NY Death Caused By
African Bird Virus Never
Seen Here Before
ATLANTA (Reuters) - At least one of three deaths in New York City originally blamed on St. Louis encephalitis was confirmed as being caused by a bird virus previously unseen in the Western Hemisphere, federal health officials said on Sunday. Researchers are reviewing three deaths and 15 illnesses that occurred in New York during the past month after the discovery in dead birds last week of a virus usually seen only in Africa and Asia.
"DNA sequencing on brain tissue from one of the case patients of this outbreak determined that it was West Nile virus in the sample," Barbara Reynolds, a spokeswoman for the Centres for Disease Control and Prevention (CDC), said on Sunday.
The CDC said the virus, called the West Nile-like virus, is closely related to St. Louis encephalitis. The two viruses are difficult to tell apart with commonly used tests.
"CDC is continuing to look and retest some of our serology samples from patients in this outbreak to determine whether in fact they also have been infected with West Nile-like virus," she said.
Reynolds said researchers were working to identify the exact virus strain to determine if it had been reported elsewhere.
"We're going to be doing further testing to determine what subtype this is of West Nile and see if it's one that we recognise from other places in the world or if this is a new variant," she said.
New York City health officials began mosquito control measures, including the spraying of insecticide, in an effort to control the mosquitoes that spread encephalitis.
Duane Gubler, director of the CDC's Division of Vector-Borne Infectious Diseases, said there was "considerable potential" for the West Nile-like virus, never before reported in the Western Hemisphere, to spread to Central and South America as birds migrate.
The West Nile-like virus and the St. Louis encephalitis virus are both transmitted through the bite of a mosquito that has become infected by feeding on an infected bird. Neither virus is transmitted directly from person to person or from birds to people.
West Nile-like Virus in the United States
CDC, in collaboration with the New York City and New York State departments of health, has isolated and identified a West Nile-like virus from birds that died in New York City and were submitted for testing by the Bronx Zoo.
West Nile virus is an arbovirus closely related to St. Louis encephalitis virus, but generally causes a milder disease in humans. Both viruses are transmitted through the bite of a mosquito that becomes infected with the virus by feeding on an infected bird. Like St. Louis encephalitis, West Nile virus is not transmitted from person to person or from birds to persons. West Nile virus never before has been recognized in the United States or any other area of the Western Hemisphere.
Since late August, New York City has been experiencing an outbreak of arboviral (mosquito-borne) encephalitis. Previously, diagnostic tests on serum from human cases in this outbreak were reported as consistent with St. Louis encephalitis virus infection. At present, the relationship between this isolation of West Nile-like virus from birds in New York City and the outbreak of encephalitis among persons in New York City remains uncertain and further laboratory testing is underway. The CDC is testing these and additional human specimens for the possibility of West Nile-like virus infection.
CDC and city and state health departments emphasize that current mosquito control efforts by individuals and communities are appropriate because the same mosquito species transmit both viruses. Individuals should continue to do the following to reduce their contact with mosquitoes:
When outdoors, wear clothing that covers the skin such as long sleeve shirts and pants; spray clothing and exposed skin with insect repellant. Curb outside activity at dawn, dusk and during the evening. Communities should continue to do the following:
Raise public awareness about the outbreak, control measures, and personal protection. Continue current efforts of mosquito control. CDC further recommends that communities in the area should consider mosquito spraying if they have not yet done so.