Strongyloidiasis in northern Vietnam: epidemiology, clinical characteristics and molecular diagnosis of the causal agent

Abstract

BackgroundStrongyloidiasis is a health problem in Vietnam, but appropriate information is still limited. The aim of this study was to determine the prevalence, geographical distribution, epidemiological aspects, symptoms and other health indicators of Strongyloides stercoralis infections in patients from 27 provinces of northern Vietnam attending the Hanoi Medical University Hospital during 2016 and 2017.MethodsBlood samples of 2000 patients were analyzed for S. stercoralis infection with an IgG ELISA test. Seroprevalence was analyzed by gender, age group, locality of origin (rural or urban areas) and symptoms. Stools from the seropositive patients were examined for the detection of worms which were subsequently used for species identification by morphology and rDNA ITS1 sequencing.ResultsA seroprevalence of 20% was detected, showing an increasing prevalence from young to older age groups but without significant gender difference. Seroprevalence was higher in rural areas than in urban areas, both in general and individually in all provinces without exception, and lower in the mountainous areas than in the large valley lowlands. The follow-up of the 400 patients showed eosinophilia in 100% of cases, diarrhoea in 64.5%, digestion difficulties in 58.0%, stomachache in 45.5%, stomach and duodenal ulcers in 44.5%, itching in 28.0% and fever in 9.5%. The prevalence of symptoms and signs were also higher in older age groups than in younger age groups. Worms were detected in stools of 10.5% of the patients. Sequencing of a 501-bp nuclear ribosomal DNA ITS1 fragment allowed for the verification of infection by Strongyloides stercoralis.ConclusionsTo our knowledge, this study is the largest survey of human strongyloidiasis in Vietnam so far and the first molecular identification of this nematode species in this country. Long-term chronicity may probably be usual in infected subjects, mainly in the older age groups.

Asymptomatic Strongyloidiasis among Latin American Migrants in Spain: A Community-Based Approach

“…We found significant differences in strongyloidiasis prevalence by sex, an observation that does not match the results of other articles [ 29 ]. On the other hand, we also found a significant difference in relation with age, which is consistent with other studies performed in endemic areas [ 9 , 31 ].…”

Handling of Fresh Vegetables: Knowledge, Hygienic Behavior of Vendors, Public Health in Maputo Markets, Mozambique

“…Hazard Analysis and Critical Control Points are not being regulated or frequently applied in any stage of handling or processing food, from the field to the vendor, and interfere with food safety, especially fresh food. Moreover, many gastrointestinal diseases, whose prevalence is strongly linked with the ingestion of pathogenic organisms in food and water contaminated by feces from humans or animals excreting those organisms, often associated with poor sanitation or low standards of personal and domestic hygiene [ 10 ]. In fact, this is the leading cause of gastrointestinal diseases, especially in children in developing countries, where 21% of children do not reach the age of five (about 2.5 millions of deaths per year) [ 11 ].…”

Vietnam: Neglected tropical diseases in an emerging and accelerating economy

“…Beyond the 3 major soil-transmitted helminth infections highlighted above, strongyloidiasis is also endemic, especially in the rural central highlands, but even in major urban areas. The highest prevalence of strongyloidiasis and evidence of clinical symptoms occurs among older rural populations [ 39 , 40 ].…”