Malaria has been one of the most common illnesses that causes over 200 million infections every year globally. A team of researchers has now discovered how the Malaria parasite behaves and migrates inside the human body by forming a vortex largely determined by physical principles.
Using computer simulation, the team discovered that the parasites in infected salivary glands can be mobilised as a collective. Malaria, the acute febrile illness, is caused by Plasmodium parasites, which are spread to people through the bites of infected female Anopheles mosquitoes.
The study published in the journal Nature Physics states that the malaria parasite has evolved flexibility as an essential means to adapt to its mechanical environment and to ensure efficient transmission. “Our work demonstrates how single-particle shape and mechanics can determine the dynamics of large, active collectives,” the paper read.
Plasmodium parasites are single-celled organisms that is injected into the skin through a mosquito bite, developing first in the liver and then later in the blood. Because Plasmodium acts as a single cell in most of its stages until now, its collective properties were hardly studied. In the salivary gland of the mosquito, the parasite has a long and curved shape, similar to a crescent moon, and is known as a sporozoite.
Prof. Dr. Friedrich Frischknecht, who was part of the study said, “As soon as sporozoites are injected into the skin by the mosquito, individual parasites begin to quickly move toward the blood vessels. This is the critical phase of the infection because it is successful only if a pathogen reaches the bloodstream.”
They discovered that the parasites in infected salivary glands can be mobilised as a collective. To do so, the salivary glands are dissected from the mosquito and carefully pressed between two small glass plates. The researchers were surprised to discover that the crescent moon-shaped cells from rotating vortices in the new preparation.
Indian researcher Dr. Pintu Patra, a postdoctoral researcher at the Institute for Theoretical Physics, Heidelberg University, who led the research, simulated the movement, shape, and other features of the sporozoites by creating a virtual world using a computer program where hundreds of such parasites interact and spontaneously from these vortices.
Using cutting-edge methods of image processing, the team was able to track individual parasites in the rotating vortices and measure both their speed and curvature. The team, using the data around the interplay of active movement, the curved shape of the cell, and chirality in conjunction with mechanical flexibility, explained the sorting and oscillation phenomena in the parasite vortices.
“These findings not only reveal that malaria’s parasites’ curved shape and flexibility is crucial to their storage and migration into different host environments but also present a new example of shape-driven pattern formation in the field of collective behavior,” Dr. Patra said.
Researchers are now looking to understand and explain how the chirality of movement comes about since the structure of sporozoites suggests different possibilities that can be studied in experiments with genetic mutations.