Contrary to popular belief, rabies is not confined to the so-called “dogdays” of July and August. Most cases in Texas occur in the spring, probably because there are more opportunities for transmissions during the spring mating seasons of wild carnivores. Rabies does occur through the entire year in Texas in both wild and domestic animals. Rabies in bats occurs mostly in the warmer months.
Unvaccinated dogs and cats bitten by a known rabid animal should be destroyed immediately. If the owner is unwilling to have this done, the animal should be vaccinated and placed in strict isolation for 90 days and given booster vaccinations during the third and eighth weeks of isolation. If the animal is currently vaccinated, it should be revaccinated immediately and restrained (leashing and confinement) for 45 days.
Formerly, hazards connected with taking anti-rabies treatment were considerable; however, the rabies vaccine and antiserum in current use have excellent safety records. Since the chances of developing the disease are so much greater than the chances of adverse reaction to the vaccine, anti-rabies treatment should be administered in all cases of known or uncertain exposure.
All warm-blooded animals, including humans, are susceptible to rabies. In Texas, skunks, bats, coyotes, and foxes are the most commonly infected animals. This does not mean that wildlife eradication campaigns should be started. Wild species are highly beneficial in keeping pests under control, but it is wise to realize that they can carry rabies, and that contact with them should be avoided at all times-especially with those which are obviously sick. Domestic dogs, cats, and livestock usually acquire rabies infections from wild animals; while the numbers of rabid domestic animals are fewer, their danger is greater because of their close association with humans.
Each year many cases of rabies develop among Texas wildlife and domestic animals. Rabies is a disease of overpopulation. It thrives where there is an abundance of wildlife, as there is in most counties in Texas. It is possible to control this disease. People in several foreign countries and in some of our own states have, by working closely with their health and wildlife authorities, eliminated rabies as a threat to both animal and human life. The more we understand about an enemy, the easier it is to overcome. That is the purpose of this pamphlet – to impress upon the reader what rabies is and is not so he or she can help control it.
Here are some facts about rabies:
Rabies is a viral infection that primarily spreads through a bite from an infected animal. Without early treatment, it is usually fatal.
It is an RNA virus of the rhabdovirus family that can affect the body in one of two ways. It can enter the peripheral nervous system directly and migrate to the brain. It can also replicate within muscle tissue, where it is safe from the host’s immune system. From here, it enters the nervous system through the neuromuscular junctions.
Once inside the nervous system, the virus produces acute inflammation of the brain. Coma and death soon follow.
There are two types of rabies. The first type, furious or encephalitic rabies, occurs in 80% of human cases, and a person with it is more likely to experience hyperactivity and hydrophobia. The second type, called paralytic or “dumb” rabies, causes paralysis as a dominant symptom.
Rabies is most common in countries where stray dogs are present in large numbers, with Asia and Africa accounting for 95% of cases.
As saliva carries the virus, rabies can develop if an infected animal bites someone. It can also occur if saliva from an infected animal gets into an open wound or through a mucous membrane, such as the eyes or mouth. However, the virus cannot pass through unbroken skin.
In the U.S., raccoons, coyotes, bats, skunks, and foxes are the animals most likely to spread the virus. Bats carrying rabies exist in all U.S. states except Hawaii.
Any mammal can harbor and transmit the virus, but smaller mammals, such as rodents, rarely become infected or transmit rabies. Rabbits are also unlikely to spread rabies.
Rabies progresses in five distinct stages:
Incubation is the time before symptoms appear. It usually lasts from 2–3 months and varies from 1 week to 1 year, depending on where the virus entered the body and the number of viral particles involved. The closer the bite is to the brain, the sooner the effects are likely to appear.
By the time symptoms appear, rabies is usually fatal. Anyone who has exposure to the virus should seek medical help immediately, without waiting for symptoms.
During prodrome, early, flu-like symptoms occur, including:
During this stage, neurologic symptoms develop, including:
Toward the end of this phase, breathing becomes rapid and inconsistent.
A person may enter a coma, and most people then die within 3 days. During the coma stage, even with supportive therapy, virtually no person survives rabies.
Awareness on rabies and preventing dog bites
Education on dog behaviour and bite prevention for both children and adults is an essential extension of a rabies vaccination programme and can decrease both the incidence of human rabies and the financial burden of treating dog bites. Increasing awareness of rabies prevention and control in communities includes education and information on responsible pet ownership, how to prevent dog bites, and immediate care measures after a bite. Engagement and ownership of the programme at the community level increases reach and uptake of key messages.
The same vaccine is used to immunize people after an exposure (see PEP) or before exposure to rabies (less common). Pre-exposure immunization is recommended for people in certain high-risk occupations such as laboratory workers handling live rabies and rabies-related (lyssavirus) viruses; and people (such as animal disease control staff and wildlife rangers) whose professional or personal activities might bring them into direct contact with bats, carnivores, or other mammals that may be infected.
Pre-exposure immunization might be indicated also for outdoor travellers to and expatriates living in remote areas with a high rabies exposure risk and limited local access to rabies biologics. Finally, immunization should also be considered for children living in, or visiting such areas. As they play with animals, they may receive more severe bites, or may not report bites.
The incubation period for rabies is typically 2–3 months but may vary from 1 week to 1 year, dependent upon factors such as the location of virus entry and viral load. Initial symptoms of rabies include a fever with pain and unusual or unexplained tingling, pricking, or burning sensation (paraesthesia) at the wound site. As the virus spreads to the central nervous system, progressive and fatal inflammation of the brain and spinal cord develops.
There are two forms of the disease:
Current diagnostic tools are not suitable for detecting rabies infection before the onset of clinical disease, and unless the rabies-specific signs of hydrophobia or aerophobia are present, clinical diagnosis may be difficult. Human rabies can be confirmed intra-vitam and post mortem by various diagnostic techniques that detect whole viruses, viral antigens, or nucleic acids in infected tissues (brain, skin or saliva)2
People are usually infected following a deep bite or scratch from an animal with rabies, and transmission to humans by rabid dogs accounts for up to 99% of cases.
In the Americas, bats are now the major source of human rabies deaths as dog-mediated transmission has mostly been broken in this region. Bat rabies is also an emerging public health threat in Australia and Western Europe. Human deaths following exposure to foxes, raccoons, skunks, jackals, mongooses and other wild carnivore host species are very rare, and bites from rodents are not known to transmit rabies.
Transmission can also occur if saliva of infected animals comes into direct contact with human mucosa or fresh skin wounds. Contraction of rabies through inhalation of virus-containing aerosols or through transplantation of infected organs is described, but extremely rare. Human-to-human transmission through bites or saliva is theoretically possible but has never been confirmed. The same applies for transmission to humans via consumption of raw meat or milk of infected animals.
Post-exposure prophylaxis (PEP) is the immediate treatment of a bite victim after rabies exposure. This prevents virus entry into the central nervous system, which results in imminent death. PEP consists of:
Starting the treatment soon after an exposure to rabies virus can effectively prevent the onset of symptoms and death.
This first-aid measure includes immediate and thorough flushing and washing of the wound for a minimum of 15 minutes with soap and water, detergent, povidone iodine or other substances that remove and kill the rabies virus.
Dog & Cat Bites – Everything You Need To Know – Dr. Nabil Ebraheim
Each year many cases of rabies develop among Texas wildlife and domestic animals. Rabies is a disease of overpopulation. It thrives where there is an abundance of wildlife, as there is in most counties in Texas. It is possible to control this disease. People in several foreign countries and in some of our own states have, by working closely with their health and wildlife authorities, eliminated rabies as a threat to both animal and human life. The more we understand about an enemy, the easier it is to overcome. That is the purpose of this pamphlet – to impress upon the reader what rabies is and is not so he or she can help control it.
Rabies – sometimes called “hydrophobia” – has its roots in antiquity. Centuries before the birth of Christ, it was recognized in both animals and man. Cases were described with amazing clinical accuracy during the lifetime of Aristotle. The name hydrophobia, meaning “fear of water,” was given to it at that time because the ancient Greeks observed rabid animals aversion to water. Actually, the truth is that they cannot drink because of throat paralysis. It is this fact which produces the classic picture of a beast with foam-flecked jaws. Saliva accumulates in the paralyzed throat and drools from the corners of the mouth, giving the impression of mad-dog foam. Certainly it isnt hard to understand why those ancient people were terror stricken by such a sight, and even thought the animal was demon-possessed. Writers of the day attributed rabies to an invasion of the body by a evil spirit. Through the years, a wall of superstition was built. The wall has never been completely torn down. Even today, many people believe that the bite of a civet cat (or “hydrophobia cat”), a small spotted skunk, invariably leads to rabies. Actually, while all skunks are susceptible to rabies, laboratory studies have proved it is wrong to assume all civet cats are rabid.
Rabies is a virus disease of the central nervous system. It can be transmitted by the bite of a rabid animal, or through the saliva of a rabid animal being introduced into a fresh scratch or similar skin break, and rarely by other routes. Saliva in contact with unbroken skin – or even on a scratch wound over 24 hours old, one where a scab has formed-usually will not require anti-rabies treatment. You should definitely see a doctor if you think the animal could be rabid.
At one time or another, rabies has occurred in almost every part of the world. An exception is Australia, where a case has never been diagnosed. Some countries once affected have eliminated rabies entirely by stringent control and enforcement measures. Denmark, Sweden, Norway, Hawaii, and the British isles have been free of the disease for many years. Although it had been completely eliminated from England prior to World War 1, it was reintroduced and had to be reeradicated. Currently, rabies is probably most prevalent in Russia, Belgium, France, the United States, Africa, Mexico and the lower Americas. In some sections of the United States, rabies is extremely rare.