Zoonosis Reports


Texas Animal Health Commission
Box l2966 *Austin, Texas 78711 *(800) 550-8242* FAX (512) 719-0719
Linda Logan, DVM, PhD* Executive Director
For info, contact Carla Everett, information officer, at 1-800-550-8242,
ext. 710,
or ceverett@tahc.state.tx.us

For Immediate Release August 8, 2002

West Nile Virus (WNV) Advances Westward

A horse in Haskell County, about 50 miles north of Abilene, tested positive
Wednesday, August 7, for the mosquito-borne disease West Nile Virus (WNV).
This is the 21st horse to test positive for WNV in Texas, and is the
westernmost detection of the virus in the state.

"Previously, WNV had been detected only as far west as Travis County,"
reported Dr. Joe Garrett of the Zoonosis Control Division of the Texas
Department of Health.  "The virus was confirmed in a dead blue jay
submitted from southwest Austin on July 17."
He noted that infected birds have been found in seven counties: Collin,
Dallas, Galveston, Harris, Montgomery, Tarrant and Travis. Infected
mosquitoes have been detected in Dallas, Fort Bend, Harris, Orange and
Jefferson counties.

"We credit the Texas Department of Health with confirming infection in the
Haskell County horse.  The private veterinary practitioner, suspecting that
the animal might have rabies, submitted the brain to the TDH laboratory,
where rabies testing is conducted. After ruling out that disease, health
department laboratory technicians tested the tissue for West Nile Virus and
confirmed infection," said Dr. Linda Logan, Texas' state veterinarian and
executive director for the Texas Animal Health Commission (TAHC), the
state's livestock health regulatory agency.  She said unless rabies is
suspected, WNV testing for horses is usually conducted at the Texas
Veterinary Medical Diagnostic Laboratory (TVMDL) at College Station.  WNV
testing for humans, birds and mosquitoes are conducted by the Texas
Department of Health (TDH).

"We're continuing to urge owners to have their horses, donkeys, mules and
other equids vaccinated against this form of 'sleeping sickness' which
continues to spread westward," said Dr. Linda Logan, Texas' state
veterinarian and executive director for the Texas Animal Health Commission
(TAHC). "To gain protection against the virus, however, equids need two
injections of WNV vaccine administered at least three to six weeks apart.
The animal will not develop full immunity for about four to six weeks after
the second injection."  Dr. Logan advised owners to further protect horses
with insect repellents, and if possible, house the animals at night in
stalls with screens to prevent contact with potentially infected mosquitoes.

"Likewise, we urge residents to apply insect repellents if they are going
to be outside when mosquitoes are active," commented Dr. Joe Garrett of the
Zoonosis Control Division of the Texas Department of Health.  "There is no
vaccine for humans, so disease prevention is our only option. Drain all
sources of stagnant water, keep pools optimally chlorinated, and change
water in birdbaths daily to prevent mosquitoes from using these sites for
breeding grounds.  Because some mosquitoes breed in grassy areas, it's also
a good idea to keep areas around homes mowed"

Although blue jays, crows and more than 70 other species of birds carry the
virus, they do not pose a direct WNV health risk to humans or horses,
stressed Dr. Logan. She explained that the disease cycle must involve
mosquitoes that feed on the infected birds, then transmit the disease to
humans or horses.

"We want receive samples of dead blue jays and crows, particularly from
areas west of Houston, so that we can track the progression of this disease
as it advances westward," said Dr. Garrett.  "For surveillance testing at
the Texas Department of Health, we need 'freshly' dead birds that have not
begun to decompose.  If you have a dead bird to submit, call your local
health department, or the state office at 1-512-458-7255 for instructions.
If you handle the bird, wear gloves to protect yourself against any
possible parasites or other diseases the bird may have contracted, and
double-bag the carcass.  Prior to laboratory submission, it's best to place
the bird in a cool place, such as an ice chest, to slow decomposition."

"WNV will continue to spread, but like the veterinarian in Haskell County,
we need always to consider rabies or other diseases, if animals stagger,
are unable to rise, or become disoriented," said Dr. Logan.  "Although
fairly rare, rabies can strike livestock, and if owners handle an animal
stricken with the disease, they must receive preventive medical treatment.
It's important to have a diagnosis when livestock become extremely sick or
die.  If your animals are exhibiting signs of neurological distress, notify
your veterinary practitioner and TAHC at 1-800-550-8242."

WEST NILE VIRUS, HUMAN - USA (TEXAS): CONFIRMED *********************************************** A ProMED-mail post ProMED-mail is a program of the International Society for Infectious Diseases Date: Tue 23 Jul 2002 From: Harry Rakosky Source: Houston Chronicle, Tue 23 Jul 2002 [edited] Texas: First Human West Nile Case Confirmed; 4 More Houston Cases Suspected --------------------------------------------------------------------------- A 50-year-old man from Orange County is the first human case of West Nile virus infection in Texas, blood tests confirmed today. In addition, health officials are waiting for more test results on a 74-year-old man hospitalized on 16 Jul 2002 with altered mental status, a West Nile symptom. Test results are pending on 3 more suspected adult cases as well. The Orange County man who contracted West Nile virus infection was hospitalized last week at the Houston Veteran's Affairs Medical Center, where he was in stable condition today. He went to an emergency room in Orange County where he reported having a fever, headache, vomiting and neck stiffness. He was then transferred to the VA hospital here. Dr. Daniel Musher, head of infectious disease at the VA, had strongly suspected West Nile virus infection in his patient for a number of reasons [see preceding ProMED-mail post: "West Nile virus, human - USA (Texas): suspected"]. Today's test results are to be sent to the Texas Department of Health for confirmation. 7/8/02 This from Roy Burton, TDH Vector Control Division - a pool of Culex tarsalis
mosquitoes from El Paso has turned up positive for Western Equine.

This also courtesy of Roy Burton, TDH Vector Control Division
Excerpted from a press release:
Case of West Nile suspected in Hammond
June 30, 2002
HAMMOND (AP) - A 78-year-old man from Hammond may have Louisiana's first case of
West Nile virus this year.

Dr. Raoult Ratard, Louisiana's state epidemiologist, said Friday that he notified
Mississippi authorities because the man spends time outdoors
at a lake in the Brookhaven area, as well as in the Hammond area.
The man has encephalitis caused by a virus of the type which includes both West
Nile and St. Louis, Ratard said.

A test Friday confirmed the virus family. It will be at least two weeks before
doctors know which it is, Ratard said.

Tangipahoa Parish President Gordon Burgess said he got the news Friday afternoon.

He is concerned and said officials need to wait on the test results to get more

"We will continue to spray ditches and ponds and in fact, we will probably step up
the spraying effort," Burgess said.

West Nile is suspected because the virus is known to be established in birds
around Lake Pontchartrain, Ratard said.

The man is being treated at North Oaks Medical Center, said Bob Johannesen,
spokesman for the state Department of Health and Hospitals.

Ratard said the hospital sent a blood sample June 21 to a laboratory for tests.
He did not know if the man was hospitalized then.

That same week, officials stopped testing birds from Tangipahoa Parish for West
Nile because it was clear that the virus was well established in the area.
Ratard is waiting for tests on another suspected case of encephalitis this year
in Louisiana - a child in Vernon Parish.


This early case report courtesy of Dr Joe Garrett in the TDH Austin office.

> USDA has reported the first West Nile "preliminarily" positive sera and CSF
from a horse in Texas. The horse was located in Katy, Harris County, and
was showing symptoms and eventually euthanized. Three more horses from the same
stables are also ill. The test was done at the National Veterinary Services
Laboratory (NVSL) in Ames, Iowa. Final results will be available within one
week, but NVSL is certain they will be positive.

> USDA and Texas Animal Health Commission have decided to release the
information based on the preliminary results.


This from James Wright, TDH Zoonosis Division, Tyler, TX

A horse in Jasper County was euthanized on June 23rd after being confirmed with
a titer of 1:320. Onset was June 21.


GONZALES -- Test results from a horse that died in Gonzales [Louisiana]
indicate the animal succumbed to West Nile virus, Ascension Parish Mosquito
Control Supervisor David Matassa said Wednesday.

Matassa said Dr. Gary Balsmo, a veterinarian with the state Department of
Health and Hospitals, told him Tuesday afternoon that the horse died as a result
of the virus.

The parish plans to increase spraying to kill mosquitoes and their larva,
Matassa said.

The virus is transmitted by more than 40 species of mosquitoes, from bird
to bird, according to the state Office of Public Health. The disease is called
arboviral encephalitis because the virus is transmitted or borne by insects.

Encephalitis is an infection of the brain that destroys nerve cells and
results in inflammation and swelling, according to the Office of Public Health.

Most people infected with the virus have no illness or, at most, they
experience symptoms similar to a mild flu with fever, headache and fatigue, according
to the state health office.

However, in rare cases, the virus multiplies in the central nervous system,
causing brain disease.

In addition to fever, headache and drowsiness, those infected will experience
loss of muscular power, double vision, speech impairment, convulsions
and coma.

The federal Centers for Disease Control and Prevention in Atlanta said that
in areas where mosquitoes carry the West Nile virus, less than 1 percent are
infected. The agency added that the chances that a person bitten by a
mosquito would become severely ill are very small.

Three other cases of West Nile virus have been confirmed in Louisiana
horses this year, Commissioner of Agriculture Bob Odom said.

"I believe every horse owner should vaccinate their animal for West Nile
just like they would for Eastern equine encephalitis and other transmittable
diseases," he said.

"West Nile has now established itself in the state and it's not going to go
away," Odom said. "It is important for equine owners to be diligent
in vaccinating for this and other forms of encephalitis during their annual
health routine. It's the only way we can control the spread."

West Nile vaccine is available for purchase through veterinarians only.


News from Roy Burton (TDH Vector Control Division) on a pool of Culex
quinquefasciatus that turned up positive for St. Louis Encephalitis in
Corpus Christi. This pool was collected on 6-11-2002.

News from James Wright (TDH Zoonosis Division) is that a horse up in Tyler county
went down with Eastern Equine Encephalitis - died on June 19th.

Meanwhile, Harris County did an aerial application the other evening
with Dibrom targeting Culex quinquefasciatus - an attempt to do something about the
fact that it's raining bluejays in NW Harris county! We need to keep on top
of that one, as it's kind of breaking ground aerial application-wise for this WNV
thing here in Texas.



The University of Texas Medical Branch laboratory at Galveston has identified
West Nile Virus in two blue jays collected from Western Harris County.
The Texas Department of Health was informed by Dr. Arafat with the Houston City
Health Department. This was also communicated to our Houston Regional Office.
This is, of course, the first detection of WNVirus transmission
in Texas. No known human disease has been associated with it.

General information, including Q & A's, and facts sheets for physicians and
veterinarians on West Nile Virus can be found at:



Informational faxes will be sent to Texas veterinarians overnight tonight
(June 19th, 2002)

Jim Schuermann
Staff Epidemiologist, Zoonosis Control Division
Texas Department of Health
voice: 512.458.7255, fax: 512.458.7454
visit our website at:

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