Rabies

Rabies is an illness not much thought about in this country any more, but unfortunately it is still a common disease in some parts of the world. A bite from a domestic or wild animal that is infected with rabies is a very serious medical condition that, without treatment, can and most often does result in death. There is, however, a very effective antidote available for rabies, but in many poorer nations it is not readily available to most of the population. Join me as we discuss what rabies is, how it affects the body, and most importantly, how to avoid getting a rabies infection.

What is Rabies?

Rabies is a viral disease that aggressively attacks the central nervous system in humans and all other mammals. The virus that causes rabies is from the family Rhabdovirus, and in almost all cases it is transmitted via a bite from an animal who’s saliva is infected with the virus. Rabies is also known as hydrophobia, which literally means “fear of water.” The term came about because many people who have developed the symptoms of rabies have such difficulty swallowing that they are repulsed by water and other liquids. Left untreated, the vast majority of rabies cases are fatal, although in rare cases patients have recovered after manifesting the symptoms.

It is estimated that the number of rabies cases worldwide is between 30,000-50,000 every year, and it is found almost exclusively in underdeveloped nations of Asia, Africa, and Latin America, with a particularly high incidence in India. Here in the United States, rabies is extremely rare, usually resulting in only one or two deaths per year. The reasons for this are easy availability of a vaccine that can be administered after a person has been exposed to rabies, and the wholesale vaccination of domestic animals, particularly dogs, in the US. Rabies was much more common in America up until the 1950’s when vaccines for both people and pets became widely available.

Dog bites account for most cases of rabies world wide, followed by those from wild animals such as the bat, wolf, and mongoose. In the US, rabies is most often transmitted through the bites of wild animals, with bats being the number one source of exposure. Other wild animals in the US that may carry rabies include foxes, skunks, raccoons, and coyotes. Smaller mammals such as squirrels, chipmunks, rats, and mice are rarely rabid because they are usually killed when bitten by an infected animal. In rare cases, rabies can be spread through contact with bodily fluids other than saliva, and can even be contracted through inhaling the virus in an enclosed area such as a laboratory or a cave that has a population of infected bats.

What Are the Signs and Symptoms of Rabies?

The virus that causes the rabies infection appears under the microscope as “rod or bullet-shaped,” and once it is introduced into the body, usually at the site of a bite, it begins to multiply and travel along the peripheral nerves that lead away from the brain and spinal chord, specifically known as the efferent nerves. Rabies eventually infects the entire central nervous system, as well as the salivary glands. The virus may be present in a dormant state for up to several weeks or even a few months, and rare cases have been reported that were dormant for up to six months. During this stage there are no symptoms. Once signs of rabies begin to occur, the mortality rate of the disease is almost 100%.

Initial signs of rabies include:

• Pain and burning in the area of the bite
• Fever
• Headache
• Fatigue
• Sore throat
• Nausea and vomiting
• Diarrhea
• Poor appetite

As you can see, these early symptoms of rabies are very common to many other illnesses, such as the flu. Therefore, it is difficult to make a diagnosis based on these signs.

As the disease develops, the symptoms become more severe, including:

• Thickened saliva
• Drooling
• Excessive tearing and perspiration
• Dilated pupils
• Hypotension (low blood pressure)
• Insomnia
• Anxiety

In the final stages of rabies, victims may experience:

• Mental confusion
• Supersensitivity to light, noise, and / or touch
• Aggressive and combative behavior
• Hallucinations
• Convulsions
• Partial paralysis
• Difficulty swallowing
• Revulsion of water and other liquids (hydrophobia)
• Difficulty breathing
• Coma

Most victims succumb to death, usually from respiratory failure, within 3-20 days after the symptoms first appear. The length of time for progression of the disease varies, often based on factors such as the severity of a bite and where the bite occurs. Bites in the head, for example, may develop symptoms much faster than a bite in the leg. It is very important that persons who have been exposed to rabies be treated with a vaccine as soon as possible.

Are There Factors That Can Increase the Risk for Rabies?

Yes, there are certain things that can make it more likely for a person to contract rabies. The most common ones include:

• Certain occupations: Anyone that is exposed to unvaccinated domestic animals or wild animals is at greater risk. Examples include: Zookeepers, animal trainers, animal exterminators, farm and ranch workers, veterinarians, animal control officers, forest rangers, loggers, and laboratory workers.
• Handling animals: Be very careful when touching wild animals. Many people like to feed wild creatures or have them as “pets,” but you should be aware that it is possible to be bitten, scratched, or even simply licked by a rabid animal, and contract rabies yourself. Be especially aware of any animal that is acting strangely or has lost its natural fear of man. Another warning sign is an animal, such as a raccoon or skunk, that is normally nocturnal, but is active during the day. Children should be coached to stay away from any wild animal or pet that they are not familiar with. In recent years the number of domestic cats with rabies has risen, and many municipalities do not require a rabies vaccination for cats as they do for dogs.
• Watch out for Bats: Be careful if you are working or recreating in an area with a significant bat population. Rabid bats can bite, so be especially careful if handling one. In addition, there have been cases of people who have developed rabies from inhaling the virus in caves where infected bats live. If you are a spelunker (cave explorer), it would behoove you to inquire with the local health department about the potential presence of rabies in the area before you go caving.

What Treatments Are Available for Rabies?

There is no cure for rabies. Once symptoms have begun to develop, rabies is nearly 100% fatal. I wouldn’t normally recommend vaccinations, as they contain many harmful substances and can have serious, life threatening consequences in some cases. However, when it comes to rabies, anyone who has been exposed to the virus, or is reasonably sure that they have been, must receive a vaccine or they risk death.

Just to clear things up, there are 3 basic types of rabies vaccines: One for animals to prevent them from contracting rabies; one for people who have been bitten by a suspected animal; and a prophylactic one that is often recommended for people with occupations or hobbies that place them in a high-risk group for getting rabies.

There are not any reliable tests that can clearly point to rabies before symptoms have begun, and after they have begun it is too late. So how do I determine if a vaccination is necessary? Here are some general guidelines:

• If you are bitten by a domestic animal and you can track the animal and its owner, try to determine the status of the animal’s rabies vaccinations. Most municipalities require these for dogs, and many are starting to for cats as well. A tag is usually put on the animal’s collar, or the owner may have a paper record. If you are quite sure that the animal is up to date on its shots, you have no risk of getting rabies from the bite, and it is not necessary to be vaccinated.
• If you are bitten by a domestic or wild animal and a doubt exists about whether it carries rabies or not, the animal can be either killed and analyzed in a laboratory to see whether it is carrying rabies, or it can be quarantined for about 10 days and observed to see whether it is rabid.
• If you do get a high-risk animal bite, and have never gotten a prophylactic vaccine, you will need a series of 6 injections over a 28 day period. No body in the US has ever died from rabies after having these injections, as they are highly effective against the virus. The technology has improved somewhat. Years ago people who received these vaccines were exposed to painful injections in the abdomen, which was especially hard for children to endure. Nowadays, about half the shots are given at the site of the bite, and the rest as normal intramuscular injections. If you have gotten the prophylactic vaccine, you will still need additional vaccines after receiving a high-risk bite, but you will not need as many injections.

Whether or not to expose yourself to rabies vaccinations if you have been bitten can be a difficult decision. The toxins and potential risks associated with any vaccine can be significant, so you want to be sure it is warranted. However, when it comes to a potentially fatal disease such as rabies, you do not want to refuse vaccination if you need it. Take all the available information and weigh the evidence, as you make the best decision possible. It is very helpful to determine the prevalence (or lack thereof) of rabies in the local area where you were possibly exposed, especially as related to the animal that bit you.

Rabies is an illness that can, for the most part, be prevented by using common sense. If you own pets, be sure that they receive timely rabies vaccinations for the protection of your family, others, and the pets as well. Stay away from wild animals, and teach children to do the same. The chance of being exposed to rabies in the US is quite small, but given the deadly nature of the disease, be sure to take the necessary steps to receive treatment if you have come into contact with the virus. Be extra careful if you are traveling in a part of the world where rabies is more common.