While pblp blood stages initially grew at the same rate in mice as the WT parasites, there was a significant decrease in parasitemia levels throughout the course of infection, indicating that the mutants were unable to achieve the same level of growth as the WT parasites. The mutants produced smaller schizonts with visibly fewer merozoites when compared to WT parasites.

Oocyst numbers in A. stephensi were comparable to wild type (mean of 188 oocysts per mosquito compared to 169 in wild type). Sporozoite formation is blocked inside the oocysts and only few oocysts were found that contained sporozoites. Strongly reduced numbers of hemocoel and salivary gland sporozoites (see phenotype 'Sporozoite').

While there were no observable differences in exflagellation, pblp parasites produced approximately 30% fewer oocysts, resulting in significantly fewer oocyst-derived sporozoites as compared to the WT.

Sporozoite formation is blocked inside the oocysts and only few oocysts were found that contained sporozoites. Strongly reduced numbers of hemocoel and salivary gland sporozoites in infected A. stephensi mosquitoes (mean of 2625 sporozoites per salivary gland compared to over 10.000 in wild type).

Although there was also a decrease in the number of salivary gland sporozoites of pblp as compared to the WT, it was roughly proportional to the reduction of oocyst-derived sporozoite numbers. Evidence is presented that oocysts produced normal numbers of sporozoites. However, pblp sporozoites were visibly thinner than WT sporozoites with altered CSP staining although the inner membrane complex (IMC) was unaffected when assessed by myosin A-tail interacting protein (MTIP) staining. Additionally, pblp sporozoites displayed altered intracellular staining patterns for BIP and TRAP, which implies that PBLP might have an additional role in sporozoite maturation. pblp sporozoites show reduced host cell traversal and invasion in vitro and in vivo, resulting in a delay of prepatent period (1-2 days) when mice are infected with sporozoites. pblp sporozoites are less motile than WT sporozoites.

Strongly reduced numbers of hemocoel and salivary gland sporozoites in infected A. stephensi mosquitoes (mean of 2625 sporozoites per salivary gland compared to over 10.000 in wild type). No blood stage infections developed when mice were infected by bite of infected mosquitoes. Also intravenous injection of sporozoites (12x10(4)) did not result in blood stage infections. Sporozoites showed in vitro hepatocyte HepG2) traversal and invasion.

pblp sporozoites show reduced host cell traversal and invasion in vitro and in vivo, resulting in a delay of prepatent period (1-2 days) when mice are infected with sporozoites.pblp parasites display a delay in liver stage development.