Infectious Disease Update

Vaccine Update:

The American Association of Equine Practioners (AAEP) has recently updated its guidelines for vaccination in the horse. Although a vaccine protocol should be tailored to the individual farm depending on exposure to disease.

The AAEP considers the CORE vaccines to be against the following diseases

Tetanus

Eastern/Western Equine Encephalomyelitis

West Nile Virus

Rabies virus.

The AAEP considers a core vaccination to be “those that protect from disease that are endemic to the region, those with potential public health significant, required by law, virulent/highly infectious, and/or those posing a risk of severe disease.

Rabies Review:

Rabies information is available on state websites. For North Carolina – see links below

http://www.epi.state.nc.us/epi/vet.html and

http://204.211.171.13/VirologySerology/Rabies/PositiveCountBySourceCounty.asp

What is the most common domestic animal in North Carolina and most of the United States that gets infected with rabies?

The Cat

What is the most common non domesticated terrestrial animal in North Carolina infected with rabies?

The raccoon

Because rabies is common in raccoons in North Carolina, it is very important to protect our pets, including horses, by vaccinating them against rabies. Pets act as a buffer between humans and wildlife. Protecting the pet population indirectly protects their owners. Vaccinating pets against rabies is the single most important public health measure to protect against rabies.

If you are bitten or scratched by any animal be sure to see your doctor right away. Because any mammal can transmit rabies, the animal that bit you may have to be evaluated or tested to see if it has rabies. If a dog or cat bit you, try and remember what the animal looks like and where it was so that animal control can find the dog or cat and put it into a 10-day confinement. Find your animal control agency.

In North Carolina, the public health department only tests wild animals that have bitten a person or unvaccinated domestic animal or dogs and cats that have died within 10 days of biting a person. Your animal control agency will have all the information needed to submit animals for rabies testing.

What is the most common non-domesticated non terrestrial mammal in North Carolina infected with rabies?

The bat

Do not try to catch any wild animal that bites or scratches you. Call animal control. They may collect it for testing. If you find a bat in your home don’t let it outside. Instead leave the room it is in and close the doors. Call animal control so it can be caught for testing. Most human rabies cases in the United States are due to bat bites, which you may not recognize because their teeth are so small. Most bats do not carry rabies, in fact in NC only about three percent are infected with the disease.

What is the highest risk of rabies transmission?

Being bitten by an infected animal.

Direct contact of an open cut with saliva or central nervous tissue from a rabid animal may result in transmission of rabies. It is a common misconception that a person or animal exposed to blood, urine or feces of a rabid animal is at risk for the disease. This is not true.

What are some rabies factoids?

Petting a dog after it was attacked by a rabid animal does not put a person at risk of getting rabies. For one reason – The rabies virus can not penetrate unbroken skin. For another reason – the virus does not survive on the coat of an animal.

Assume the following scenarios:

Your pet was attacked by a rabid animal a couple of days ago. The pet was not vaccinated and now it licks a cut on the owner’s hand. Is the owner at risk of getting rabies from this pet? No - The incubation period for rabies is weeks to months. Therefore the pet can only transmit rabies once it is sick with the disease or testing positive.

A bat is found in your child’s bedroom. It is tested and found to be positive for rabies. Is it decided that the child does not need post exposure prophylaxis because no bite can be found. Wrong. Bites from bats can be very small and difficult to find. Better to be safe than sorry. This child should undergo the rabies post-exposure prophylaxis treatment.

West Nile is here to stay. Public health officials have said that the West Nile virus epidemic of 2002 marked the largest arboviral menigoencephalitis epidemic in the western hemisphere. The number of states that reported West Nile activity in 2002 almost doubled from 2001. In 1999, West Nile viral infections first appeared in the United States in New York and by 2002, the virus had made its way across country to California. Over 14,000 cases of West Nile virus infection were confirmed in horses in 2002.

West Nile virus is a mosquito-borne virus that causes inflammation in the brain of humans and animals. The first indicator of disease in your area may be die-offs of birds such as jays, crows, magpies and other migratory wild birds. If any dead birds are found in your area, it is important not to handle these birds as the disease can be spread from bird to human. You should report any finding of dead birds to your local public health department. Dead birds infected with the West Nile virus were found in Person county in 2002 and this is likely to happen again in 2003. The mosquito can transmit the disease from birds to horses. The good news is that horses have not been found to transmit the disease to other animals or humans.

Clinical signs can be vague. Sometimes the horse is reported to be lame in the hind end several days before signs of brain inflammation become apparent. There are other disease that can cause similar signs including sleeping sickness, EPM, rabies, botulism and more. Thus is is important to contact your veterinarian if your horse is exhibiting any signs such as anorexia, incoordination, head-pressing, aimless wandering and inability to rise.

Although vaccination is not a 100% guarantee against infection, it can greatly increase the horse’s chance of fighting the disease when used properly. It is important to get the second booster within 3-6 weeks of the first vaccination. The length of protection that the vaccination provides is unknown at this time. It has been suggested that the vaccine may only provide protection for 3-4 months. The goal of vaccination is to maximize protection during the months when exposure to the virus is most likely.

Prevention is the name of the game. The first line of defense is vaccination however, environmental control is important as well. The key to environmental control is mosquito control. Although eliminating standing water on your property is ideal, you should at least minimize your horse’s exposure to standing water. Peak mosquito times are dawn and dusk. Use of incandescent lighting away from stable perimeters in conjunction with bug zappers and avoiding lights in stable areas during peak hours can be helpful. Other alternatives include the use of fans to increase air movement, insect repellents, screening of stable doors and stabling horses during peak mosquito hours.