Prevalence and clustering of soil-transmitted helminth infections in a tribal area in southern India.
OBJECTIVE
To estimate the prevalence, spatial patterns and clustering in the distribution of soil-transmitted helminth (STH) infections, and factors associated with hookworm infections in a tribal population in Tamil Nadu, India.


METHODS
Cross-sectional study with one-stage cluster sampling of 22 clusters. Demographic and risk factor data and stool samples for microscopic ova/cysts examination were collected from 1237 participants. Geographical information systems mapping assessed spatial patterns of infection.


RESULTS
The overall prevalence of STH was 39% (95% CI 36%–42%), with hookworm 38% (95% CI 35–41%) and Ascaris lumbricoides 1.5% (95% CI 0.8–2.2%). No Trichuris trichiura infection was detected. People involved in farming had higher odds of hookworm infection (1.68, 95% CI 1.31–2.17, P < 0.001). In the multiple logistic regression, adults (2.31, 95% CI 1.80–2.96, P < 0.001), people with pet cats (1.55, 95% CI 1.10–2.18, P = 0.011) and people who did not wash their hands with soap after defecation (1.84, 95% CI 1.27–2.67, P = 0.001) had higher odds of hookworm infection, but gender and poor usage of foot wear did not significantly increase risk. Cluster analysis, based on design effect calculation, did not show any clustering of cases among the study population; however, spatial scan statistic detected a significant cluster for hookworm infections in one village.


CONCLUSIONS
Multiple approaches including health education, improving the existing sanitary practices and regular preventive chemotherapy are needed to control the burden of STH in similar endemic areas.
Saravanakumar Puthupalayam
SP
Kaliappan
Santosh
S
George
Mark Rohit
MR
Francis
Deepthi
D
Kattula
Rajiv
R
Sarkar
Shantidani
S
Minz
Venkata Raghava
VR
Mohan
Kuryan
K
George
Sheela
S
Roy
Sitara Swarna Rao
SS
Ajjampur
Jayaprakash
J
Muliyil
Gagandeep
G
Kang
D000328:Adult; D000818:Animals; D001196:Ascariasis / Q000453:epidemiology; D017164:Ascaris lumbricoides; D002648:Child; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D005243:Feces / Q000469:parasitology; D005260:Female; D006373:Helminthiasis / Q000453:epidemiology* / Q000635:transmission; D006725:Hookworm Infections / Q000453:epidemiology; D006801:Humans; D007194:India / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012959:Socioeconomic Factors; D012987:Soil / Q000469:parasitology
D012987:Soil