ISB News

Malaria Researchers’ Findings May Have Implications for Preventing Spread of Deadly Disease

ISB researchers and their collaborators are using systems biology approaches to learn how the malaria parasite is able to transfer to humans via the bite of an infected mosquito. The information they have uncovered may help identify new ways to prevent people from contracting the deadly disease.

Malaria is caused by Plasmodium parasites that are transmitted to humans through the bite of infected mosquitoes. Once inside the human host, the parasites invade the liver, multiply, and emerge to infect the blood, at which point they cause the clinical symptoms of malaria. 

Mosquitoes that feed on infected blood are themselves infected and can spread the disease to others. In 2017, there were an estimated 219 million cases of malaria that resulted in 435,000 deaths, according to the WHO World Malaria Report. More than 60 percent of these deaths were children under five years of age. 

Kristian Swearingen, PhD

Kristian Swearingen, PhD, is a co-first author of a paper published in the journal Nature Communications that details how the malaria parasite is able to transfer to humans via the bite of an infected mosquito. The information they have uncovered may help identify new ways to prevent people from contracting the deadly disease.

“One of the reasons malaria remains such a formidable disease is the lack of an effective vaccine,” said ISB’s Dr. Kristian Swearingen, who studies the Plasmodium parasites.

The form of the malaria parasite that is transferred to humans – sporozoites – develop in cysts in the midgut of the mosquito and then travel to the insect’s salivary glands. There, the parasites lay in wait until the mosquito bites a human and injects parasite-laden saliva into the victim’s skin. 

‘Promising targets’ for antimalarials

Swearingen, a senior research scientist in ISB’s Moritz Lab, used mass spectrometry to identify and compare the proteins present in sporozoites found in either mosquito midguts or salivary glands. Swearingen’s long-time collaborator, Professor Scott Lindner, and his team at Penn State quantified the messenger RNA (mRNA) in the same types of parasites.

The researchers found that, although parasites from midguts and salivary glands look identical under a microscope, there are certain genes that are only expressed in one stage or the other. For example, some of the proteins that are encoded by these genes are only used for infecting mosquito salivary glands, and are then switched off in favor of other genes that encode proteins the parasite will use for infecting humans. 

“The proteins that are only made once the parasite is ready to infect a human represent promising targets for new antimalarial interventions, such as vaccines that train the immune system to recognize invading sporozoites,” Swearingen said.

One of the striking findings of the study arose from comparing the results of the two different technologies – transcriptomics (measuring which genes have been read into mRNA) and proteomics (measuring which proteins were actually translated from the mRNA). The research team found that, for certain genes, the ready-to-invade parasite makes an abundance of mRNA, but stores it away rather than letting it be translated into protein. Only when the parasite has invaded a human will it make the protein, which it then uses to infect the liver. 

The proteins under this translational repression program also represent promising targets for antimalarials.

Swearingen and Lindner are co-first authors of a paper detailing these findings in the journal Nature Communications.

Recent Articles

  • Dr. Christian Diener, postdoc in ISB's Gibbons Lab.

    New Modeling Tool Allows Microbiome Researchers to Map Community Ecology to Ecosystem Function

    A promising new open-source metabolic modeling tool provides microbiome researchers a path forward in predicting ecosystem function from community structure. News of the software package, called MICOM, was developed in part by researchers in ISB’s Gibbons Lab, and its uses were published in the journal mSystems.

  • Dr. Jim Heath

    ISB Marking 20th Anniversary with Year-Long Celebration

    Letter from the president: Dr. Jim Heath announces the kickoff of a 2020 celebration marking ISB’s 20th anniversary. The year-long celebration will include an ISB-Town Hall Seattle speaker series focusing on some of the most important topics in science and health care.

  • A Scientist-Approved Science-Themed Holiday Gift Guide

    When putting together a science-themed gift guide, you have to go to the source. So we asked ISB’s researchers for their ideas and to share what’s on their lists. Whether you’re buying for a scientist or wanting to give the gift of science, this gift guide is for you.