Wolbachia strain wAlbA blocks Zika virus transmission in Aedes aegypti

• Published in: Medical and veterinary entomology Vol. 34; no. 1; pp. 116 - 119
• Main Authors: Chouin‐Carneiro, T., Ant, T. H., Herd, C., Louis, F., Failloux, A. B., Sinkins, S. P.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.03.2020; Wiley Subscription Services, Inc
• Subjects: Aedes - microbiology; Aedes - virology; Aedes aegypti; Aedes albopictus; Animals; Dengue fever; dengue virus arbovirus; Female; Injection; Mosquito Vectors - microbiology; Mosquito Vectors - virology; pathogen blocking; Replication; RNA viruses; Saliva; Short Communication; Short Communications; Wolbachia; Wolbachia - physiology; Zika virus; Zika Virus - physiology; Zika Virus Infection - transmission; Aedes albopictus; Aedes aegypti; Zika virus; Wolbachia; dengue virus arbovirus; pathogen blocking
• ISSN: 0269-283X; 1365-2915
• DOI: 10.1111/mve.12384

Transinfections of the maternally transmitted endosymbiont Wolbachia pipientis can reduce RNA virus replication and prevent transmission by Aedes aegypti, and also have the capacity to invade wild‐type populations, potentially reaching and maintaining high infection frequencies. Levels of virus transmission blocking are positively correlated with Wolbachia intracellular density. Despite reaching high densities in Ae. aegypti, transinfections of wAlbA, a strain native to Aedes albopictus, showed no blocking of Semliki Forest Virus in previous intrathoracic injection challenges. To further characterize wAlbA blocking in Ae. aegypti, adult females were intrathoracically challenged with Zika (ZIKV) and dengue viruses, and then fed a ZIKV‐containing bloodmeal. No blocking was observed with either virus when challenged by intrathoracic injection. However, when ZIKV was delivered orally, wAlbA‐infected females showed a significant reduction in viral replication and dissemination compared with uninfected controls, as well as a complete absence of virus in saliva. Although other Wolbachia strains have been shown to cause more robust viral blocking in Ae. aegypti, these findings demonstrate that, in principle, wAlbA could be used to reduce virus transmission in this species. Moreover, the results highlight the potential for underestimation of the strength of virus‐blocking when based on intrathoracic injection compared with more natural oral challenges. A transinfection of the wAlbA Wolbachia strain in Aedes aegypti blocks Zika virus transmission in saliva when virus is delivered orally via an infectious bloodmeal. Significant Zika blocking by wAlbA was not observed when virus was delivered via intrathoracic injection, suggesting that the midgut barrier plays an important role in blocking. Intrathoracic challenges can misrepresent virus blocking strength and may underestimate the true blocking potential of a strain.