Vertical Transmission of Zika Virus in Aedes aegypti Mosquitoes

[Gert van der Hoek]

Published online August 29, 2016 , doi:10.4269/ajtmh.16-0448Am J Trop Med Hyg 2016 16-0448


Abstract

Previous experimental studies have demonstrated that a number of mosquito-borne flavivirus pathogens are vertically transmitted in their insect vectors, providing a mechanism for these arboviruses to persist during adverse climatic conditions or in the absence of a susceptible vertebrate host. In this study, designed to test whether Zika virus (ZIKV) could be vertically transmitted, female Aedes aegypti and Aedes albopictus were injected with ZIKV, and their F₁ adult progeny were tested for ZIKV infection. Of 69 Ae. aegypti pools, six consisted of a total of 1,738 F₁ adults, yielded ZIKV upon culture, giving a minimum filial infection rate of 1:290. In contrast, none of 803 F₁ Ae. albopictus adults (32 pools) yielded ZIKV. The MFIR for Ae. aegypti was comparable to MFIRs reported for other flaviviruses in mosquitoes, including dengue, Japanese encephalitis, yellow fever, West Nile, and St. Louis encephalitis viruses. The results suggest that vertical transmission may provide a potential mechanism for the virus to survive during adverse conditions.

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[Gert van der Hoek]

Adult mosquitoes can pass Zika to their offspring: U.S. study

Mon Aug 29, 2016

Adult female mosquitoes can pass the Zika virus along to their offspring, U.S. researchers said on Monday, a finding that makes clear the need for pesticide programs that kill both adult mosquitoes and their eggs.

The findings, published in the American Journal of Tropical Medicine and Hygiene, show that as with many related viruses, including dengue and yellow fever, Zika can be transmitted from female mosquitoes to their offspring.

Dr. Robert Tesh of the University of Texas Medical Branch in Galveston, Texas, a study co-author, said the fact that the virus can be passed along to mosquito offspring makes Zika harder to control.

"Spraying affects adults, but it does not usually kill the immature forms - the eggs and larvae. Spraying will reduce transmission, but it may not eliminate the virus," he said.

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