The new study, conducted by the University of Glasgow in collaboration with Stockholm University, is published in Nature Communications. It details how certain parasites can create unique cellular structures to control energy creation and thus survive in different hosts.
Malaria and toxoplasmosis, potentially fatal diseases, are caused by similar parasites that organize to use their host’s energy resources to infect and transfer themselves to new hosts. However, scientists still do not fully understand the detailed mechanisms of this process.
Researchers have finally solved the parasite mystery underlying how these deadly organisms can survive in different hosts to pass themselves on.
Toxoplasmosis is a disease caused by the Toxoplasma parasite and is believed to be carried by about 33% of the world’s dormant population. However, in people with weakened immune systems, this parasite can wake up and cause complications such as stroke and brain damage. Malaria, a mosquito-borne infectious disease, currently affects more than 200 million people and kills nearly half a million people every year, mostly children.
To survive, these parasites rely on the resources of their host: in the case of Toxoplasma, they are animals and humans, and in the case of malaria, also insects. This means that to survive, infect a host, and transfer between hosts, these parasites must be flexible in creating energy, depending on what methods of obtaining energy are available.
Scientists have studied ATP synthase, which produces vital energy in parasites. In addition to producing energy, ATP synthase can combine into large structures that together form the mitochondrial membrane, controlling the rate of energy production and being the key to its survival. The researchers found that in these parasites, ATP synthase is capable of creating complex and unique pentagonal pyramidal structures, unlike anything produced by the same systems in the human host.
“We have made significant progress in understanding how the parasites that cause toxoplasmosis and malaria can adapt their way of generating energy to the environment in which they live. This is critical for the parasite’s ability to spread in various tissues and be transmitted between hosts. In addition to understanding how these parasites manage to survive and remain flexible as they move through different host environments, these results are important in generating knowledge that can inform drug discovery.”
Dr. Lilach Scheiner, one of the lead study authors from the University of Glasgow
Toxoplasmosis is usually transmitted through undercooked meat, soil, or contact with cat feces. Although an estimated 33% of the UK population carries the parasite’s inactive form, symptoms of infection in healthy adults usually go unnoticed.
However, toxoplasmosis can be dangerous for unborn babies and people with weakened immune systems, such as those with AIDS. When Toxoplasma “wakes up” in people with weakened immune systems, it can cause stroke and, in infants, severe brain damage.
Malaria is caused by a related parasite, Plasmodium, which enters humans through a mosquito’s bite. The parasite then grows in the liver and red blood cells of our blood. Parasites can also change in the blood to male and female forms, which can reinfect mosquitoes when they bite and suck on infected people’s blood.