'Jamestown Canyon Virus'
In CT - Another Mosquito Virus
From Patricia Doyle, PhD

Hello Jeff: New one on me. I must admit this is one that I have not heard about, unless by another name.
The article and its author makes it sound as though Jamestown Canyon Virus is a household name. Sorry, I don't know of it. The article also goes on as though JCV has been here for eons. Maybe, but this is the first I have heard of it.
I will try to find some data on what the virus is, its family, etc and send it to you.
I wondered if this is a new way of informing people about a new virus. i.e. make us think it has been around for eons and we all know about it.
This is turning out to be a very bad year for mosquitos, insects and vectored diseases. My pool is closed for the season.
Mosquitoes Bite Back With Another Virus
Heavy Rains Boost Mosquito Population
HARTFORD, Conn. -- June's heavy rains provided a boost in the mosquito population, which has reappeared in the state with another virus.
The Jamestown Canyon virus (JCV), unlike West Nile virus, appears to be relatively common in Connecticut.
Jamestown Canyon virus, which usually causes only mild fever and headache, has been discovered in trapped mosquitoes in Cromwell and Danbury, according to the Connecticut Agricultural Experiment Station.
June's rain spurred a population explosion among human-biting mosquitoes that thrive in swampy areas and tend to carry Jamestown Canyon virus, but not West Nile virus, Theodore Andreadis, chief medical entomologist at the agricultural station said Monday.
Jamestown Canyon virus has been detected in mosquitoes every year for the past six years that tests have been conducted, Andreadis said. Two studies suggest that many Connecticut residents might have been infected but experienced few or no symptoms.
Symtoms of JCV are variable, but might include a flu-like illness and fever.
For the latest news and updates on this story, stay tuned to NBC 30 Connecticut News and
OK...Here's more on it...
Looks like this is not a new virus. It appears that it is related to La Corsse and other California serogrup viruses. Bunyaviridae.
Host is White Tail Deer (again.)
Jamestown Canyon Virus: Seroprevalence in Connecticut
To the Editor: Jamestown Canyon virus (JCV), a member of the California serogroup, has a wide geographic distribution throughout much of temperate North America. It causes mild febrile illness and, rarely, aseptic meningitis or primary encephalitis (1). JCV has been isolated from mosquitoes each year that surveys have been done in Connecticut, and 28 positive pools from 10 mosquito species were found during 2000 (T. Andreadis, pers. commun.). In contrast, only 14 positive mosquito pools were found to contain West Nile virus (WNV), which has recently been introduced into Connecticut (2). JCV has been isolated from Aedes mosquitoes in Connecticut, and serologic evidence suggests it is widespread in deer (3,4). No recent seroprevalence surveys have been done in Connecticut, nor have any human cases of infection or disease due to JCV been documented.
We report the results of two seroprevalence surveys done with standard indirect fluorescent assays (IFA) to detect immunoglobulin G antibodies to JCV. One survey examined 1,086 sera collected in 1990 from blood donors. The second survey examined 1,016 sera submitted to the Connecticut State Public Health Laboratory in 1995.
The IFA used JCV-infected baby hamster kidney cells (BHK-21). Infected and uninfected cell suspensions were air dried and fixed onto Teflon-coated, 12-well slides. Prepared slides were stored at -70°C. Sera were tested at a minimum dilution of 1:16. After incubation and washing of the fluorescein-conjugated counterstain, slides were dried and examined by fluorescent microscope (American Optical, Buffalo, NY). The positive human control serum was designated as the 4+ baseline with which the test sera were compared. Selected sera were tested by a serum dilution plaque reduction neutralization test (PRNT) assay with JCV, La Crosse virus, and trivittatus virus.
Of the 1,086 sera collected from blood donors in 1990, 164 (15%) were positive by IFA at a minimum dilution of 1:16. Because IFA screening procedures are known to have poor specificity, a subset of 39 IFA-positive and 5 IFA-negative sera was tested by PRNT. None of the IFA-negative sera were positive, while 26 (67%) of the 39 IFA-positive sera were positive for JCV antibodies. Extrapolating the PRNT results to the 164 IFA-positive sera yields an overall positivity rate of 10.1%.
The second serosurvey, performed on 1,016 sera collected in 1995 from apparently healthy patients requesting immune status testing to viruses such as varicella zoster or measles, had 57 IFA-positive specimens. Extrapolating additional PRNT results from 26 sera, of which 18 (69%) were positive, yields a 3.9% positivity rate.
In addition to our study, with crude seroprevalence rates ranging from 3.9% to 10.1%, another recent study demonstrated JCV antibodies in 2.9% to 13.3% of ill persons in Massachusetts (Tonry J et al., unpub. data). Although the screening results of our first serosurvey (10.1% positive) differed widely from those of the second serosurvey (3.9% positive), even the lower rate indicates substantial levels of human infection in Connecticut.
This report suggests that JCV infection is fairly frequent in Connecticut and that illness may occur, as corroborated by data from neighboring Massachusetts (Tonry J et al., unpub. data) and unpublished laboratory findings from the Connecticut State Public Health Laboratory. The interest in arboviral disease will continue unabated, spurred by the continued occurrence of WNV, and systematic testing for JCV infection may be timely, at least throughout the northeastern United States.
Donald Mayo,* Nick Karabatsos, Frank J. Scarano, Timothy Brennan,* Daniel Buck,§ Terry Fiorentino,§ John Mennone,§ and San Tran§
*Connecticut Department of Public Health Laboratory, Hartford, Connecticut, USA; CDC Division of Vector-Borne Infectious Diseases, Fort Collins, Colorado, USA; University of Massachusetts Dartmouth, Dartmouth, Massachusetts, USA; and §Yale University Department of Epidemiology and Public Health, New Haven, Connecticut, USA
Grimstad PR. California group virus disease. In: Monath TP, editor. Arboviruses Vol. II. Boca Raton (FL): CRC Press 1988. p. 99-136.
Centers for Disease Control and Prevention. 2000 update: West Nile virus activity. MMWR Morb Mortal Wkly Rep 2000; 49:1044-7.
Zamparo JM, Andreadis TG, Shope RE, Tirrell SJ. Serologic evidence of Jamestown Canyon virus infection in white-tailed deer populations from Connecticut. J Wildl Dis 1997;33:623-7.
Sprana HE, Main AJ, Wallis RD. Jamestown Canyon virus in Connecticut. Mosq News 1978;38:392-5.
Serologic evidence of Jamestown Canyon virus infection in white-tailed deer populations from Connecticut.
Zamparo JM, Andreadis TG, Shope RE, Tirrell SJ.
Yale Arbovirus Research Unit, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
We determined the prevalence and distribution of Jamestown Canyon (JC) virus antibody in white-tailed deer (Odocoileus virginianus) populations in Connecticut, USA. Sera were collected from hunter-killed deer during 1993. Antibody to JC virus was detected by enzyme-linked immunosorbent assay (ELISA) in 92 (21%) of 446 deer sera, and was uniformly distributed among geographic sites. Twenty-one ELISA-positive sera were tested and confirmed positive by plaque reduction neutralization testing. This represents the first serologic evidence of JC virus in a reservoir host population from the northeastern United States. No cross-reactivity was seen with California encephalitis, Keystone, or snowshoe hare viruses, but a varying degree of cross-reactivity was obtained with Guaroa, Jerry Slough, La-Crosse, San Angelo, and trivittatus viruses. We conclude from this investigation and previous isolations of JC virus from mosquitoes in the state that JC virus occurs enzootically in Connecticut.
PMID: 9249710 [PubMed - indexed for MEDLINE]
Patricia A. Doyle, PhD
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