Experimental test for premunition in a lizard malaria parasite (Plasmodium mexicanum).
Premunition in Plasmodium spp. is the prevention of superinfection by novel genotypes entering an already established infection in a vertebrate host. Evidence for premunition was sought for the lizard malaria parasite, P. mexicanum, in its natural host, the fence lizard, Sceloporus occidentalis. Clonal diversity (= alleles for the haploid parasite) was determined with the use of 3 microsatellite markers. Both naturally infected lizards (N = 25) and previously noninfected lizards (N = 78) were inoculated intraperitoneally (IP) with blood from donor infections and followed over a 3-mo period. Compared to the success of clonal establishment in all the naive lizards (78/78 successful), clones entering preexisting infections had a significant disadvantage (9/25 successful). The number of preexisting clones (1-2 vs. 3-4) within recipient infections had no effect on the success of superinfection. Infections that excluded entering novel clones did not have higher initial asexual parasitemia, but had a higher initial density of gametocytes, suggesting they were older. Infections allowing superinfection experienced a higher final parasitemia.
Vardo
Anne M
AM
Department of Biology, University of Vermont, Burlington, Vermont 05405, USA. anne.vardo@uvm.edu
Kaufhold
Kimberly D
KD
Schall
Jos J
JJ
D000818:Animals; D005838:Genotype; D008116:Lizards / Q000469:parasitology*; D008288:Malaria / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D008297:Male; D018895:Microsatellite Repeats; D018512:Parasitemia / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D010961:Plasmodium / Q000145:classification / Q000235:genetics* / Q000276:immunology; D015163:Superinfection / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*