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Impact of seven years of mass drug administration and recrudescence of Schistosoma haematobium infections after one year of treatment gap in Zanzibar: repeated cross-sectional studies
- Source :
- PLoS Neglected Tropical Diseases, PLoS Neglected Tropical Diseases, Vol 15, Iss 2, p e0009127 (2021)
- Publication Year :
- 2021
-
Abstract
- Background Considerable progress towards the elimination of urogenital schistosomiasis was made by the Zanzibar Elimination of Schistosomiasis Transmission project from 2012 till 2016, when biannual praziquantel mass drug administration (MDA) alone or with additional snail control or behaviour change interventions were implemented. Annual MDA was continued in 2017 and 2018, but not in 2019, imposing a 16-month treatment gap. We monitored the Schistosoma haematobium prevalence from 2012 till 2020 and assessed recrudescence patterns with focus on 2020. Methodology Repeated cross-sectional surveys were conducted from 2011/12 till 2020 in 90 communities and 90 schools in Zanzibar. Annually, around 4,500 adults and up to 20,000 schoolchildren were surveyed. The S. haematobium prevalence was detected by urine filtration and reagent strips. In 2020, risk factors for infection were investigated using generalized estimated equation models. Principal findings In adults, the apparent S. haematobium prevalence was 3.9% in 2011 and 0.4% in 2020. In schoolchildren, the prevalence decreased from 6.6% in 2012 to 1.2% in 2019 with vicissitudes over the years. Prominent recrudescence of infection from 2.8% in 2019 to 9.1% (+225%) in 2020 was observed in 29 schools with historically moderate prevalences (≥10%). Compared with 2019, reinfection in 2020 was particularly striking in boys aged 9–16 years. Being male was a risk factor for infection in 2020 (adults: odds ratio (OR): 6.24, 95% confidence interval (95% CI): 1.96–19.60; schoolchildren: OR: 2.06, 95% CI: 1.52–2.78). Living near to a natural freshwater body significantly increased the odds of infection in adults (OR: 2.90, CI: 1.12–7.54). Conclusions/Significance After 11 rounds of MDA over 7 years and a 16-month treatment gap, the urogenital schistosomiasis prevalence considerably rebounded in hotspot areas. Future elimination efforts in Zanzibar should focus on re-intensifying MDA plus additional interventions in hotspot areas. In low-prevalence areas, the strategy might be adapted from MDA to targeted surveillance-response.<br />Author summary Schistosomiasis is a neglected tropical disease caused by parasitic blood flukes of the genus Schistosoma. On the Zanzibar islands, United Republic of Tanzania, interventions to eliminate urogenital schistosomiasis commenced in 2012. From 2012 to 2016, the population was treated biannually with praziquantel and, additionally, some areas received mollusciciding against the intermediate host snail, or educational measures for behavior change. Mass drug administration (MDA) with praziquantel was continued annually in 2017 and 2018, but not in 2019. As a result of the interventions, the overall S. haematobium prevalence was reduced to 0.4% in adults and 3.4% in schoolchildren in 2020. However, in some areas, the MDA gap in 2019 resulted in a considerable rebound of infections. The recrudescence in 2020 was particularly striking for boys aged 9–16 years. In general, in 2020, male participants had higher odds of infection than females. Adults living near to a natural freshwater body also showed an increased risk of S. haematobium infection. Future elimination efforts in Zanzibar should focus on re-intensifying elimination interventions, including MDA, snail control and behavior change in hotspot areas. In low-prevalence areas, the strategy might be adapted from MDA to targeted interventions, such as surveillance-response.
- Subjects :
- Male
Cross-sectional study
Physiology
Epidemiology
RC955-962
Snails
Social Sciences
Marine and Aquatic Sciences
Fresh Water
Urine
Tanzania
Praziquantel
Geographical Locations
Schistosomiasis haematobia
Medical Conditions
Sociology
Recurrence
Risk Factors
Arctic medicine. Tropical medicine
Medicine and Health Sciences
Prevalence
Schistosomiasis
Child
Schistosoma haematobium
Schools
biology
Eukaryota
Middle Aged
Body Fluids
Infectious Diseases
Helminth Infections
Schistosoma
Educational Status
Mass Drug Administration
Female
Public aspects of medicine
RA1-1270
Anatomy
medicine.drug
Research Article
Freshwater Environments
Neglected Tropical Diseases
Adult
Adolescent
Schoolchildren
Education
Young Adult
Helminths
parasitic diseases
medicine
Parasitic Diseases
Animals
Humans
Risk factor
Mass drug administration
business.industry
Ecology and Environmental Sciences
Public Health, Environmental and Occupational Health
Organisms
Biology and Life Sciences
Aquatic Environments
Odds ratio
medicine.disease
biology.organism_classification
Tropical Diseases
Invertebrates
Confidence interval
Cross-Sectional Studies
Medical Risk Factors
People and Places
Africa
Earth Sciences
Population Groupings
business
Zoology
Demography
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- PLoS Neglected Tropical Diseases, PLoS Neglected Tropical Diseases, Vol 15, Iss 2, p e0009127 (2021)
- Accession number :
- edsair.doi.dedup.....efd2193511d50b598a35e78741d0d45b