National intestinal helminth survey among schoolchildren in Tajikistan: prevalences, risk factors and perceptions.
Solid evidence regarding the epidemiology of intestinal helminth infections in Tajikistan is currently lacking. As such information is essential for the evidence-based design, implementation and evaluation of control interventions, a national intestinal helminth survey was conducted with the following objectives: (i) to assess the prevalence of intestinal helminth infections among school-aged children nationally and stratified by region; (ii) to identify locally relevant risk factors for infection; and (iii) to better understand the children's knowledge and perception of intestinal helminth infections, and asses their haemoglobin status. Standard field and laboratory procedures including the Kato-Katz thick smear and tape test were employed. Complete data was obtained for 1642 children from 33 randomly selected primary schools from different parts of the country. Across the country, prevalences of E. vermicularis, A. lumbricoides, H. nana and T. trichiura were 26.5%, 16.9%, 15.5% and 2.7% respectively. The prevalence of common soil-transmitted helminth (A. lumbricoides and T. trichiura) infections was 19.4%. No hookworm infections were detected, and prevalences of various infections differed significantly between administrative districts (all P<0.05). Hand washing after toilet usage (OR=0.78; P=0.047) and handling animals (OR=0.66; P=0.009) were identified as significant protective factors against E. vermicularis infections. H. nana infection was associated with a 2.85g/L decrease in haemoglobin levels (P<0.001) despite already low average haemoglobin levels. The proportions of children with knowledge about intestinal helminths and protective hygiene practices varied significantly between regions (both P<0.001). Mass albendazole administration to school-aged children and women of child-bearing age against intestinal helminths has been conducted in Tajikistan in spring 2012, followed by mass albendazole and praziquantel distribution to school-aged children in autumn 2012. In the longer term, an integrated approach including chemotherapy, provision of safe water and proper sanitation as well as targeted health education will be necessary to achieve sustainable control.