Drawing of Amblyomma pomposum male (By Drawing of Amblyomma pomposum female (By courtesy of JB Walker, OVI, Onderstepoort) courtesy of JB Walker, OVI, Onderstepoort) Distribution Heartwater occurs wherever ticks capable of transmitting the organism are present. The endemic area encompasses most of sub-Saharan Africa, including the islands of Madagascar, Sao Tomé, Réunion, Mauritius, and Zanzibar. The disease is absent from the Kalahari Desert and dry coastal areas of Namibia and South Africa. Heartwater also occurs on the French Antillean islands of Guadeloupe and Antigua in the Caribbean Sea. Distribution of various Amblyomma species in Africa Hosts/Reservoirs Amblyomma hebraeum ticks feeding on E. ruminantium-infected sheep have been shown to become infected during a period from two days after the commencement of the temperature reaction to two days after the animals have been treated for heartwater. The transmission of E. ruminantium by A. variegatum feeding on Creole goats in Guadeloupe is apparently somewhat different. Ostensibly healthy ruminant hosts have been shown to remain infective to ticks for long periods, at least 361 days in cattle and 11 months in Creole goats. In the latter case the carrier status could not be detected permanently during the 11-month period, demonstrating the danger which could be posed by the movement of apparently negative carrier animals to areas free from the disease. Heartwater originated in Africa and African wild ruminants probably constitute the natural reservoir of the disease. It appears that the most important natural ruminant reservoirs in southern Africa may be African buffalo and eland. Although blesbok and black wildebeest are potential reservoir hosts, the natural habitat of these two antelope species is unsuitable for A. hebraeum, so it is unlikely that they are important reservoirs under natural conditions, except where these hosts are translocated to heartwater-endemic areas.
Drawing of Amblyomma pomposum male (By courtesy of JB Walker, OVI, Onderstepoort) Drawing of Amblyomma pomposum female (By courtesy of JB Walker, OVI, Onderstepoort) Distribution Heartwater occurs wherever ticks capable of transmitting the organism are present. The endemic area encompasses most of sub-Saharan Africa, including the islands of Madagascar, Sao Tomé, Réunion, Mauritius, and Zanzibar. The disease is absent from the Kalahari Desert and dry coastal areas of Namibia and South Africa. Heartwater also occurs on the French Antillean islands of Guadeloupe and Antigua in the Caribbean Sea. Distribution of various Amblyomma species in Africa Hosts/Reservoirs Amblyomma hebraeum ticks feeding on E. ruminantium-infected sheep have been shown to become infected during a period from two days after the commencement of the temperature reaction to two days after the animals have been treated for heartwater. The transmission of E. ruminantium by A. variegatum feeding on Creole goats in Guadeloupe is apparently somewhat different. Ostensibly healthy ruminant hosts have been shown to remain infective to ticks for long periods, at least 361 days in cattle and 11 months in Creole goats. In the latter case the carrier status could not be detected permanently during the 11-month period, demonstrating the danger which could be posed by the movement of apparently negative carrier animals to areas free from the disease. Heartwater originated in Africa and African wild ruminants probably constitute the natural reservoir of the disease. It appears that the most important natural ruminant reservoirs in southern Africa may be African buffalo and eland. Although blesbok and black wildebeest are potential reservoir hosts, the natural habitat of these two antelope species is unsuitable for A. hebraeum, so it is unlikely that they are important reservoirs under natural conditions, except where these hosts are translocated to heartwater-endemic areas.