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release [edited]





Stakes high in fight against the cattle fever tick; pest could spread 

coast-to-coast

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Livestock health officials say it could cost upwards of USD 13 

million and take as long as 2 years to stop an incursion of fever 

ticks into the formerly fever tick-free areas of 5 counties along the 

Texas-Mexico border. The fever tick, less than a 1/8-inch (3 mm) 

long, is capable of carrying and transmitting 'babesia,' a blood 

parasite deadly to cattle.



"For most of the country, the fever tick has been pushed out of 

sight, out of mind, since the 1940s. This tick, however, is capable 

of transmitting a foreign animal disease and it's sitting in our 

backyard," said Dr. Bob Hillman, Texas' state veterinarian and 

executive director of the Texas Animal Health Commission (TAHC), the 

state's livestock and poultry health regulatory agency.



"If we do not stop it, the fever tick could spread from coast to 

coast, except the arid lands of New Mexico and Arizona, and as far 

north as Washington D.C.," stressed Dr. Hillman. "As the tick spreads 

so will the need for personnel and resources. Win the battle along 

the Rio Grande in Texas, and other states won't have to fight the war."



The TAHC has placed temporary fever tick quarantines on 1116.3 square 

miles (2891.2 sq km) in 5 Texas border counties, including parts of 

Starr and Zapata counties, and a contiguous area encompassing parts 

of Maverick, Dimmit, and Webb Counties. In addition, an 852-square 

mile (2207 sq km) permanent quarantine zone butts up against the Rio 

Grande from Del Rio to Brownsville and is under the management of the 

US Department of Agriculture's (USDA) 60-person Fever Tick Force.



The USDA, which is adding up to 30 temporary tick inspectors, and the 

TAHC, which has detailed inspectors to south Texas on a rotating 

basis, are working with ranchers to locate, 'corral,' and eradicate 

the tick. In this area about the size of Delaware, all cattle, 

horses, penned deer, llamas, camels, and any other species that can 

host the tick are being manually inspected -- or "scratched" -- by 

TAHC or USDA inspectors.



If animals in these quarantined areas are moved from their premises, 

they'll undergo another "scratch" inspection, then be dipped or 

sprayed, and permitted for movement. Because horses can give ticks a 

lift, these animals are put under 14-day inspections and treatment, 

if they're moved routinely from their home base.



When fever tick-infested livestock are detected, the premises are 

quarantined for 6 to 9 months. As of early October [2007], this 

included at least 25 premises in the temporary quarantine areas and 

about 56 premises in the permanent quarantine zone.



Cattle remaining on tick-infested premises must be inspected and 

dipped every 14 days or treated with doramectin every 28 days. 

Alternatively, the animals may be moved to a new site, but only after 

undergoing 2 consecutive tick-free inspections and dippings. A 

movement permit then is issued, and the cattle must be transported immediately.



"The USDA has made USD 340 000 available for immediate fever tick 

needs in south Texas, and the state legislature granted the TAHC an 

extra USD 150 000 to purchase additional Co-Ral, the acaricide used 

for dipping vats and in spray rigs," Dr. Hillman said. He reported 

that a USDA assessment concluded that to eliminate fever ticks from 

the temporary preventive quarantine areas, at least USD 13 million 

was needed to hire additional personnel, repair or replace worn out 

portable tick dipping equipment, purchase new spray rigs and 

supplies, and procure other essential equipment.



"To get a handle on potential fever tick spread, the TAHC field staff 

also is tracing the movement of cattle from infested premises in the 

temporary quarantine area within the past year," Dr. Hillman noted. 

So far, this has involved nearly 800 animals, of which about 459 have 

been located, inspected, and found to be fever tick-free. Some were 

found in Kansas or Texas Panhandle feed yards, and others were 

scattered across the state and to 2 other states.



"Many of these animals had been moved as calves without any 

identification, except the livestock market back tag, or clearly 

defined destination," he said. "This slows down our work, but we 

don't give up until all avenues are exhausted."



"The fever tick, by itself, will not cause disease. However, cattle 

tick fever is imminent if the fever tick is carrying babesia, and 

transmits it to cattle that are 'naive,' meaning they have no 

resistance to the organism that quickly breaks down red blood cells," 

said Dr. Hillman. "There are 2 potential scenarios with fever ticks 

that keep the TAHC, the Tick Force, and border ranchers awake at night."



The 1st scenario, explained Dr. Hillman, involves Mexico, where fever 

ticks and babesia have not been eradicated. Young calves there may be 

exposed to the babesia, survive the disease and develop immunity, but 

continue to carry the organism.



"Even if Mexican feeder cattle carry babesia, they will not cause a 

disease problem unless there is fever tick involvement," said Dr. 

Hillman, setting the scene for the scenario. "Mexican-origin feeder 

cattle enter the US under strict USDA fever tick inspection and 

dipping requirements. To keep them away from fever ticks, the TAHC 

requires Mexican-imported cattle to have an "M" branded on their hip 

and prohibits these animals from being maintained in the permanent 

quarantine zone."



"If fever ticks are moved to sites where Mexican feeder cattle are 

pastured, the pests may pick up babesia. The babesia infected female 

tick transmits the disease to the next generation of fever ticks. 

Only one element then would be missing from the dangerous disease 

Hillman. "If native US cattle, which are susceptible to babesiosis or 

'cattle tick fever,' are infested with babesia-infected fever ticks, 

then disease transmission to the native cattle will occur. Most 

likely, this will cause significant death loss of native cattle. It's 

crucial to keep the fever tick pushed beyond the border, and support 

and fund surveillance activities in the permanent fever tick quarantine zone."



Dr. Hillman said the 2nd scenario involves wildlife as effective 

alternative hosts and sources for movement of ticks into Texas from 

Mexico and from the permanent quarantine zone to the free area of 

Texas. For once, noted Dr. Hillman, the beleaguered feral (wild) hog 

is not implicated. Fever ticks have not acclimated to swine, goats, 

sheep, or dogs. On the other hand, elk, white-tailed deer, nilgai, 

and red deer, serve as effective hosts for fever ticks, but are not 

affected by babesia.



"Free-ranging cervids do not respect national borders, shallow 

rivers, low fences, quarantines, or permits for movement," he said. 

"Wildlife hosts may crisscross the Rio Grande, hauling in fever 

ticks. Right now, wildlife presents the greatest risk for fever tick movement."



In spring 2007, more than 30 nilgai were depopulated in the Lower Rio 

Grande Valley National Wildlife Refuge, due to fever tick 

infestation. Of the 42 free-ranging white-tailed deer that were 

trapped and examined this year [2007], 28 also were "ticky."



"Treating wildlife is a tricky proposition, because current methods 

are limited to feeding cervids ivormectin-treated corn or drawing 

them to '4-poster' stations where they rub against pyrethrin-treated 

posts, which transfers the chemical," he said. "Ivormectin use 

requires a 60-day withholding period prior to slaughter or harvest, 

so wildlife feeding treatments will be delayed until hunting season ends."



In the meantime, the USDA or TAHC must inspect, treat, and permit the 

movement of hides from deer or exotic hoof stock harvested on 

tick-infested or exposed premises. (Meat may be moved without 

inspection.) To avoid the possibility of transporting fever ticks, 

ranchers and hunters are urged to practice good sanitary measures 

when leaving a ranch. Brush off clothing to dislodge any ticks that 

may be on the fabric. Clean off boots and shake out jackets or items 

that have been on the ground.



"The fever tick is not a human health threat," said Dr. Hillman. "But 

be careful. Don't transport ticks to new sites. Getting and keeping 

the fever tick out of Texas and the US is critical for disease 

control and our continued ability to move livestock without restrictions."



"If we are ultimately to be successful in our battle against the 

fever tick and 'cattle tick fever,' we must eliminate the current 

fever tick incursions in the free areas of Texas, then push the pest 

back into Mexico. To accomplish this, we must acquire resources 

necessary to fulfill the long-range fever tick eradication plan, fund 

research, and develop additional treatment products and methods. We 

also must aid our Mexican neighbors in their fight against the fever 

tick and 'cattle tick fever,'" concluded Dr. Hillman.



Texas Animal Health Commission

Box l2966, Austin, Texas 78711

(800) 550-8242 * FAX (512) 719-0719

Bob Hillman, DVM, Executive Director



For info, contact Carla Everett, information officer, at 

1-800-550-8242, ext. 710, or 





--



[The fact that the quarantine zone has expanded with ticks being 

found is significant. In the early 1900's this represented a 

significant economic impact as it was wide spread and was years 

before it was under control. The possibility of this spreading again 

and having economic impact is frightening; enough that USDA has 

detailed help to Texas.



Bovine babesiosis is a major tick-borne disease of cattle caused by 

protozoan parasites (_Babesia_ spp). The parasite is usually 

transmitted by the _Boophilus_ spp. tick.



Cattle with advanced babesiosis have a low exercise tolerance and 

sometimes collapse and die while being moved. Generally, older 

animals are more acutely affected and animals younger than 6 months 

rarely demonstrate clinical signs. Abortions may occur when pregnant 

animals are severely affected. 2 organisms carried by ticks cause 

similar clinical signs. However, the course of the disease differs 

markedly. Clinical signs include, fever, anorexia, depression, 

increased respiratory rate particularly following exertion, muscle 

tremor, reluctance to move, hemoglobinuria, and occasionally 

neurological signs such as head pressing, circling, and convulsions.



While these signs are seen very early in the course of _Babesia 

bovis_ infections, they only develop in _Babesia bigemina_ infections 

in the latter stages when there is advanced parasitemia. Anemia and 

jaundice develop steadily with _B. bovis_ but they are much more 

precipitous with _B. bigemina_. Animals affected with _B. bigemina_ 

may exhibit irritability and aggression but not the central nervous 

system signs.



Findings on necropsy my be variable but could include varying degrees 

of congestion, pallor or jaundice, red urine, blood that seems watery 

or thin, sub-serosal hemorrhages -- especially in the heart and 

intestines --, an enlarged pulpy red spleen, and an enlarged, brown 

or yellow liver with the gall bladder filled with thick, granular bile.



Differential diagnosis should include other causes of hemolytic 

anemia such as anaplasmosis, leptospirosis, and chronic copper poisoning.



The best treatment is prevention with insecticides. - Mod.TG]



[The southwestern state of Texas can be located on the map at 

- CopyEd.MJ]



2000

----

Babesiosis - USA (New York) 20000830.1452

1999

----

Babesiosis - USA (Rhode Island) 19990815.1406

1998

----

Babesiosis & Lyme disease, concurrent - Canada (02) 19980625.1178

Babesiosis & Lyme disease, concurrent - Canada (Ont.) 19980623.1165

1996

----

Babesiosis, possible - Bosnia (4) 19960625.1165

Babesiosis, possible - Bosnia (3) 19960621.1144

Babesiosis, possible - Bosnia (2) 19960617.1121

Babesiosis, possible - Bosnia 19960614.1101]

...................................tg/mj/mpp