Mahmood Farida, Chiles Robert E, Fang Ying, Barker Christopher M, Reisen William K
Center for Vectorborne Diseases, School of Veterinary Medicine, Old Davis Road, University of California, Davis, California 95616, USA.
J Med Entomol. 2004 Sep;41(5):965-72. doi: 10.1603/0022-2585-41.5.965.
Nestling mourning doves and house finches produced elevated viremias after inoculation with 2-3 log10 plaque-forming units (PFU) of St Louis encephalitis (SLE) virus and infected 67 and 70% of Culex tarsalis Coquillett that engorged upon them, respectively. Mosquito infection rates as well as the quantity of virus produced after extrinsic incubation increased as a function of the quantity of virus ingested and peaked during days 3-5 postinoculation in mourning doves and days 2-4 in house finches. Only female Cx. tarsalis with body titers > or = 4.6 log10 PFU were capable of transmitting virus. Overall, 38% of females infected by feeding on mourning doves and 22% feeding on house finches were capable of transmission. The quantity of virus expectorated was variable, ranging from 0.8 to 3.4 log10 PFU and was greatest during periods when avian viremias were elevated. Our data indicated that nestling mourning doves and house finches were competent hosts for SLE virus and that the quantity of virus ingested from a viremic avian host varies during the course of the infection and determines transmission rates by the mosquito vector.
雏鸟期的哀鸽和家朱雀在接种2-3个对数10蚀斑形成单位（PFU）的圣路易斯脑炎（SLE）病毒后产生了较高的病毒血症，分别有67%和70%吸食过它们血液的致倦库蚊（Culex tarsalis Coquillett）被感染。蚊子的感染率以及在外部潜伏期后产生的病毒量随着摄入病毒量的增加而增加，并在接种后第3-5天（哀鸽）和第2-4天（家朱雀）达到峰值。只有体内病毒滴度≥4.6个对数10 PFU的雌性致倦库蚊能够传播病毒。总体而言，通过吸食哀鸽血液而感染的雌性中有38%能够传播病毒，吸食家朱雀血液的为22%。咳出的病毒量各不相同，范围为0.8至3.4个对数10 PFU，且在鸟类病毒血症升高期间最大。我们的数据表明，雏鸟期的哀鸽和家朱雀是SLE病毒的适宜宿主，并且从病毒血症鸟类宿主摄入的病毒量在感染过程中会发生变化，并决定了蚊媒的传播率。
