Published Date: 2003-08-30 23:50:00
Subject: PRO/AH/EDR> West Nile virus, sentinel chickens - USA (CA)
Archive Number: 20030830.2187
WEST NILE VIRUS, SENTINEL CHICKENS - USA (CALIFORNIA)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Sat 30 Aug 2003
From: Eleanor Kellon <Drkellon@aol.com>
Source: California Arbovirus Surveillance Bulletin, Week 35, Thu 28 Aug
California: 5 Sentinel Chicken Flocks Confirmed West Nile Virus-positive
21 chickens from 5 sentinel flocks in Imperial County have been confirmed
positive for West Nile virus (WNV) by the Viral and Rickettsial Disease
Laboratory (VRDL) and the Davis Arbovirus Research Unit (DARU). The flocks
are located near Seeley, El Centro, Niland, and Holtville. Dried blood
spots collected on 4 Aug 2003 from chickens in each of these flocks
screened positive for flavivirus (SLE/WNV). These results were confirmed
with blood collected last week.
Dried blood spot specimens from sentinel chickens submitted each week to
the DHS Viral and Rickettsial Disease Laboratory (VRDL) are tested for the
presence of antibodies to western equine encephalomyelitis (WEE), West Nile
virus (WNV) and St. Louis encephalitis (SLE) viruses by EIA and IFA. The
VRDL forwards serum specimens from sentinel chicken in which antibodies are
detected in new geographic areas to the Davis Arbovirus Research Unit
(DARU) for additional testing for WNV, SLE, and WEE antibodies.
All mosquito pools are currently tested by in situ EIA for WEE, SLE, and
WNV. And all species except _Culex tarsalis_ are also tested for California
encephalitis virus. All pools are being tested by Taqman for WNV (primers
for WEE and SLE will soon be available to include these viruses in the
Taqman assay). Additional viral testing [may include reverse transcriptase
polymerase chain reaction (RT-PCR)] of mosquito pools for California
encephalitis and other arboviruses is performed as appropriate. All dead
bird kidney tissues are tested by DARU using the Taqman assay. Organ pools
from the carcasses are tested using cell culture for virus isolation.
Eleanor Kellon, V.M.D.
[Dr. Kellon has commented that one of these sites is located in very close
proximity to the Salton Sea (where a West Nile virus-positive mosquito pool
was reported previously); the others are located to the south of this site.