BSP Spring Meeting 2019
Schedule : Back to Dr Petra Schneider

When to make an entrance.

Mon15  Apr05:30pm(15 mins)
Renold C16


P Schneider1; A J O'Donnell1; S E Reece1
1 University of Edinburgh, Institute of Evolutionary Biology, UK


Recently, we highlighted the importance of daily rhythms of both mosquitoes and hosts/parasites for the transmission of malaria parasites from the vertebrate host to mosquitoes. But how important is the time of transmission for entering the vertebrate host? Asking whether transmission from mosquito to vertebrate host is more - or less - efficient during the daytime versus night time matters given reports of mosquitoes changing the time-of-day they blood feed in response to bednet use. Here we investigate how well Plasmodium berghei establishes liver-stage infections in mice, after night time (host active phase) or daytime (host resting phase) transmission. We control for any role of mosquito and parasite rhythms to focus on the importance of host time-of-day for the successful establishment and replication of incoming parasites. Furthermore, we also examine whether pyrimethamine prophylaxis mediates the effects of host time-of-day. We find that liver infections reach higher levels in hosts that are infected by mosquitoes during the daytime (host resting phase) compared to the night time (host active phase). Pyrimethamine reduces liver infection levels and negates any time-of-day effects. Our results could be explained by differences in host rhythms for immunity and/or metabolism. Making an entrance at the right time helps parasites establish successful liver infections. If we extrapolate our results from malaria in nocturnal mice to malaria in humans (with the usual caveats), liver infection levels would reach higher levels - and prophylaxis would have higher relative efficacy -after night time compared to daytime infections. This could have implications for epidemiology and disease control, especially if bednet use alters mosquito biting times.

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British Society for Parasitology (BSP)

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