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Newsletter of Penn Dutch Cow Care                                            October 2003

Hi Folks,

            After three years of writing this newsletter nearly every month, I am for once not going to talk about dairy cows. Instead, I think it would be wise to talk about the new “hot” diagnosis – West Nile Virus, especially as it pertains to the many horses we have here in Lancaster County. In one week’s time I had about 15 calls regarding West Nile Virus from clients. Since I work predominantly with dairy cows and only some with horses, I can’t even imagine how many calls the equine vets are getting about West Nile.

            At any rate, the disease certainly has everyone thinking about it, especially if one of their horses steps oddly, doesn’t eat quite right, acts depressed or simply isn’t doing well. Instead of giving opinions which could become rumors or helping to create myths about this disease, I will relay some factual information as I have obtained it from the Pennsylvania Bureau of Animal Health and Diagnostic Services. Then I will give some treatment advice at the end.

            1) What is West Nile (WNV) disease? It is a type of encephalitis, which means an inflammation of the brain and central nervous system. Prior to 1999, it was found only in Africa, Eastern Europe and West Asia. It established itself in the U.S. in August 1999.

            2) How do animals or people become infected with WNV? Certain birds act as reservoirs for the virus (it multiplies in them) and certain species of mosquitoes act as vectors (spread the disease). A mosquito must bite a bird which has WNV and only then can the mosquito infect other warm-blooded animals or people. Person-to-person transmission has also been documented in 2002 through (1) blood transfusion and organ donation (2) breast milk (3) during pregnancy and (4) lab personnel from needle or scalpel cuts when working with infected birds.

            3) What animals can become infected with WNV? Any warm-blooded animal. It has been identified in sheep, alpacas, cattle, dogs, cats and squirrels. But it is horses and birds that are appear to be the most susceptible.

            4) Does infection always lead to illness? Like many contagious infections, that will depend upon the immune system of the animal. Horses appear to be a species that is susceptible to illness after infection with the virus. Clinical signs may include a general loss of appetite and depression, in addition to any combination of the following signs: fever, weakness of hind limbs, paralysis of hind limbs, uncoordinated gait, down with trouble rising, head pressing, aimless wandering, seizures, inability to swallow, walking in circles, hyper-excitability and coma.

            The main symptoms that I have seen are uncoordinated gait, weakness of hind limbs, down with trouble rising, hyper-excitability and twitching muscles.

            5) How many horses have been affected by WNV? In 2002, more than 14,000 cases of West Nile were reported in the U.S. The majority were not vaccinated.

            6) Can an animal infected with WNV infect other animals? There is no evidence that infected animals (other than birds) transmit the virus to other animals, people, or mosquitoes under naturally occurring conditions.

            7) What are the symptoms of WNV in people? Mild infections may be common and include fever, headache, and body aches, often with a skin rash and swollen lymph glands. In those susceptible to disease, signs can be severe and may include headache, high fever, weakness, neck stiffness, stupor, disorientation, coma, tremors, convulsions, paralysis and possibly death. In 2002, more than 3,000 cases and 200 deaths were attributed to WNV infection reported in the United States.

            8) Do birds infected with the virus die or become ill? Many species of birds appear to be susceptible to infection with West Nile, and may act as reservoirs of the virus, allowing mosquitoes to become infected when taking blood meals from these birds. Certain species, including crows and blue jays, often become ill and die as a result of infection. WNV has been identified in more than 110 species of birds.

            9) Can ticks spread WNV? Some ticks in Europe and Asia have been found to be infected with the virus. It’s not yet known if ticks in the U.S. can spread the virus.

            As of September 26, 2003, WNV has been identified in every Pennsylvania County. There were reported (through 9/26) 101 human cases and 300 equine cases. The majority of positives are located in Lancaster County (103), but a large number are also located in Chester and Berks Counties.

            Nationwide, as of September 24th, almost 5,000 human cases have been reported, 1,500 being in Colorado. The number of equine cases reported nationwide is 2,168. There are many, many more equine cases which go un-reported and simply treated by the vet and the owner in the barn when clinical signs point to a WNV diagnosis.

Most of the above information can be found on the internet at www.pda.state.pa.us  or www.padls.org . 

            The disease itself is thought to run its course in about 2 weeks’ time. It probably has a 2-4 week incubation period. Please remember that this disease is new to the country and much research is needed to be done regarding it. Vaccinated horses in general do not get it, or, if they do it is much milder than with unvaccinated horses. The vaccinated horses which have gotten it are generally older horses, 20-30 years old and probably did not mount a good immune response to the vaccine or they were vaccinated at the wrong times. The vaccine should be given twice, three weeks apart, in the muscle. Ideally, mid-May into June would be the best time to vaccinate because it takes a few weeks for immunity to develop and the vaccine unfortunately does not seem to impart a long duration of immunity. The most important coverage needs to be during August and September. 

             Horses that do show the signs will vary in their severity. Conventional treatment mainly relies on using anti-inflammatories (since the brain is basically on fire), namely flunixin (Banamine) and dexamethasone or prednisone. DMSO given orally is also advocated, both by conventional vets and alternative minded folks. DMSO is also an anti-inflammatory and can be given orally or is sometimes rubbed over the backbone area. There is absolutely no use in giving antibiotics since it is a virus infection and antibiotics won’t help a bit. Antibiotics will be useful, however, if the horse is all banged up and has infected swellings (like on the head, eyes or legs). There is also a serum available now which is effective against the disease and its symptoms. It is available through veterinarians. I have mentioned to people to go to the blacksmith in Georgetown and get stocked up on the mineral-probiotic-plant extract products from Advanced Biological Concepts that really seem to keep the horses perky and supported through the course of the disease. Using silver water or colloidal silver in the vein and in the mouth is another supportive measure. Perhaps the most helpful combination that I have seen work is using Banamine™ and the natural treatments together. Whatever can be done to support the horse through the crisis period is worthy of consideration. Using a sling to help keep a weak horse standing would be very good in allowing it to relax by being supported with the sling and not be down thrashing around trying to get up.

            Does WNV affect the fetus in pregnant mares? Does a horse that has had WNV become immune to it? And if so, for how long? These questions remain to be answered. Please bear in mind that West Nile is established and here to stay. Plan ahead for next year. Think about vaccinating your horses and, above all, minimize mosquito breeding grounds!

 

For Bovinity Health, information on functional alternatives to antibiotics see:
www.bovinityhealth.com

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