Blood meals from ‘dead-end’ vertebrate hosts enhance transmission potential of malaria-infected mosquitoes

Abstract

ABSTRACTIngestion of an additional blood meal(s) by mosquitoes can accelerate parasite migration to the salivary glands in infected mosquitoes. Most studies, however, offer blood from the same vertebrate host species as the original challenge (for e.g., human for primary and additional blood meals). Here, we show a second blood meal from bovine and canine hosts can also enhance sporozoite migration inAnopheles stephensimosquitoes infected with the human- and rodent-restrictedPlasmodium falciparumandP. bergheirespectively. The extrinsic incubation period (time to sporozoite appearance in salivary glands) showed more consistent reductions with blood from human and bovine donors than canine blood, although the latter’s effect may be confounded by the toxicity, albeit non-specific, associated with the anticoagulant used to collect whole blood from donors. The complex patterns of enhancement highlight the limitations of a laboratory system but are nonetheless reminiscent of parasite host-specificity and mosquito adaptations, and the genetic predisposition ofAn. stephensifor bovine blood. We suggest that in natural settings, a blood meal from any vertebrate host could accentuate the risk of human infections byP. falciparum, although our observations should also be applicable to other species ofPlasmodiumand indeed other vector-borne diseases such as arboviruses for instance.Graphical AbstractHIGHLIGHTSPlasmodium falciparumandP. bergheicause malaria in humans and rodents, respectively.They are vectored byAnophelesspecies that can also imbibe blood from other vertebrate species.Parasite development is enhanced after another blood meal, usually from the same host (e.g., human).Here, bovine, and canine blood also enhanced development ofPlasmodiumspecies inAn. stephensi.In natural settings, blood from any host could enhance development of vector transmitted parasites.