Enriquez G F, Garbossa G, Macchiaverna N P, Argibay H D, Bua J, Gürtler R E, Cardinal M V
Laboratory of Eco-Epidemiology, Faculty of Exact and Natural Sciences, University of Buenos Aires, Argentina; Institute of Ecology, Genetics and Evolution of Buenos Aires (UBA-CONICET), Argentina.
Laboratory of Clinical and Environmental Parasitology, Faculty of Exact and Natural Sciences, University of Buenos Aires, (IQUIBICEN-CONICET-UBA), Public Health Research Institute, Argentina.
Vet Parasitol. 2016 Jun 15;223:186-94. doi: 10.1016/j.vetpar.2016.04.042. Epub 2016 Apr 27.
Interactions among different species of parasites co-infecting the same host could be synergistic or antagonistic. These interactions may modify both the frequency of infected hosts and their infectiousness, and therefore impact on transmission dynamics. This study determined the infectiousness of Trypanosoma cruzi-seropositive dogs (using xenodiagnosis) and their parasite load (quantified by qPCR), and tested the association between both variables and the presence of concomitant endoparasites. A cross-sectional serosurvey conducted in eight rural villages from Pampa del Indio and neighboring municipalities (northeastern Argentina) detected 32 T. cruzi-seropositive dogs out of 217 individuals examined for infection. Both the infectiousness to the vector Triatoma infestans and parasite load of T. cruzi-seropositive dogs examined were heterogeneous. A statistically significant, nine-fold higher mean infectiousness was registered in T. cruzi-seropositive dogs co-infected with Ancylostoma caninum and a trematode than in T. cruzi-seropositive dogs without these infections. The median parasite load of T. cruzi was also significantly higher in dogs co-infected with these helminths. An opposite trend was observed in T. cruzi-seropositive dogs that were serologically positive to Toxoplasma gondii or Neospora caninum relative to dogs seronegative for these parasites. Using multiple logistic regression analysis with random effects, we found a positive and significant association between the infectiousness of T. cruzi-seropositive dogs and co-infections with A. caninum and a trematode. Our results suggest that co-infections may be a modifier of host infectiousness in dogs naturally infected with T. cruzi.
共同感染同一宿主的不同种类寄生虫之间的相互作用可能是协同的或拮抗的。这些相互作用可能会改变受感染宿主的频率及其传染性，从而影响传播动态。本研究确定了克氏锥虫血清阳性犬的传染性（采用虫媒接种诊断法）及其寄生虫负荷（通过定量聚合酶链反应进行量化），并测试了这两个变量与伴随的体内寄生虫存在之间的关联。在潘帕德尔印第奥及其邻近市镇（阿根廷东北部）的八个乡村进行的横断面血清学调查中，在217只接受感染检测的个体中检测出32只克氏锥虫血清阳性犬。所检测的克氏锥虫血清阳性犬对媒介昆虫骚扰锥蝽的传染性和寄生虫负荷均存在异质性。与未感染犬弓首蛔虫和一种吸虫的克氏锥虫血清阳性犬相比，同时感染犬弓首蛔虫和一种吸虫的克氏锥虫血清阳性犬的平均传染性在统计学上显著高出九倍。同时感染这些蠕虫的犬只中，克氏锥虫的寄生虫负荷中位数也显著更高。相对于对刚地弓形虫或犬新孢子虫血清阴性的犬只，对刚地弓形虫或犬新孢子虫血清阳性的克氏锥虫血清阳性犬呈现出相反的趋势。通过使用具有随机效应的多元逻辑回归分析，我们发现克氏锥虫血清阳性犬的传染性与犬弓首蛔虫和一种吸虫的共同感染之间存在正相关且显著的关联。我们的结果表明，共同感染可能是自然感染克氏锥虫犬只宿主传染性的一个影响因素。
