Soil-transmitted helminth reinfection four and six months after mass drug administration: results from the delta region of Myanmar

Autor: Dunn, Julia C., Bettis, Alison A., Wyine, Nay Yee, Lwin, Aye Moe Moe, Tun, Aung, Maung, Nay Soe, Anderson, Roy M.
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Male
Ascaris Lumbricoides
HOOKWORM INFECTION
Nematoda
Epidemiology
RC955-962
Myanmar
Geographical Locations
Soil
Risk Factors
Arctic medicine. Tropical medicine
Medicine and Health Sciences
Child
11 Medical and Health Sciences
Anthelmintics
Ascariasis
Ascaris
Eukaryota
CHEMOTHERAPY
ASCARIS-LUMBRICOIDES
COMMUNITY
CONTAMINATION
Infectious Diseases
Helminth Infections
Mass Drug Administration
Female
Public aspects of medicine
RA1-1270
Life Sciences & Biomedicine
Research Article
Neglected Tropical Diseases
Adult
Asia
Adolescent
Albendazole
Hookworm Infections
Young Adult
Tropical Medicine
Helminths
Parasitic Diseases
Animals
Humans
Trichuriasis
Science & Technology
HOUSEHOLD
Organisms
Biology and Life Sciences
06 Biological Sciences
Tropical Diseases
Invertebrates
PREDISPOSITION
Health Care
Soil-Transmitted Helminthiases
Hookworms
Age Groups
People and Places
PATTERNS
Parasitology
Population Groupings
Health Statistics
Morbidity
RESISTANCE
Zdroj: PLoS Neglected Tropical Diseases
PLoS Neglected Tropical Diseases, Vol 13, Iss 2, p e0006591 (2019)
ISSN: 1935-2735
1935-2727
Popis: Background Mass drug administration (MDA), targeted at school-aged children (SAC) is the method recommended by the World Health Organization for the control of morbidity induced by soil-transmitted helminth (STH) infection in endemic countries. However, MDA does not prevent reinfection between treatment rounds and research suggests that only treating SAC will not be sufficient to bring prevalence to low levels and possibly interrupt transmission of STH. In countries with endemic infection, such as Myanmar, the coverage, who is targeted, and rates of reinfection will determine how effective MDA is in suppressing transmission in the long-term. Methods/principal findings In this paper, data from an epidemiological study on STH, comprising three surveys conducted between June 2015 and June 2016 in the delta region of Myanmar, are analysed to determine how STH prevalence and intensity in the study community changes over the course of a year, including reinfection after two MDA rounds in which the whole study sample (all age groups, n = 523) were treated with albendazole. Prevalence in the first survey (August 2015) was 27.92% for any STH, 5.54% for Ascaris lumbricoides, 17.02% for Trichuris trichiura and 9.75% for hookworm. Over the year (survey one to survey three), prevalence of any STH decreased by 8.99% (P < 0.001) and mean EPG significantly decreased for T. trichiura (P < 0.01) and hookworm (P < 0.001). Risk ratios (RRs) for a four-month reinfection period (August to December) were statistically significant and were below one, indicating that STH prevalence had not bounced back to the prevalence levels recorded immediately prior to the last round of treatment (any STH RR = 0.67, 95% CI 0.56–0.81; A. lumbricoides RR = 0.31, 95% CI 0.16–0.59; T. trichiura RR = 0.70, 95% CI 0.55–0.88; hookworm RR = 0.69, 95% CI 0.50–0.95). The only statistically significant RR for the six-month reinfection period (December to June) was for A. lumbricoides infection in SAC (RR = 2.67, 95% CI 1.37–5.21). All six-month RRs were significantly higher than four-month RRs (P < 0.05). Evidence of predisposition to infection (low and high), as measured by the Kendall Tau-b statistic, was found for all species overall and within most age groups stratifications, except for hookworm infection in preschool-aged children. Conclusions/significance This study demonstrates that, for certain demographic groups, a six-month gap between MDA in these communities is enough time for STH infection to return to STH prevalence levels recorded immediately before the previous MDA round, and that on average the same individuals are being consistently infected between MDA rounds.
Author summary Mass drug administration (MDA), treating either whole communities or targeted groups without a prior diagnosis, is used as a control strategy for many neglected tropical diseases, including soil-transmitted helminth (STH) infection. MDA takes place at set intervals, aiming to reduce morbidity caused by the target disease. Research and policy focus is also increasingly considering the potential of interrupting STH transmission, leading to elimination. In this study we measure STH infection in two villages in the delta region of Myanmar over the course of a year, both before and after MDA rounds, to quantify the effect of treatment on infection and to identify groups with persistent infections. We found that whilst overall prevalence of STH infection decreased over the year, intensity of infection, measured by eggs per gram of faeces, did not significantly decrease. We also found evidence to suggest that particular people are predisposed to STH infection. This is possibly due to non-compliance to MDA, or behavioural and social factors. The findings presented here will provide evidence to support continuing Myanmar’s MDA programme for STH control and using accurate diagnostics to identify and target “predisposed” people for sustained treatment.
Databáze: OpenAIRE
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