Predicting the likelihood and intensity of mosquito infection from sex specific Plasmodium falciparum gametocyte density
- London School of Hygiene and Tropical Medicine, United Kingdom
- Radboud University Medical Center, Netherlands
- Institut de Recherche en Sciences de la Santé, Burkina Faso
- Institut de Recherche pour le Développement, France
- University of Science, Techniques and Technologies of Bamako, Mali
- Centre National de Recherche et de Formation sur le Paludisme, Burkina Faso
- Université de Douala, Cameroon
- University of California, San Francisco, United States
- Imperial College London, United Kingdom
Abstract
Understanding the importance of gametocyte density on human-to-mosquito transmission is of immediate relevance to malaria control. Previous work (Churcher et al., 2013) indicated a complex relationship between gametocyte density and mosquito infection. Here we use data from 148 feeding experiments on naturally infected gametocyte carriers to show that the relationship is much simpler and depends on both female and male parasite density. The proportion of mosquitoes infected is primarily determined by the density of female gametocytes though transmission from low gametocyte densities may be impeded by a lack of male parasites. Improved precision of gametocyte quantification simplifies the shape of the relationship with infection increasing rapidly before plateauing at higher densities. The mean number of oocysts per mosquito rises quickly with gametocyte density but continues to increase across densities examined. The work highlights the importance of measuring both female and male gametocyte density when estimating the human reservoir of infection.
Data availability
All raw data can be found in Source Data Supplements to the relevant figures
Article and author information
Author details
Funding
Bill and Melinda Gates Foundation (AFIRM OPP1034789)
- Chris Drakeley
- Teun Bousema
European Commission (ERC-2014-StG 639776)
- Will Stone
- Teun Bousema
PATH (Malaria Vaccine Iniative)
- Dari FA DA
- Isabelle Morlais
- Anna Cohuet
- Teun Bousema
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Urszula Krzych, Walter Reed Army Institute of Research, United States
Version history
- Received: December 21, 2017
- Accepted: May 26, 2018
- Accepted Manuscript published: May 31, 2018 (version 1)
- Version of Record published: June 21, 2018 (version 2)
Copyright
© 2018, Bradley 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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Predicting the likelihood and intensity of mosquito infection from sex specific Plasmodium falciparum gametocyte density
eLife 7:e34463.
https://doi.org/10.7554/eLife.34463
Further reading
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Background:
Circulating omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) have been associated with various chronic diseases and mortality, but results are conflicting. Few studies examined the role of omega-6/omega-3 ratio in mortality.
Methods:
We investigated plasma omega-3 and omega-6 PUFAs and their ratio in relation to all-cause and cause-specific mortality in a large prospective cohort, the UK Biobank. Of 85,425 participants who had complete information on circulating PUFAs, 6461 died during follow-up, including 2794 from cancer and 1668 from cardiovascular disease (CVD). Associations were estimated by multivariable Cox proportional hazards regression with adjustment for relevant risk factors.
Results:
Risk for all three mortality outcomes increased as the ratio of omega-6/omega-3 PUFAs increased (all Ptrend <0.05). Comparing the highest to the lowest quintiles, individuals had 26% (95% CI, 15–38%) higher total mortality, 14% (95% CI, 0–31%) higher cancer mortality, and 31% (95% CI, 10–55%) higher CVD mortality. Moreover, omega-3 and omega-6 PUFAs in plasma were all inversely associated with all-cause, cancer, and CVD mortality, with omega-3 showing stronger effects.
Conclusions:
Using a population-based cohort in UK Biobank, our study revealed a strong association between the ratio of circulating omega-6/omega-3 PUFAs and the risk of all-cause, cancer, and CVD mortality.
Funding:
Research reported in this publication was supported by the National Institute of General Medical Sciences of the National Institute of Health under the award number R35GM143060 (KY). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
