Aug. 18, 2005 07:20 AM
TUCSON
- Health officials have confirmed Pima County's first human case of
West Nile virus this year.
The case involves a 51-year-old Tucson man with no symptoms of illness, whose infection was discovered during routine screening for contagious viruses when he tried to donate blood.
Like 80 percent of people infected with the West Nile virus, the man never became ill. Only 20 percent show flulike symptoms, with 1 in 150 developing severe brain-affecting illness that can prove fatal.
It's the first West Nile case discovered in Pima County though blood screening.
Nationwide testing for the virus in donated blood began in 2003 after it became clear the virus could be transmitted through the nation's emergency blood supply.
Pima County's nine other reported human cases - two in 2003, including one death, and seven last year - occurred in people who developed neurologic complications, including meningitis, encephalitis or other severe symptoms.
West Nile virus is transmitted to humans only through the bite of a mosquito infected by biting sick birds. The virus jumped to the United States from Europe and the Middle East in 1999, first surfacing in New York, then spreading west ever since.
In Maricopa County, more than 350 people were reported infected by the West Nile virus last year and eight died.
The case involves a 51-year-old Tucson man with no symptoms of illness, whose infection was discovered during routine screening for contagious viruses when he tried to donate blood.
Like 80 percent of people infected with the West Nile virus, the man never became ill. Only 20 percent show flulike symptoms, with 1 in 150 developing severe brain-affecting illness that can prove fatal.
It's the first West Nile case discovered in Pima County though blood screening.
Nationwide testing for the virus in donated blood began in 2003 after it became clear the virus could be transmitted through the nation's emergency blood supply.
Pima County's nine other reported human cases - two in 2003, including one death, and seven last year - occurred in people who developed neurologic complications, including meningitis, encephalitis or other severe symptoms.
West Nile virus is transmitted to humans only through the bite of a mosquito infected by biting sick birds. The virus jumped to the United States from Europe and the Middle East in 1999, first surfacing in New York, then spreading west ever since.
In Maricopa County, more than 350 people were reported infected by the West Nile virus last year and eight died.