Gürtler R E, Petersen R M, Lauricella M A, Wisnivesky-Colli C
Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
Ann Trop Med Parasitol. 1992 Apr;86(2):111-9. doi: 10.1080/00034983.1992.11812640.
The influence of reinfections on the infectivity to Triatoma infestans of dogs seropositive to Trypanosoma cruzi was investigated in Amamá, north-west Argentina, before (1984) and after (1986-1987) elimination of domestic bugs with residual insecticides in 1985. Infectivity was quantified by the percentage of infected bugs in each xenodiagnosis of a seropositive dog, i.e. the infective force (IF). Exposure to reinfection was represented by the domiciliary density of infected bugs and by an index of the potentially-infective contacts (IPIC) experienced by each dog (calculated as the product of the relative density of bugs per dog, the proportion of infected bugs, and the proportion of bugs taking blood meals from the dog). IF was unrelated to the dog's age or sex, or the level of specific antibodies to T. cruzi. Before vector elimination, the IF of seropositive dogs was significantly associated with both the density of infected bugs and the IPIC. After vector elimination, seropositive dogs resident at houses which had 10-70 infected bugs before spraying showed a higher median IF (67-75%) than those living in houses with zero to eight infected bugs before spraying (47-55%). The age-specific IF of seropositive dogs aged one year or older, recorded before (45-64%) and after (52-56%) the elimination of domestic bugs, did not differ significantly. Our data suggest that the infectivity of seropositive dogs to bugs is modified by previous or current exposure to bug-mediated reinfections, and that this relationship might be irreversible in the short term.
在阿根廷西北部的阿马马，于1985年用残留杀虫剂消灭家栖昆虫之前（1984年）和之后（1986 - 1987年），研究了再感染对克氏锥虫血清阳性犬对侵扰锥蝽感染性的影响。通过对血清阳性犬每次异种接种中感染昆虫的百分比来量化感染性，即感染力（IF）。再感染的暴露情况通过感染昆虫的居家密度以及每只犬经历的潜在感染接触指数（IPIC）来表示（计算方法为每只犬的昆虫相对密度、感染昆虫比例以及从犬身上吸血的昆虫比例的乘积）。IF与犬的年龄、性别或针对克氏锥虫的特异性抗体水平无关。在消灭病媒之前，血清阳性犬的IF与感染昆虫的密度和IPIC均显著相关。在消灭病媒之后，居住在喷洒前有10 - 70只感染昆虫房屋中的血清阳性犬的中位IF（67 - 75%）高于居住在喷洒前有0至8只感染昆虫房屋中的犬（47 - 55%）。在消灭家栖昆虫之前（45 - 64%）和之后（52 - 56%）记录的一岁及以上血清阳性犬的年龄特异性IF没有显著差异。我们的数据表明，血清阳性犬对昆虫的感染性会因之前或当前暴露于昆虫介导的再感染而改变，并且这种关系在短期内可能是不可逆的。
