By Marice Richter
DALLAS, Sept 26 (Reuters) – When Dr. Robert Haley spotted a
dead blue jay lying in his neighbor’s driveway early this summer
he became suspicious. When he saw another blue jay dead in the
birdbath at his Dallas home the next morning, he knew it was a
bad omen of disease.
What he could not predict at the time was that the bird
corpses heralded one of the worst U.S. outbreaks of West Nile
virus on record, with nearly 40 percent of cases in Texas alone.
“It’s unusual to see dead birds lying in the open,” said
Haley, chief of epidemiology at the University of Texas
Southwestern Medical Center. “Typically, birds die in some
out-of-sight place or they are carried off by animals if they
die out in the open.”
West Nile is transmitted from sick birds to humans and other
mammals by mosquitoes and was first detected in the United
States 13 years ago, in New York City. Texas declared a state of
emergency last month after seeing the worst toll from West Nile
this year, which has reached 3,545 total cases and 147 deaths
nationwide, according to the U.S. Centers for Disease Control
and Prevention. Other states with large outbreaks include
Mississippi, Michigan, South Dakota, Louisiana, Oklahoma and
California.
“From the beginning, I thought it could be a bad year,” said
Haley, who spent 10 years working for the CDC and now lives in
the epicenter of the outbreak. “But it turned out to be much
worse than anyone imagined. It was a public health disaster.”
Experts hope the outbreak has peaked as cooler weather sets
in and widespread pesticide spraying takes effect. Now is the
time to learn the lessons for the future.
GOOD WEATHER FOR BUGS
Five counties within the Dallas-Fort Worth area – the fourth
largest metropolitan area in the country – recorded 28 of the 63
deaths and 869 of the 1,429 cases reported to the Texas
Department of State Health Services by Tuesday. Dallas County
alone has recorded 16 deaths and 371 cases, according to county
authorities.
CDC and state officials believe a year’s worth of record
high temperatures and intermittent rainfall this past spring
contributed to the severity of the epidemic by affecting bird
and mosquito populations. Following a record hot summer and
drought conditions in 2011, Dallas-Fort Worth had a warm winter
with fewer than normal freezes followed by bouts of rain in the
spring, officials said.
“One of the things we are closely looking at is the effect
of weather on this year’s outbreak,” said Lyle Petersen,
director of the CDC’s Division of Vector-Borne Infectious
Diseases. “West Nile outbreaks tend to be difficult to predict.
Why it occurred in Dallas more than other areas is a matter of
speculation at this point, and it’s something that we’re going
to be looking at very carefully.”
In addition, health officials in the region have witnessed
an especially large number of neuroinvasive cases, the more
severe form of the disease that often leads to meningitis and
encephalitis.
Haley estimates that about 25,000 people likely were
infected with West Nile in Dallas County this summer. Of those,
about 80 percent showed no symptoms at all, while many of the
remaining residents came down with West Nile Fever, a mild form
of the disease that is largely under-reported and only
sporadically tested. State figures show only that Dallas County
recorded 168 West Nile fever cases and 154 neuroinvasive cases.
HOPES FOR A RESPITE
Haley and others say the worst should be over in terms of
new infections, but more cases are expected to be reported due
to the lag time between infection, testing for the virus and
reporting to state agencies and the CDC. The death toll is also
likely to rise as it can take weeks to months for patients to
deteriorate.
In the meantime, Dallas residents are still coming to terms
with the ravages of the outbreak, which dwarfs the four deaths
seen in the region in 2006.
With no vaccine to prevent West Nile in humans, the only
defense is prevention – wearing insecticide outdoors and
pesticide spraying by ground and air.
Dr. Don Read, a surgeon in Dallas, who was infected by
neuroinvasive West Nile in 2005 while walking in his Dallas
neighborhood and now runs a support group for survivors, said
people tend to think they are invincible. “I didn’t think I
would get it until I did. It only takes one mosquito bite.”
Read, who was infected at age 63, spent almost five weeks in
the intensive care unit. He now wears braces on his legs due to
polio-like paralysis, but considers himself lucky to be alive.
The sound of a plane buzzing overhead spreading insecticide
in the suburban community of Southlake was a welcome sound to
Ann Dachniwsky, 47, who spent much of the summer so fatigued
from neuroinvasive West Nile that her only activity was “going
from the bed to the couch back to the bed.”
At the height of her illness, her husband and three children
took turns waking her up every few hours to force her to drink.
“My balance and sight were affected so I could barely work
or see. I was flat on my back for weeks,” she said. “I was a
healthy, active person. I’m getting better but I can barely
manage one activity without needing to lay down afterwards.”
Dachniwsky’s family had pleaded with the Southlake City
Council to allow aerial spraying of pesticide for the first time
since an encephalitis outbreak nearly 50 years ago. Dallas and
nearby Denton counties conducted aerial spraying missions in
August. Southlake, which is partially in Denton and Tarrant
counties, was sprayed. Officials in Tarrant County, home of Fort
Worth, chose to spray only by ground.
As the outbreak has slowed, Dallas County health officials
continue to be criticized both for not moving fast enough to
start spraying and also for going too far in the breadth of the
aerial spraying program once it started.
“We had a protocol in place and we followed it,” said Zach
Thompson, director of the Dallas County Department of Health and
Human Services. “We started with public education, followed by
localized ground spraying, then enhanced ground spraying and
finally aerial spraying.”
As research and analysis of the outbreak continue, Thompson
said officials will work diligently to avoid a repeat of
history.
“We were surprised by the magnitude of the outbreak this
year but we feel that our response was appropriate,” Thompson
said. “Hindsight is 20/20.”
(Editing by Michele Gershberg and Claudia Parsons)
