Feral Cat Veterinary Resource Center
What You Need to Know About Rabies
Rabies is an acute viral infection of the central nervous system.
Rabies viruses can infect most mammals, and are usually spread when saliva from a rabid animal enters the body via a mucous membrane, a puncture wound, or open cut. Once inside the body, the virus travels from the initial point of contact to the nerves, spinal cord, and, finally, the brain. The incubation period between exposure to the virus and onset of symptoms for humans can last for months, and as long as treatment begins before symptoms arise, rabies can be completely prevented. Once symptoms begin, the disease nearly always turns fatal. However, according to the Centers for Disease Control and Prevention’s Rabies Surveillance in the United States 2010 report, “recent cases of recovery after treatment and abortive rabies virus infection suggest the disease may possibly not be universally fatal.”1
People most often contract rabies via a bite of a rabid animal.
Rabies is transmitted through the saliva or tissue of an infected animal, and this happens most often via the bite of a rabid animal. Infected saliva must enter an open wound or mucous membrane to transmit the virus.
Cases of human rabies are exceedingly rare in the U.S.
Only two human rabies cases were reported in 2010. Over the last decade, just 21 cases of domestically-acquired human rabies have been reported in the U.S.—that’s an average of two cases per year. (Of the 29 total cases reported from 2001 to 2011, eight of the exposures took place in other countries.) Wildlife account for the majority of exposures and make up more than 90% of all reported rabid animals.
A person exposed to a rabid animal can easily be treated to avoid contracting rabies.
Treatment for humans who have been exposed to the rabies virus, called post-exposure prophylaxis (PEP), is completely effective when begun before the onset of symptoms. The incubation period in humans generally lasts three to eight weeks, but can extend even longer if the infection occurred distant from the brain, for instance in a foot.
Rabies shots do not involve a bunch of painful shots in the stomach anymore.
While it’s true that rabies shots given after an exposure once consisted of numerous injections to the stomach, those days are long over. Today, rabies shots are given in the arm and are no more painful than a flu shot. The number of doses required has also changed. In June of 2009, the Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention revised their guidelines to recommend a single dose of human rabies immune globulin followed by four booster shots, rather than the five boosters previously recommended.
Wildlife is the number one source of rabies.
Surveillance statistics show that bats are now the number one source of human rabies exposure in the U.S., and that raccoons and skunks are the most commonly infected species, followed by bats and foxes. According to the Centers for Disease Control and Prevention, wildlife have accounted for more than 80% of reported rabid animals in the United States since 1975. Today, more than 90% of rabies cases occur in wildlife—92% of cases in 2009 and 2010.
Cat to human transmission of rabies is rare.
The last confirmed cat to human transmission of rabies occurred more than 35 years ago. While it's possible for feral cats to become infected with rabies, feral cat colonies themselves do not generally serve as a source of the disease. “We see rabies more often in raccoons and bats than in the cat population,” says Roberta Lillich, DVM, president of the American Association of Feline Practitioners.
Rabies is caused by a virus that exists in several different variants, some of which are specially adapted to specific animal species. For instance, dogs can develop canine rabies, and this canine rabies variant can thrive in unvaccinated dog populations, which in turn may serve as an ongoing source of rabies in a community. But rabies has never developed a specific feline variant, and thus cats are merely incidental victims, says Julie Levy, DVM, PhD, at the University of Florida in Gainesville.
Cat behavior may explain why rabies is relatively uncommon in felines, says Lillich. “Skunks and raccoons are major sources of rabies, and most cats who are faced with a challenge by a skunk or raccoon will run away, whereas a dog is more likely to attack,” she says. When faced with non-prey animals, “cats are generally defensive animals rather than offensive animals,” Lillich says, and the small rodents such as squirrels, chipmunks, rats, mice, and rabbits that feral cats may hunt are rarely infected with rabies. Feral cat colonies managed with Trap-Neuter-Return programs do not harbor rabies, because the vaccinations they receive as part of the program are proven to protect them from the disease for multiple years.
The rabies vaccine has helped to make rabies a public health victory.
“The rabies vaccine has been one of the big public health successes of the past 50 years,” says Susan Dicks, DVM, a private practitioner in Albuquerque who also has wildlife experience. Studies show that rabies vaccines induce a long-lasting immunity, and widespread immunization campaigns for both pets and wildlife have come close to eliminating the disease in cats and dogs. In fact, a variant of dog-coyote rabies that once thrived in Texas was eradicated in the U.S. in 2008, thanks to the widespread use of Oral Rabies Vaccine (ORV) in wildlife. The fact that wildlife, not domestic cats and dogs, now serve as the prime sources of rabies exposure in the U.S. is proof that vaccination programs work. “Rabies will never be controlled or eliminated in the U.S. until effective programs to eradicate rabies in wildlife are carried out,” says Levy. Learn more about Wildlife and Rabies.
Rabies vaccines outlast their expiration dates.
“Even a single dose of rabies vaccination provides years of protection against rabies infection,” says Levy. In one study*, 12-week-old kittens given a single rabies vaccine were completely protected against rabies four years later when they were exposed to the rabies virus, she says. “There is solid evidence that a single rabies vaccine produces multi-year immunity.” (*Note: Alley Cat Allies is against testing on animals, as it is against all cruelty toward animals. There are better alternatives to animal testing—including mathematical and computer modeling or using cultures from cells, organs, or tissues—that are precise and sophisticated.)
Vaccination schedules that require one or three year boosters are based on state and local laws, not evidence about the vaccines’ efficacy, says Lillich. Most local laws require rabies vaccination either yearly or every three years and so vaccine manufacturers tailor their studies and products to these time periods. In fact, one vaccine manufacturer produces multiple versions of the identical vaccine with different labels according to the locally mandated vaccination schedules.
Studies suggest that the vaccines last a minimum of three years, but due to expense and logistics, large-scale studies have never been extended past three years, Lillich says. Some trials suggest that the vaccines last beyond three years, and the Rabies Challenge Fund (RCF) was founded in 2005 to determine the duration of immunity that rabies vaccines provide in hopes of convincing lawmakers to change laws mandating excessive vaccinations. The RCF aims to extend the required interval for rabies boosters to at least seven years. Learn more about Vaccinations and Feline Cancer.
Trap-Neuter-Return programs help control rabies.
By vaccinating feral cats against rabies and preventing the vacuum effect, Trap-Neuter-Return programs, also known as TNR, prevent rabies from infecting feral cat colonies and their communities. Rabies vaccinations provide multi-year immunity, and since feral cats involved in TNR programs are vaccinated and therefore cannot acquire or transmit the virus, they pose no threats to humans or other animals. Learn more about Rabies and Trap-Neuter-Return programs.
1 Blanton, Jesse D., Dustyn Palmer, Jessie Dyer and Charles E. Rupprecht. Rabies Surveillance in the United States during 2010. Journal of the American Veterinary Medical Association 239 (2011): 773-783.