Camus E, Barré N
IEMVT-CIRAD, Pointe-à-Pitre, Guadeloupe, French West Indies.
Ann N Y Acad Sci. 1992 Jun 16;653:33-41. doi: 10.1111/j.1749-6632.1992.tb19627.x.
Heartwater has been diagnosed in Guadeloupe, Marie-Galante, and Antigua; it induces important losses among goats and European or cross-bred cattle when local zebu creole are highly resistant to infection. Amblyomma variegatum is the vector of the disease in the Caribbean. The tick strain of Martinique, occurring in that island that has apparently been disease-free since 1948, has not lost its ability to experimentally transmit the disease. In Guadeloupe 97% of nymphs and nearly 100% of adults feed on cattle and goats. Some immature ticks (4.5%) feed on wildlife, including birds that may be involved in the spread of infected ticks. Only 1 to 4% of adult ticks are infected and only a proportion of infected ticks are really infective: 53%, 9%, and 50% of nymphs, males, and females, respectively. Nymphs play the major role in the transmission: they are more numerous than adults and engorge faster. Infected ticks have the same maximum longevity as noninfected ticks, that is, 18 months for nymphs and nearly 23 months for adults. Cowdria is not transmitted immediately after tick fixation but after a delay of 2-3 days for nymphs and 4 days for adults. The disease is more often fatal when transmitted by tick biting rather than by needle transmission. The daily infection rate that summarizes all the parameters is very low (0.14% and 0.20% for goats and cattle, respectively), resulting in an unstable epidemiological situation. The transmission of Cowdria by A. variegatum in Guadeloupe shows significant differences compared with the transmission by A. hebraeum in Africa.
瓜德罗普岛、玛丽 - 加朗特岛和安提瓜岛已确诊有牛心水病；当当地的泽布克里奥尔牛对感染具有高度抗性时，该病会在山羊以及欧洲或杂交牛中造成重大损失。变异革蜱是加勒比地区这种疾病的传播媒介。马提尼克岛的蜱虫菌株存在于自1948年以来显然无病的该岛屿上，并未丧失通过实验传播该病的能力。在瓜德罗普岛，97%的若蜱和近100%的成蜱以牛和山羊为食。一些未成熟蜱（4.5%）以野生动物为食，包括可能参与传播感染蜱的鸟类。只有1%至4%的成年蜱被感染，且只有一部分被感染的蜱具有真正的传染性：若蜱、雄蜱和雌蜱的感染率分别为53%、9%和50%。若蜱在传播中起主要作用：它们数量比成蜱多，吸血速度也更快。感染蜱的最长寿命与未感染蜱相同，即若蜱为18个月，成年蜱近23个月。考德里氏体不是在蜱附着后立即传播，而是若蜱延迟2 - 3天、成年蜱延迟4天后传播。通过蜱叮咬传播的疾病比通过针头传播更常致命。总结所有参数的每日感染率非常低（山羊和牛分别为0.14%和0.20%），导致流行病学状况不稳定。瓜德罗普岛变异革蜱传播考德里氏体与非洲希伯来革蜱的传播相比存在显著差异。
