Soil-transmitted helminthiasis in four districts in Bangladesh: household cluster surveys of prevalence and intervention status

Abstract

Background: In 2016, after 8 years of twice-annual nationwide preventive chemotherapy (PC) administration to school-age children (SAC), the Bangladesh Ministry of Health & Family Welfare (MOHFW) sought improved impact and intervention monitoring data to assess progress toward the newly adopted goal of eliminating soil-transmitted helminthiasis (STH) as a public health problem. Methods: We surveyed four Bangladeshi districts between August and October 2017. We conducted a multi-stage, cluster-sample, household survey which produced equal-probability samples for preschool-age children (PSAC; 1-4 years), SAC (5-14 years), and adults (≥ 15 years). Standardized questionnaires were administered, using Androidbased smart phones running an Open Data Kit application. Stool samples were collected and testing for STH prevalence and infection intensity used the Kato-Katz technique. Results: In all, 4318 stool samples were collected from 7164 participants. Estimates of STH prevalence by risk group in three of the four surveyed districts ranged from 3.4 to 5.0%, all with upper, 1-sided 95% confidence limits < 10%. However, STH prevalence estimates in Sirajganj District ranged from 23.4 to 29.1%. Infections in that district were spatially focal; four of the 30 survey clusters had > 50% prevalence in at least one risk group. Among all tested specimens, Ascaris lumbricoides was the most common STH parasite [8.2% (n = 352)], followed by Trichuris trichiura [0.9% (n = 37)], and hookworm [0.6% (n = 27)]. In each district, PC coverage among SAC was above the 75% program target but did not exceed 45% among PSAC in any district. Improved sanitation at home, school, or work was over 90% in all districts.

Intestinal Parasitic Infections Among Pediatric Patients in a Metropolitan City of Bangladesh With Emphasis on Cryptosporidiosis

“…Another study demonstrated 0.6% of Trichuris trichiura ova, but Ascaris lumbricoides was 9% [ 112 ]. Other studies reported the prevalence of Ascaris lumbricoides and Trichuris trichiura ova as 1.5-8.2% and 0.8-0.9%, respectively [ 38 , 113 ]. In our research, a relatively low number of helminths was detected probably because of the urban setting of the study population, which may have had better sanitation and hygiene practices.…”

Intestinal Parasitic Infections among the Pediatric Patients in a Metropolitan City of Bangladesh with Emphasis on Cryptosporidiosis

“…Another study demonstrated 0.6% of Trichuris trichiura ova, but Ascaris lumbricoides was 9% [102]. Another study reported prevalence of Ascaris lumbricoides and Trichiuris trichura ova was 8.2% and 0.9%, respectively [103]. In our research, the relatively low number of helminths was detected because of the urban setting of the study population, who probably had better sanitation and hygiene practices.…”

Community-wide prevalence and intensity of soil-transmitted helminthiasis and Schistosoma mansoni in two districts of Sierra Leone

“…In each selected cluster, one segment was then randomly selected. The full methodology has been previously described in detail [ 19 ], and is also available on the CWW website ( https://childrenwithoutworms.org/icspm-reference-manual/ ).…”

“…Since ICSPM produces an equal-probability sample of risk-group members within strata, all clusters in each district were selected from the same sampling frame, and analyses were kept separate for each district, no weight variables were added. One-sided 95% upper confidence limits (UCLs) were reported for measures of prevalence, including prevalence of MHII and HII, as the survey is designed to determine the lowest threshold under which the true prevalence lies [ 19 ]. Two-sided 95% confidence intervals (CIs) were calculated for all other estimates.…”