Currently, few antimalarial treatments exist that effectively kill liver-stage malaria parasite Plasmodium vivax, which can lay dormant for months or even years. Researchers have reported a new drug that could eliminate liver-stage malaria parasites completely. Using an insect virus, known as a baculovirus, the researchers investigated the ability of baculovirus to mediate innate immunity against malaria infection. This work could pave the way for developing new and more effective antimalarial treatments.
Malaria is caused by Plasmodium, a parasite spread by the Anopheles mosquito as it feasts on blood. The parasite is released into the bloodstream and travels to the liver to mature, before being released back into the bloodstream where it infects red blood cells. Symptoms normally appear a few days or weeks later, but in the case of P. vivax, the parasites can also lay dormant in the liver with disease recurring months or even years later (known as hypnozoites). P. vivax is the most widely distributed human malaria parasite in the world (a major health risk to 2.85 billion people worldwide). The active blood-borne form of P. vivax can be targeted with artemisinin, but only a single drug, primaquine, is available for the hypnozoites.
However, primaquine is associated with a high risk of life-threatening hemolytic anemia in people with glucose-6-phosphate-dehydrogenase enzyme deficiency. In addition, even effective doses can cause several side effects including nausea and vomiting. “Malarial infection affects a large number of individuals each year, many of whom are young children aged under five.” says first author Talha Bin Emran. “Current treatments can have serious side effects for some individuals, hence safer radical curative drugs that efficiently kill the hypnozoites are urgently needed.”