The Medical Research Centre, Institute of Medical Research and Medicinal Plant Studies, Ministry of Scientific Research and Innovation, Yaoundé, Cameroon.
Division of Immunology, Health Science Faculty, University of Cape Town, Cape Town, South Africa.
Front Immunol. 2018 Oct 9;9:2295. doi: 10.3389/fimmu.2018.02295. eCollection 2018.
Schistosomiasis is debilitating and reported to impair immune responsiveness of infected hosts. In Cameroon, mass drug administration (MDA) is used in schoolchildren to reduce transmission of and . The effects of MDA and the impact of schistosomiasis on the titers of antibodies in vaccinated children have been poorly studied. We therefore assessed the prevalence of schistosomiasis in schoolchildren, eight months after MDA, in two locations: Barombi Koto (BK), endemic for ( = 169) and Yoro (Y), endemic for ( = 356). Age, gender, residence time and frequency of contact with river water were assessed as risk factors for infection and morbidity in both localities. In 70 schoolchildren from BK and 83 from Y, ultrasound was used to assess morbidity according to the WHO guidelines. Evaluation of measles antibodies was performed in previously vaccinated schoolchildren (14 with and 12 egg-negative controls from BK and 47 with and12 egg-negative controls from Y). The prevalence of was 25. 4% in BK (43/169) and 34.8% for in Y (124/356), indicating the persistent transmission of schistosomiasis despite MDA. Older age (AOR 1.31; 95%CI 1.12-1.54) and higher frequencies of exposure to river water (AOR 1.99; 95%CI 1.03-3.86) were identified as risks for infection in BK whereas only older age (OR 1.15; 95%CI 1.04-1.27) was a risk for infection in Y. Bladder pathology (score 2 to 5) was observed in 29.2% (7/24) of egg-positive children in BK and liver pathology (pattern C) in 31.1% (19/61) of egg-positive children in Y. There was a positive correlation between egg burden and bladder pathology (AOR 1.01; 95% CI 0.99-1.02) and positive correlation between -driven liver pathology and female gender (AOR 3.01; 95% CI 0.88-10.26). Anti-measles antibodies in vaccinated children were significantly lower in -infected when compared to egg-negative controls ( = 0.001), which was not observed in the -infected group from BK. Our results demonstrate a questionable efficacy of MDA alone in halting schistosomiasis transmission and confirm a possible immunomodulatory effect of on response to vaccines.
血吸虫病会使人身体虚弱，并据报道会削弱受感染宿主的免疫反应。在喀麦隆，采用大规模药物治疗（MDA）对学童进行治疗，以降低 和 的传播。MDA 的效果以及血吸虫病对接种儿童抗体滴度的影响研究甚少。因此，我们评估了在 MDA 后 8 个月，在两个地点（巴龙比科托（BK），有 感染（=169）和 Yoro（Y），有 感染（=356））的学童中的血吸虫病流行情况。在这两个地方，年龄、性别、居住时间和与河水接触的频率被评估为感染和发病的危险因素。在 BK 的 70 名和 Y 的 83 名学童中，使用超声根据世卫组织指南评估发病率。在以前接种过疫苗的学童中（BK 中 14 名有 和 12 名阴性对照卵，Y 中 47 名有 和 12 名阴性对照卵），评估了麻疹抗体。BK 中 的流行率为 25.4%（43/169），Y 中 的流行率为 34.8%（124/356），表明尽管 MDA 仍在持续传播血吸虫病。年龄较大（AOR 1.31；95%CI 1.12-1.54）和接触河水的频率较高（AOR 1.99；95%CI 1.03-3.86）被确定为 BK 感染的风险因素，而只有年龄较大（OR 1.15；95%CI 1.04-1.27）是 Y 感染的风险因素。BK 中 43 名阳性卵儿童中有 29.2%（7/24）出现膀胱病理（评分 2-5），61 名阳性卵儿童中有 31.1%（19/61）出现肝病理（C 型）。卵负荷与膀胱病理呈正相关（AOR 1.01；95%CI 0.99-1.02），-驱动的肝病理与女性性别呈正相关（AOR 3.01；95%CI 0.88-10.26）。与阴性对照卵相比，接种疫苗的 -感染儿童的麻疹抗体明显较低（=0.001），而 BK 的 -感染组则没有观察到这种情况。我们的研究结果表明，单独使用 MDA 治疗很难阻止血吸虫病的传播，并证实 可能对疫苗反应产生免疫调节作用。
