Infection, dissemination, and transmission potential of North American Culex quinquefasciatus, Culex tarsalis, and Culicoides sonorensis for Oropouche virus

Authors: McGregor, Bethany; CONNELLY, C,ROXANNE - Centers For Disease Control And Prevention (CDC) - United States; KENNEY, JOAN - Centers For Disease Control And Prevention (CDC) - United States

Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2021
Publication Date: 2/2/2021
Citation: McGregor, B.L., Connelly, C., Kenney, J.L. 2021. Infection, dissemination, and transmission potential of North American Culex quinquefasciatus, Culex tarsalis, and Culicoides sonorensis for Oropouche virus. Viruses. 113(2):226. https://doi.org/10.3390/v13020226.
DOI: https://doi.org/10.3390/v13020226

Interpretive Summary: Oropouche virus (OROV) is a vector-borne virus that circulates in South and Central America. While this virus causes febrile illness with high rates of morbidity, it has not caused documented fatalities. OROV is transmitted by numerous South and Central American vectors including mosquitoes and Culicoides biting midges. The present research aimed to determine the vector competence of three common North American arthropod vectors including Culex tarsalis, Culex quinquefasciatus, and Culicoides sonorensis. Groups of each species were fed blood containing OROV and incubated for 10- or 14-days post infection to determine their ability to become infected and spread the virus in their saliva. Competence was variable based on species with the greatest vector competence detected for Culicoides sonorensis and the poorest vector competence in Culex tarsalis These data have important implications for the potential spread and control of OROV in the event of a North American introduction.

Technical Abstract: Oropouche virus (OROV), a vector-borne Orthobunyavirus circulating in South and Central America, causes a febrile illness with high rates of morbidity but with no documented fatalities. Oropouche virus is transmitted by numerous vectors including multiple genera of mosquitoes and Culicoides biting midges. Due to the broad vector range for this pathogen, it is likely that additional competent vectors are present in other parts of the world. The present study investigated the vector competence of three common North American arthropod vectors, Culex tarsalis, Culex quinquefasciatus, and Culicoides sonorensis for OROV. Cohorts of each species were fed an infectious blood meal containing 6.5 log10 PFU/mL OROV and incubated at 28°C for 10- or 14-days post infection. Culex tarsalis demonstrated infection (3.13%) but not dissemination or transmission potential. At 10 and 14 DPI, Cx. quinquefasciatus demonstrated 9.71% and 19.3% infection, 30% and 6.38% dissemination, and 33.33% and 66.67% transmission, respectively. Culicoides sonorensis demonstrated 86.63% infection, 95.97% dissemination, and 23.78% transmission at 14 DPI. Based on these data, Cx. tarsalis is unlikely to be a competent North American vector for OROV. Culex quinquefasciatus demonstrated infection, dissemination, and transmission, although at relatively low rates indicating low competence that may be overcome by high species abundance in some urban areas. Finally, Culicoides sonorensis demonstrated high infection and dissemination but may have a salivary gland infection and escape barrier to the virus. These data have important implications for the potential spread and control of OROV in the event of a North American introduction.