Infection with parasitic worms such as Schistosoma may increase the likelihood of becoming infected with HIV, scientists say. The groups from the Centre for Disease Control and Prevention, the Dana Farber Cancer Institute and Harvard Medical School, all in the U.S., showed that in rhesus monkeys the dose of simian HIV needed for infection was 17 times lower in the monkeys infected with Schistosoma than those not infected.
Schistosoma, a parasitic worm that causes the disease schistosomiasis, is endemic to many tropical countries and over half of the 200 million people estimated to be infected with them live in Africa, also where over 65% of the world’s AIDS cases are.
The probable reason that infection with parasitic worms increases susceptibility to HIV infection is that the infection with Schistosoma decreases the numbers of memory T cells; white blood cells that are involved in recognizing and mounting the body’s defences against invading pathogens such as the HIV virus. With fewer of them, the virus is more able to take hold in the body.
The scientists have suggested that treatments for these worm infections may be useful in trying to combat the spread of HIV/AIDS in the developing world.