Some malaria parasites transform to increase their chances of being picked up by a mosquito and ensure their survival. Photo: Walter and Eliza Hall Institute
Scientists have been developing millions of “sexy” malaria parasites to try to stop the disease spreading.
Almost half the world is at risk to the mosquito-borne infectious disease, a fact that has driven a team at Griffith University to dedicate the better part of seven years trying replicate a specific stage of the parasite.
Griffith University Eskitis Institute senior research assistant Dr Sandra Duffy said her team had developed a process that “pushes” the malaria parasite from being asexual, the form where it does the most damage to a person, to sexual, to test ways they could stop the disease from transferring between people.
Transmitted via infected mosquitoes, the malaria parasite multiplies in the liver and then invades red blood cells. Photo: Penny Stephens
“The breakthrough was the ability to produce millions of these parasites, which was technically difficult,” she said.
The malaria parasite goes through three stages. When a person is bitten by a mosquito, the parasite invades the liver and turns into an asexual parasite, going into the bloodstream and causing symptoms of malaria.
Some of the parasites then make themselves “sexual” and transfer back into a mosquito when the infected person is bitten.
The parasite develops in the mosquito’s salivary glands, ready to be transmitted to the next person and start the cycle over again.
How the parasite matures into what is known as a gametocyte is still largely unknown, however Dr Duffy said it did so to ensure it could survive and transition to continue its lifespan.
“If you have someone who is getting very ill, the parasite is basically destroying its living conditions and so to make sure it can survive … some to go into a sexual form so it can continue.
“I always think of it as a means of an escape route; it needs to have another way to continue because unfortunately malaria causes the death of many who are infected and if a person dies the parasite will die with them.”
The development occurs naturally in the human body, where some of the asexual parasites replicating themselves begin to differentiate, however it had never been replicated in such a large amount in a laboratory.
Dr Duffy said targeting and killing the sexual stage of the parasite, the gametocyte stage, was key to stopping the spread of malaria, which has meant she “cares” for hundreds of millions of gametocytes.
“It is very important to be able to kill this stage of the parasite, and by killing them you block the transmission of malaria,” she said.
“My goal is to keep the little suckers alive, make them sexy, get them all developed into the nicest sexual part they can be and kill them.
“If we can identify a compound that is active against the gametocyte and kill them at this mature stage, we will then test them as well to see if they kill the asexual parasite (the stage where they inflict the most harm).
“If you can have one compound that will kill the parasite that causes the symptoms plus the one responsible for the transmission then you will have the ideal drug.”
Dr Duffy said the research, published in Nature Protocols, would help other researchers “push” millions of parasites into the mature state.
“We don’t work isolated, there have been many people who have come before us and investigated the different parameters that might cause this effect,” she said.
“My hope from this work is that other researchers will be able to do the same that we have been able to do and use it for their role in research in the hope it will help to advance the ultimate eradication of malaria.
“I think by 2030, they hope to have eradicated malaria, that is the goal of the research in malaria.
“There are always people who say that will never happen, but it is still a goal that we work to.”