A method to preserve low parasitaemia Plasmodium-infected avian blood for host and vector infectivity assays

Background Avian malaria vector competence studies are needed to understand more succinctly complex avian parasite-vector-relations. The lack of vector competence trials may be attributed to the difficulty of obtaining gametocytes for the majority of Plasmodium species and lineages. To conduct avian malaria infectivity assays for those Plasmodium spp. and lineages that are refractory to in vitro cultivation, it is necessary to obtain and preserve for short periods sufficient viable merozoites to infect naive donor birds to be used as gametocyte donors to infect mosquitoes. Currently, there is only one described method for long-term storage of Plasmodium spp.—infected wild avian blood and it is reliable at a parasitaemia of at least 1 %. However, most naturally infected wild-caught birds have a parasitaemia of much less that 1 %. To address this problem, a method for short-term storage of infected wild avian blood with low parasitaemia (even ≤0.0005 %) has been explored and validated.