Rabies  /  West Nile Virus  /  La Crosse Encephalitis

Rabies

Rabies is a virus capable of infecting warm-blooded animals.  Rabies mainly affects the brain.  The disease has been recognized since ancient times, and is now common in wildlife in North America- notably in bats, skunks, raccoons and foxes. There have not been any naturally occurring cases identified in birds and it is extremely rare in rodents. The disease is usually spread by the bite or scratch of an infected animal. The virus is transmitted through the saliva. Rabies has also been known as hydrophobia because the sight of water can make infected animals excited.

An exposure to rabies occurs when a person is bitten or scratched by a rabid animal. The virus is “injected” or “scratched-in.” Although the risk is much lower, rabies can also be transmitted when saliva from a rabid animal comes in contact with open cuts or mucous membranes (e.g. mouth, eyes).  Other means of transmission can occur, but are very rare and involve extraordinary circumstances. A potential exposure occurs when a person is bitten or scratched by an animal capable of carrying rabies, especially a wild animal, that cannot be captured for observation or examination.  Exposures can occur any time of year.

Most exposures occur because people don’t consider the risk of rabies.  Exposures occur through contact with wildlife or with domestic animals exposed to rabid wildlife. Therefore, avoid raccoons, skunks, foxes, bats and stray or unfamiliar dogs and cats. In addition, wild species, including wild/domestic crossbreeds should not be kept as pets. State law requires that all dogs and cats be vaccinated against rabies. This is especially important for “farm or barn” cats and hunting/outdoor dogs.  If a cow acts like it is choking, call your veterinarian or wear a plastic obstetrical sleeve if you examine its throat.

WASH THE WOUND - Immediately wash the wound with warm, soapy water - this can greatly reduce your risk of contracting rabies. Consult your family physician or health care provider for further wound care follow-up.

CONTACT YOUR LOCAL HEALTH DEPARTMENT- Report any potential exposure to the Environmental Health Section of the local health department. Be ready to provide detailed information about the circumstances of the exposure, the animal involved, including any distinctive markings and the name of the owner. Information about post exposure vaccine may also be available.

Domestic cats and dogs properly vaccinated for rabies will need to be confined and observed. Stray or wild animals may need to be captured and/or killed and tested for rabies at the state public health laboratory. Animals do not always have to be sacrificed in response to a potential rabies exposure! Local health department officials will assist in determining what to do with the animal. If the animal must be killed, be careful not to damage or destroy the brain tissue. Also, take precautions to avoid additional exposure to saliva and brain or other central nervous system tissue. Contact your local animal control officer or local law enforcement official for assistance.

Because many people do not routinely vaccinate cats against rabies, they have replaced dogs as the more common pet animal threat to humans. The symptoms of rabies vary. Domestic animals such as cats, dogs and cows may exhibit symptoms of “furious rabies”, “dumb rabies” or rarely, no symptoms at all. Cats often bat at drooling saliva, contaminating their claws. Because of this, cat scratches are almost as dangerous as bites. Reasonably priced rabies vaccines are available for valuable breeding stock. These should be administered annually by a veterinarian. Although any warm-blooded animal can be infected with rabies, some animals are more susceptible than others. Raccoons, foxes, other canines and skunks are most commonly found to be rabid. Rodent rabies is very rare in the U.S. simply because the small rodents do not survive attacks by larger, rabid animals. The one exception to this is the groundhog.  Rabies is often isolated in many fruit- and insect-eating bat species in the U.S. Rabid bats can attack humans without provocation.  Any contact with a bat in which a bite cannot be ruled out, is considered a potential exposure to rabies. Bats should not be caught or handled.  Any normally nocturnal, wild animal, seen during daylight hours, could be rabid. Wild animals should be avoided, especially those that appear ill.

temperament change - friendly animals become aggressive, aggressive animals seem friendly or restless

unprovoked attacks, biting or scratching anything that moves

change in bark of dogs

protruding third eyelid

drooling or appearance of choking

tremors, lack of coordination, loss of balance

paralysis and respiratory failure

staggering or erratic behavior Foxes, dogs and possibly skunks, with furious rabies, can run all night, biting everything in their path.

Back to top

West Nile

West Nile virus is transmitted by the bite of an infected mosquito. It is widespread in Africa, southern Europe, and western Asia. It first appeared in the United States in 1999 and had spread to all of the New England states and south to North Carolina by 2000. It has caused illness and mortality in humans, wildlife and domestic animals, especially birds and horses. In humans, it causes an influenza-like illness that may lead to aseptic meningitis, encephalitis, and death, especially in persons over 50 years of age.

What you can do to prevent West Nile Virus

Mosquitoes lay their eggs in standing water, which includes puddles, stagnant ditches, and containers such as old tires, buckets, cans, neglected swimming pools, etc. Storm sewers, culverts, and catch-basins, etc. provide an outdoor resting place for the adult Culex pipiens mosquito (the common house mosquito) which is most commonly associated with West Nile virus. This mosquito commonly enters homes through unscreened windows or doors, or broken screens. Prevention measures include:  

Make sure that doors and windows have tight-fitting screens. Repair or replace all torn screens in your home.

Remove all discarded tires from your property.

Dispose of tin cans, plastic containers, ceramic pots, or similar water-holding containers.

Make sure roof gutters drain properly. Clean clogged gutters in the spring and fall.

Clean and chlorinate swimming pools, outdoor saunas and hot tubs. If not in use, keep empty and covered.

Drain water from pool covers.

Change the water in bird baths at least once a week.

Turn over plastic wading pools, wheelbarrows, etc. when not in use.

Eliminate any standing water that collects on your property.

Remind or help neighbors to eliminate breeding sites on their properties.

Repellents
If you will be outside during evening, nighttime and dawn hours, consider the use of an insect repellant containing 10% or less DEET (N, N-diethyl-methyl-meta-toluamide) for children and no more than 30% DEET for adults. DEET is effective for approximately four hours. Avoid prolonged or excessive use of DEET and use it sparingly to cover exposed skin and clothing. Do not use DEET on infants or pregnant women and do not apply DEET directly to children. Apply it to your own hands and then put it on the child. Always use DEET according to the manufacturer’s instructions.

Remember that that Vitamin B, ultrasonic devices, incense and bug zappers have not been shown to be effective in preventing mosquito bites. Community-wide mosquito spraying is also not recommended by the local health department due to its high cost and temporary effect.

Symptoms in humans
Mild infections are common and include fever, headache, and body aches, often with skin rash and swollen lymph glands. Headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, occasional convulsions, and paralysis mark more severe infection. In some individuals, especially the elderly, West Nile virus can cause serious disease that affects brain tissue. At its most serious, it can cause permanent brain damage and can be fatal.

Back to top

La Crosse Encephalitis is another mosquito carried disease.

One of the most preventable, La Crosse encephalitis is carried by a species commonly called the "tree hole" mosquito. This mosquito breeds in tree cavities that hold water, and in similar areas in which water collects such as old tires, buckets, cans or other man-made items.

As with the mosquitoes that carry West Nile, eliminating places where disease-carrying mosquitoes can breed (such as filling in tree holes, and cleaning up man-made items where water could collect) is the best way to prevent cases of La Crosse encephalitis. In addition, trees with cavities or holes that hold water for a week or more can be a breeding site. Drain the hole or fill with cement.

Symptoms develop within 3 weeks after the bite of an infected mosquito. These symptoms include headache, fever, drowsiness, lethargy, nausea, vomiting, disorientation, mental confusion, and in some cases seizures.

Back to top