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West Nile Virus was first detected in the United States in August of 1999. West Nile Virus can be a threat to human and equine populations alike. Signs of infection may range from unnoticed or very mild symptoms to a life threatening neurologic condition. This virus was initially diagnosed in the New York City metropolitan area in humans, horses, and various bird species. Horses appear to be more susceptible than other livestock or companion animals to West Nile infections. Since 1999, positive detections have been made in a great majority of the United States and Canadian provinces.

Infected birds serve as the reservoir host for the West Nile Virus. Crows and blue jays are noted for serving as an infected reservoir. The infected birds develop a large number of virus particles in their circulatory system. Mosquitos become infected by taking a blood meal from an infected bird and in turn transmit the disease to horses by biting them. The time between exposure to the virus and appearance of the first signs is estimated to be between 3-15 days. Humans and horses are known as “dead-end” or “terminal” host because no evidence indicates that humans or horses can transmit West Nile to other horses, birds, or humans. These “dead end” hosts have so few virus particles in their bloodstream that a mosquito cannot accumulate enough virus particles to subsequently transmit the infection. Despite this fact, caution should be used when handling samples or tissue from suspect animals.

West Nile Virus affects the central nervous system and may include one or more of the following signs:  weakness, incoordination, muscle tremors, a “dog sitting position” altered mental status, cranial nerve deficits, recumbency, seizures and blindness to list a few. Risk of infection seems to increase with the animal’s age. A blood sample may be sent to the diagnostic lab for conformation of West Nile Encephalitis. Rabies, botulism, EPM-(equine protozoal myeloencephalitis), EHV-1 (Rhino-Neurologic form) and the other types of sleeping sickness (VEE, WEE, and EEE) need to be included in a differential diagnosis of West Nile. There are currently four USDA licensed WNV equine vaccines available for use in the United States. These products provide approximately one year immunity when used according to the labeled instructions in healthy animals. Currently a human vaccine is not available. It is important to note that horses vaccinated against Eastern, Western and Venezuelan equine encephalitis WILL NOT be protected against the West Nile Virus.

Treatment for this viral disease is symptomatic and involves the use of anti-inflammatory agents and other methods to reduce the brain inflammation. Fluids and nutritional supportive care may also be required in certain cases. Neurologically impaired animals should be handled carefully to prevent injuring themselves and their owners. Even when clinically ill horses have recovered from West Nile, some horses may have residual gait abnormalities or demonstrate a change in their temperament and behavior.

Prevention and control of West Nile evolve around the reduction and elimination of mosquito populations.  Reducing exposure to mosquito bites through the use of mosquito repellants, protective clothing for humans and equine vaccinations are all methods to reduce the incidence of West Nile Virus infection. Prevention in horses is best accomplished by the proper use of WNV vaccinations.

The State-Federal Cooperative Bovine Tuberculosis (TB) Eradication Program is now in its 96th year, and although the national herd prevalence has dropped dramatically since the program's inception, eradication efforts have not eliminated the disease from the United States Many factors contribute to the current situation regarding Bovine TB in the U.S., and some variation exists depending on US cattle herd demographics. Although the primary focus of Bovine TB surveillance moved from live animal testing to slaughter inspection in the early 1960's, testing of animals for interstate commerce still remains vital to eradication efforts. The purpose of this article is to reiterate the factors involved in using the Caudal Fold Test (CFT) for detection of Bovine TB.

Since the CFT is a presumptive test, it is imperative that tuberculin be handled properly and that protocol of injection and observation be followed as correctly as possible. Because of the potential for the presence of Mycobacterium avium, Mycobacterium paratuberculosis, and saprophytic Mycobacterial species, the expected response rate for the CFT in a normal population ranges from 1 – 5%. This expected false positive rate is based on the historical statistical analysis of millions of properly performed CFT tests. A chart outlining the expected response rate for any number of cattle tested can be found on the last page of the USDA Bovine Tuberculosis Eradication Uniform Methods and Rules.

The Texas Animal Health Commission (TAHC) routinely monitors response rates of accredited veterinarians in an effort to increase the overall confidence of TB testing in Texas. Factors that influence the likelihood of a valid response include, but are not limited to:

• Proper intradermal injection of tuberculin
• Presence of pre-existing skin lesions at injection site
• Interpretation of response
• Potency of tuberculin
• Proper needle/syringe size

If a bleb at the injection site was not observed, then the injection was most likely subcutaneous and the result will not be valid. To help ensure a proper intradermal injection is applied, tuberculin should only be injected using 1cc syringes with a 26 gauge 3/8" intradermal bevel needle. Skin lesions and swellings present at the injection site prior to injection of tuberculin will play a role in accuracy of reading the response at time of observation, and a different injection site should be chosen in those cases with notation on the test chart. The CFT is not a quantitative test, therefore any response at the injection site, whether a noticeable nodule or simply a slight increase in skin thickness, should be reported as "suspect".

Improper handling of tuberculin can also result in an invalid test. Since tuberculin denatures from exposure to light, it should be stored in the dark at 35-45 degrees F. Tuberculin is susceptible to oxidation; therefore any partial opened vials should be discarded within four weeks. Finally, it has been demonstrated that the potency of tuberculin is decreased by as much as 98% when stored in plastic containers for more than 12 hours, therefore any unused tuberculin in syringes should be discarded. All suspect animals disclosed on the caudal fold test reading date should be immediately reported to the appropriate TAHC regional office so that follow up testing can be planned. Further evaluation of a suspect on the CFT will involve either the Comparative Cervical Test performed a TAHC or USDA veterinarian within 10 days of CFT injection, or, more commonly in Texas the Bovigam "gamma" interferon blood test. The TAHC now approves private practitioners to collect blood for TB gamma testing. Contact your local TAHC region office if you are interested in being approved for this as the TB gamma test requires special handling and shipping procedures to be effective.

All test results should be recorded on a USDA test chart VS 6-22 including acceptable forms of official identification on the cattle and submitted to the appropriate TAHC regional office within seven days of reading the results.

Recognition of the factors involved in a valid CFT test and adherence to the principles outlined above will provide the greatest confidence for detecting TB in cattle intended for interstate commerce.

A requirement for adult cattle in Texas to have an approved form of permanent identification in place at change of ownership will go into effect January 1, 2013, per Texas Animal Health Commission (TAHC) rule. One form of approved identification is a USDA metal ear tag, and the TAHC is seeking to develop partnerships with interested veterinary practitioners to help distribute these free tags. While producers may apply the tags themselves, veterinarians will have the opportunity to provide tagging services to their clients. >> Read more.

In late 2009, regulatory veterinarians learned of positive cases of EP on a ranch in South Texas. Since that time, the TAHC has worked closely with the ranch management in conducting the epidemiology of this outbreak and in the tracing and testing of all horses connected with the ranch. This case has now been successfully closed. The overwhelming majority of new cases disclosed are represented by the racing Quarter horse population in Texas. Other breeds infected have included Thoroughbreds, Saddlebreds, and working ranch Quarter horses.

TAHC continues to follow up on new positive cases as they are made known to us through the work you do for your clients. Currently there are 58 horses that remain confined to regularly-inspected quarantine facilities in various locations throughout the state. When new cases are disclosed to us, our first priority is to verify the case by ownership, identity and location of the horse. The suspect is re-bled immediately for test confirmation, scratched for ticks, sprayed with Permectrin II® (2.5 oz/ gallon of water) and placed under quarantine. In addition, all horses on the premises are sprayed and, depending on exposure to the suspect, these "cohorts" are tested as well.

Having accurate identification of the suspect horse and having valid owner contact information are critical steps in the work that we do, and is an area in which you as a practitioner can be of tremendous help to us. Some of the cases we have dealt with became complicated when we have been presented with horses of dubious identity for re-testing or euthanasia, or when the suspects were being hidden from us. Having complete owner contact information is something that extends down to the level of your front office and we certainly appreciate your staff's diligence in capturing that information. In our continuing effort to work expediently in getting these cases resolved while avoiding legal entanglements associated with identification and ownership issues, you are now required to use the TAHC Piroplasmosis test chart (TAHC 10-07) any time you submit a EP test to either the state or federal laboratory. You may access the forms from the TAHC Piroplasmosis web page. We have found that the digital-photo-enabled form is a quick and accurate way to identify your test subjects, but you may also elect to draw-in the markings on this form, similar to that of the Coggin's test chart. It is now required that all horses entering a sanctioned race track in Texas have a negative piroplasmosis test and that it be on the new test chart.

Most veterinarians with the TAHC have had several years of practice experience so we are sensitive to issues that you face every day in running a practice. However, the converse of that is probably not true in most cases. You might be amazed at the legal and compliance scenarios that develop in the regulatory practice world! Your assistance in providing us with information is always appreciated, and although the use of the TAHC form 10-07 may take a few more minutes to complete, the information captured on the form actually saves the State of Texas time and resources in closing these new cases of EP. Plus, the form gives your clients and their horses a level of professionalism that reflects the standard of care which you provide to them - something that we can all be proud of as veterinarians.

Cattle Trichomoniasis, known as "Trich," is a venereal disease of cattle caused by the Tritrichomonas foetus protozoa, which is about the size of a sperm. Infected bulls carry the organism on their penis and prepuce. Trichomoniasis is then transmitted to cows through breeding. Cows may abort early in the pregnancy and become temporarily infertile. Only testing will confirm the presence or absence of the disease.

Cattle producers can lose valuable income from the extended breeding seasons and diminished calf crops caused by this disease. The cattle industry and trade associations in Texas requested that the Texas Animal Health Commission develop regulations to stop the introduction and spread of this disease.

The Texas Animal Health Commission (TAHC) adopted revisions to Texas' cattle Trichomoniasis (Trich) program during the quarterly Commission Meeting on October 5, 2010.
Revisions to the current regulations are:

• A negative cattle trichomoniasis test will now be valid for 60 days provided that the bull is kept separate from female cattle during that time. Additionally, the test may be transferred within that time frame with the original signature of the consignor.
• A virgin certificate is now valid for 60 days provided that the bull is kept separate from female cattle. A virgin certificate may now also be transferred within that timeframe with the original signature of the consignor.
• Revised entry requirements now exempt out-of-state breeding bulls from an entry trichomoniasis test, if they come from a Certified Semen Service (CSS) artificial insemination facility, where they are isolated from female cattle. The bulls must be accompanied by documents with an original signature by the veterinarian or manager of the facility.
• Revised regulations now allow untested, non-virgin Texas bulls to be sold and moved to a trichomoniasis certified feedlot prior to slaughter. Under previous regulations, untested, non-virgin bulls were allowed to be sold only for direct movement to slaughter. This change does not apply to non-Texas origin bulls. Producers may also still purchase untested bulls for movement under a TAHC-issued hold order /permit to a location away from female cattle, where the bull is to be tested for Trich.

The TAHC recently adopted changes to its cattle Trichomoniasis (Trich) rules August 14, 2011.

The following is an overview of rule changes for the Texas cattle Trichomoniasis program.

1. Texas will no longer accept "virgin" bulls for entry from other states. All breeding bulls more than 12 months of age shall be tested and must have a negative Polymerase Chain Reaction (PCR) Trich test prior to entry.
2. Texas will no longer accept a negative culture test(s) for entry of breeding bulls into the state. Only PCR tests will be accepted.
3. Untested out-of-state bulls are now allowed entry into Texas if consigned directly to Trich certified feedyard facilities, and accompanied by a permit issued by an accredited veterinarian from the state of origin.
4. A "Control Herd Plan" option has been created that allows large cattle operations up to three years to eradicate Trich from their herd. The enrolled herds are allowed to test once per year (preferably prior to breeding season) instead of two or more times as normally required, but in exchange they must consult with a veterinarian and enter into a plan designed to remove the disease from the herd. In the interim, all bulls leaving the herd must be sold for slaughter or feeding for slaughter only until their quarantine is released.
5. The TAHC will now allow an approved laboratory to "pool" individually submitted samples (up to 5 samples) for PCR testing, to count as one of the two tests normally required to release a herd from quarantine. Pooled samples will still not be allowed for change of ownership testing however. This change was designed as a cost saving measure for producers, and must be approved in advance by TAHC regional management in consultation with the owner or veterinarian.

Current Trich regulations are posted on the TAHC website in English as well as Spanish.

At this time I would like to remind all veterinarians involved with Trich testing program of a few major items.

• A TAHC Trich Test Record must accompany samples when submitted to TVMDL for official results (must have official ID) . See the TAHC Trich page.
• Copies of all Test Records must be sent to your local TAHC Regional Office.
• Veterinarian(s) must be TAHC Trich approved to do official Trich testing. If you have not completed this approved training, contact your local TAHC Regional Office for information for approval.
• If you are shipping livestock to other states or countries, contact them to obtain requirements. These requirements can change from day to day.
  Visit the USAHA web site for state contact info.

The TAHC Trich Program has advanced significantly since its inception in 2009. If you have suggestions or recommendations, please forward to the TAHC for discussion at the next Trich Working Group Meeting.

Thanks to all practicing veterinarians, lab personnel, and producers involved with the TAHC Trich Program.

For more information, contact your regional office.

A Certificate of Veterinary Inspection (CVI) is a document which is issued by an accredited veterinarian. A vet will examine the animal and by issuing a CVI is stating that the animal is not showing signs of an infectious, contagious, and/or communicable disease and that the animal appears healthy.

A CVI is also issued as a requirement for certain movements of livestock. This movement may be intrastate as in the case of entries into shows/fairs/exhibitions/special sales, but often times the movement is interstate. A CVI is valid for 30 days on all species except for equine, in which case it is valid for 45 days.

The CVI is to accompany the shipment and is used to identify the animals in the shipment as well as providing documentation that the animals have met entry requirements including any necessary tests, examinations, and/or treatments.

In Texas, CVIs can only be obtained by accredited veterinarians and once issued, copies are to be received in the TAHC central office within 30 days. Upon receipt in the TAHC central office, copies are then forwarded to the state of destination if the movement is interstate. These CVIs are then reviewed by the receiving state to verify the shipment is in compliance with entry requirements. If deficiencies are noted, the receiving state will either notify the issuing veterinarian directly or the TAHC central office of the deficiencies. If the TAHC central office is notified, copies of the documents are then forwarded to the appropriate TAHC regional office for follow-up contact with the issuing veterinarian. This may lead to compliance action depending upon the number and severity of deficiencies. Most of these deficiencies noted to date have been failure to obtain prior entry permit, failure to record test results or certification statements, failure to record official identification on cattle, as well as delinquent CVIs . Most states consider a CVI delinquent if it was not received in the TAHC central office within the required 30 day time period. It may be necessary for veterinarians to submit copies of CVIs twice per month in order to ensure timely receipt. If test documents are attached to the shipper's copy of the CVI, be sure such documents are attached to all other copies as well. Official means of identification of cattle includes breed registration brands/tattoos, Brite metal eartags, or RFID eartags. Owner bangle tags are not considered an official identification device.

Finally, veterinarians should contact the state office of destination to verify entry requirements prior to issuing a CVI for interstate movement. For reference purposes, be sure to record the name of the person with whom you spoke.

See the TAHC Health Certificates web page for information about how to order CVI's.

It's Fall and with that comes an increase in trail rides, stock shows, rodeos, and other equine related events. Current Texas Animal Health Commission (TAHC) regulations require owners to have a current (within the previous 12 months) Equine Infectious Anemia (EIA, aka Coggins) test on all equine that are sold or co-mingled with other equine at events, exhibitions, public stables, or other assemblies.

Producers of these events are responsible for checking the EIA test paperwork at the event. Often a TAHC employee will assist them. Please remind your clients not to be surprised if they are asked to present their EIA test paperwork prior to entering an event.

Below are a few helpful tips that may make their next trip go smoother. By following these simple tips it should speed up the process for them and those behind them running late at the gate for that next event.

• Advise your client to check the date on their EIA test document. Make sure that the blood draw date for the sample is within the previous 12 months.
• Make sure that they have test papers for every equine they are hauling, even if the animal is owned by someone else.
• Make sure that the test papers describe the horse correctly. As a veterinarian you can help by utilizing electronic forms and photos. If you still use the standard test form (10-11) make sure that you identify all markings, scars, brands, tattoos, correctly to eliminate any potential problems.
• You may want to offer to make additional copies of the test papers for the truck and/or trailer that they commonly use. Copies are acceptable as long as they are legible, and they need to have an original signature from the veterinarian who did the testing.
• Call ahead and verify what the event requires for entry. In some cases a CVI (Certificate of Veterinary Inspection) or additional tests may be required. Most Interstate events require CVI's and some states require entry permits. A simple call to the receiving state can save a lot of headaches for both the veterinarian and your client.
• We also suggest and recommend maintaining a filing system that would allow you and/or your staff to quickly access an EIA test document if needed.

By following these simple tips, your client's next trip should go smoother for them and prevent those frantic last minute calls.

After the USDA deemed Texas free from cattle brucellosis, many cattlemen and veterinarians felt that the brucellosis calfhood vaccination of heifer calves was no longer warranted. In reality, the decision not to vaccinate replacement heifers is now having repercussions during the drought. Not only does vaccination protect herds against brucellosis if it ever makes a comeback in Texas, it also eases the burden for ranchers that are in desperate need of moving cattle north in search of grazing. Several producers have found pasture and care or have sold their herd to a buyer in the other states only to find out that their cows must be vaccinated against brucellosis prior to entering the state of destination.

The brucellosis entry requirement can be satisfied by one of two ways, calfhood and adult vaccination. If the cows were not vaccinated prior to a year old, these animals must be "adult vaccinated" in order to enter. The Texas Animal Health Commission has made the decision to allow accredited veterinarians to perform adult vaccination but only with a negative brucellosis test. Also, adult vaccination is not without risk. Unlike calfhood vaccination performed when the heifer is between 4 and 12 months of age, inoculating adult animals may cause abortions in some instances and therefore this low level of risk should be discussed between the veterinarian and client.

The cattle industry's success is dependent on a multitude of variables such as commodity prices, weather, and location. Ensuring interstate marketability of both calves and adult animals is essential for an operation to be profitable. No one knows what the future will bring so all producers need to prepare for changes in disease status, grazing conditions, and marketing opportunities. Continuing to calfhood vaccinate replacement heifers will not only allow the cattleman to take advantage of trading avenues but also will protect the herd if brucellosis ever makes a comeback.

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Reminder: $7 per certificate for CVIs. CVIs are sold in books of 10 certificates per book so a book is now $70.
More information about the fee increase
For more information regarding CVIs, click on the Health Certificates tab or call 1-800-550-8242, Ext: 788.