What is Rabies?
Rabies is a viral disease that causes inflammation of the brain in humans and other mammals. It is transmitted through contact with infected saliva, usually via a bite from an infected animal. Rabies affects the central nervous system and is almost always fatal once symptoms appear. However, it is completely preventable if treatment is provided shortly after exposure.
Rabies is caused by rhabdoviruses in the genus Lyssavirus. There are many different strains of the rabies virus, with some more lethal than others. The most common strain affecting humans is the “classical rabies virus.” Other strains like Mokola virus and Duvenhage virus have also caused rabies in humans.
In the United States, wild animals like raccoons, skunks, foxes and bats are the most common carriers of rabies. Unvaccinated pets and livestock are also at risk. Rabies is spread when infected saliva gets into open wounds or mucous membranes like the eyes, mouth and nose. This often happens through animal bites, but exposure can also occur if the saliva makes contact with those areas.
According to the CDC, about 55,000 people worldwide die of rabies each year, with 95% of cases occurring in Africa and Asia. In the U.S., human deaths from rabies are rare, with only 1-3 cases reported each year. This low incidence is thanks to widespread pet vaccination programs and availability of post-exposure treatment. However, about 60,000 Americans still receive post-exposure prophylaxis annually after being potentially exposed to rabies virus.
What are the Symptoms of Rabies?
Rabies has an incubation period that averages 1-3 months but can range from under a week to over a year after exposure. The initial symptoms are nonspecific and may include:
– Fever
– Headache
– Nausea
– Vomiting
– Agitation
– Anxiety
As the virus spreads to the brain and central nervous system, more specific symptoms develop:
– Hyperactivity and agitation
– Hallucinations and delirium
– Hydrophobia – fear of water
– Hypersalivation
– Difficulty swallowing
Eventually, the infection leads to paralysis, coma and death. The time from onset of symptoms to death is usually 2-10 days. Rabies is difficult to diagnose in animals based on clinical signs alone. Unusual behavior like aggression, nocturnal activity in daytime, and unprovoked attacks are sometimes early signs in affected animals.
How is Rabies Transmitted?
The main routes of rabies transmission are:
– Bites – This is the most common mode of transmission. The virus is present in the saliva of rabid animals and enters the body through broken skin. Bites to the face and hands carry highest risk.
– Scratches – Scratches from animals can also transmit rabies if saliva makes contact with wound.
– Mucous membranes – If infectious material like saliva gets in the eyes, nose or mouth.
– Inhalation – Rarely, inhaling aerosol droplets with virus can spread rabies.
– Transplants – Rabies can be spread through transplanted organs taken from infected donors.
Animals most likely to transmit rabies in the U.S.:
– Bats – Most common source of human rabies due to bites being imperceptible.
– Skunks
– Raccoons
– Foxes
– Coyotes
– Dogs – Unvaccinated dogs are at risk for getting infected and spreading to humans.
– Cats
Rodents like squirrels, chipmunks and rats very rarely carry rabies. Lagomorphs including rabbits and hares are also rarely infected.
Who is at Risk of Rabies Exposure?
Any mammal can be infected with rabies, but these groups are at highest risk of exposure:
– Children – More likely to approach wild animals and get bitten on the face/hands.
– Hikers and campers – May encounter rabid wildlife in woods.
– Veterinarians and animal handlers
– International travelers visiting areas with endemic dog rabies
– People with outdoor occupations like wildlife officers, forestry workers
– Anyone exposed to a bat – Bites can be tiny and not noticed.
Factors that increase likelihood of transmission if exposed:
– Bites to highly innervated parts of body like head, neck, fingers
– Deep wounds
– Exposure to large viral loads in saliva
– Increased amount of contact time with saliva
How to Prevent Rabies Before Exposure
Here are some key ways to avoid rabies exposure in the first place:
– Vaccinate pets – Keep dogs and cats up to date on rabies shots as recommended by your vet. Rabies vaccination is required by law in most areas.
– Don’t handle wild animals – Do not touch or feed wild mammals like raccoons, bats, foxes, skunks, or stray dogs and cats.
– Avoid animal bites – Be cautious around both wild and domestic animals. Do not approach or try to handle unknown animals.
– Prevent pet interactions with wildlife – Keep pets indoors and supervise them outside. Make sure your home does not attract wild animals.
– Vaccinate livestock – Horses, sheep, cattle and other livestock should have regular rabies immunization.
– Install bat-proofing – Ensure attics, roofs and chimneys are sealed to prevent bat entry. Contact wildlife control professionals if needed.
– Report rabid animals – Call animal control if you see wildlife acting strangely as they may be infected with rabies.
– Consider pre-exposure prophylaxis – People at high risk like veterinarians can get pre-exposure rabies vaccination for added protection.
What to do if Exposed to Rabies
If you are bitten by an animal or otherwise exposed to rabies:
1. Wash the wound – Immediately clean bite wounds and scratches thoroughly with soap and water for at least 15 minutes. Use a virucidal agent like povidone-iodine if possible.
2. Get medical attention – See a doctor for care of the wound and to assess rabies risk. Tell them about the exposure and animal involved.
3. Report bite – Notify animal control or authorities to arrange testing or observation of the animal. The head of a dead animal may need to be submitted for rabies testing.
4. Get post-exposure prophylaxis – If the animal tests positive or can’t be located/tested, you will need to receive rabies shots for protection. This involves:
– Rabies immune globulin (RIG) – Given only once to provide immediate antibodies. The RIG injection is near the bite wound to flood the area with rabies antibodies.
– Vaccine series – You will receive 4-5 rabies vaccine doses over 2-4 weeks depending on vaccine type. The vaccines stimulate your immune system to produce antibodies against the rabies virus.
Prompt post-exposure prophylaxis can prevent the onset of rabies and is nearly 100% effective if administered properly within the incubation period.
Medical Treatment for Rabies
Unfortunately there is no effective cure for rabies once symptoms appear. However, experimental treatments have saved a small number of infected patients so far.
– Milwaukee Protocol – This pioneering treatment approach involves inducing a temporary coma and antiviral drugs. It allowed one patient to recover in 2004 after showing symptoms. Since then, there have been over 35 attempts with a low survival rate of about 8%.
– New research – Scientists continue to look for better rabies treatments. A few potential options:
– Ribavirin – Antiviral medication that stops viral replication.
– Ketamine and midazolam – Used to reduce brain inflammation.
– Monoclonal antibodies – Synthesized antibodies that neutralize the virus.
– RNA interference – Small interfering RNA molecules that inhibit viral genes.
However, preventing rabies altogether by avoiding exposure remains the only reliable medical intervention at this time.
Tips for Avoiding Rabies When Traveling
If traveling to a country with a high incidence of rabies like India, Thailand, or the Philippines, take these extra precautions:
– Consider pre-exposure vaccination if staying for over a month.
– Do not approach unfamiliar animals. Admire dogs and cats from a distance – do not pet or feed them.
– Avoid contact with wild animals like monkeys. Do not keep them as pets.
– Prevent bats from entering lodging. Watch children closely.
– If bitten or scratched, immediately wash the wound thoroughly with soap and water for at least 15 minutes. Seek post-exposure treatment locally and continue the series upon returning home.
– Follow warning signs about rabies risks in certain areas. For example, stay away from monkey temples.
– Keep hands and body parts away from the cages, pens, or tanks of any animal.
– Seek advice from travel health clinics on rabies prevention in your destination.
Following simple rules can help travelers protect themselves from rabies exposure abroad. Planning ahead is key before visiting countries with higher rabies risk.
Frequently Asked Questions
How long does it take to show symptoms of rabies after being infected?
The incubation period following rabies exposure is typically 1-3 months but can vary from under a week to over a year. The average is 20-60 days before initial symptoms emerge.
Can you get rabies from being scratched by an animal?
Yes, rabies can be transmitted through scratches. If an infected animal’s saliva makes contact with wound, the virus can enter the body and cause rabies. Scratches are lower risk than bites, but still require medical assessment.
What happens if you don’t get treated for rabies?
If post-exposure treatment is not administered and the initial symptoms are ignored, rabies has an almost 100% fatality rate. Rabies is incurable once the virus reaches the brain and neurological symptoms begin.
Can pets transmit rabies without showing symptoms?
It is possible for pets to spread rabies during the late incubation period before they become symptomatic. This underscores the importance of keeping pets currently vaccinated even if they seem healthy.
Is rabies airborne?
Rabies is primarily transmitted through direct contact with infected saliva into open wounds or mucosa. In extremely rare cases, it may be possible to acquire rabies from inhaling aerosol droplets in enclosed areas with high virus concentration.
Conclusion
Rabies is a deadly viral disease transmitted through infected saliva. While human rabies is rare in the U.S., the serious nature of the illness means preventing exposure is crucial. Avoid contact with wild mammals, vaccinate pets, and seek prompt medical care if bitten or scratched. Post-exposure prophylaxis administered in time is effective protection. With vigilance and caution, you can safeguard against this dangerous but preventable infection. Being aware of the risks, symptoms, and treatment is vital to stay rabies-free.