Abstract:
Introduction: Current global helminth control guidelines focus on regular deworming of
targeted populations for morbidity control. However, water, sanitation, and hygiene
(WASH) interventions may also be important for reducing helminth transmission. We
evaluated the impact of different potential helminth protective packages on infection
prevalence, including repeated treatment with albendazole and praziquantel with and
without WASH access.
Methodology/principal findings: We conducted a cohort study nested within a
randomized trial of empiric deworming of HIV-infected adults in Kenya. Helminth
infections and infection intensity were diagnosed using semi-quantitative real-time PCR.
We conducted a manual forward stepwise model building approach to identify if there
are packages of interventions that may be protective against an STH infection of any
species (combined outcome) and each helminth species individually. We conducted
secondary analyses using the same approach only amongst individuals with no
anthelmintis exposure. We used interaction terms to test for potential intervention
synergy. Approximately 22% of the 701 stool samples provided were helminth-infected,
most of which were of low to moderate intensity. The odds of infection with any STH
species were lower for individuals who were treated with albendazole (aOR:0.11,
95%CI: 0.05, 0.20, p<0.001), adjusting for age and sex. Although most WASH
conditions demonstrated minimal additional benefit in reducing the probability of
infection with any STH species, access to safe flooring did appear to offer some
additional protection (aOR:0.34, 95%CI: 0.20, 0.56, p<0.001). For schistosomiasis, only
treatment with praziquantel was protective (aOR:0.30 95%CI: 0.14, 0.60, p = 0.001).
Amongst individuals who were not treated with albendazole or praziquantel, the most
protective intervention package to reduce probability of STH infections included safe
flooring (aOR:0.34, 95%CI: 0.20, 0.59, p<0.001) and latrine access (aOR:0.59, 95%CI:
0.35, 0.99, p = 0.05). Across all species, there was no evidence of synergy or antagonism
between anthelmintic chemotherapy with albendazole or praziquantel and WASH
resources.
Conclusions/significance: Deworming is effective in reducing the probability of helminth
infections amongst HIV-infected adults. With the exception of safe flooring, WASH
offers minimal additional benefit. However, WASH does appear to significantly reduce
infection prevalence in adults who are not treated with chemotherapy.