The Extrinsic Incubation Period of Zika Virus in Florida Mosquitoes Aedes aegypti and Ae. albopictus.

Rebecca A Zimler,Barry W Alto

doi:10.3390/pathogens10101252

Rebecca A Zimler, Barry W Alto

Open Access

https://doi.org/10.3390/pathogens10101252

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Abstract

The Asian genotype of Zika virus (ZIKV) emerged in Brazil in 2015 and subsequently spread throughout the Americas. In July 2016, Florida experienced its first locally acquired ZIKV infection in the continental U.S. Concerns about health risks from ZIKV infection have increased the need to investigate the interactions between potential mosquito vectors and ZIKV. The time it takes for an arbovirus to propagate within a mosquito, and become transmissible, is the extrinsic incubation period (EIP). The EIP for potential mosquito vectors in Florida is unknown. To address this gap in the understanding of ZIKV epidemiology, Florida Aedes aegypti (L.) and Ae. albopictus (Skuse) were orally exposed to ZIKV infected blood meals and fully engorged mosquitoes were held at a constant temperature of 28 °C through the duration of the experiment. Saliva expectorates were collected from cohorts of mosquitoes and tested for the presence of ZIKV at three-day intervals over a period of 24 days to allow for an evaluation of the EIP of the emergent Asian lineage of ZIKV. High rates of infected bodies in Ae. albopictus (75–94%) and Ae. aegypti (68–86%) were observed throughout the incubation period, which did not differ by species. Higher rates of disseminated infection were observed later during the incubation period but did not differ between species. We calculated the 50% EIP to be shorter in Ae. albopictus than Ae. aegypti (16.2 and 18.2 days post infection, respectively). The competence for ZIKV observed in both species may contribute to high rates of ZIKV transmission in Florida populations.

Highlights

Viral titrations of the infectious blood meal showed a final concentration of 7.5 Log10
Mosquito bodies were tested for the presence of Zika virus (ZIKV) infection at eight time points post infection by qRT-PCR (446 mosquitoes; 359 Ae. aegypti, 87 Ae. albopictus)
Aedes aegypti and Ae. albopictus females had similar susceptibility to Pathogens 2021, 10, 1252 infection during the time monitored after ingestion of Zika virus-infected blood (Table 1)

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Zika virus (ZIKV) is a primarily mosquito-borne Flavivirus first identified in Uganda in. ZIKV infection in humans is often asymptomatic (approximately 80%), infection can cause acute febrile illness with clinical presentations including malaise, fever, maculopapular rash, headache, and conjunctivitis [2]. Severe illness associated with ZIKV infection, such as microcephaly and Guillain Barré syndrome, has caused global concern for the disease and sparked an urgent need for the understanding of ZIKV epidemiology

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