Protective efficacy and safety of liver stage attenuated malaria parasites.

During the clinically silent liver stage of a Plasmodium infection the parasite replicates from a single sporozoite into thousands of merozoites. Infection of humans and rodents with large numbers of sporozoites that arrest their development within the liver can cause sterile protection from subsequent infections. Disruption of genes essential for liver stage development of rodent malaria parasites has yielded a number of attenuated parasite strains.

Actin regulation in the malaria parasite.

Many intracellular pathogens hijack host cell actin or its regulators for cell-to-cell spreading. In marked contrast, apicomplexan parasites, obligate intracellular, single cell eukaryotes that are phylogenetically older than the last common ancestor of animals and plants, employ their own actin cytoskeleton for active motility through tissues and invasion of host cells. A hallmark of actin-based motility of the malaria parasite is a minimal set of proteins that potentially regulate microfilament dynamics.