Abstract
Bites of Anopheles mosquitoes transmit Plasmodium falciparum parasites that cause malaria, which kills hundreds of thousands of people every year. Since the turn of this century, efforts to prevent the transmission of these parasites via the mass distribution of insecticide-treated bed nets have been extremely successful, and have led to an unprecedented reduction in deaths from malaria1. However, resistance to insecticides has become widespread in Anopheles populations2,3,4, which has led to the threat of a global resurgence of malaria and makes the generation of effective tools for controlling this disease an urgent public health priority. Here we show that the development of P. falciparum can be rapidly and completely blocked when female Anopheles gambiae mosquitoes take up low concentrations of specific antimalarials from treated surfaces—conditions that simulate contact with a bed net. Mosquito exposure to atovaquone before, or shortly after, P. falciparum infection causes full parasite arrest in the midgut, and prevents transmission of infection. Similar transmission-blocking effects are achieved using other cytochrome b inhibitors, which demonstrates that parasite mitochondrial function is a suitable target for killing parasites. Incorporating these effects into a model of malaria transmission dynamics predicts that impregnating mosquito nets with Plasmodium inhibitors would substantially mitigate the global health effects of insecticide resistance. This study identifies a powerful strategy for blocking Plasmodium transmission by female Anopheles mosquitoes, which has promising implications for efforts to eradicate malaria.
This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
Data availability
Raw data for infection experiments are available as Supplementary Data. All further data are available upon request.
References
Bhatt, S. et al. The effect of malaria control on Plasmodium falciparum in Africa between 2000 and 2015. Nature 526, 207–211 (2015).
Toé, K. H. et al. Increased pyrethroid resistance in malaria vectors and decreased bed net effectiveness, Burkina Faso. Emerg. Infect. Dis. 20, 1691–1696 (2014).
Van Bortel, W. et al. The insecticide resistance status of malaria vectors in the Mekong region. Malar. J. 7, 102 (2008).
Dykes, C. L. et al. Knockdown resistance (kdr) mutations in Indian Anopheles culicifacies populations. Parasit. Vectors 8, 333 (2015).
Ondeto, B. M. et al. Current status of insecticide resistance among malaria vectors in Kenya. Parasit. Vectors 10, 429 (2017).
Raghavendra, K. et al. Chlorfenapyr: a new insecticide with novel mode of action can control pyrethroid resistant malaria vectors. Malar. J. 10, 16 (2011).
N’Guessan, R., Odjo, A., Ngufor, C., Malone, D. & Rowland, M. A chlorfenapyr mixture net Interceptor® G2 shows high efficacy and wash durability against resistant mosquitoes in West Africa. PLoS ONE 11, e0165925 (2016).
Ngufor, C. et al. Olyset Duo® (a pyriproxyfen and permethrin mixture net): an experimental hut trial against pyrethroid resistant Anopheles gambiae and Culex quinquefasciatus in Southern Benin. PLoS ONE 9, e93603 (2014).
World Health Organization. World Malaria Report 2018 https://www.who.int/malaria/publications/world-malaria-report-2018/report/en/ (World Health Organization, Geneva, 2018).
World Health Organization. Guidelines for Testing Mosquito Adulticides for Indoor Residual Spraying and Treatment of Mosquito Nets. http://www.who.int/iris/handle/10665/69296 (World Health Organization, 2006).
Owusu, H. F., Chitnis, N. & Müller, P. Insecticide susceptibility of Anopheles mosquitoes changes in response to variations in the larval environment. Sci. Rep. 7, 3667 (2017).
Parker, J. E. et al. Infrared video tracking of Anopheles gambiae at insecticide-treated bed nets reveals rapid decisive impact after brief localised net contact. Sci. Rep. 5, 13392 (2015).
Fowler, R. E., Billingsley, P. F., Pudney, M. & Sinden, R. E. Inhibitory action of the anti-malarial compound atovaquone (566C80) against Plasmodium berghei ANKA in the mosquito, Anopheles stephensi. Parasitology 108, 383–388 (1994).
Delves, M. et al. The activities of current antimalarial drugs on the life cycle stages of Plasmodium: a comparative study with human and rodent parasites. PLoS Med. 9, e1001169 (2012).
Fiorenzano, J. M., Koehler, P. G. & Xue, R. D. Attractive toxic sugar bait (ATSB) for control of mosquitoes and its impact on non-target organisms: a review. Int. J. Environ. Res. Public Health 14, E398 (2017).
Childs, L. M. et al. Disrupting mosquito reproduction and parasite development for malaria control. PLoS Pathog. 12, e1006060 (2016).
Knox, T. B. et al. An online tool for mapping insecticide resistance in major Anopheles vectors of human malaria parasites and review of resistance status for the Afrotropical region. Parasit. Vectors 7, 76 (2014).
Srivastava, I. K., Rottenberg, H. & Vaidya, A. B. Atovaquone, a broad spectrum antiparasitic drug, collapses mitochondrial membrane potential in a malarial parasite. J. Biol. Chem. 272, 3961–3966 (1997).
Painter, H. J., Morrisey, J. M., Mather, M. W. & Vaidya, A. B. Specific role of mitochondrial electron transport in blood-stage Plasmodium falciparum. Nature 446, 88–91 (2007).
Richards, W. H. & Maples, B. K. Studies on Plasmodium falciparum in continuous cultivation. I. The effect of chloroquine and pyrimethamine on parasite growth and viability. Ann. Trop. Med. Parasitol. 73, 99–108 (1979).
Nam, T. G. et al. A chemical genomic analysis of decoquinate, a Plasmodium falciparum cytochrome b inhibitor. ACS Chem. Biol. 6, 1214–1222 (2011).
Witschel, M., Rottmann, M., Kaiser, M. & Brun, R. Agrochemicals against malaria, sleeping sickness, leishmaniasis and Chagas disease. PLoS Negl. Trop. Dis. 6, e1805 (2012).
Goodman, C. D. et al. Parasites resistant to the antimalarial atovaquone fail to transmit by mosquitoes. Science 352, 349–353 (2016).
Blake, L. D. et al. Menoctone resistance in malaria parasites is conferred by M133I mutations in cytochrome b that are transmissible through mosquitoes. Antimicrob. Agents Chemother. 61, e00689-17 (2017).
Boysen, K. E. & Matuschewski, K. Arrested oocyst maturation in Plasmodium parasites lacking type II NADH:ubiquinone dehydrogenase. J. Biol. Chem. 286, 32661–32671 (2011).
Hino, A. et al. Critical roles of the mitochondrial complex II in oocyst formation of rodent malaria parasite Plasmodium berghei. J. Biochem. 152, 259–268 (2012).
Sturm, A., Mollard, V., Cozijnsen, A., Goodman, C. D. & McFadden, G. I. Mitochondrial ATP synthase is dispensable in blood-stage Plasmodium berghei rodent malaria but essential in the mosquito phase. Proc. Natl Acad. Sci. USA 112, 10216–10223 (2015).
Trager, W. & Jensen, J. B. Human malaria parasites in continuous culture. Science 193, 673–675 (1976).
Ifediba, T. & Vanderberg, J. P. Complete in vitro maturation of Plasmodium falciparum gametocytes. Nature 294, 364–366 (1981).
Christiansen-Jucht, C., Erguler, K., Shek, C. Y., Basáñez, M. G. & Parham, P. E. Modelling Anopheles gambiae s.s. population dynamics with temperature- and age-dependent survival. Int. J. Environ. Res. Public Health 12, 5975–6005 (2015).
Smith, D. L., Drakeley, C. J., Chiyaka, C. & Hay, S. I. A quantitative analysis of transmission efficiency versus intensity for malaria. Nat. Commun. 1, 108 (2010).
Boudin, C., Olivier, M., Molez, J. F., Chiron, J. P. & Ambroise-Thomas, P. High human malarial infectivity to laboratory-bred Anopheles gambiae in a village in Burkina Faso. Am. J. Trop. Med. Hyg. 48, 700–706 (1993).
Killeen, G. F., Ross, A. & Smith, T. Infectiousness of malaria-endemic human populations to vectors. Am. J. Trop. Med. Hyg. 75, 38–45 (2006).
Acknowledgements
We thank N. Singh, E. Lund and K. Thornburg for Plasmodium and Anopheles culture; M. Bernardi for help with graphics; D. Wirth, S. Bopp, H. Ranson, and the members of the Catteruccia laboratories for comments and suggestions on the manuscript. Malaria prevalence and LLIN coverage map data were retrieved from the Malaria Atlas Project (www.map.ox.ac.uk). Insecticide resistance data were retrieved from the IR Mapper database (www.irmapper.com). F.C. is funded by a Faculty Research Scholar Award by the Howard Hughes Medical Institute (HHMI) and the Bill & Melinda Gates Foundation (BMGF) (Grant ID: OPP1158190), and by the National Institutes of Health (NIH) (R01 AI124165, R01 AI104956). L.M.C. is supported by Simons Foundation Collaboration Grant 524390. C.O.B. is supported by NIGMS Maximizing Investigator's Research Award (MIRA) R35GM124715-02. The findings and conclusions within this publication are those of the authors and do not necessarily reflect positions or policies of the HHMI, the BMGF, Simons Foundation or the NIH.
Reviewer information
Nature thanks Jaline Gerardin, Janet Hemingway, Elizabeth Winzeler and the other anonymous reviewer(s) for their contribution to the peer review of this work.
Author information
Authors and Affiliations
Contributions
D.G.P. carried out and analysed infection and fitness experiments. M.A.I. carried out immunofluorescent assays. L.M.C. and I.E.H. generated code and carried out mathematical modelling. C.O.B. and F.C. supervised the study.
Corresponding author
Ethics declarations
Competing interests
A patent application (US provisional application no. 62/726,757) covering the concept of the application of antimalarial compounds to mosquitoes has been filed on behalf of F.C. and D.G.P. by the President and Fellows of Harvard University. The authors state that they have no other competing interests.
Additional information
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data figures and tables
Extended Data Fig. 1 Effects of ATQ exposure on survival and post-blood-feeding egg production in A. gambiae female mosquitoes.
a, ATQ exposure has no effect on the acute or long-term survival of A. gambiae female mosquitoes (two-sided log-rank Mantel–Cox, n = 189, df = 1, χ2 = 0.00, P = 0.9951). The sigmoidal fit used for subsequent modelling is shown. b, The production of eggs after an infectious blood meal is unaffected by ATQ exposure (two-sided, unpaired Student’s t-test, n = 75, df = 1, t = 0.826, P = 0.4115). Means and 95% confidence intervals of the mean are indicated. ns, not significant; n indicates the number of biologically independent mosquito samples.
Extended Data Fig. 2 Model structure and population parameters.
a, Schematic of the mosquito life cycle model with the time step of one day. Mosquitoes spend three days as eggs (Ei) and ten days as larvae (Li) (which includes the pupal stage). Adult female mosquito compartments fall within the dashed box, and begin with a rest day (R0) followed by mating (M) or feeding (F). After feeding, female mosquitoes undergo two days of rest (Ri), followed by a day for egg laying (EL). Then, the cycle repeats. Shaded boxes denote when exposure to insecticide or ATQ could occur. These are the same compartments in which mosquitoes can become infected or transmit infections, assuming they have been infected for a period longer than the incubation time. b, Survival of the mosquito population as a function of age. The curve is a Gompertz distribution with scale parameter b = 0.1868 and shape parameter η = 0.0293. c, Functions relating infection levels of humans and mosquito to risk of infection. Subpanel (i) shows the risk of a human becoming infected, βH, as a function of the number of infectious feeders, f. Subpanel (ii) shows the risk of a mosquito becoming infected, βM, as a function of the fraction of the human population that is infected, IH.
Extended Data Fig. 3 Sensitivity of model results to variation in prevalence, coverage and insecticide resistance.
The graphs show the enhanced effectiveness of insecticide combined with ATQ (relative to insecticide alone) in reducing human prevalence under varying levels of coverage (across panels), prevalence (along x axis), and insecticide resistance (IR) (bar colour). The enhanced effectiveness of the interventions is defined as human prevalence with only insecticide − human prevalence with insecticide and ATQ, divided by human prevalence with insecticide alone, and is represented by positive values when the addition of ATQ is beneficial. Prevalence is quantified after ten years of simulation. The coverage is varied from 20–80% (top left panel 20%; top right panel 40%; bottom left panel 60%; and bottom right panel 80%). In each panel, the position of the bars determines the malaria prevalence under no intervention, from 20–80%. In the complete absence of insecticide resistance, all mosquitoes that contact insecticide are killed; all dark-green bars equal zero.
Extended Data Fig. 4 Malaria transmission model predicting the effects of adding ATQ to insecticide-treated nets in additional malaria prevalence settings.
a, b, The heat maps show changes in malaria transmission for bed net-like interventions using insecticide alone or insecticide plus an ATQ-like compound, relative to no intervention at varying coverage and varying insecticide resistance levels. The model considers both 20% (a) and 70% (b) prevalence of malaria. The effectiveness of the interventions is defined as (1 − proportion reduction in malaria transmission relative to no intervention), and is represented as colours ranging from yellow (no change in malaria transmission) to dark blue (elimination of malaria transmission) at varying levels of coverage (x axis) and insecticide resistance (y axis). Insecticide resistance is the percentage of mosquitoes that are impervious to insecticide. Coverage is the probability of a mosquito encountering an intervention during a single feeding episode. The model output demonstrates that addition of ATQ significantly increases the ability of an LLIN-like intervention to reduce and even eliminate malaria transmission.
Extended Data Fig. 5 Testing additional compounds for fitness costs and transmission-blocking activity through tarsal contact.
a, Mosquito survival relative to an untreated control 48 h after exposure to ATQ, DEC, PYR, HYD, ACE and PER. The proportion of female A. gambiae surviving exposure to each compound (1 mmol per m2, 60 min) relative to the proportion of individuals surviving exposure to an untreated control is shown. PER exposure causes almost complete mortality (proportionate survival relative to controls = 0.055, pairwise two-sided chi-squared test with Bonferroni correction, n = 80, df = 1, χ2 = 76.10, P < 0.0001), whereas all other compounds behave comparably to controls. b, Neither PYR nor DEC (1 mmol per m2, 6 min) are capable of reducing the prevalence of P. falciparum through tarsal contact, relative to controls (pairwise two-sided chi-squared test with Bonferroni correction: DEC, n = 93, df = 1, χ2 = 2.42, P = 0.12; PYR, n = 92, df = 1, χ2 = 0.55, P = 0.46). Similarly, DEC and PYR had no effect on the intensity of infection, compared to a mock-treated control (Wilcoxon with Dunn’s post hoc test, n = 183, df = 3, P = 0.31 (DEC) and P = 0.99 (PYR)). Letters indicate groups that are statistically different from one another. ****P < 0.0001. Medians are indicated; n denotes the number of biologically independent mosquito samples.
Extended Data Fig. 6 ATQ exposure via a netting substrate completely inhibits P. falciparum development.
A. gambiae female mosquitoes were allowed to rest for 60 min on 100-denier polyester netting that had been treated with either a 0.5 mg ml−1 (0.05% w/v) solution of ATQ in acetone, or acetone alone. Females exposed to ATQ in this way failed to become infected after an infectious P. falciparum blood meal, demonstrating that a netting substrate is also capable of delivering sufficiently high doses of ATQ to inhibit infection (two-sided chi-squared test, n = 98, df = 1, χ2 = 75.55, P < 0.0001). ****P < 0.0001. Medians are indicated; n denotes the number of biologically independent mosquito samples.
Supplementary information
Rights and permissions
About this article
Cite this article
Paton, D.G., Childs, L.M., Itoe, M.A. et al. Exposing Anopheles mosquitoes to antimalarials blocks Plasmodium parasite transmission. Nature 567, 239–243 (2019). https://doi.org/10.1038/s41586-019-0973-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41586-019-0973-1
This article is cited by
-
Attractive targeted sugar bait: the pyrrole insecticide chlorfenapyr and the anti-malarial pharmaceutical artemether–lumefantrine arrest Plasmodium falciparum development inside wild pyrethroid-resistant Anopheles gambiae s.s. mosquitoes
Malaria Journal (2023)
-
Sub-lethal exposure to chlorfenapyr reduces the probability of developing Plasmodium falciparum parasites in surviving Anopheles mosquitoes
Parasites & Vectors (2023)
-
Overcoming insecticide resistance in Anopheles mosquitoes by using faster-acting solid forms of deltamethrin
Malaria Journal (2023)
-
The interplay between malaria vectors and human activity accounts for high residual malaria transmission in a Burkina Faso village with universal ITN coverage
Parasites & Vectors (2023)
-
Antimalarial drug discovery: progress and approaches
Nature Reviews Drug Discovery (2023)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.