Differential Vector Competency of Aedes albopictus Populations from the Americas for Zika Virus

Abstract

To evaluate the potential role of Aedes albopictus (Skuse) as a vector of Zika virus (ZIKV), colonized mosquitoes of low generation number (≤ F5) from Brazil, Houston, and the Rio Grande Valley of Texas engorged on viremic mice infected with ZIKV strains originating from Senegal, Cambodia, Mexico, Brazil, or Puerto Rico. Vector competence was established by monitoring infection, dissemination, and transmission potential after 3, 7, and 14 days of extrinsic incubation. Positive saliva samples were assayed for infectious titer. Although all three mosquito populations were susceptible to all ZIKV strains, rates of infection, dissemination, and transmission differed among mosquito and virus strains. Aedes albopictus from Salvador, Brazil, were the least efficient vectors, demonstrating susceptibility to infection to two American strains of ZIKV but failing to shed virus in saliva. Mosquitoes from the Rio Grande Valley were the most efficient vectors and were capable of shedding all three tested ZIKV strains into saliva after 14 days of extrinsic incubation. In particular, ZIKV strain DakAR 41525 (Senegal 1954) was significantly more efficient at dissemination and saliva deposition than the others tested in Rio Grande mosquitoes. Overall, our data indicate that, while Ae. albopictus is capable of transmitting ZIKV, its competence is potentially dependent on geographic origin of both the mosquito population and the viral strain.

Figure 1.

Infection, dissemination, and potential transmission of three Zika virus strains by Aedes albopictus from the Rio Grande Valley, TX, following bloodmeal from viremic A129 mice infected with (A) FSS 13025 (Cambodia, 2010), (B) MEX 1-7 (Mexico, 2015) or (C) DakAR 41525 (Senegal 41525) and assays on day 3 (N = nine mosquitoes per virus), day 7 (N = 14), and day 14 (N = 14).

Figure 2.

Infection, dissemination, and potential transmission of three Zika virus strains by Aedes albopictus from Houston, TX, following bloodmeal from viremic A129 mice infected with (A) PB 81 (Brazil, 2015), (B) MEX 1-7 (Mexico, 2015) or (C) PRVABC 59 (Puerto Rico 2015) and assays on day 3 (N = 12 mosquitoes per virus), day 7 (N = 15), and day 14 (N = 15).

Figure 3.

Infection, dissemination, and transmission of two Zika virus strains by Aedes albopictus from Salvador, Brazil, following bloodmeal from viremic A129 mice infected with (A) PB 81 (Brazil, 2015) or (B) MEX 1-7 (Mexico, 2015) and assays on day 3 (N = 15 mosquitoes per virus), day 7 (N = 15), and day 14(N = 15).