Heartwater: An overview of the clinical signs
Heartwater (also known as cowdriosis, nintas, and ehrlichiosis) is a tick-borne rickettsial disease. Heartwater is an infectious, noncontagious, tick-borne disease of domestic and wild ruminants, including cattle, sheep, goats, antelope and buffalo.
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| Heartwater disease: ehrlichiosis |
The disease is caused by an intracellular rickettsial parasite, Cowdria ruminantium, and is transmitted by a number of species of ticks in the genus Amblyomma.
𝗔𝗳𝗳𝗲𝗰𝘁𝗲𝗱 𝘀𝗽𝗲𝗰𝗶𝗲𝘀
✓Cattle
✓Buffalo
✓Sheep
✓G𝗼𝗮𝘁
𝗘𝘁𝗶𝗼𝗹𝗼𝗴𝘆
It is caused by Ehrlichia ruminantium (formerly Cowdria ruminantium) - 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
𝗖𝗹𝗶𝗻𝗶𝗰𝗮𝗹 𝘀𝗶𝗴𝗻𝘀
The acute form of heartwater is the most commonly observed presentation of the disease. A sudden high fever (107° F) is followed by loss of appetite, depression and respiratory problems. Animals may initially have an increased respiratory rate, followed within a few days by severe respiratory distress.
➪by an increased vascular permeability and consequent oedema and hypovolemia.
➪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.
Amblyomma hebraeum, a vector of heartwater disease
𝗗𝗶𝗮𝗴𝗻𝗼𝘀𝗶𝘀
To definitively diagnose the disease, C. ruminantium must be demonstrated either in preparations of the hippocampus under Giemsa staining or by histopathology of brain or kidney.
𝗧𝗿𝗲𝗮𝘁𝗺𝗲𝗻𝘁 𝗮𝗻𝗱 𝗰𝗼𝗻𝘁𝗿𝗼𝗹
✓𝗔nimals may be treated with sulfonamides and tetracyclines.
✓A live blood vaccine is available for protection of young stock, but animals may require treatment for the disease after vaccination.
✓Ectoparasiticides, used as dips, can be used to reduce exposure the animals exposure to bont ticks.