By Sunanda Creagh, The Conversation
New Australian research has, for the first time, shown exactly how blood cells called platelets kill the parasite that causes malaria infection and revealed a new reason why people from Africa are more predisposed to the disease than others.
Malaria, which is caught from infected mosquitoes, is usually fatal if left untreated. According to the World Health Organization, 90% of all malaria deaths in 2010 occurred in Africa and most of the victims were less than five-years-old.
In a new study published in the journal Science, Macquarie University researchers showed that platelets produce a molecule called Platelet Factor 4 or PF4, which binds with another molecule on red blood cells called Duffy to kill the Plasmodium falciparum strain of malaria.
The Duffy molecule has been known about for over 20 years but the new research shows that the parasite will not die unless PF4 docks onto Duffy.
Duffy is not present in the bodies of people from Africa, which may help explain the prevalence of the Plasmodium falciparum strain of malaria in the region.
“This finding can’t be directly used in the form of a new treatment but it does tell us a lot about how the body normally protects itself against malaria,” said lead author Associate Professor Brendan McMorran, from Macquarie University’s Australian Advance School of Medicine.
“Getting a better understanding of the body’s responses to infections will help us learn to manage them better and, if we are lucky, lead to treatment in future.”
Associate Professor McMorran said that people from Africa who lack the Duffy molecule can’t get infected with another strain of malaria called Plasmodium vivax.
Professor James McCarthy, a malaria researcher from the Queensland Institute of Medical Research, said the research was very interesting.
“Humans in Africa have evolved so they have lost the ability to get infected with this vivax parasite but in so doing they have increased their vulnerability to Plasmodium falciparum. It’s swings and round abouts,” said Professor McCarthy, who was not involved in the research.
“It’s really interesting in understanding how humans have evolved in relation to malaria, more so than it is for immediately figuring out a new drug or vaccine to treat malaria,” he said.
“It might lead in the longer term to a treatment but in the short term it won’t.”
Dr Christian Engwerda, a malaria expert from the Queensland Institute of Medical Research’s Immunology and Infection Laboratory, said the research was important because it identified a new immune pathway in humans that kills malaria parasites.
“By understanding how our own body kills these parasites, we can identify vulnerable features of the parasite that can be targeted by new drugs,” he said.