Signs and Symptoms

When we think of rabies, we often conjure up the picture of a ferocious dog with a foaming mouth. With its name derived from the Latin word for madness or fury, this disease has been around for thousands of years and still poses a significant threat to both animals and humans. In fact, this frightening and devastating viral disease can infect any warm-blooded animal. With the exception of a few rabies-free areas, such as Britain and Hawaii, humans, dogs, and other animals worldwide are at risk of contracting this virus. Since rabies is invariably fatal for dogs, it’s important for us, as pet owners, to be educated on the subject so that we can protect our beloved canine companions and ourselves.

The rabies virus primarily affects an animal’s nervous system, causing inflammation of the brain (encephalitis) and spinal cord. As a result, animals with this virus always display unusual and abnormal behavior. Rabies progresses through three stages — prodromal, furious, and paralytic — and each phase of the disease is characterized by certain symptoms and warning signs. The first phase that an infected dog will experience is the prodromal stage. This phase lasts for approximately two or three days and is characterized by temperament changes that can cause a canine to become unusually aggressive or unusually quiet and timid. Other signs that arise during this stage of the disease include fever and slow eye reflexes. Some dogs may also chew at the spot where they were bitten by the animal that infected them.

The second stage of rabies is the furious stage, which lasts between two to four days. A dog experiencing this phase of rabies will exhibit erratic behaviors such as restlessness, barking, roaming, and attacking inanimate objects. Some dogs will also become disoriented and may experience seizures. Finally, the last stage of this disease is the paralytic stage. Lasting approximately two to four days, this phase is characterized by the onset of paralysis. Often this paralysis will begin in the part of the animal’s body where it was bitten. At this point, the rabies virus affects the nerves in the dog’s face and head, causing excessive drooling, foaming at the mouth, and difficulty with swallowing. Paralysis of the face and throat can also lead to a change in the dog’s bark and distortion of its facial features. These symptoms will be followed by a violent seizure or coma, which will then lead to death. Typically, death will occur within three to seven days of the animal beginning to show symptoms.

If your dog or any other animal is exhibiting these symptoms, it’s a very serious matter. Only a veterinarian or animal control officer should deal with the situation, in order to reduce the chance of transmission of the disease from the infected animal to any humans, pets, or other animals.

Diagnosis

Unfortunately, there is no pre-mortem test or method for conclusively diagnosing rabies in dogs. Thus, diagnosis of this viral disease in canines is based upon whether or not the dog has recently been bitten by another animal and the emergence of clinical signs. If a dog has been bitten, it will typically be quarantined for a period of time, during which the animal will be observed for any signs and symptoms of rabies. If the dog has not begun to exhibit any symptoms after the isolation period, it will likely be declared rabies free.

Once an infected animal has died of the disease or has been euthanized, it is then possible to conclusively determine whether or not the animal was suffering from rabies. This is especially helpful if there’s a possibility that the animal infected another animal or person before its death. Postmortem diagnosis is achieved through analysis of the animal’s brain tissue for signs of infection. This involves staining the brain tissue so that the pathologist can search for Negri bodies in the nerves.

Pathophysiology

Rabies is a viral disease that is capable of infecting pets, humans, and wild animals. A deadly and vicious disease, rabies has been around for thousands of years and has been known to be a danger since the twenty-third century B.C. A very widespread problem, rabies is present on all continents with the exception of Australia and Antarctica, and is a potential danger in all but a handful of countries around the world. For unvaccinated dogs, rabies is always deadly and prior to death it causes a variety of severe and frightening symptoms.

The rabies virus is an RNA virus and belongs to the genus Lyssavirus. This virus attacks the nervous system of the infected animal, damaging the brain and spinal cord. Primarily, rabies causes inflammation of the brain (encephalitis) which causes a number of neurological symptoms such as unusual and erratic behavior and seizures. Transmission of this virus occurs when an animal is bitten and becomes infected with the saliva of another animal that already has rabies. The incubation period of rabies varies quite significantly and can range from between two to eight weeks, or even more. Factors that can affect the length of incubation include how close the site of the bite is to the brain and spinal cord, the severity of the bite, and the amount of virus transmitted via saliva when the bite occurs.

Causes

Rabies is spread through the infected saliva or tissues of an animal carrying the virus. Typically, transmission occurs as a result of a bite from an infected animal. For both humans and domesticated pets such as dogs, bites from wild animals are the most common cause of rabies. Wild animals in Europe and North America that are most likely to be carrying this disease and to transmit it to humans or pets include raccoons, skunks, bats, and foxes. In Africa and Latin America, the most common source of infected bites is stray dogs.

When a dog is bitten by a rabid animal, the virus enters the canine’s system via the infected saliva and travels along the nerves to the spinal cord and brain. During this stage of infection, the dog cannot infect other animals or humans with its saliva. However, once the rabies virus has reached the brain, it quickly becomes present in the dog’s salivary glands. From this point on, the dog is contagious and is capable of spreading the disease. Since rabies can cause aggressive and erratic behavior, bites from a rabid animal are a real danger. Therefore, any form of contact with an animal that could potentially be infected with this virus should be avoided by other animals and unqualified humans.

Treatment

Unfortunately, there is no treatment for this viral disease when it affects dogs. Once a canine has contracted rabies, it will need to be euthanized in order to prevent the spread of the disease and to save the animal from suffering from terrible symptoms such as paralysis and seizures. Since there is no cure for dog rabies, prevention is of the utmost importance. In order to protect yourself and your pets, the best thing you can do is to become educated on the subject.

One of the most important keys to preventing your dog from contracting rabies is to make sure that your pet has up-to-date rabies vaccinations from a veterinarian. In fact, in most countries this is required by law. Depending upon the particular vaccination used, a dog will typically be protected for between one and three years after each shot. These vaccinations stimulate the development of antibodies that will fight off the rabies virus, but are only effective if administered prior to contracting the disease. If a dog is not re-vaccinated regularly, its immunity to the virus will lapse. This is why it’s so important to make sure that your dog is always up-to-date with its vaccinations.

In addition to keeping your dog vaccinated, there are also other steps you can take to prevent the transmission of rabies to your beloved pet. First of all, it’s best not to allow your dog to chase or disturb wildlife. Carcasses of wild animals should also be avoided. Keep yourself and your dog away from any animal that is behaving oddly. Behaviors to watch out for include disorientation, aggression, and unusual tameness in wild animals. If you suspect that an animal may have rabies, don’t attempt to approach or handle the animal on your own. Instead, contact a veterinarian, animal control department, or Police Department so that properly qualified and equipped people can come and take care of the matter. By following these steps you can keep yourself and your canine companions safe from the terrible rabies virus.