Reiter P, Cordellier R, Ouma J O, Cropp C B, Savage H M, Sanders E J, Marfin A A, Tukei P M, Agata N N, Gitau L G, Rapuoda B A, Gubler D J
Dengue Branch, Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, San Juan, Puerto Rico 00921-3200, USA.
Am J Trop Med Hyg. 1998 Oct;59(4):650-6. doi: 10.4269/ajtmh.1998.59.650.
The first recorded outbreak of yellow fever in Kenya occurred from mid-1992 through March 1993 in the south Kerio Valley, Rift Valley Province. We conducted entomologic studies in February-March 1993 to identify the likely vectors and determine the potential for transmission in the surrounding rural and urban areas. Mosquitoes were collected by landing capture and processed for virus isolation. Container surveys were conducted around human habitation. Transmission was mainly in woodland of varying density, at altitudes of 1,300-1,800 m. The abundance of Aedes africanus in this biotope, and two isolations of virus from pools of this species, suggest that it was the principal vector in the main period of the outbreak. A third isolate was made from a pool of Ae. keniensis, a little-known species that was collected in the same biotope. Other known yellow fever vectors that were collected in the arid parts of the valley may have been involved at an earlier stage of the epidemic. Vervet monkeys and baboons were present in the outbreak area. Peridomestic mosquito species were absent but abundant at urban sites outside the outbreak area. The entomologic and epidemiologic evidence indicate that this was a sylvatic outbreak in which human cases were directly linked to the epizootic and were independent of other human cases. The region of the Kerio Valley is probably subject to recurrent wandering epizootics of yellow fever, although previous episodes of scattered human infection have gone unrecorded. The risk that the disease could emerge as an urban problem in Kenya should not be ignored.
肯尼亚首次有记录的黄热病疫情于1992年年中至1993年3月发生在裂谷省的南凯里奥山谷。1993年2月至3月，我们开展了昆虫学研究，以确定可能的病媒，并确定周边农村和城市地区的传播潜力。通过人诱捕法收集蚊子并进行病毒分离处理。在人类居住地周围进行容器调查。传播主要发生在海拔1300 - 1800米、密度各异的林地。该生物群落中非洲伊蚊数量众多，且从该物种的样本中分离出两株病毒，这表明它是疫情主要阶段的主要病媒。第三株病毒分离株来自肯尼亚伊蚊的样本，该物种鲜为人知，是在同一生物群落中采集到的。在山谷干旱地区收集到的其他已知黄热病病媒可能在疫情早期就已涉及。黑长尾猴和狒狒出现在疫情爆发地区。家栖周边地区的蚊虫种类在疫情爆发地区不存在，但在该地区以外的城市地区数量众多。昆虫学和流行病学证据表明，这是一次丛林型疫情，其中人类病例与动物流行病直接相关，且与其他人类病例无关。凯里奥山谷地区可能易受黄热病反复出现的游荡性动物流行病影响，尽管此前零星的人类感染事件未被记录。该病在肯尼亚演变成城市问题的风险不容忽视。
