What is Wolbachia, and how can Wolbachia-based strategies reduce disease transmission?

• A. Wolbachia is a maternally transmitted endosymbiotic bacterium; certain strains reduce vector competence by reducing pathogen replication; cytoplasmic incompatibility reduces population.
• B. Wolbachia is a virus that infects mosquitoes and blocks pathogens; cytoplasmic incompatibility increases populations.
• C. Wolbachia is a fungus that infects mosquitoes; it increases pathogen replication.
• D. Wolbachia is a gene-editing technique used to modify the mosquito genome.

Answer: (D)

Wolbachia is a maternally transmitted endosymbiotic bacterium that lives inside mosquito cells. Some strains, when established in mosquito populations, can interfere with pathogen replication in the mosquito, reducing its vector competence and the likelihood that a biting mosquito can transmit diseases such as dengue, Zika, or chikungunya. This means the mosquitoes become less capable of spreading these pathogens.

Another key feature is cytoplasmic incompatibility, a reproductive effect where certain crosses between infected and uninfected mosquitoes produce few or no viable offspring, while infected females still pass Wolbachia to all their offspring. This reproductive barrier helps Wolbachia spread through the population and can lead to a shift toward Wolbachia-infected mosquitoes, which are typically less able to transmit pathogens.

So, Wolbachia-based strategies reduce disease transmission by both lowering the mosquito’s ability to carry and pass pathogens and by using reproductive changes to spread the infection through mosquito populations, potentially replacing wild mosquitoes with less infectious ones. It’s not a virus, fungus, or a gene-editing technique; it’s a bacterium that is inherited from mother to offspring.