Malaria caused by Plasmodium parasites is a life-threatening infectious disease that kills at least half a million people annually while causing over 200 million new infections. In some cases, complications can quickly develop such as cerebral malaria, respiratory distress and severe anemia, often leading to death. The majority of patients recover from disease, however, there is increasing evidence to suggest that survivors experience long-term ‘hidden’ pathologies due to infection that are as yet poorly defined.
Malaria parasites leave a trail of destruction in an infected person’s body. The microscopic invaders massacre red blood cells, produce harmful chemicals, and sometimes damage the brain. A new mouse study suggests that the parasites can also weaken bones. If they do the same in people, they could stunt the growth of children infected with the disease. But the study also provides some good news, identifying a potential way to prevent the skeletal decline with a compound similar to vitamin D.
Malaria parasites, which are transmitted through the bite of an infected mosquito, cause the most destruction during the part of their life cycle when they dwell in red blood cells circulating through the body. There, they reproduce and feast on oxygen-carrying hemoglobin proteins, releasing noxious byproducts. The parasites eventually explode from the blood cells, killing them in droves. Although researchers have also detected the parasites in bone marrow, where blood-forming stem cells reside, no one has known until now whether they damage the skeleton.
To find out, a team led by graduate student Michelle Lee and immunologist Cevayir Coban of Osaka University in Japan infected mice with either of two species of malaria parasites. The rodents’ immune systems fought off the parasites, but the animals’ skeletons showed the effects of the infection. “We found bone loss for both types of infections,” Coban says. In adult mice, the spongy material inside the bones began to break down. It contained more gaps, and support structures were thinner and less numerous. Similar changes occur in the bones of people with osteoporosis, Coban says.
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