Regional, Household and Individual Factors that Influence Soil Transmitted Helminth Reinfection Dynamics in Preschool Children from Rural Indigenous Panamá

Abstract

BackgroundFew studies have investigated the relative influence of individual susceptibility versus household exposure factors versus regional clustering of infection on soil transmitted helminth (STH) transmission. The present study examined reinfection dynamics and spatial clustering of Ascaris lumbricoides, Trichuris trichiura and hookworm in an extremely impoverished indigenous setting in rural Panamá over a 16 month period that included two treatment and reinfection cycles in preschool children.Methodology/Principle FindingsSpatial cluster analyses were used to identify high prevalence clusters for each nematode. Multivariate models were then used (1) to identify factors that differentiated households within and outside the cluster, and (2) to examine the relative contribution of regional (presence in a high prevalence cluster), household (household density, asset-based household wealth, household crowding, maternal education) and individual (age, sex, pre-treatment eggs per gram (epg) feces, height-for-age, latrine use) factors on preschool child reinfection epgs for each STH. High prevalence spatial clusters were detected for Trichuris and hookworm but not for Ascaris. These clusters were characterized by low household density and low household wealth indices (HWI). Reinfection epg of both hookworm and Ascaris was positively associated with pre-treatment epg and was higher in stunted children. Additional individual (latrine use) as well as household variables (HWI, maternal education) entered the reinfection models for Ascaris but not for hookworm.Conclusions/SignificanceEven within the context of extreme poverty in this remote rural setting, the distinct transmission patterns for hookworm, Trichuris and Ascaris highlight the need for multi-pronged intervention strategies. In addition to poverty reduction, improved sanitation and attention to chronic malnutrition will be key to reducing Ascaris and hookworm transmission.

Cross-sectional Study of the Burden of Vector-Borne and Soil-Transmitted Polyparasitism in Rural Communities of Coast Province, Kenya

“…On a finer scale, within communities, our spatial analyses detected hot spots for each of the parasitic infections that we studied. Similar spatial heterogeneity at household level has also been reported for schistosomiasis in Kenya [1], [40], malaria in Mali [72], filariasis in Tanzania [73], and STH in Brazil and Panamá [14], [71]. We recorded co-infection clusters more often in those locations where several hot-spots of single infections overlapped, emphasizing the increased risk of polyparasitism where increased risk for individual infections is locally combined.…”

Interactions Among Urogenital, Intestinal, Skin, and Oral Infections in Pregnant and Lactating Panamanian Ngäbe Women: A Neglected Public Health Challenge

“…This is consistent with our recent finding that high-prevalence spatial clusters of Ascaris did not overlap with those of Trichuris or hookworm in Panamanian preschool children. 77 Interestingly, Ascaris epg was positively associated the presence of AB/UTI, the quantity of vaginal lactobacilli, and the severity of vaginal diplococcal infection. To our knowledge, these associations have not been previously reported.…”

Soil-Transmitted Helminths, Poverty, and Malnutrition in Honduran Children Living in Remote Rural Communities

“…23 However, it is important to remain vigilant for the emergence of benzimidazole resistance in this parasite. 21 Finally, when an analysis was done by an age-group with a cutoff at five years of age, some expected associations were found: (1) older children were more parasitized, as they are more likely exposed by both virtue of their age and contact with the environment; (2) younger children, being preschoolers, are dewormed less frequently, which is congruent with the fact that the WHO's recommendation to deworm all children is fairly recent. However, an unexpected finding was that the proportion of moderate-to-heavy infections in both the age groups showed no statistical difference.…”

“…These findings coincide with other studies not only highlighting the importance of geographical accessibility to health care in Honduras 15,19 but also demonstrating that among the poor, those residing in remote rural communities face an even greater risk of STH infection. 20,21 Despite their challenges, it was encouraging to find that these communities had greater deworming treatment coverage than the country as a whole. For example, the latest DHS-HN survey reports that only 55% of Honduran children 6-59 months of age had received deworming treatment in the six months prior to the survey.…”