Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon.
Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.
PLoS One. 2023 Jul 31;18(7):e0288560. doi: 10.1371/journal.pone.0288560. eCollection 2023.
The double burden of malaria and helminthiasis in children poses an obvious public health challenge, particularly in terms of anemia morbidity. While both diseases frequently geographically overlap, most studies focus on mono-infection and general prevalence surveys without molecular analysis. The current study investigated the epidemiological determinants of malaria, schistosomiasis, and geohelminthiasis transmission among children in the North Region of Cameroon.
School and pre-school children aged 3-15 year-of-age were enrolled from three communities in March 2021 using a community cross-sectional design. Capillary-blood samples were obtained, and each was examined for malaria parasites using rapid-diagnostic-test (RDT), microscopy, and PCR while hemoglobin level was measured using a hemoglobinometer. Stool samples were analyzed for Schistosoma mansoni, S. guineensis, and soil-transmitted-helminthiasis (STH) infections using the Kato Katz method, and urine samples were assessed for the presence of S. haematobium eggs (including hybrids) using the standard urine filtration technique.
A malaria prevalence of 56% (277/495) was recorded by PCR as opposed to 31.5% (156/495) by microscopy and 37.8% (186/495) by RDT. Similarly, schistosomiasis was observed at prevalence levels of up to 13.3% (66/495) overall [S. haematobium (8.7%); S. mansoni (3.8%); mixed Sh/Sm (0.6%); mixed Sh/Sm/Sg (0.2%). Both infections were higher in males and the 3-9 year-of-age groups. A high frequency of PCR reported P. falciparum mono-infection of 81.9% (227/277) and mixed P. falciparum/P. malariae infection of 17.3% (48/277) was observed. Malaria-helminths co-infections were observed at 13.1% (65/495) with marked variation between P. falciparum/S. haematobium (50.8%, 33/65); P. falciparum/S. mansoni (16.9%, 11/65) and P. falciparum/Ascaris (9.2%, 6/65) (χ2 = 17.5, p = 0.00003). Anemia prevalence was 32.9% (163/495), categorically associated with P. falciparum (45.8%, 104/227), Pf/Sh (11.5%, 26/227), and Pf/Sm (3.9%, 9/227) polyparasitism.
Polyparasitism with malaria and helminth infections is common in school-aged children despite periodic long-lasting insecticide-treated nets (LLINs) distribution and regular school-based praziquantel (for schistosomiasis) and albendazole (for STH) campaigns. Co-existence of Plasmodium parasites and helminths infections notably Schistosoma species among children may concurrently lead to an increase in Plasmodium infection with an enhanced risk of anemia, highlighting the necessity of an integrated approach for disease control interventions.
儿童同时感染疟疾和寄生虫病(主要是血吸虫病和土壤传播性蠕虫病)对公共卫生构成了明显的挑战,尤其是在贫血发病率方面。尽管这两种疾病经常在地理上重叠,但大多数研究都集中在单一感染和一般流行情况调查上,没有进行分子分析。本研究调查了喀麦隆北部地区儿童中疟疾、血吸虫病和土壤传播性蠕虫病传播的流行病学决定因素。
2021 年 3 月,采用社区横断面设计,从三个社区中招募了 3-15 岁的学童和学龄前儿童。采集末梢血样,用快速诊断检测(RDT)、显微镜和聚合酶链反应(PCR)检查疟疾寄生虫,用血红蛋白计测量血红蛋白水平。用加藤氏厚涂片法检查粪便样本中的曼氏血吸虫、几内亚血吸虫和土壤传播性蠕虫病(STH)感染,用标准尿过滤技术检查尿液样本中的埃及血吸虫卵(包括杂交种)。
PCR 检测到疟疾的流行率为 56%(277/495),而显微镜检测为 31.5%(156/495),RDT 检测为 37.8%(186/495)。同样,血吸虫病的流行率高达 13.3%(66/495)[埃及血吸虫(8.7%);曼氏血吸虫(3.8%);混合 Sh/Sm(0.6%);混合 Sh/Sm/Sg(0.2%)]。这两种感染在男性和 3-9 岁年龄组中更为常见。PCR 报告的疟原虫单一感染率很高,为 81.9%(227/277),混合疟原虫感染率为 17.3%(48/277)。观察到疟疾-寄生虫混合感染率为 13.1%(65/495),其中恶性疟原虫/埃及血吸虫(50.8%,33/65)、恶性疟原虫/曼氏血吸虫(16.9%,11/65)和恶性疟原虫/蛔虫(9.2%,6/65)(χ2 = 17.5,p = 0.00003)差异显著。贫血的流行率为 32.9%(163/495),与恶性疟原虫(45.8%,104/227)、Pf/Sh(11.5%,26/227)和 Pf/Sm(3.9%,9/227)多重寄生虫感染显著相关。
尽管定期发放长效驱虫蚊帐(LLINs)和定期开展学校基阿奇达唑(治疗血吸虫病)和阿苯达唑(治疗 STH)运动,但在校儿童中,疟疾和寄生虫感染的多重感染仍然很常见。儿童中恶性疟原虫寄生虫和蠕虫感染的共存,特别是血吸虫属物种的共存,可能会同时增加恶性疟原虫感染的风险,导致贫血增加,这突出表明需要采取综合方法来开展疾病控制干预措施。