Melbourne scientists have made the surprise discovery that
malaria1 parasites3 can 'talk' to each other -- a social behaviour to ensure the
parasite2's survival and improve its chances of being transmitted to other humans. The finding could provide a
niche4 for developing antimalarial drugs and
vaccines5 that prevent or treat the disease by cutting these communication networks.
Professor Alan Cowman, Dr Neta Regev-Rudzki, Dr Danny Wilson and colleagues from the Walter and Eliza Hall Institute's Infection and
Immunity6 division, in
collaboration7 with Professor Andrew Hill from the University of Melbourne's Bio21 Institute and Department of Biochemistry and
Molecular8 Biology showed that malaria parasites are able to send out messages to communicate with other malaria parasites in the body. The study was published today in the journal Cell.
Professor Cowman said the researchers were shocked to discover that malaria parasites work in
unison9 to enhance '
activation10' into sexually mature forms that can be picked up by mosquitoes, which are the carriers of this deadly disease.
"When Neta showed me the data, I was absolutely amazed, I couldn't believe it," Professor Cowman said. "We repeated the experiments many times in many different ways before I really started to believe that these parasites were signalling to each other and communicating. But we came to appreciate why the malaria parasite really needs this
mechanism11 -- it needs to know how many other parasites are in the human to sense when is the right time to
activate12 into sexual forms that give it the best chance of being transmitted back to the mosquito."
Malaria kills about 700,000 people a year, mostly children
aged13 under five and pregnant women. Every year, hundreds of millions of people are infected with the malaria parasite, Plasmodium, which is transmitted through mosquito bites. It is estimated that half the world's population is at risk of contracting malaria, with the disease being concentrated in tropical and subtropical regions including many of Australia's near neighbours.
Dr Regev-Rudzki said the malaria parasites inside red blood cells communicate by sending packages of
DNA14 to each other during the blood stage of infection. "We showed that the parasites inside infected red blood cells can send little packets of information from one parasite to another, particularly in response to stress," she said.