AUTHOR=Reyes-Villanueva Filiberto , Russell Tanya L. , Rodríguez-Pérez Mario A. 

TITLE=Estimating Contact Rates Between Metarhizium anisopliae–Exposed Males With Female Aedes aegypti

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2021.616679

DOI=10.3389/fcimb.2021.616679

ISSN=2235-2988

ABSTRACT=<sec><title>Introduction</title><p>Effective control of <italic>Aedes aegypti</italic> will reduce the frequency and severity of outbreaks of dengue, chikungunya, and Zika; however, control programs are increasingly threatened by the rapid development of insecticide resistance. Thus, there is an urgent need for novel vector control tools, such as auto-dissemination of the entomopathogenic fungi <italic>Metarhizium anisopliae</italic> and <italic>Beauveria bassiana.</italic> The aim of this study was to estimate contact rates of <italic>M. anisopliae</italic>-exposed males with wild female <italic>Ae. aegypti</italic>. As a control the contact rates of untreated males with wild females was contrasted.</p></sec><sec><title>Methods</title><p>The study was conducted in Reynosa, Mexico. The treatment and control households (n = 15 per group) were geographically separated by an arid and hot area that naturally prevented the flight of males between arms. In each control household, 40 <italic>M. anisopliae</italic>-exposed male <italic>Ae. aegypti</italic> were released per week for 8 weeks (specimens were exposed to a concentration of 5.96 × 10<sup>7</sup> conidia/cm<sup>2</sup> for 24 h; n = 4,800 males). In each control household, 40 untreated males were released per week for 8 weeks (n = 4,800 males). All specimens were dust-marked prior to release. Mosquito abundance was monitored with human landing collections, and captured <italic>Ae. aegypti</italic> were examined for any dust-marking.</p></sec><sec><title>Results</title><p>In the treatment households, the contact rate of <italic>Ae. aegypti</italic> females with marked, fungus-treated males was 14% (n = 29 females marked from 197). Where in the control households, the contact rate of females with marked, untreated males was only 6% (n = 22 marked from 365). In the treatment households the recapture rate of released males was at 5% and higher than that for the control households (which was 2%). Auto-dissemination of <italic>M. anisopliae</italic> from infected males to female <italic>Ae. aegypti</italic> was demonstrated through the recovery of an infected female from the floor of a household.</p></sec><sec><title>Conclusions</title><p>Overall, the contact rate between <italic>M. anisopliae</italic>-infected males with the natural female population was 60% higher than for the control group of healthy males. The results provide further support to the release of fungus-exposed males as a potentially useful strategy against <italic>Ae. aegypti</italic>, though further research is required.</p></sec>