Prevalence of intestinal schistosomiasis in pre-school aged children: a pilot survey in Marolambo District, Madagascar

Abstract

School-aged children (SAC) have a considerable burden of intestinal schistosomiasis in Madagascar yet its burden in pre-school aged children (PSAC) is currently overlooked. To assess the at-risk status of PSAC, we undertook a pilot epidemiological survey in June 2019 examining children (n = 89), aged 2–4-years of balanced gender, in six remote villages in Marolambo District, Madagascar. Diagnosis included use of urine-circulating cathodic antigen (CCA) dipsticks and coproscopy of stool with duplicate Kato-Katz (K-K) thick smears. Prevalence of intestinal schistosomiasis by urine-CCA was 67.4% (95% confidence interval [CI]: 56.5–77.2%) and 35.0% (95% CI: 24.7–46.5%) by K-K. The relationship between faecal eggs per gram (epg) and urine-CCA G-scores (G1 to G10) was assessed by linear regression modelling, finding for every increment in G-score, epg increased by 20.4 (6.50–34.4, P = 0.006). Observed proportions of faecal epg intensities were light (78.6%), moderate (17.9%) and heavy (3.6%). Soil-transmitted helminthiasis was noted, prevalence of ascariasis was 18.8% and trichuriasis was 33.8% (hookworm was not reported). Co-infection of intestinal schistosomiasis and soil-transmitted helminthiasis occurred in 36.3% of PSAC. These results provide solid evidence highlighting the overlooked burden of intestinal schistosomiasis in PSAC, and they also offer technical guidance for better surveillance data for the Madagascan national control programme.

Predictive Risk Mapping of Schistosomiasis in Madagascar Using Ecological Niche Modeling and Precision Mapping

“…In Madagascar, the burden of schistosomiasis is high [3], with 107/144 districts reporting the disease as endemic in 2016 [11,12]. Only 11% of the population has access to improved methods of sanitation, and 44% practice open defecation [13,14].…”

“…Likewise, Schistosoma mansoni, which causes an intestinal version of the disease, is prevalent in the eastern and southern districts. Co-endemicity between these species is noted in the north-central and southwest [11,12]. The burden of the disease is felt considerably by school-aged (SAC) and pre-school-aged children.…”

“…The burden of the disease is felt considerably by school-aged (SAC) and pre-school-aged children. National control campaigns offering mass drug administration (MDA) of praziquantel for children aged 5-15 often struggle with logistical challenges due to the remoteness of some endemic regions [12]. Much of the Malagasy population in rural areas have limited access to government-run primary health care centers, which often lack physicians and laboratory testing equipment [16].…”

Pediatric schistosomiasis in hard-to-reach areas and populations: a scoping review

“…In one article [20], the Kato-Katz test for S. mansoni was complemented by an ELISA test using soluble worm antigen, which did not distinguish between Schistosoma species [21]. The prevalence of S. mansoni in the included articles was estimated at 12.9% in Ghana [22], 3.6-80.3% in Kenya [20,23], 35.0% in Madagascar [24], 9.6-78.0% in Senegal [25], 11.2-35.4% in Sierra Leone [26], 44.4-54.9% in Tanzania [27,28], and 39.3-74.9% in Uganda [9,[29][30][31].…”

“…We noted discordant prevalence results with POC-CCA (Table 2). For instance, in Kenya, Sassa et al, documented a prevalence of 90.5% with POC-CCA versus 3.6% with Kato-Katz [23], while in Madagascar a S. mansoni prevalence of 67.4% with POC-CCA versus 35.0% with Kato-Katz was recorded [24]. In Tanzania, Mueller and co-workers established a S. mansoni prevalence of 54.9% with Kato-Katz versus 95.8% with POC-CCA [28].…”