New Malaria Drug Appears Effective To Stop Deadly Infection

Researchers found a new way to stop the spread of malaria. The method targets an enzyme that supports the development of the parasite and blocks its ability to be transmitted between humans and mosquitoes.

The new study, published in Cell Reports, suggests that using plasmepsin V could help scientists create new drugs to fight malaria. The enzyme plays an important role in the development of gametocytes, the only form of the parasite, Plasmodium falciparum, that can be transmitted from humans to mosquitoes.

P. falciparum has been linked to 90 percent of all cases of malaria across the world. Scientists previously found it difficult to prevent the spread of malaria because the parasite constantly mutates and can develop resistance to existing therapies.

To block plasmepsin V during its growth, researchers used small molecule inhibitors. The method mainly cuts the “transmission stage” of P. falciparum’s life cycle. 

"It was exciting to find that plasmepsin V plays a role in malaria transmission, and that our inhibitors could target plasmepsin V and block transmission to the mosquito from occurring," Justin Boddey, lead researcher and an associate professor at the Walter and Eliza Hall Institute and University of Melbourne, said in a statement. “This shows plasmepsin V is a target for transmission-blocking drugs.”

He added they only needed optimal concentration of the inhibitors or lower dose to kill gametocytes and prevent it from being transmitted to mosquitoes. The latest study supports previous findings that showed plasmepsin V was an effective drug target for killing the malaria parasite.

In 2014, researchers discovered that blocking the enzyme could help kill the malaria parasite in the asexual blood stage of its lifecycle. This is the stage when symptoms of the disease, such as fever, chills, muscle pain and nausea, start to appear. 

“Our research demonstrates that an antimalarial treatment targeting plasmepsin V has potential, not only in treatment of the disease, but also as a preventative population control measure,” Brad Sleebs, a chemical biologist at the Walter and Eliza Hall Institute, said. 

The team plans to continue the study to see how their method affects plasmepsin V in the last part of malaria lifecycle -- the liver stage. Researchers aim to use the enzyme to develop a multi-stage drug target that would work both for treating and preventing the spread of malaria.

Malaria Mosquito that transmits malaria. Walter and Eliza Hall Institute of Medical Research