Rabies, which means, “rage” or “madness” in Latin, is a disease recognized since antiquity. It is primarily a disease of animals and exists worldwide with a few isolated exceptions. Since vaccines have become available its incidence in the United States has been dramatically reduced. However, worldwide, there are still a large number of deaths per year, up to 50,000 annually, particularly in Africa, Asia and parts of Latin America.
In the U.S., there were an average 50 deaths a year from rabies in the first half of the 20th century. In 1940, a canine vaccination program was introduced and the average number of cases dropped to two per year. Undomesticated canines, such as coyotes, wolves and foxes, continue to be a reservoir for the virus. Rabies in the U.S. mostly involves raccoons, skunks, bats and undomesticated canines. Domestic farm animals can become infected, as well.
In New Jersey in 2015, there were 154 raccoons, 42 skunks, 11 foxes. 15 cats 4 groundhogs and 78 bats found to be infected with rabies. Cats have accounted for 90 percent of the domestic animal cases in New Jersey since 1989.
Rabies is a virus that enters at the site of exposure, through a bite, scratch or mucous membranes splash or contact. It then invades the local nervous system. The first signs of the disease are often pain or paresthesia at the site of the wound, a hallmark of the disease.
The virus then travels up the peripheral nerves toward the brain. This causes the variability in the time to progression of illness. If the exposure site is far from the brain, such as the lower leg or hand, the time to progression takes longer than if the site of inoculation is the face.
The average incubation period is 20 to 90 days, with most cases occurring within one year. Once the brain is reached, the disease becomes fulminant with confusion, seizures and coma. It then goes to the salivary glands, where it is shed in saliva. It is at this stage when the person or animal is contagious.
Once the infection has progressed to the point of illness, the disease is nearly 100 percent fatal, with rare exception. There is no specific treatment for rabies once illness develops. Exposure prevention and vaccination are important measures to prevent illness.
Pre-exposure vaccination is given for veterinarians, wild life workers, researchers and occasionally to travelers depending on their travel plans and risk of exposure. After potential exposure, vigorously cleaning the wound immediately is considered essential. Medical evaluation regarding whether post-exposure prophylaxis is indicated is required. Post exposure prophylaxis involves giving the vaccine along with rabies specific antibodies. The injections are given in the arm and are well tolerated.
If the animal that caused the exposure is available, it can be quarantined for 10 days and observed, or sacrificed and an autopsy is done to see if it was infected. If under observation, if the animal is alive after ten days it is deemed safe as animals only transmit rabies toward the end of their own illness.
Limiting the risk of rabies involves a number of simple measures:
- teach children not to handle stray animals or wildlife, especially bats found on the ground
- report any animals that are sick or acting strangely to the local public health authorities
- consult medical attention if a bat is seen in the home at night, even if a bite is not suspected
- keep pets indoors at night
- keep pet food and water dishes indoors
- have professional animal trappers remove bat colonies from homes and barns
- handle sick or dead animals with heavy gloves and shovels
- keep trash container lids tight and maintain compost piles away from dwelling.
These simple measures can keep us and our loved ones safe.