Epidemiology of soil transmitted helminths and risk analysis of hookworm infections in the community: Results from the DeWorm3 Trial in southern India

• Published in: PLoS neglected tropical diseases 2021-04, Vol.15 (4), p.e0009338-e0009338
• Main Authors: Ajjampur, Sitara S R, Kaliappan, Saravanakumar Puthupalayam, Halliday, Katherine E, Palanisamy, Gokila, Farzana, Jasmine, Manuel, Malathi, Abraham, Dilip, Laxmanan, Selvi, Aruldas, Kumudha, Rose, Anuradha, Kennedy, David S, Oswald, William E, Pullan, Rachel L, Galagan, Sean R, Ásbjörnsdóttir, Kristjana, Anderson, Roy M, Muliyil, Jayaprakash, Sarkar, Rajiv, Kang, Gagandeep, Walson, Judd L
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Animals; Ascariasis - epidemiology; Ascariasis - parasitology; Ascariasis - transmission; Ascaris lumbricoides - isolation & purification; Biology and Life Sciences; Child; Child, Preschool; Control; Disease transmission; Family Characteristics; Feces - parasitology; Female; Health aspects; Helminths - isolation & purification; Hookworm disease; Hookworm Infections - epidemiology; Hookworm Infections - parasitology; Hookworm Infections - transmission; Households; Humans; India - epidemiology; Logistic Models; Male; Medicine and Health Sciences; Middle Aged; People and Places; Prevalence; Research and Analysis Methods; Risk Factors; Sanitation; Schools; Soil - parasitology; Statistics; Toilet Facilities; Trichuriasis - epidemiology; Trichuriasis - parasitology; Trichuriasis - transmission; Trichuris - isolation & purification; Young Adult
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0009338

Since 2015, India has coordinated the largest school-based deworming program globally, targeting soil-transmitted helminths (STH) in ~250 million children aged 1 to 19 years twice yearly. Despite substantial progress in reduction of morbidity associated with STH, reinfection rates in endemic communities remain high. We conducted a community based parasitological survey in Tamil Nadu as part of the DeWorm3 Project-a cluster-randomised trial evaluating the feasibility of interrupting STH transmission at three geographically distinct sites in Africa and Asia-allowing the estimation of STH prevalence and analysis of associated factors. In India, following a comprehensive census, enumerating 140,932 individuals in 36,536 households along with geospatial mapping of households, an age-stratified sample of individuals was recruited into a longitudinal monitoring cohort (December 2017-February 2018) to be followed for five years. At enrolment, a total of 6089 consenting individuals across 40 study clusters provided a single adequate stool sample for analysis using the Kato-Katz method, as well as answering a questionnaire covering individual and household level factors. The unweighted STH prevalence was 17.0% (95% confidence interval [95%CI]: 16.0-17.9%), increasing to 21.4% when weighted by age and cluster size. Hookworm was the predominant species, with a weighted infection prevalence of 21.0%, the majority of which (92.9%) were light intensity infections. Factors associated with hookworm infection were modelled using mixed-effects multilevel logistic regression for presence of infection and mixed-effects negative binomial regression for intensity. The prevalence of both Ascaris lumbricoides and Trichuris trichiura infections were rare (