Laboratório de Mosquitos Transmissores de Hematozoários, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, RJ, Brazil.
Laboratório de Imunologia Viral, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, RJ, Brazil.
PLoS Negl Trop Dis. 2020 Sep 8;14(9):e0008527. doi: 10.1371/journal.pntd.0008527. eCollection 2020 Sep.
Zika virus (ZIKV) emerged in the Pacific Ocean and subsequently caused a dramatic Pan-American epidemic after its first appearance in the Northeast region of Brazil in 2015. The virus is transmitted by Aedes mosquitoes. We evaluated the role of temperature and infectious doses of ZIKV in vector competence of Brazilian populations of Ae. aegypti and Ae. albopictus.
METHODOLOGY/PRINCIPAL FINDINGS: Two Ae. aegypti (Rio de Janeiro and Natal) and two Ae. albopictus (Rio de Janeiro and Manaus) populations were orally challenged with five viral doses (102 to 106 PFU / ml) of a ZIKV strain (Asian genotype) isolated in Northeastern Brazil, and incubated for 14 and 21 days in temperatures mimicking the spring-summer (28°C) and winter-autumn (22°C) mean values in Brazil. Detection of viral particles in the body, head and saliva samples was done by plaque assays in cell culture for determining the infection, dissemination and transmission rates, respectively. Compared with 28°C, at 22°C, transmission rates were significantly lower for both Ae. aegypti populations, and Ae. albopictus were not able to transmit the virus. Ae. albopictus showed low transmission rates even when challenged with the highest viral dose, while both Ae. aegypti populations presented higher of infection, dissemination and transmission rates than Ae. albopictus. Ae. aegypti showed higher transmission efficiency when taking virus doses of 105 and 106 PFU/mL following incubation at 28°C; both Ae. aegypti and Ae. albopictus were unable to transmit ZIKV with virus doses of 102 and 103 PFU/mL, regardless the incubation temperature.
CONCLUSIONS/SIGNIFICANCE: The ingested viral dose and incubation temperature were significant predictors of the proportion of mosquito's biting becoming infectious. Ae. aegypti and Ae. albopictus have the ability to transmit ZIKV when incubated at 28°C. However Brazilian populations of Ae. aegypti exhibit a much higher transmission potential for ZIKV than Ae. albopictus regardless the combination of infection dose and incubation temperature.
寨卡病毒（ZIKV）最初出现在太平洋地区，2015 年首次出现在巴西东北部地区后，随后在整个美洲引发了一场大规模的流行疫情。该病毒通过埃及伊蚊传播。我们评估了温度和 ZIKV 感染剂量在巴西埃及伊蚊和白纹伊蚊种群媒介能力中的作用。
方法/主要发现：用巴西东北部分离的寨卡病毒株（亚洲基因型）对 2 种埃及伊蚊（里约热内卢和纳塔尔）和 2 种白纹伊蚊（里约热内卢和马瑙斯）种群进行了 5 个病毒剂量（102 至 106 PFU/ml）的经口挑战，并在模拟巴西春季-夏季（28°C）和冬季-秋季（22°C）平均温度的条件下孵育 14 和 21 天。通过细胞培养中的噬斑测定分别检测身体、头部和唾液样本中的病毒颗粒，以确定感染、传播和传播率。与 28°C 相比，在 22°C 时，两种埃及伊蚊种群的传播率均显著降低，而白纹伊蚊则无法传播病毒。即使以最高病毒剂量挑战，白纹伊蚊的传播率也很低，而两种埃及伊蚊种群的感染、传播和传播率均高于白纹伊蚊。在 28°C 孵育后，当以 105 和 106 PFU/ml 的病毒剂量摄入时，埃及伊蚊表现出更高的传播效率；无论孵育温度如何，埃及伊蚊和白纹伊蚊均无法以 102 和 103 PFU/ml 的病毒剂量传播 ZIKV。
结论/意义：摄入的病毒剂量和孵育温度是蚊子叮咬传染性比例的重要预测因子。当在 28°C 孵育时，埃及伊蚊和白纹伊蚊都有传播 ZIKV 的能力。然而，无论感染剂量和孵育温度如何组合，巴西埃及伊蚊种群对 ZIKV 的传播潜力都明显高于白纹伊蚊。
