Journal Article

Embryonic development and egg viability of wMel-infected Aedes aegypti

Belinato, Thiago Affonso, Gesto, João Silveira Moledo, Farnesi, Luana Cristina, Martins, Ademir Jesus, Moreira, Luciano Andrade, Bruno, Rafaela Vieira

2019

Overview

Background Aedes aegypti is a major disease vector in urban habitats, involved in the transmission of dengue, chikungunya and Zika. Despite innumerous attempts to contain disease outbreaks, there are neither efficient vaccines nor definite vector control methods nowadays. In recent years, an innovative strategy to control arboviruses, which exploits the endosymbiotic bacterium Wolbachia pipientis , emerged with great expectations. The success of the method depends on many aspects, including Wolbachia ’s cytoplasmic incompatibility and pathogen interference phenotypes, as well as its effect on host fitness. In this work, we investigated the influence the Wolbachia strain w Mel exerts on embryo development and egg viability and speculate on its field release use. Methods Wild-type (Br or Rockefeller) and Wolbachia -harboring specimens ( w MelBr) were blood-fed and submitted to synchronous egg laying for embryo development assays. Samples were analyzed for morphological markers, developmental endpoint and egg resistance to desiccation (ERD). Quiescent egg viability over time was also assessed. Results w MelBr samples completed embryogenesis 2–3 hours later than wild-type. This delay was also observed through the onset of both morphological and physiological markers, respectively by the moments of germband extension and ERD acquisition. Following the end of embryonic development, w MelBr eggs were slightly less resistant to desiccation and showed reduced viability levels, which rapidly decayed after 40 days into quiescence, from approximately 75% to virtually 0% in less than a month. Conclusions Our data revealed that the w Mel strain of Wolbachia slightly delays embryogenesis and also affects egg quality, both through reduced viability and desiccation resistance. These findings suggest that, although embryonic fitness is somehow compromised by w Mel infection, an efficient host reproductive manipulation through cytoplasmic incompatibility seems sufficient to overcome these effects in nature and promote bacterial invasion, as shown by successful ongoing field implementation.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Aedes aegypti / Analysis / Animal embryos / Aquatic insects / arboviruses / bacteria / Biomedical and Life Sciences / Biomedicine / Control / Control methods / Cytoplasmic incompatibility / dengue / Dengue fever / Desiccation / Desiccation resistance / Disease control / Disease outbreaks / Disease transmission / disease vectors / Drying / Egg laying / egg quality / Egg viability / Eggs / Eggs (Food) / Embryo / Embryogenesis / Embryonic development / Embryonic growth stage / Embryos / Entomology / Fitness / Host-bacteria relationships / Human diseases / Incompatibility / Infectious Diseases / Laboratories / Markers / Microbiological strains / Mosquitoes / Outbreaks / Parasitology / Pathogens / Phenotypes / Physiology / Prevention / Public health / Risk factors / Tropical Medicine / Vaccines / vector control / Vector-borne diseases / Veterinary Medicine/Veterinary Science / Viability / Viral diseases / Virology / wMel strain / Wolbachia / Wolbachia pipientis / Yellow fever / Zika virus