In most cases, the disease is transmitted via a bite wound and it is mostly wildlife that gets infected. When wildlife starts coming into contact with the pet population, then pets become infected and when pets get infected, human infection is not far behind. Because this infection has nearly 100% mortality, preventing it in pets becomes crucial to preventing it in people. Of course, people can get infected by wildlife contact as well. Despite vaccination being readily available, every year the U.S. reports approximately 50 canine deaths, 250 feline deaths, and several human deaths from rabies. Worldwide, some 55,000 human deaths occur annually from rabies even now in the 21st century.

The most common wildlife species to spread rabies to domestic animals and humans in the Northern Hemisphere are skunks, bats, raccoons, foxes, and coyotes. Wildlife (especially bats) are able to gain access to indoor areas where they can come in close contact with both pets and people. Indoor pets are not without risk.

Many people do not realize how fast death occurs from rabies.

The virus in the infected animal’s saliva enters the victim’s tissues during the bite. The virus attaches to the local muscle cells for a couple of days before penetrating local nerves and beginning its slow ascent to the brain. Once within nervous tissue, the virus is not accessible to the immune system and may safely proceed toward the brain. The journey is slow and can take up to a year but the average time is three to eight weeks depending on the species. Virus ultimately reaches the brain and in two to three days more is evident in all body secretions, including saliva. At this point, the disease becomes transmissible and symptoms begin.

It can take up to a year from the time of the initial bite before symptoms begin to show. In dogs, typical incubation periods are 21-80 days. In cats, it’s 28-42 days. Once symptoms show, treatment is nearly impossible.

Prodromal Stage (The First 2-3 Days After Symptoms Have Started)

A change in personality is noted. Friendly animals become shy, etc. The larynx begins to spasm and a voice change may be noted (especially true in rabid cattle). Most infected animals will actively lick or scratch the site of the original bite.

Excitative Stage (Next 1-7 Days)

Classically, this would be the “mad dog” stage, though, in reality, most animals skip this phase altogether. The animal has no fear and suffers from hallucinations. If confined, the animal often attacks the bars of the cage.

Paralytic or Dumb Stage (Next 2-4 Days)

Weakness/paralysis sets in. The larynx is paralyzed, resulting in an inability to swallow, thus drooling and “foaming at the mouth” result. The animal dies when the intercostal muscles that control breathing are paralyzed. It is from animals in this stage where most human exposure occurs. There is no treatment for animals or humans once clinical signs appear.

When human exposure to the animal in question is involved, what happens depends on an assortment of criteria. If the animal in question is dead, its brain can be tested for rabies. There is no test for rabies in a living animal but since we know that death follows quickly after the virus becomes contagious, a living animal can be confined for 10 days. If the animal is still alive 10 days after biting a person, then the bite could not have transmitted rabies.

Prevention

For Our Pets

Happily, rabies prevention is accomplished with vaccination and limiting exposure to wildlife. The standard killed virus vaccines are available for both dogs and cats and, after the initial dose which is good for one year, subsequent doses are generally good for three years. Because tumors have developed in cats who received the killed virus vaccine, a recombinant product is now available that uses a portion of rabies viral DNA cloned into a harmless canarypox virus. This arrangement allows the pet to realize the benefits of live virus vaccination without any risk of exposure to the living rabies virus.

Rabies vaccination protocols are typically controlled by municipal regulations. Most communities legally require the vaccination of all dogs. The American Association of Feline Practitioners recommends rabies vaccination as a core vaccine for all pet cats.

For pets not current on rabies vaccination that have been exposed to biting wildlife, the Texas Post-Exposure Rabies Prophylaxis Protocol has been particularly helpful. In this situation, the pet should be vaccinated for rabies as soon as possible after the wildlife bite with booster vaccines given three weeks post-bite and eight weeks post-bite. The pet should be strictly isolated for 90 days. This protocol has been extremely successful in preventing rabies symptoms and contagion when normal rabies vaccination had lapsed. 

Treatment for Humans (Post Exposure Prophylaxis or PEP)

Every year a small number of people die of rabies in the U.S. Most of these people were bitten by a dog, bat, or some other animal and did nothing other than basic first aid. Recall that it takes many weeks for the rabies virus to reach the brain. This allows time for the vaccine to be given so that when the virus “comes out” of its neurologic hiding place and is ready to infect the brain, a substantial immunologic response is waiting. The virus is foiled and clinical rabies does not result.

If you are bitten by an animal and its rabies vaccination history is unknown, there are definite steps to take. A fresh bite wound should be washed out with water quickly as this may wash out viral particles. The time it takes for the virus to reach the brain depends on the amount of virus in addition to how close the wound is to the head. This simple step can be life-saving.

If the biting animal is alive, its vaccination status should be confirmed as soon as possible and it will need to be confined according to local law. The bite wound should be reported to the health department as soon as possible. Only rodent and rabbit bites are not reportable.

If the animal is dead then its brain can be tested for rabies. The head of the biting animal is submitted to the health department for fluorescent antibody testing for the rabies virus. This process takes a matter of hours so that any bite victims can know right away if they will require rabies treatment.

If the animal is not available or its vaccination status is in question, further treatment may be needed. Hyperimmune (antibody-rich) serum is flushed into the wound in hope of inactivating the virus before it may penetrate to the nerves. The patient receives a vaccination on a regular schedule for about a month, as described above.

Veterinarians have a rabies exposure risk of more than 300 times that of the general population. 

Anyone pursuing a career with animals should consider vaccination against rabies.

The purpose of the quarantine period is to determine if the rabies virus could have been in the animal’s saliva at the time of the bite. An animal infected with rabies and shedding virus will certainly be dead within ten days.

If the biting animal is known to have been exposed to wildlife, the situation is different. A vaccinated animal must be re-vaccinated within the time period required by local regulations and confined for observation for the specified duration. Unvaccinated animals may be confined for a specified time period according to local/regional law, or be euthanized and tested for rabies. In the U.S., all bites to humans that break the skin are reportable to local health departments. Rabies vaccination requirements vary from state to state, and country to country.  Contact your veterinarian if you think your pet has come into contact with or been bitten by a wild animal. Regardless of the vaccination status of your pet, wild animal bites may lead to painful wounds and infection.

Again, laws regarding biting dogs and rabies vaccination are highly regional. Check with your local animal regulation department, your veterinarian, or visit rabiesaware.org to find out what you need to know in the U.S..

Quarantines when Traveling

Great Britain, Hawaii, Japan, New Zealand, and several other island areas have successfully eradicated rabies from their territory. These places are EXTREMELY cautious about allowing in potential carriers of rabies. Because of the long incubation period of rabies, a very long quarantine is needed; however, this must be balanced by the expense associated with quarantine and owners’ reluctance to be separated from their pets. Most places that have eradicated rabies have protocols for avoiding or minimizing quarantine. Typically, a microchip is implanted in the pet for identification purposes, a rabies antibody titer (a measurement of vaccine-induced protection) must be performed at an approved laboratory, and rabies vaccine documentation is necessary.

For listings of what each state requires for entry, go to the USDA. 

For travel to another country check with that country’s consulate, but guidelines are also available at USDA.

Other Links

The CDC’s rabies home page has, in addition to basic information, a children’s education area that is particularly helpful for families who go camping.

The annual World Rabies Day calls attention to this problem to raise awareness and provides information about rabies in both humans and animals.

In Summary:

You can’t treat rabies once symptoms set in; all you can do is prevent it.

Rabies is a virus transmitted through saliva or brain tissue. Without rapid preventive treatment, it is almost always fatal. That’s why your pets are required to have rabies vaccines in many areas of the world.

The most common wildlife species to spread rabies to animals and people in the Northern Hemisphere are bats, skunks, raccoons, foxes, and coyotes. 

It is generally caused by a bite wound, and mostly wildlife gets infected.

Rabies affects a mammal’s central nervous system. It can take up to a year before symptoms begin to show, but the average time is 3-8 weeks depending on the species. In dogs, the typical incubation period is 21-80 days. In cats, it’s 28-42 days. Once symptoms begin, treatment is nearly impossible.

If you are bitten, you need a preventive injection immediately as it only works during the incubation period. Once even mild symptoms begin, death occurs within 10 days.

After symptoms have started:

•  First 2-3 days: a personality change is seen, and the larynx spasms, resulting in a voice change.
•  Next 1-7 days: this is the “mad dog” stage in which an animal has no fear and suffers from hallucinations, but many skip this stage.
•  Next 2-4 days: weakness and paralysis set in. The larynx becomes paralyzed so the animal cannot swallow, causing drooling and foaming at the mouth.
•  The animal dies when the muscles that control breathing finally become completely paralyzed. Most people get bitten in this stage.

Symptoms may not be obviously recognizable, making diagnosis difficult if not impossible. There is no diagnostic test for rabies in a living animal.

What happens after people are exposed depends on the situation. If the animal is dead, its head is sent to a laboratory so the brain tissue can be tested. In some circumstances/locations, a living animal can be quarantined for 10 days at the owner’s expense; if the animal is still alive, then the bite could not have transmitted rabies.

The vaccine protocols are typically controlled by municipal regulations. Most communities legally require all dogs to be vaccinated and recommend it for cats. Vaccination requirements vary from state to state, and country to country. 

Exposed pets not current on rabies vaccination should be given booster vaccines at 3 and 8 weeks post-bite. The pet should be strictly isolated for 90 days.

Exposed humans should wash the bite with water as it may wash out some virus particles; the time it takes for the virus to reach the brain depends on the amount of virus in addition to how close the wound is to the head.  This step could save a life.

Animal bites need to be reported to local health departments.

Veterinarians have a rabies exposure risk of more than 300 times that of the general population. Anyone in an animal-oriented job should consider preventive vaccination.

This was not always the case. In the 40s, 50s and 60s — well over half a century ago — death from anesthesia was about 1 in 400 for dogs and 1 in 260 for cats. These numbers are from referral hospitals, which are generally anesthetizing sicker patients, and that could increase the numbers over what you would expect to see in healthier pets in a general practice. There is a study from the early 2000s in the U.K. that followed mortality in a variety of practices (from general practices all the way to referral hospitals) and included dogs, cats, birds and pocket pets; in it, they found a death rate from 1 in 588 for dogs and 1 in 416 for cats. The risk has continued to drop, so that today those fatality numbers are around 1.7 in 1,000 dogs and 2.4 in 1,000 cats.

Although only statistics for dogs and cats have been created, the same improvement in risk applies to other pets such as rabbits, rats, hedgehogs, bearded dragons, and even goldfish as equipment and teaching new methods of anesthesia have improved over the years.

How does it work?

General anesthesia is given through an IV or an inhaled gas, or sometimes a combination of the two. It is similar, on a smaller scale, to a medically-induced coma. Oftentimes a sedative is given first.

It works by interrupting nerve signals in your pet’s brain and body. It keeps them temporarily unconscious: asleep, relaxed, and pain free during a procedure or surgery. It slows down automatic functions like breathing, heart rate, and circulation. During that coma-like period, brains cannot process pain, nor will the pet remember what happened during surgery.

During the procedure, the veterinarian or veterinary anesthesiologist will check some basic functions while your pet is under, such as breathing, temperature, heart rate, blood pressure, blood oxygen level, and fluid levels (as would happen in a human surgery). Monitoring doesn’t have to be done with expensive equipment, as having a trained person monitoring the depth of anesthesia as well as certain physical parameters can be just as valuable. Computerized anesthesia monitors can be used to enhance, but not replace, that person’s ability.

If those functions aren’t where the veterinarian wants them to be, adjustments in the level of anesthesia can correct them.

Monitoring doesn’t stop when surgery is over, or even when the equipment is removed. About half of the anesthesia deaths in small animals happen during the first 3 hours after surgery. The causes are usually breathing or heart problems. That makes this time critical for patient safety. Careful monitoring by a trained observer of physical variables, especially oxygenation and temperature, can help make this time period safer.

What main factors influence anesthetic risk?

Not unsurprisingly, the first is the health of the animal. Healthy patients, or patients with mild, controlled disease, are at less risk than patients who are sick. For healthy dogs, about 1 in 2,000 are expected to have a fatality and about 1 in 1000 cats would have one. In sicker patients, it would be closer to 13 dogs and 14 cats out of 1,000.

Having anesthesia in an emergency can also increase risk. That makes sense if you think about it. When you have time to plan a procedure, stabilize your patient and can schedule surgery at a time that is optimal for everyone, things go better. Having said that, the risk of anesthetic death with an emergency procedure, while higher than regular procedures, is still low.  Emergencies are emergencies because they can’t wait, and there are times that the pet will die if surgery is not done as soon as possible, such as with bloat.  

Veterinarians can decrease risk by focusing on monitoring and supportive care before, during, and after anesthesia. Preoperative planning is done with a good history, physical examination, and often baseline lab work to check liver and kidney function, among other things. Any abnormalities identified before surgery can be corrected if needed.

Follow all of your veterinarian’s pre-operative instructions exactly, including when to stop giving food the night before. Anesthetized patients lose their ability to swallow. If there is food in the stomach, the pet could vomit while under anesthesia or soon afterwards. If vomiting occurs before the swallowing reflex comes back, the vomited material can enter into the lungs, causing aspiration pneumonia. For emergency surgery, this factor is overlooked, but not for elective surgery.

While anesthetic risk is not zero and never will be, the risks are low and shouldn’t prevent any pet owner from providing health care for their pet whether it’s a dental cleaning or major surgery.

The Corneal Erosion

There are several causes of acutely red and painful eyes and one of the most common causes is a wound or scrape to the surface of the eye. The clear surface of the eye is called the cornea; because it is the outermost layer of the eye, it is prone to scrapes and tears. Common causes of corneal erosions include:

• Rough contact with plants, thorns, or bushes
• Scratches from another animal (note: the cat scratch wound can be especially serious as the wound quickly heals over, sealing infection within the eye.)
• Self-trauma (rubbing or scratching at a painful ear or even at the eye due to some other eye problem can lead to an inadvertent scratch to the eye.)
• Chemical irritation (such as getting shampoo in the eye during a bath.)
• Foreign body injury (plant material can get stuck under an eyelid and can scrape the cornea.)

A special fluorescent stain is used to confirm if there is an ulcer or erosion. Normally, water will run smoothly off the surface of the cornea, like rain washing off a windshield. If the cornea is damaged, the stain will stick to the damaged area and look bright green under a fluorescent lamp.

Treatment

Antibiotics

A routine corneal ulcer or erosion should heal easily. Since the damaged cornea is at risk of becoming infected (or may even already be infected, as demonstrated by a purulent discharge), a topical antibiotic is needed and ideally should be used four times a day or more. Since it is a rare pet owner that can accommodate any medication administration four times a day, we usually have to make do with three times a day but to properly sterilize the eye surface, the antibiotic should be used four times a day. Either drops or ointment can be used depending on the owner’s preference.

Pain Relief

The second part of treatment is pain relief: Atropine 1% drops or ointment. The atropine acts by temporarily paralyzing the pupil’s ability to constrict (the main source of pain is spasm in the pupil). Pupillary dilation is expected when this medication is used and the pet may be reluctant to experience bright sunlight while under the influence of this medication. Because the tear duct system is connected to the nose and mouth, the patient will also taste the above medications and atropine is famous for its bitter taste. Dogs do not seem to mind this unduly but cats will drool shortly after the medication is given in an effort to get the taste out of their mouths. This is a normal reaction to the Atropine as is the dilated pupil.

Some other procedures, and possibly a visit to a veterinary ophthalmologist, may be necessary. 

 If the inflammation associated with the ulcer goes deeper into the eye, the situation becomes more serious; it is very important not to skip that one-week re-check. If there is any question about the eye’s healing progress, the eye should be re-checked sooner.

It is important that the owner observe the progression of healing at home. If the eye is doing well but suddenly becomes more painful, if a discharge develops, or if the eye simply does not look right, have your vet recheck the pet sooner than the planned one-week appointment.

Some Special Ulcer Conditions

Indolent Ulcer

Some ulcers form with a small lip on their edge.  Since the ulcer is trying to heal from the bottom up, the lip interferes and creates an ulcer that seems to never get any smaller. Several techniques can be used to remedy this situation: the lip can be rubbed away, hyaluronan or PSGAG eye drops can be used to strengthen the cornea, or surgery can be performed. A technique that has gained popularity over recent years is called the grid keratectomy where a needle is used to scratch a grid of lines on the cornea. The cornea is then able to heal in, grid by grid. Poodles and boxers are notorious for these ulcers but they can occur in any breed. 

Melting Ulcers

When infection is present, the cornea will develop a yellow or tan gooey appearance because the bacteria or fungi causing the infection elaborate enzymes that actually dissolve corneal collagen fibers. The cornea softens and appears to be melting and can actually perforate. Culture and cell sampling for analysis are very helpful in determining the right antimicrobial therapy. In addition to antibiotic drops, the eye will need some sort of medication to inactivate the aforementioned collagen-dissolving enzymes. Often, this involves taking a blood sample from the patient and actually delivering the patient’s own serum as an eye drop.

Descemetocele

(Pronounced des’ĕ-met’ō-sēl) Descemet’s membrane is the thin attachment of the cornea to the fluid of the eye below. A Descemetocoele is an ulcer that has penetrated through the cornea completely except for the last thin membrane. An eye with a descemetocoele is at high risk for rupture and measures must be taken to protect the eye. Usually, surgery is needed. The brachycephalic breeds (Pekingese, pug, etc.) are predisposed to this problem due to their prominent eyes.

Again, corneal ulcers and erosions usually heal routinely but stay alert for any changes that could indicate a more serious turn of events. Be sure self-trauma (rubbing the eye) is prevented and be sure to go to a recheck at the proper time. If anything seems not to be proceeding properly, be sure to contact your veterinarian.