Immunity can be weakened by parasites

INFECTIONS caused by certain parasites can compromise the immune system, leaving it less well equipped to deal with other diseases, according to the first study of its kind by Edinburgh scientists.

Research into the tropical disease snail fever could help scientists better understand why, in areas where the infection is endemic, vaccines for other conditions may not be fully effective.

It could also impact on the development of vaccines for snail fever, which is caused by a parasitic worm contracted from water.

In the first study of its kind, scientists from Edinburgh University examined the immune systems of people in parts of rural Zimbabwe that are endemic for snail fever. People who had developed natural resistance to snail fever over years of exposure to the disease were compared with participants from the same area who remained infected by the parasites.

They found that in infected people, overall immunity was compromised, with reduced levels of a cell type that helps the body remember infections after first being exposed to them, and prevent repeat episodes of disease.