Protective barrier

Malaria is a parasite that affects many organisms, yet mosquitoes can carry the disease without it triggering an immune response. How?

"Scientists. . . have found that when the mosquito takes a blood meal, that act triggers two enzymes to form a network of crisscrossing proteins around the ingested blood. The formation of this protein barrier, the researchers found, is part of the normal digestive process that allows so-called "healthy" or commensal gut bacteria to grow without activating mosquito immune responses."

"But there is a downside: The barrier also prevents the mosquito's immune defense system from clearing any disease-causing agents that may have slipped into the blood meal, such as the Plasmodium malaria parasite, which in turn can be passed on to humans." However, scientists believe that disrupting "the protein barrier. . . can trigger mosquito immune defenses to intervene and protect the insect from infection." It is possible that the mosquito's immune defenses will combat and eliminate malaria parasites before they are passed on to humans. Researchers are investigating a vaccine that "would generate antibodies" in humans which, "after a mosquito feeds on" the vaccinated human, "could disrupt the barrier, reduce parasite survival in the mosquito and prevent malaria transmission."

Source:

NIH/National Institute of Allergy and Infectious Diseases (2010, March 14). Barrier in mosquito midgut protects invading pathogens. ScienceDaily. Retrieved March 14, 2010, from http://www.sciencedaily.com¬ /releases/2010/03/100311175043.htm