News Release

PO 360
Trenton, NJ 08625-0360
Christine Grant
For Release:
August 22, 2000
For Further Information Contact:
Dennis McGowan
NJ Home Page DHSS Home Page

West Nile Virus Testing Update

TRENTON - A sampling of mosquitoes collected in late July in Bergen County has tested positive for the presence of West Nile virus (WNV). Bergen County has since intensified control activities and adult mosquito populations continue to be low.

The mosquitoes, taken from four pools that included Culex pipiens and Culex restuans species, were collected by the Rutgers Mosquito Research and Control Unit and tested by the federal Centers for Disease Control and Prevention (CDC). The Rutgers' program is funded by the New Jersey Department of Environmental Protection.

The positive mosquitoes were among more than 10,500 collected and tested as part of an on-going CDC and United States Geological Survey (USGS) study to help determine the prevalence of WNV in Northern New Jersey and New York City and State. The study will look at early season aspects of WNV transmission, its geographical spread and what role ecological and environmental factors might play in its spread. Knowledge gained by the study may help refine control strategies.

In addition to mosquitoes, the CDC also analyzed more than 1,000 house sparrows. No sparrows with WNV were discovered in New Jersey.

While birds and mosquitoes have been found with WNV in New Jersey, no state resident has been confirmed with the virus to date.

The West Nile virus, an arboviral disease, is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird. WNV is not directly transmitted from birds to humans or from person to person. WNV infection generally causes no symptoms or just mild, flu-like symptoms; however, the elderly are at higher risk of more severe disease.

Blood and/or spinal fluid samples from 16 residents have been or are in the process of being tested for the presence of WNV. To date, samples from 5 residents have tested negative and the other test results are still pending. These individuals either had symptoms or signs that met the established WNV testing criteria or exhibited most of the symptoms and are from counties where dead crows with the virus have been discovered.

The department has also been contacted by doctors of more than 2 dozen patients with symptoms that did not meet all WNV testing criteria. The physicians were given the option of sending samples of their patients' blood to private laboratories for analysis using the St. Louis Encephalitis (SLE) screening test. Since SLE and WNV are closely related viruses, a WNV case will most likely react to a SLE test. The department has not been notified of any positive SLE tests to date.

To date, 165 birds (164 crows and a cockatiel) found in 9 counties have tested positive for the presence of WNV. Positive birds have been found in Bergen (51), Essex (10), Hudson (18), Middlesex (40), Monmouth (13), Morris (1), Passaic (17), Somerset (1) and Union (14) Counties. Negative birds have been found in these and all other counties. The tests were conducted at the Department of Health and Senior Services' lab in Trenton: the CDC confirmed early season results.

To date, 705 mosquito pools collected in New Jersey and tested at the state health lab have been negative for WNV. Blood samples taken weekly from sentinel chicken flocks placed in all 21 counties and tested by the New Jersey Department of Agriculture for the presence of WNV have all been negative to date.

New Jersey residents can take personal precautions to minimize their WNV exposure risk. Such measures include spraying insect repellent on their clothing and exposed skin in accordance with labeling directions and wearing long sleeved shirts and pants when outdoors. Residents can also curb outdoor activities at dawn, dusk and during the evening. Residents should also eliminate standing water on their own property that can serve as a breeding ground for mosquitoes.

New Jersey's WNV surveillance, control and prevention efforts involve the coordinated efforts of a number of federal, state and local agencies. These include the New Jersey Departments of Health and Senior Services, Environmental Protection, and Agriculture, the federal Centers for Disease Control and Prevention (CDC), the State Mosquito Control Commission, the Rutgers Mosquito Research and Control Unit, and local health and mosquito control agencies.

For more information on West Nile virus, visit the State Department of Health and Senior Services' website at; the State Department of Environmental Protection's site at; the State Department of Agriculture's site at; or the federal Centers for Disease Control and Prevention's site at

# # #

NJ Home Page DHSS Home Page