Experimental Transmission of Eastern Equine Encephalitis Virus by Ochlerotatus j. japonicus (Diptera: Culicidae)

• Published in: Journal of medical entomology 2002-05, Vol.39 (3), p.480-484
• Main Authors: Sardelis, Michael R., Dohm, David J., Pagac, Benedict, Andre, Richard G., Turell, Michael J.
• Format: Article
• Language: English
• Subjects: Aedes - virology; Analysis; Animals; Asian tiger mosquito; Biological and medical sciences; Chickens; Culex - virology; Culicidae - virology; Disease Models, Animal; Disease transmission; eastern equine encephalitis virus; Encephalitis; Encephalitis Virus, Eastern Equine - physiology; Encephalomyelitis, Eastern Equine - transmission; Encephalomyelitis, Eastern Equine - virology; Equine encephalomyelitis; Female; Fundamental and applied biological sciences. Psychology; Genetic vectors; Health aspects; Insect Vectors - virology; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; Ochlerotatus j. japonicus; transmission; vector competence; Vectors. Intermediate hosts; Virus Replication
• ISSN: 0022-2585; 1938-2928
• DOI: 10.1603/0022-2585-39.3.480

We evaluated the potential for Ochlerotatus j. japonicus (Theobald), a newly recognized invasive mosquito species in the United States, to transmit eastern equine encephalitis (EEE) virus. Aedes albopictus (Skuse) and Culex pipiens (L.) were similarly tested for comparison. Ochlerotatus j. japonicus and Ae. albopictus became infected and transmitted EEE virus by bite after feeding on young chickens 1 d after they had been inoculated with EEE virus (viremias ranging from 107.0–8.7 plaque-forming units [PFU]/ml of blood). No Cx. pipiens (n = 20) had detectable levels of virus 14 d after feeding on an EEE-virus infected chicken with a viremia of 108.1 PFU per ml of blood. Depending on the viral titer in the donor chicken, infection rates ranged from 55–100% for Oc. j. japonicus and 93–100% for Ae. albopictus. In these two species, dissemination rates were identical to or nearly identical to infection rates. Depending on the viral titer in the blood meal, estimated transmission rates ranged from 15 to 25% for Oc. j. japonicus and 59–63% for Ae. albopictus. Studies of replication of EEE virus in Oc. j. japonicus showed that there was an “eclipse phase” in the first 4 d after an infectious blood meal, that viral titers peak by day 7 at around 105.7 per mosquito, and that virus escaped the mid-gut as soon as 3 d after the infectious blood meal. These data, combined with the opportunistic feeding behavior of Oc. j. japonicus in Asia and the reported expansion of its range in the eastern United States, indicate that it could function as a bridge vector for EEE virus between the enzootic Culiseta melanura (Coquillett)-avian cycle and susceptible mammalian hosts.