Cowdria ruminantium, causal rickettsia of heartwater in\ud ruminants, was until recently only known to occur in Africa. It\ud is transmitted by Amblyomma ticks.\ud Amblyomma variegatum, one of its African vectors, was introduced\ud into the Caribbean area with cattle from Senegal about 1830. Before\ud 1900 only Guadeloupe and Antigua were known to be infested.\ud Martinique was invaded as late as 1948. The spread of the tick\ud accelerated afterwards, especially during the last decade. It has\ud now been found on Guadeloupe (Grande Terre and Basse Terre),\ud Antigua, Martinique, St. Croix, Puerto Rico, St. Lucia, Nevis,\ud St. Kitts, St. Maarten/St. Martin, Vieques, Anguilla, Marie-\ud Galante and La Désirade. All of these islands are probably still\ud infested today, except possibly St. Croix and La Désirade.\ud The existence of heartwater on Guadeloupe has been suspected\ud since 1966, and was at last confirmed in 1980, having almost\ud certainly been present for a century and a half. A strain of\ud C.ruminantium was isolated in 1982. Retrospectively, a bovine\ud disease with symptoms like those of heartwater has been known on\ud the island since 1932. Two other African infections of which A.\ud variegatum is a vector, Theileria mutans and T.velifera, also occur\ud in cattle on Guadeloupe.\ud Heartwater has so far been diagnosed only in Guadeloupe and in\ud near-by Marie-Galante. An investigation for its presence has been\ud started on other islands where A.variegatum occurs. However, it\ud has been shown that the American tick Amblyornma maculatum is a\ud good experimental vector, and that A.cajennense can also transmit\ud C.ruminantium, but probably not very efficiently. If the agent\ud can adapt to these and other American Amblyomma species, it could\ud spread to large areas in the western hemisphere, well outside those where the strictly tropical A.variegatum would find a\ud suitable habitat.\ud An assessment of the extent of this serious threat to the livestock\ud industry of the Americas should be followed by urgent action\ud while there is still hope of removing the danger as long as the\ud disease remains limited to a few of the smaller islands.\ud Apart from a survey of the distribution of the disease and\ud Amblyomma ticks, information is needed on animal movements between\ud islands, on migration routes of birds (hosts of immature stages),\ud animal husbandry methods, and species and numbers of domestic\ud animals, as well as wild hosts which may interfere with tick\ud eradication.\ud Severe dermatophilosis (cutaneous streptothricosis) of cattle\ud appears to be closely linked with the presence of A.variegatum and\ud causes high losses on the infested islands. This will make it\ud easier to obtain the collaboration of livestock owners and authorities\ud for eradication campaigns, even on islands where heartwater\ud does not (yet) occur
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