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Heartwater (also known as cowdriosis, nintas and ehrlichiosis) is a tick-borne rickettsial disease of domestic and wild ruminants. It is caused by ''Ehrlichia ruminantium'' (formerly ''Cowdria ruminantium'')〔http://www.ebi.ac.uk/2can/genomes/bacteria/Ehrlichia_ruminantium.html〕 - an intracellular gram-negative coccal bacterium (also referred to as ''Rickettsia ruminantium''). The disease is spread by bont ticks, which are members of the genus ''Amblyomma''. Affected mammals include cattle, sheep, goats, antelope, and buffalo, but the disease has the biggest economic impact on cattle production in affected areas. The disease’s name is derived from the fact that fluid can collect around the heart or in the lungs of infected animals.〔 The disease is common in sub-Saharan Africa and some of the West Indian islands. It was first identified in sheep in South Africa in the 1830s, and had reached the Caribbean by 1980.〔 The ticks which carry the disease occur in Africa and the Caribbean, and feed on a wide variety of vertebrate hosts. In the Caribbean, at least, the cattle egret has been implicated in the spread of heartwater since it colonized the islands in the 1950s. Animals often acquire the disease when moved on to heartwater infected grazing. Cowdriosis is notifiable to the World Organisation for Animal Health. ==Clinical signs== Clinical disease is more common in young animals and non-native breeds. The clinical signs of disease are caused by an increased vascular permeability and consequent oedema and hypovolaemia. The symptoms include neurological signs such as tremors and head pressing, respiratory signs such as coughing and nasal discharge, and systemic signs such as fever and loss of appetite. Physical examination may reveal petechiae of the mucous membranes, tachycardia and muffled heart sounds. Cowdriosis can also cause reproductive and gastrointestinal disease. It is frequently fatal. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ehrlichia ruminantium」の詳細全文を読む スポンサード リンク
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