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Abstract：
BACKGROUND: The Gran Chaco ecoregion is a well-known hotspot of several neglected tropical diseases (NTDs) including Chagas disease, soil-transmitted helminthiasis and multiparasitic infections. Interspecific interactions between parasite species can modify host susceptibility, pathogenesis and transmissibility through immunomodulation. Our objective was to test the association between human co-infection with intestinal parasites and host parasitaemia, infectiousness to the vector and immunological profiles in Trypanosoma cruzi-seropositive individuals residing in an endemic region of the Argentine Chaco.
METHODS: We conducted a cross-sectional serological survey for T. cruzi infection along with an intestinal parasite survey in two adjacent rural villages. Each participant was tested for T. cruzi and Strongyloides stercoralis infection by serodiagnosis, and by coprological tests for intestinal parasite detection. Trypanosoma cruzi bloodstream parasite load was determined by quantitative PCR (qPCR), host infectiousness by artificial xenodiagnosis and serum human cytokine levels by flow cytometry.
RESULTS: The seroprevalence for T. cruzi was 16.1% and for S. stercoralis 11.5% (n = 87). We found 25.3% of patients with Enterobius vermicularis. The most frequent protozoan parasites were Blastocystis spp. (39.1%), Giardia lamblia (6.9%) and Cryptosporidium spp. (3.4%). Multiparasitism occurred in 36.8% of the examined patients. Co-infection ranged from 6.9% to 8.1% for T. cruzi-seropositive humans simultaneously infected with at least one protozoan or helminth species, respectively. The relative odds of being positive by qPCR or xenodiagnosis (i.e. infectious) of 28 T. cruzi-seropositive patients was eight times higher in people co-infected with at least one helminth species than in patients with no such co-infection. Trypanosoma cruzi parasite load and host infectiousness were positively associated with helminth co-infection in a multiple regression analysis. Interferon-gamma (IFN-γ) response, measured in relation to interleukin (IL)-4 among humans infected with T. cruzi only, was 1.5-fold higher than for T. cruzi-seropositive patients co-infected with helminths. The median concentration of IL-4 was significantly higher in T. cruzi-seropositive patients with a positive qPCR test than in qPCR-negative patients.
CONCLUSIONS: Our results show a high level of multiparasitism and suggest that co-infection with intestinal helminths increased T. cruzi parasitaemia and upregulated the Th2-type response in the study patients.
METHODS: We conducted a cross-sectional serological survey for T. cruzi infection along with an intestinal parasite survey in two adjacent rural villages. Each participant was tested for T. cruzi and Strongyloides stercoralis infection by serodiagnosis, and by coprological tests for intestinal parasite detection. Trypanosoma cruzi bloodstream parasite load was determined by quantitative PCR (qPCR), host infectiousness by artificial xenodiagnosis and serum human cytokine levels by flow cytometry.
RESULTS: The seroprevalence for T. cruzi was 16.1% and for S. stercoralis 11.5% (n = 87). We found 25.3% of patients with Enterobius vermicularis. The most frequent protozoan parasites were Blastocystis spp. (39.1%), Giardia lamblia (6.9%) and Cryptosporidium spp. (3.4%). Multiparasitism occurred in 36.8% of the examined patients. Co-infection ranged from 6.9% to 8.1% for T. cruzi-seropositive humans simultaneously infected with at least one protozoan or helminth species, respectively. The relative odds of being positive by qPCR or xenodiagnosis (i.e. infectious) of 28 T. cruzi-seropositive patients was eight times higher in people co-infected with at least one helminth species than in patients with no such co-infection. Trypanosoma cruzi parasite load and host infectiousness were positively associated with helminth co-infection in a multiple regression analysis. Interferon-gamma (IFN-γ) response, measured in relation to interleukin (IL)-4 among humans infected with T. cruzi only, was 1.5-fold higher than for T. cruzi-seropositive patients co-infected with helminths. The median concentration of IL-4 was significantly higher in T. cruzi-seropositive patients with a positive qPCR test than in qPCR-negative patients.
CONCLUSIONS: Our results show a high level of multiparasitism and suggest that co-infection with intestinal helminths increased T. cruzi parasitaemia and upregulated the Th2-type response in the study patients.
摘要：
背景：GranChaco生态区是几种被忽视的热带病（NTDs）的热点，包括恰加斯病，土壤传播的蠕虫病和多寄生虫感染。寄生虫物种之间的种间相互作用可以改变宿主的易感性，通过免疫调节的发病机理和传播性。我们的目的是测试人类与肠道寄生虫共感染和宿主寄生虫血症之间的关联。居住在阿根廷查科流行地区的克氏锥虫血清阳性个体对媒介和免疫学特征的传染性。
方法：我们在两个相邻的农村村庄进行了T.cruzi感染的横断面血清学调查以及肠道寄生虫调查。通过血清诊断对每位参与者进行了克氏T.cruzi和类圆圆线虫感染的测试，并通过协同检查检测肠道寄生虫。通过定量PCR(qPCR)测定克氏锥虫血流寄生虫载量,通过人工异种诊断和流式细胞术检测血清人细胞因子水平。
结果：克氏锥虫的血清阳性率为16.1％，胸骨S为11.5％（n=87）。我们发现25.3％的蠕虫病患者。最常见的原生动物寄生虫是囊胚菌。（39.1%），蓝氏贾第鞭毛虫(6.9%)和隐孢子虫。（3.4%）。36.8％的受检患者发生多寄生虫症。同时感染了至少一种原生动物或蠕虫物种的克鲁氏杆菌血清阳性人类的共感染范围为6.9％至8.1％，分别。通过qPCR或28T的异种诊断（即感染性）为阳性的相对几率。与至少一种蠕虫共感染的人相比，Cruzi血清反应阳性的患者比没有这种共感染的患者高八倍。在多元回归分析中，克氏锥虫寄生虫载量和宿主传染性与蠕虫共感染呈正相关。干扰素-γ（IFN-γ）反应，在仅感染克氏锥虫的人中测量与白细胞介素（IL）-4的关系，比同时感染蠕虫的克鲁氏锥虫血清阳性患者高1.5倍。qPCR检测阳性的克氏锥虫血清阳性患者的IL-4中位数浓度明显高于qPCR阴性患者。
结论：我们的结果显示了高水平的多寄生虫，并提示在研究患者中，与肠道蠕虫共同感染增加了克氏螺旋体寄生虫血症并上调了Th2型反应。
方法：我们在两个相邻的农村村庄进行了T.cruzi感染的横断面血清学调查以及肠道寄生虫调查。通过血清诊断对每位参与者进行了克氏T.cruzi和类圆圆线虫感染的测试，并通过协同检查检测肠道寄生虫。通过定量PCR(qPCR)测定克氏锥虫血流寄生虫载量,通过人工异种诊断和流式细胞术检测血清人细胞因子水平。
结果：克氏锥虫的血清阳性率为16.1％，胸骨S为11.5％（n=87）。我们发现25.3％的蠕虫病患者。最常见的原生动物寄生虫是囊胚菌。（39.1%），蓝氏贾第鞭毛虫(6.9%)和隐孢子虫。（3.4%）。36.8％的受检患者发生多寄生虫症。同时感染了至少一种原生动物或蠕虫物种的克鲁氏杆菌血清阳性人类的共感染范围为6.9％至8.1％，分别。通过qPCR或28T的异种诊断（即感染性）为阳性的相对几率。与至少一种蠕虫共感染的人相比，Cruzi血清反应阳性的患者比没有这种共感染的患者高八倍。在多元回归分析中，克氏锥虫寄生虫载量和宿主传染性与蠕虫共感染呈正相关。干扰素-γ（IFN-γ）反应，在仅感染克氏锥虫的人中测量与白细胞介素（IL）-4的关系，比同时感染蠕虫的克鲁氏锥虫血清阳性患者高1.5倍。qPCR检测阳性的克氏锥虫血清阳性患者的IL-4中位数浓度明显高于qPCR阴性患者。
结论：我们的结果显示了高水平的多寄生虫，并提示在研究患者中，与肠道蠕虫共同感染增加了克氏螺旋体寄生虫血症并上调了Th2型反应。
