Assessment of the nail contamination with soil-transmitted helminths in schoolchildren in Jimma Town, Ethiopia.

BACKGROUND: Large-scale deworming programs have been successful in reducing the burden of disease due to soil-transmitted helminth (STH; Ascaris lumbricloides, Trichuris trichiura and hookworm) infections, but re-infection in absence of other measures is unavoidable. We assessed the role of nail contamination as a source of infection with the goal to evaluate the potential of nail clipping as a simple measure to further reduce STH-attributable morbidity. METHODS: A cross-sectional study was conducted in Jimma Town (Ethiopia). Both stool samples and clipped nails were collected from 600 schoolchildren and microscopically screened for the presence of STHs. We also interviewed the children to gain insights into their hygiene practices. Subsequently, we explored any associations between infection, nail contamination and personal hygiene. RESULTS: Any STH infections were observed in 24.3% of the children (A. lumbricoides: 18.5%; T. trichiura: 9.8%; hookworm: 0.5%). The intensity of the infections was mainly low, only in a few cases a moderate-to-heavy intensity infection was observed (A. lumbricoides: 4.3%; T. trichiura: 0.2%). Other helminth species observed were Schistosoma mansoni (5.0%), Hymenolepis nana (2.7%), Taenia spp. and Enterobius vermicularis (<1.0%). The analysis of the nail material revealed the presence of A. lumbricoides (1.7%), Taenia spp. (1.0%), T. trichiura (0.5%), E. vermicularis (0.5%) and H. nana (0.2%). The odds of infection with any STH increased as the frequency of trimming decreased. The odds of nail contamination with any STH and A. lumbricoides were higher for younger children. CONCLUSIONS: The presence of helminth eggs under the nails of children highlights a poor personal hygiene. The association between any STH infection and frequency of nail trimming needs to be explored in an intervention study. The recent prevalence of any STH infections indicated that scaling down of the frequency of deworming is justified but that STH is still a public health problem.

Assessment of environmental contamination with soil-transmitted helminths life stages at school compounds, households and open markets in Jimma Town, Ethiopia.

BACKGROUND: It remains largely unknown where and how infections with soil-transmitted helminths (STHs; Ascaris, Trichuris, Necator and Ancylostoma) occur. We therefore aimed to identify possible sources of infection by assessing the environmental contamination in an STH-endemic area. METHODS: We first performed a series of laboratory experiments designed to optimize a soil straining-flotation method to detect and quantify Ascaris and Trichuris eggs in soil, and to validate the diagnostic performance of the optimized method when followed by microscopy and qPCR. In a second phase, we applied this method to assess the level of STH contamination in 399 environmental samples collected from 10 school compounds, 50 households and 9 open markets in Jimma Town (Ethiopia). Subsequently, we explored associations between the environmental contamination and both the corresponding STH epidemiology at the level of the schools and the household characteristics. Finally, we assessed the knowledge, attitude and practice (KAP) towards STHs in school children. PRINCIPAL FINDINGS: Our soil straining-flotation method has an analytical sensitivity of 50 eggs per 100 grams of soil and egg recovery rate of 36.0% (Ascaris) and 8.0% (Trichuris). The analysis of field samples with both microscopy and qPCR revealed the presence of 8 different helminth species of medical importance, including but not limited to the human STHs. There was a significant association between the environmental contamination and prevalence of any STH infections at the school level only. The KAP indicated a lack of knowledge and awareness of STHs. CONCLUSIONS/SIGNIFICANCE: Our optimized straining-flotation method has a moderate diagnostic performance and revealed that life stages of helminths are ubiquitous in the environment, which might be due to the poor sanitary facilities at both the schools and the households, and a poor level of KAP towards STHs. Further research is required to gain more insights into the contribution of these life stages to transmission.