinase and BUN. Upon autopsy, the animals exhibited mild ascites and hydrothorax, prominent hydropericardium, with large pale-yellow clear fluid coagulum, prominent epicardial petechiation, as well as severe pulmonary edema associated with frothy fluid in airways. Brain edema with congestion of meningeal and parenchymal vessels was prominent. Histopathology revealed severe congestion and edema of both lung and brain as well as cardiac myopathy. Ehrlichia ruminantium colonies (the causative organism of cowdriosis; OIE-listed disease) were demonstrated in the capillary endothelium of fresh brain squash and lung macrophages. This is the first report of natural E. ruminantium infection in Arabian tahr, the highly endangered species, based on typical clinical signs of acute cowdriosis and demonstration of E. ruminantium colonies in the brain capillary endothelial cells.

Ehrlichia ruminantium infection (heartwater) in wild animals

Several wild animal species have been implicated as hosts of Ehrlichia ruminantium (formerly Cowdria ruminantium), the rickettsial agent causing heartwater, a fatal disease of domestic ruminants in sub-Saharan Africa and eastern Caribbean. However, evidence for infection in most wild species is inconclusive because of inadequate diagnostic techniques. Infection has been proven only in 12 African ruminants, three non-African ruminants and two African rodents. A subclinical carrier state occurs in eight of the African ruminant species. Further studies on E. ruminantium infection in wild animal species are needed in order to determine the host range of this pathogen accurately. The host range of Ehrlichia ruminantium in wildlife is reviewed here and the role played by these species in the epidemiology and spread of heartwater is discussed.