Mapping imported malaria in Bangladesh using parasite genetic and human mobility data
Abstract
For countries aiming for malaria elimination, travel of infected individuals between endemic areas undermines local interventions. Quantifying parasite importation has therefore become a priority for national control programs. We analyzed epidemiological surveillance data, travel surveys, parasite genetic data, and anonymized mobile phone data to measure the spatial spread of malaria parasites in southeast Bangladesh. We developed a genetic mixing index to estimate the likelihood of samples being local or imported from parasite genetic data and inferred the direction and intensity of parasite flow between locations using an epidemiological model integrating the travel survey and mobile phone calling data. Our approach indicates that, contrary to dogma, frequent mixing occurs in low transmission regions in the southwest, and elimination will require interventions in addition to reducing imported infections from forested regions. Unlike risk maps generated from clinical case counts alone, therefore, our approach distinguishes areas of frequent importation as well as high transmission.
Data availability
All genetic data are included in Supplementary file 4 and all travel matrices are included in Supplementary file 5.
Article and author information
Author details
Funding
National Institute of General Medical Sciences (U54GM088558)
- Hsiao-Han Chang
Burroughs Wellcome Fund
- Amy Wesolowski
Bill and Melinda Gates Foundation (CPT000390)
- Ipsita Sinha
- Sazid Ibna Zaman
- Richard J Maude
Medical Research Council (G0600718)
- Christopher G Jacob
- Eleanor Drury
- Sonia Gonçalves
- Mihir Kekre
- Dominic Kwiatkowski
National Institute of General Medical Sciences (R35GM124715-02)
- Caroline Buckee
Bill and Melinda Gates Foundation (OPP1118166)
- Christopher G Jacob
- Olivo Miotto
- Caroline Buckee
Bill and Melinda Gates Foundation (OPP1129596)
- Ipsita Sinha
- Sazid Ibna Zaman
- Richard J Maude
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Neil M Ferguson, Imperial College London, United Kingdom
Publication history
- Received: November 9, 2018
- Accepted: March 14, 2019
- Accepted Manuscript published: April 2, 2019 (version 1)
- Version of Record published: April 23, 2019 (version 2)
Copyright
© 2019, Chang et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Further reading
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Background: In Italy, Regions have the mandate to implement population-based screening programs for breast, cervical, and colorectal cancer. From March to May 2020, a severe lockdown was imposed due to the COVID-19 pandemic by the Italian Ministry of Health, with the suspension of screening programs. This paper describes the impact of the pandemic on Italian screening activities and test coverage in 2020 overall and by socio-economic characteristics.
Methods: The regional number of subjects invited and of screening tests performed in 2020 were compared with those in 2019. Invitation and examination coverage were also calculated. PASSI surveillance system, through telephone interviews, collects information about screening test uptake by test provider (public screening and private opportunistic). Test coverage and test uptake in the last year were computed, by educational attainment, perceived economic difficulties, and citizenship.
Results: A reduction of subjects invited and tests performed, with differences between periods and geographic macro areas, was observed in 2020 vs. 2019. The reduction in examination coverage was larger than that in invitation coverage for all screening programs. From the second half of 2020, the trend for test coverage showed a decrease in all the macro areas for all the screening programs. Compared with the pre-pandemic period, there was a greater difference according to the level of education in the odds of having had a test last year vs. never having been screened or not being up to date with screening tests.
Conclusions: The lockdown and the ongoing COVID-19 emergency caused an important delay in screening activities. This increased the pre-existing individual and geographical inequalities in access. The opportunistic screening did not mitigate the impact of the pandemic.
Funding: This study was partially supported by Italian Ministry of Health - Ricerca Corrente Annual Program 2023.
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- Epidemiology and Global Health
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