Natural defence mechanisms (or innate factors) against malaria are most apparent in populations continually exposed to malaria parasites. For example, inherited conditions such as sickle cell anaemia and beta-thalassaemia, which cause deformities in red blood cells and are common in people from malarious regions, make it more difficult for malaria parasites to infect red blood cells.
Some people have red blood cells that lack proteins called Duffy antigens on their surface. These proteins act as receptors for Plasmodium vivax merozoites, so people without Duffy antigens are resistant to infection from this parasite.
Feature: Malaria versus the human genome
People residing in malaria-endemic regions acquire immunity to malaria through natural exposure to malaria parasites. Children living in areas of stable malaria transmission become infected early in life, and experience more severe disease symptoms during the first five years of life. But as immunity develops the disease becomes less severe and the number of parasites circulating in the blood declines. The acquired immune response to malaria is strain specific and is lost if a person moves away from a malaria endemic area.
what is meant by natural immunity to parasites?
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