The Zika virus (ZIKV) is an emerging arbovirus that is spreading rapidly in Latin America. During the onset of the continuing outbreak in Brazil, ZIKV was implicated in the rise in microcephaly, because of the sharp increase in cases of women being infected with ZIKV during pregnancy and having babies and stillborn with severe brain malformation. It has been postulated that in urban areas the yellow fever mosquito, Aedes aegypti, transmits the virus. However, recent studies have suggested that both Ae. aegypti and Ae. albopictus are poorly competent vectors of ZIKV transmission. Additionally, we have demonstrated that when the southern house mosquito, Culex quinquefasciatus, which has high population densities in Brazil and the US, was fed blood spiked with ZIKV in the laboratory, the virus crossed the mosquito?s mid-gut barrier and replicated significantly in the salivary glands. This project seeks to (1) determine unambiguously on the basis of vector capacity whether the southern house mosquito is a vector of ZIKV in Brazil and could transmit the virus in the US; (2) conduct surveillance at the epicenter of the ZIKV epidemic, and (3) investigate whether homemade, natural, and synthetic repellents are effective in fending off ZIKV- infected mosquitoes.
Aim #1 will address vector capacity by infecting laboratory and field- collected mosquitoes with a strain of the ZIKV currently circulating in Recife, Brazil, and, subsequently, determine virus replication and titer in the midgut and salivary glands. Additionally, we will investigate whether the virus is transmitted to mosquito offspring.
In Aim #2, we will conduct surveillance at the epicenter of the ZIKV epidemic in Brazil to determine whether natural populations of Culex mosquitoes carry the virus.
In Aim #3, we will compare the degree of repellence elicited in ZIKV-infected and noninfected Culex mosquitoes by homemade, natural, and synthetic repellents. The proposed work will provide relevant information to guide policy makers and abatement district personnel in their preparedness to prevent a possible Zika epidemic in the US and an endemic crisis in Brazil. Information will also be provided to the public at large about the use of repellents as a prophylactic tool to combat Zika transmission.
The explosive Zika virus infection pandemic is a growing threat to the United States (US), particularly given the increasing number of reported travelers possibly becoming infected by mosquito bites overseas and bringing the Zika virus back to the US. This project will investigate whether a common house mosquito species, Culex quinquefasciatus, which has a high population density at the epicenter of the Zika epidemic in Brazil and is also highly prevalent across the US, is a vector of the Zika virus as well as whether Zika virus-infected mosquitoes can be repelled by certain natural and synthetic repellents.
| Guedes, Duschinka Rd; Paiva, Marcelo Hs; Donato, Mariana Ma et al. (2017) Zika virus replication in the mosquito Culex quinquefasciatus in Brazil. Emerg Microbes Infect 6:e69 |
| Leal, Walter S; Barbosa, Rosângela M R; Zeng, Fangfang et al. (2017) Does Zika virus infection affect mosquito response to repellents? Sci Rep 7:42826 |
| Lu, WeiYu; Hwang, Justin K; Zeng, Fangfang et al. (2017) DEET as a feeding deterrent. PLoS One 12:e0189243 |
| Paiva, Marcelo Henrique Santos; Guedes, Duschinka Ribeiro Duarte; Leal, Walter Soares et al. (2017) Sensitivity of RT-PCR method in samples shown to be positive for Zika virus by RT-qPCR in vector competence studies. Genet Mol Biol 40:597-599 |
| Leal, Walter S (2017) Reverse chemical ecology at the service of conservation biology. Proc Natl Acad Sci U S A 114:12094-12096 |
