With 15 confirmed cases of raccoon rabies in the Hamilton, ON and surrounding areas, and a case of arctic fox rabies in Perth, ON there has been a lot of discussion, concern and questions about the virus.
Rhabdovirus AKA Rabies has been recognized for over 4,000 years. Yet, despite great advances in diagnosing and preventing it, today rabies is almost always deadly in humans who contract it and do not receive treatment.
Rabies is caused by a rod- or bullet-shaped virus that belongs to the family Rhabdoviridae. Another name for the disease is hydrophobia, which literally means fear of water, a symptom shared by half of all people infected with rabies. It is sometimes referred to as a zoonosis, or disease of animals that can be communicated to humans.
The virus is usually transmitted via an animal bite; however, cases have also been reported in which the virus penetrated the body through infected saliva, moist tissues such as the eyes or lips, a scratch on the skin, or the transplantation of infected tissues. Inhalation of the virus from the air, as might occur in a highly populated bat cave, is also thought to occur.
Five general stages are recognized in humans: incubation, prodrome, acute neurologic period, coma, and death. The incubation period is exceptionally variable, ranging from fewer than 10 days to longer than 2 years, but is usually 1–3 months.
Dumb Rabies- About 20% of cases have only two phases where the patient skips the sensory excitation phase and progresses right to the coma and paralysis phase. Dumb rabies is almost 100% fatal with only three known cases of survival.
After inoculation, rabies virus may enter the peripheral nervous system directly and migrate to the brain or may replicate in muscle tissue, remaining sequestered at or near the entry site during incubation, prior to central nervous system invasion and replication. It then spreads centrifugally to numerous other organs.
The rabies virus may lie dormant in the body for several weeks or months, but rarely much longer, before symptoms appear.
Symptoms include fever, depression, confusion, painful muscle spasms, and sensitivity to touch, loud noise, and light, extreme thirst and painful swallowing.
As the disease progresses, the patient becomes agitated and combative and may exhibit increased mental confusion. The affected person usually becomes sensitive to touch, loud noises, and bright lights. The victim also becomes extremely thirsty but is unable to drink because swallowing is painful. Some patients begin to dread water because of the painful spasms that occur.
Other severe symptoms during the later stage of the disease are excessive salivation, dehydration, and loss of muscle tone.
Death usually occurs three to 20 days after symptoms have developed. Recovery is very rare. If rabies is not prevented by immunization, it is almost always fatal.
If you’ve been bitten by an animal that is known to have rabies, you’ll receive a series of shots to prevent the rabies virus from infecting you. If the animal that bit you can’t be found, it may be safest to assume that the animal has rabies. But this will depend on several factors, such as the type of animal and the situation in which the bite occurred.
Rabies shots include:
- A fast-acting shot (rabies immune globulin) to prevent the virus from infecting you. Part of this injection is given near the area where the animal bit you if possible, as soon as possible after the bite.
- A series of rabies vaccines to help your body learn to identify and fight the rabies virus. Rabies vaccines are given as injections in your arm. You receive four injections over 14 days.
- Domesticated animals, including household pets, should be vaccinated against rabies. If a pet is bitten by an animal suspected to have rabies, its owner should contact a veterinarian immediately and notify the local animal control authorities. Domestic pets with current vaccinations should be revaccinated immediately; unvaccinated dogs, cats, or ferrets are usually euthanized (killed).
- Wild animals should not be touched or petted, no matter how friendly they may appear. It is also important not to touch an animal that appears ill or passive or whose behavior seems odd, such as failing to show the normal fear of humans. These are all possible signs of rabies. Many animals, such as raccoons and skunks, are nocturnal and their activity during the day should be regarded as suspicious.
- People should not interfere in fights between animals.
- Because rabies is transmitted through saliva, a person should wear rubber gloves when handling a pet that has had an encounter with a wild animal.
- Garbage or pet food should not be left outside the house or camp site because it may attract wild or stray animals.
- Windows and doors should be screened. Some victims of rabies have been attacked by infected animals, particularly bats, that entered through unprotected openings.
- Municipal health departments should be consulted for information about the prevalence of rabies in an area. Some areas, such as Ontario, have been rabies-free, only to have the disease reintroduced recently.
- Preventative vaccination against rabies should be considered if one’s occupation involves frequent contact with wild animals or non-immunized domestic animals.
- Bites from mice, rats, or squirrels rarely require rabies prevention because these rodents are typically killed by any encounter with a larger, rabid animal, and would, therefore, not be carriers.
- Travelers should ask about the prevalence of the disease in countries they plan to visit.
Even the most trivial bite can transmit rabies. Any bite or scratch by a rabid animal warrants the administration of rabies shots. Whether or not that animal is at risk for rabies depends somewhat on the region of the country and on the species of the animal. Any exposure to a bat where a bite cannot be ruled out must be considered a significant exposure even if you do not recall being bitten by the bat.
Persons wanting to report wildlife (e.g. raccoons, skunks, foxes, etc.) exhibiting abnormal behavior should contact the Ministry of Natural Resources and Forestry Rabies Hotline at 1-888-574-6656.
Incidents only involving domestic pets being exposed to potentially rabid animals should be reported to your local vet and/or the Ontario Ministry of Agriculture, Food and Rural Affairs’ Agricultural Information contact Centre at 1-877-424-1300.