Washington: The United
States has been hit hard by the largest ever outbreak of West Nile
virus, spread mostly by mosquito bites, that has killed 47 people
and infected an estimated 95,000 in 38 states.
The number of cases so far this year is the highest recorded
through August since the disease was first detected in the United
States in 1999, according to the Centres for Disease Control and
"The number of West Nile disease cases in people has risen
dramatically. We are in the midst of one of the largest West Nile
outbreaks ever seen," Lyle R. Petersen, director of the CDC's
division of vector-borne diseases, said at news teleconference
And it's far from over, noted WebMD, a health website, as right
now, the US is in the middle of mosquito season -- and nearly all
West Nile virus infections come from mosquito bites. Case counts
usually rise through September.
"The number of cases is trending upward in most areas," Petersen
was quoted as saying.
He noted 47 states have detected West Nile virus circulating in
mosquitoes, birds, or people. Only Alaska, Hawaii, and Vermont
have not yet detected the virus.
Petersen said that the reason for the high number of cases this
year is unclear, but that unusually warm weather could have
fostered favourable conditions for the disease's transfer to
About 75 percent of the cases are in Texas, Mississippi,
Louisiana, South Dakota and Oklahoma, CNN reported.
Texas has been at the epicentre of the outbreak, with 586
confirmed cases and 21 deaths, according to the Texas Department
of State Health Services.
David L. Lakey, Texas state health commissioner, characterised the
situation as a "disaster."
The CDC also is investigating whether the virus might have mutated
into a more dangerous form as most West Nile seasons have been
relatively mild since 2003, when the virus spread across the US
WebMD said the good news is that only one in five people infected
with West Nile virus gets West Nile fever. Symptoms appear three
days to two weeks after the bite of an infected mosquito.
So far this year, there have been 489 reported cases of West Nile
fever. Many cases go unreported.
Illness appears suddenly, said Petersen, who was infected in 2003.
(Arun Kumar can be contacted at email@example.com)