What is Anthrax?
Anthrax is the same bacteria used as a biological weapon of terrorism and can be fatal in horses just as it is in humans. The bacillus anthracis spores can live in the soil for several years and any animal that grazes there will almost certainly become infected through ingestion or breathing in the spores while eating. Although it is possible for your horse to get infected through a mosquito (or other biting insect) bite, it is much less common. Another way your pet may become infected is through contaminated bone meal or other feed source that has been around infected animals. There is a high fatality rate in anthrax cases because it is usually overlooked as a similar illness such as colic or sunstroke. There are vaccination programs for anthrax so if one of your horses has been diagnosed with anthrax, it is essential to get the other animals vaccinated. You also have to report it to the officials and quarantine your horse and other animals for two weeks.
Anthrax is a serious but uncommon disease in horses caused by spores from the bacillus anthracis bacteria. Your horse can be infected from inhalation, ingestion, or through the skin from spores or an insect (such as a mosquito) bite. This is a very dangerous condition that is often lethal in animals as well as humans, spreading through the entire body and producing a toxin that destroys the cells and tissues of vital organs and immune system. An extremely high body temperature, breathing trouble, seizures, and death occur within two or three days without immediate treatment. If you believe your horse has been infected with anthrax you should call a veterinary professional immediately and use caution when handling your pet because it can be transferred to humans and other animals.
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Symptoms of Anthrax in Horses
The signs of anthrax in horses are hard to detect in the beginning because they mimic so many other illnesses. Also, the side effects may vary depending on how your horse contracted the disease. The most common signs are:
- Skin infection (insect bite)
- Ulcerated lesion (insect bite)
- Swelling of the neck, chest, abdomen, and genitals (insect bite)
- High body temperature
- Rapid heart rate and breathing
- Abdominal pain
- Appetite loss
- Excessive sweating
- Muscle weakness
- Refusing to (or having trouble with) exercise
- Breathing difficulty
- Diarrhea (sometimes bloody)
There are three types of anthrax which depend on the method of infection.
- Cutaneous (through the skin)
Causes of Anthrax in Horses
The cause of anthrax is the bacillus anthracis bacteria. The route of transmission can vary:
- Breathing in spores from soil
- Ingesting spores through soil or infected feed source
- Transmitted from an infected animal through an insect bite
Diagnosis of Anthrax in Horses
Diagnosing anthrax in your horse is a simple blood test, although this does not often happen until after your pet has died. This is because the disease is usually mistaken for another less serious illness and it moves so rapidly through your horse’s system. It is best to have a qualified equine veterinary professional check out your horse rather than a veterinarian who normally works with small animals because an equine veterinarian is trained in how to detect illnesses and care for your horse. First, the veterinarian will perform a complete physical examination, including checking your horse for any signs of lameness. This includes body temperature, heart and respiration rates, blood pressure, weight, and a body condition score, which is a numerical score rated on visual body weight. The veterinarian will also examine your pet’s teeth, ears, eyes, nose, and skin. In addition, a quick check of the muscles, tendons, joints, and ligaments should be done if your horse is up to it. This is usually done while your horse is in motion so the veterinarian can see them working.
A complete medical history will be needed, including vaccination records, recent illnesses, and injuries. The veterinarian will then do some laboratory tests such as a complete blood count (red and white blood cells and platelets), fluorescent antibody stains, PCR tests, bacterial culture, fibrinogen (protein), chemistry analysis (liver and kidney panel, electrolytes, and protein levels), and a fecal flotation to check for parasites. The veterinarian may do radiographs (x-rays) or an ultrasound as well to check vital organs.
Treatment of Anthrax in Horses
Your veterinarian will want to treat your horse with an aggressive round of antibiotics, usually streptomycin, penicillin, doxycycline, or amoxicillin. If your pet is able to make it through 7-10 days of antibiotics, the nonencapsulated Sterne-strain vaccine should be administered one week later. It cannot be given within a week of antibiotic treatment because it is a live virus and the antibiotic will kill the immunization, leaving your pet vulnerable to the disease again.
Recovery of Anthrax in Horses
Anthrax is usually fatal within three days, so your pet should be fine, with treatment, after four days. Some horses may be more susceptible or may be infected with a more potent strain, and may not make it even with treatment. This is an extremely dangerous disease that must be treated by a veterinary professional right away if suspected.