Hide G, Angus S D, Holmes P H, Maudlin I, Welburn S C
Department of Biological Sciences, University of Salford, United Kingdom.
Exp Parasitol. 1998 May;89(1):21-9. doi: 10.1006/expr.1998.4265.
Human sleeping sickness in East Africa is characterized by periods of long-term endemicity interspersed with short-term epidemics. The factors generating these huge changes are largely uncharacterized but probably reflect complex interactions among socioeconomic factors, ecological factors, and the movement and diversity of trypanosome strains. To investigate the role of trypanosome strains in the generation of these epidemics, we addressed two important questions. (1) Are the trypanosome strains circulating within a focus the same during times of endemicity and during an epidemic? (2) How stable are trypanosome strains within a single animal reservoir host? Using restriction fragment length polymorphism analysis of repetitive DNA, we have examined the relationship between Trypanosoma brucei isolates, taken from the Busoga focus of human sleeping sickness, during an endemic period (Busia, Kenya, 1993-1994) and stocks isolated during an epidemic period (Tororo, Uganda, 1988-1990). We show that similar strains, including human infective strains, are circulating in domestic cattle (the most significant animal reservoir) in both epidemic and endemic areas of the Busoga focus. Furthermore, we show the important finding that individual animals harbor the same genotype of T. brucei for a period of time and may be clonal for a given parasite strain.
东非的人类昏睡病的特点是长期地方性流行期与短期流行期相互穿插。引发这些巨大变化的因素在很大程度上尚不明确，但可能反映了社会经济因素、生态因素以及锥虫菌株的迁移和多样性之间的复杂相互作用。为了研究锥虫菌株在这些流行病发生过程中的作用，我们探讨了两个重要问题。（1）在地方性流行期和流行期，在一个疫源地内传播的锥虫菌株是否相同？（2）在单个动物储存宿主内，锥虫菌株有多稳定？利用重复DNA的限制性片段长度多态性分析，我们研究了取自人类昏睡病布索加疫源地的布氏锥虫分离株之间的关系，这些分离株分别来自一个地方性流行期（肯尼亚布西亚，1993 - 1994年）和一个流行期（乌干达托罗罗，1988 - 1990年）分离的菌株。我们发现，在布索加疫源地的流行区和地方性流行区的家牛（最重要的动物储存宿主）中，都有相似的菌株在传播，包括人类感染性菌株。此外，我们还得出了一个重要发现，即个体动物在一段时间内携带相同基因型的布氏锥虫，并且对于给定的寄生虫菌株可能是克隆性的。
