Desquesnes M, Bengaly Z, Millogo L, Meme Y, Sakande H
Centre de Coopération Internationale en Recherche Agronomique pour le Développement-Elevage et Médecine Vétérinaire Tropicale , B.P. 5035, 34032 Montpellier Cedex 1, France.
Ann Trop Med Parasitol. 2001 Mar;95(2):141-55. doi: 10.1080/00034980120050251.
In Africa, the main pathogenic trypanosomes of livestock are Trypanosoma vivax, T. congolense and T. brucei. The geographical distributions and hosts of these three species are very similar. As they differ markedly in pathogenicity and epidemiology, however, a species-specific serological test for infection would be very useful for epidemiological studies. The antibody-ELISA (Ab-ELISA) that have been developed for detecting the Trypanosoma spp. most commonly infecting livestock give satisfactory sensitivity and genus specificity. Unfortunately, they are not species-specific because of strong cross-reactions between the pathogenic Trypanosoma spp. In the present study, carried out in Burkina Faso, the results of standardized Ab-ELISA for T. vivax, T. brucei or T. congolense were compared using 1288 plasma samples from sheep experimentally infected with T. vivax, T. evansi and/or T. congolense. If the results were interpreted, as usual, only using a positivity threshold (PT), the strong cross-reactions observed led to a mean species-specificity of < 30%. However, analysis of the reactions observed in the three types of Ab-ELISA revealed that the homologous reactions were stronger than the heterologous for almost all of the single and mixed infections (98.3% and 99.0%, respectively). In monospecific infections exceeding the PT study of the positivity score produced in each of the three types of Ab-ELISA increased species-specificity to > 96%. It therefore appears that comparison of the strengths of the reactions seen in Ab-ELISA could greatly improve sero-epidemiological surveys of trypanosome infections in domestic ruminants, although the technique remains to be evaluated in experimentally infected cattle.
在非洲，家畜的主要致病锥虫是活泼锥虫、刚果锥虫和布氏锥虫。这三种锥虫的地理分布和宿主非常相似。然而，由于它们在致病性和流行病学方面存在显著差异，因此针对感染的种特异性血清学检测对于流行病学研究将非常有用。已开发的用于检测最常见感染家畜的锥虫属物种的抗体酶联免疫吸附测定（Ab-ELISA）具有令人满意的敏感性和属特异性。不幸的是，由于致病性锥虫属物种之间存在强烈的交叉反应，它们并非种特异性的。在布基纳法索进行的本研究中，使用来自实验感染活泼锥虫、伊氏锥虫和/或刚果锥虫的绵羊的1288份血浆样本，比较了针对活泼锥虫、布氏锥虫或刚果锥虫的标准化Ab-ELISA的结果。如果像往常一样仅使用阳性阈值（PT）来解释结果，观察到的强烈交叉反应导致平均种特异性<30%。然而，对三种类型Ab-ELISA中观察到的反应进行分析发现，对于几乎所有单一和混合感染（分别为98.3%和99.0%），同源反应都强于异源反应。在超过PT的单特异性感染中，对三种类型Ab-ELISA中每种产生的阳性评分进行研究，种特异性提高到>96%。因此，尽管该技术仍有待在实验感染的牛中进行评估，但Ab-ELISA中观察到的反应强度比较似乎可以大大改善家养反刍动物锥虫感染的血清流行病学调查。
