Tuesday, 27 June 2017 15:16

Controlling Mosquito Infection by Bacterial Manipulation: Using Bacteria to Control Mosquito-Borne Diseases

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Published in mBiosphere

National Mosquito Control Awareness Week is June 26 – 30, 2017, and the issue is not only important because of the annoying bites we all experience during the warmer months. Mosquitoes carry many vector-borne diseases that are major threats to human health, including many viral pathogens. For this reason, scientists have been looking to control mosquito populations through a variety of methods.

One source of mosquito population control involves manipulation of the bacterial Wolbachia endosymbionts within a population. Male and female mosquitoes must have the same Wolbachia strains to produce viable offspring, and release of males with mismatched Wolbachia is currently being tested as a means to decrease local mosquito populations. The Wolbachia strain infection can also influence the infection of mosquitoes by pathogens such as Zika virus. A new report from the Journal of Virology showcases the ability of different Wolbachia strains to inhibit Zika virus replication in mosquito cells.

JVirology: Variable Inhibition of Zika Virus Replication by Different Wolbachia Strains in Mosquito Cell Cultures

The scientific team, led by first author Michaela Schultz and senior scientist Horacio Frydman, tested two different Wolbachia strains, one isolated from mosquitos (called wAlbB) and one isolated from planthoppers (called wStri), in a mosquito cell line. After adding different Wolbachia strains to the cell line, the researchers infected the culture with Asian or African lineage Zika virus isolates. Mosquito cells carrying the wAlbB strain showed lower African Zika virus replication but no significant decrease in the Asian Zika virus replication, while insect cells carrying the wStri strain showed decreased replication of all Zika strains tested.

Further investigation showed that the mosquito cells carry different densities of the wAlbB and wStri bacterial strains. The wStri strain is carried at a higher density, which may account for the increased inhibition by this strain. Whether this would translate to an effective infection control method depends on whether the higher carriage of the wStri Wolbachia also decreases mosquito fitness, a question that requires further studies of the interaction of the mosquito, its bacterial endosymbiont, and the infecting flavivirus. 

Previous studies have shown a Wolbachia strain derived from fruit flies, wMel, also inhibits Zika virus replication. The addition of new, well-characterized strains that inhibit virus replication can help improve control in cases where scientists hope to block multiple viral pathogens or different mosquito species—or in the case that the wMel strain adapts in a way that it no longer inhibits the virus. The next step will be to investigate whether these in vitro studies translate to in vivo inhibition in mosquitoes.


For more from first author Schultz, see her essay in The Conversation: Why We Should Infect Mosquitoes with Bacteria to Stop Zika and Dengue

Last modified on Tuesday, 27 June 2017 15:34
Julie Wolf

Julie Wolf is the ASM Science Communications Specialist. She contributes to the ASM social media and blog network and hosts the Meet the Microbiologist podcast. She also runs workshops at ASM conferences to help scientists improve their own communication skills. Follow Julie on Twitter for more ASM and microbiology highlights at @JulieMarieWolf.

Julie earned her Ph.D. from the University of Minnesota, focusing on medical mycology and infectious disease. Outside of her work at ASM, she maintains a strong commitment to scientific education and teaches molecular biology at the community biolab, Genspace. She lives in beautiful New York City.