Wilson M L, Chapman L E, Hall D B, Dykstra E A, Ba K, Zeller H G, Traore-Lamizana M, Hervy J P, Linthicum K J, Peters C J
Institut Pasteur, Dakar, Senegal.
Am J Trop Med Hyg. 1994 Jun;50(6):663-75. doi: 10.4269/ajtmh.1994.50.663.
To investigate past infection in and transmission of Rift Valley fever (RVF) virus to humans within an endemic focus, we undertook a retrospective cohort study of the seminomadic Peul people living in sub-Saharan northcentral Senegal. Residents of the rural settlement of Yonofere five years of age or older were studied during February-May 1989. Anti-RVF virus IgG was found in blood samples of 22.3% of 273 persons who responded to a standard questionnaire; none had IgM antibodies. Seropositivity was similar for males (25.4%) and females (21.1%), increased markedly with age for both sexes, and varied considerably among compounds (groups of huts) (0-37.5%). Risk factors for past RVF virus infection were nursing sick people, assisting animals during abortions/births, and treating sick animals. In all age groups, odds ratios (ORs) for RVF viral antibody among females who reported treating sick animals were three to six times greater than for those who did not. The ORs for males who reported assisting with animal births/abortions and nursing sick people were approximately five times those for males who did not. Serologic prevalence of RVF viral antibody among sheep averaged 30.1% overall (0.8% IgM), but varied among compounds (0-66.7%) in a manner different from that of humans. The seasonal abundance and relative density of potential mosquito vectors were estimated by monthly samples captured in Centers for Disease Control and Prevention-type traps. Mosquito abundance varied seasonally with rainfall (> 90% captures during four months). Species diversity was large (28 spp.), dominated by Aedes and Culex. Rift Valley fever virus was not isolated from 142 pools of 2,956 unengorged mosquitoes tested, although three other arboviruses were found. Results indicate that RVF is endemic in this region, people are at considerable risk of infection, and that a heretofore unrecognized mode of human infection under nonepizootic conditions may be transmission via contact with infected animals or humans.
为调查裂谷热（RVF）病毒在一个地方性疫源地内既往在人群中的感染情况及其向人类的传播，我们对生活在塞内加尔中北部撒哈拉以南地区的半游牧Peul人进行了一项回顾性队列研究。1989年2月至5月期间，对约诺费雷农村定居点5岁及以上的居民进行了研究。在对一份标准问卷作出回应的273人中，22.3%的人的血液样本中发现了抗RVF病毒IgG；无人有IgM抗体。男性（25.4%）和女性（21.1%）的血清阳性率相似，两性的血清阳性率均随年龄显著增加，且在不同的居住群落（茅屋群）中差异很大（0 - 37.5%）。既往RVF病毒感染的危险因素包括护理病人、在动物流产/分娩时协助以及治疗患病动物。在所有年龄组中，报告治疗患病动物的女性中RVF病毒抗体的比值比（OR）是未报告者的三至六倍。报告协助动物分娩/流产和护理病人的男性的OR约为未报告者的五倍。绵羊中RVF病毒抗体的血清学流行率总体平均为30.1%（IgM为0.8%），但在不同居住群落中有所不同（0 - 66.7%），其方式与人类不同。通过在疾病控制和预防中心型诱捕器中每月采集的样本估计了潜在蚊媒的季节性丰度和相对密度。蚊虫丰度随降雨季节性变化（四个月内捕获量超过90%）。物种多样性很大（28种），以伊蚊和库蚊为主。在对2956只未吸血的蚊子进行检测的142组样本中未分离到裂谷热病毒，不过发现了另外三种虫媒病毒。结果表明，RVF在该地区为地方性流行，人们面临相当大的感染风险，并且在非动物流行病条件下，一种迄今未被认识的人类感染模式可能是通过与受感染的动物或人类接触传播。
