Mixed-genotype infections of the rodent malaria Plasmodium chabaudi are more infectious to mosquitoes than single-genotype infections.
Interactions between parasite genotypes sharing a host are poorly understood, but have important consequences for the epidemiology and evolution of the parasite. In mixed-genotype malaria infections, patterns of asexual replication and transmission favoured by natural selection may be different from those in single-genotype infections. The infectivity to mosquitoes of mixed-genotype and single-genotype infections were compared using 2 clones of Plasmodium chabaudi inoculated into mice either together or alone. Mice given mixed-clone infections received the sum of the inocula given to the single-clone controls. Mosquitoes were fed on the mice and the numbers of oocysts which developed were counted to assess transmission intensity. For 3 combinations of starting inocula and feed days, mixed-clone infections produced more oocysts per mosquito than the sum of the 2 single-clone infections. This effect was correlated with an increase in gametocyte density, but was less clearly related to asexual infection parameters. The results show that interactions between clones in mixed-clone infections can profoundly affect transmission.
Taylor
L H
LH
University of Edinburgh, Institute of Cell, Animal and Population Biology, UK.
Walliker
D
D
Read
A F
AF
D000818:Animals; D000852:Anopheles / Q000469:parasitology*; D005838:Genotype; D006790:Host-Parasite Interactions; D007303:Insect Vectors / Q000469:parasitology*; D008288:Malaria / Q000469:parasitology / Q000635:transmission*; D051379:Mice; D008810:Mice, Inbred C57BL; D018512:Parasitemia / Q000469:parasitology; D016788:Plasmodium chabaudi / Q000235:genetics / Q000502:physiology*