Kubi C, Van den Abbeele J, Dorny P, Coosemans M, Marcotty T, Van den Bossche P
Department of Animal Health, Institute of Tropical Medicine, Antwerp, Belgium.
J Med Entomol. 2005 Nov;42(6):1035-8. doi: 10.1093/jmedent/42.6.1035.
The epidemiology of human and animal trypanosomiasis is determined to a large extent by the number of infected tsetse flies in a specific area. In the field, a substantial proportion of infected flies carry mixed trypanosome infections. The way in which these tsetse flies acquire a mixed infection is not fully understood. In particular, the susceptibility of tsetse flies to sequential infection with trypanosomes is not well understood. Accordingly, laboratory studies were made of the effects of age and prior infection on the probability of Glossina morsitans morsitans (Westwood) developing an infection of Trypanosoma congolense and Trypanosoma brucei brucei after feeding on infected mice. Results of these experiments clearly showed that 20-30-d-old G. m. morsitans can still pick up and develop a mature infection in the mouthparts/hypopharynx for T. congolense or in the salivary glands for T. b. brucei. However, their ability to acquire infection was significantly lower compared with teneral flies. Furthermore, 20-30-d-old flies that already carry a mature T. congolense or T. b. brucei infection remained at least as susceptible to a secondary trypanosome infection compared with noninfected flies of the same age. The immunological and epidemiological repercussions of those findings are discussed.
人类和动物锥虫病的流行病学在很大程度上取决于特定区域内感染采采蝇的数量。在野外，相当一部分受感染的采采蝇携带混合锥虫感染。这些采采蝇获得混合感染的方式尚未完全了解。特别是，采采蝇对锥虫连续感染的易感性尚未得到很好的理解。因此，进行了实验室研究，以探讨年龄和先前感染对冈比亚采采蝇（Westwood）在取食感染小鼠后感染刚果锥虫和布氏布氏锥虫的概率的影响。这些实验结果清楚地表明，20 - 30日龄的冈比亚采采蝇仍能在口器/下咽中感染刚果锥虫并发育成成熟感染，或在唾液腺中感染布氏布氏锥虫。然而，与刚羽化的采采蝇相比，它们获得感染的能力显著较低。此外，与同龄未感染的采采蝇相比，已经携带成熟刚果锥虫或布氏布氏锥虫感染的20 - 30日龄采采蝇对二次锥虫感染的易感性至少相同。文中讨论了这些发现的免疫学和流行病学影响。
