title: Existing Infection Facilitates Establishment and Density of Malaria Parasites in Their Mosquito Vector.
abstract: Very little is known about how vector-borne pathogens interact within their vector and how this impacts transmission. Here we show that mosquitoes can accumulate mixed strain malaria infections after feeding on multiple hosts. We found that parasites have a greater chance of establishing and reach higher densities if another strain is already present in a mosquito. Mixed infections contained more parasites but these larger populations did not have a detectable impact on vector survival. Together these results suggest that mosquitoes taking multiple infective bites may disproportionally contribute to malaria transmission. This will increase rates of mixed infections in vertebrate hosts, with implications for the evolution of parasite virulence and the spread of drug-resistant strains. Moreover, control measures that reduce parasite prevalence in vertebrate hosts will reduce the likelihood of mosquitoes taking multiple infective feeds, and thus disproportionally reduce transmission. More generally, our study shows that the types of strain interactions detected in vertebrate hosts cannot necessarily be extrapolated to vectors.
authors.affiliation: Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom; Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Pollitt
authors.affiliation: Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America.
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Bram
authors.affiliation: Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America.
authors.forename: Simon
authors.initials: S
authors.lastname: Blanford
authors.affiliation: Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Jones
authors.affiliation: Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America; Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Read
mesh_terms: D000818:Animals; D005075:Biological Evolution; D009033:Culicidae / Q000469:parasitology*; D005247:Feeding Behavior; D054884:Host-Pathogen Interactions / Q000502:physiology*; D008288:Malaria / Q000635:transmission*