Publication
Vector microbiota and immunity: modulating arthropod susceptibility to vertebrate pathogens
Authors
Eric Caragata, Assistant Professor, Florida Medical Entomology Laboratory, University of Florida
Sarah Short, Assistant Professor, Department of Entomology, The Ohio State University
Quick Take
Many animals have a whole host of other microorganisms living inside of them. These tiny microbes, which often include bacteria and fungi, make up an animal’s internal microbial system, or microbiome. These microorganisms interact, grow, and change much like any other community.
Creatures that transmit diseases—like ticks, insects, or certain flies—are called disease vectors, and they also have microbiomes. Researchers think there’s a connection between microorganisms and how susceptible these blood-sucking vectors are to infection by pathogens (and thus how well they can transmit pathogens to humans).
Controlling or disrupting the microbial communities inside these vectors might help limit the spread of pathogens. For instance, what if researchers find that a specific microorganism interacts negatively with a pathogen? Could they strengthen a tick or mosquito’s microbiome with enough of these pathogen-fighting microorganisms so that they no longer spread disease?
A CFAES researcher, in collaboration with a colleague at the University of Florida, reviewed a variety of recent studies to summarize and explain current ideas in the field. These studies help shed light on how tick, mosquito, or fly microbiomes may interact with pathogens as well as the different mechanisms influencing this relationship.
Review Findings
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Several studies that the researchers reviewed suggest that the link between microbiomes and vectors could be used advantageously. One way might be using microorganisms as biopesticides (or infecting pests with pathogens that are not harmful to humans so the vectors cannot handle other pathogens). This has shown promise in prevention of dengue virus transmission. Scientists could also engineer microbes to target and kill pathogens, a process known as paratransgenesis.
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Other research in the literature shows that introducing antibiotics to mosquitoes, tsetse flies, and sand flies may disrupt their microbiomes, and thus their ability to transmit pathogens. For example, in sand flies, it may reduce their susceptibility to parasites, and in ticks, it may lower their ability to be infected with the bacteria that causes anaplasmosis.
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The presence or absence of specific microorganisms may also reduce susceptibility to pathogens that threaten humans, like dengue virus, Zika virus, and Plasmodium parasites. Introducing beneficial microorganisms to vectors could reduce their susceptibility to these diseases.
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Results from the reviewed studies show that microorganisms impact the expression of genes that control immune responses and help vectors fight pathogens, suggesting immune signaling may be one of the mechanisms driving these interactions. Scientists in the field hope to continue studying the relationship between microorganisms, metabolism, and immunity.
Citation
Caragata, E., Short, S. “Vector microbiota and immunity: modulating arthropod susceptibility to vertebrate pathogens.” Current Opinion in Insect Science, April 2022, 50, 100875, https://doi.org/10.1016/j.cois.2022.100875