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Research Project: Rift Valley Fever Pathogenesis, Epidemiology, and Control Measures

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Title: Examining the potential transmission of SARS-CoV-2 by insect vectors

item BALARAMAN, VALMURUGAN - Kansas State University
item Wilson, William - Bill
item Drolet, Barbara
item GAUDREAULT, NATASHA - Kansas State University
item Owens, Jeana
item MEEKINS, DAVID - Kansas State University
item BOLD, DASHZEVEG - Kansas State University
item Swanson, Dustin
item Jasperson, Dane
item TRUJILLO, JESSIE - Kansas State University
item Noronha, Leela
item Nayduch, Dana
item Mitzel, Dana
item RICHT, JUERGEN - Kansas State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/21/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Objective: SARS-CoV-2 is a recently emerged, highly contagious virus and the cause of the current COVID-19 pandemic. Person-to-person transmission occurs by inhalation of infected droplets and aerosols, or by direct contact with contaminated fomites. Arthropods transmit numerous viral, parasitic, and bacterial diseases; however, the potential role of arthropods in SARS-CoV-2 transmission is not fully understood. Public health guidelines for SARS-CoV-2 stated that arthropods play no role in its transmission, despite an absence of supporting experimental scientific data. Therefore, we examined the susceptibility of biting insect species to SARS-CoV-2 infection and the role of house flies in mechanical transmission of SARS-CoV-2. Methods: First, we tested cell lines derived from biting midges (Culicoides sonorensis - W8a) and mosquitoes (Aedes aegypti - C6/36; Culex quinquefasciatus - HSU; Culex tarsalis - CxTrR2) for susceptibility to SARS-CoV-2. Second, the arthropods (biting midges and two Culex species of mosquitoes) were tested for SARS-CoV-2 susceptibility. Arthropods were orally exposed to a SARS-CoV-2-spiked blood meal and held for an incubation period to allow the ingested virus to replicate and disseminate. We processed and analyzed the arthropods for SARS-CoV-2 RNA and infectious virus. Additionally, we performed two independent studies to examine mechanical transmission of SARS-CoV-2 by house flies Musca domestica. First, house flies were tested for infectivity after exposure to SARS-CoV-2-spiked food source and second, environmental samples were tested for infectivity after contact with SARS-CoV-2-exposed flies. Results: Our results indicate that none of the cells, nor the biting insects (midges/mosquitoes), supported SARS-CoV-2 replication. Conversely, house flies were able to acquire and harbor infectious SARS-CoV-2 for up to 24 hours post-exposure and were able to mechanically transfer SARS-CoV-2 genomic RNA to the surrounding environment. Conclusions: Overall, these studies support the public health statement that insects likely do not play a significant role in SARS-CoV-2 transmission. However, further studies are warranted to determine if house fly transmission to susceptible hosts can occur and the public health implications with regard to this arthropod.