Mosquitoes have a mutually symbiotic relationship with malaria-causing pathogen

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Cornelius Vanderbilt Professor of Biological Sciences Laurence J. Zwiebel is part of a team of researchers at Vanderbilt and Johns Hopkins Malaria Research Institute working to understand how Plasmodium falciparium – the pathogen that causes malaria in humans – affects mosquitoes that spreads the disease. The research was led by Ann Carr, a current visiting researcher and former postdoctoral fellow at the Zwiebel Lab.

Through comparative analysis of mRNA between uninfected and infected mosquitoes that are old enough to transmit malaria, the researchers concluded that infected mosquitoes’ sense of smell was significantly improved, thus improving their ability to find hosts, Zwiebel said. This suggests that infection with the parasite provides the mosquito with an advantage that promotes reproduction and disease transmission.

In addition to a more sensitive olfactory response, the researchers noted that the mRNA transcript profile of infected mosquitoes resembled much younger insects. “Infected mosquitoes revealed a physiology that had all the characteristics of younger animals: more focused on reproduction, more robust immunologically, and generally more fit than their uninfected middle-aged control siblings,” Zwiebel said. “This suggests that there is a broad generalized adaptive benefit in keeping malaria pathogens in the population. This partly explains the global persistence of malaria.”

The research team conducted their study in the challenging context of real-world infections that occur at very low levels. “We made tremendous efforts to conduct this study using very low intensity infections that are consistent with the natural levels of infection seen in Africa,” Zwiebel said.

The research was published in Scientific reports.

Why it matters

By spending time and effort copying natural conditions to obtain these results, the researchers aim to demonstrate feasibility and emphasize the need to perform malaria infection studies within natural parameters.

“This research should also provide a new understanding that although P. falciparium is a deadly parasitic pathogen for humans and other mammals, it is definitely not a pathogen for mosquitoes,” Zwiebel said. “In fact, our data strongly suggest that there is a mutually symbiotic relationship between the genus Anopheles mosquito and P. falciparium.”

What’s next

These data will inform future studies of Anopheles mosquitoes and P. falciparium and the global efforts to reduce and eradicate human malaria. Zwiebel Lab will begin to unravel the molecular and cellular mechanisms responsible for the increased odor sensitivity in malaria-carrying mosquitoes.


Mosquito larvae are surprisingly complex


More information:
Ann L. Carr et al, transcriptome profiles of Anopheles gambiae housing natural low-level Plasmodium infection reveal adaptive benefits for mosquitoes, Scientific reports (2021). DOI: 10.1038 / s41598-021-01842-x

Provided by Vanderbilt University

Citation: Mosquitoes have a mutually symbiotic relationship with malaria-causing pathogen (2021, 19 November) retrieved 20 November 2021 from https://phys.org/news/2021-11-mosquitoes-mutual-symbiotic-relationship-malaria-causing.html

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