Causes and Risk Factors of Rabies

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Human rabies is extremely rare in the United States. In fact, only one to three cases are reported each year, according to the Centers for Disease Control and Prevention (CDC). Still, it’s important to understand the causes and risk factors for rabies so that you can protect yourself and your family from this potentially life-threatening disease.

Rabies is an infection caused by a virus of the genus Lyssavirus. Typically transmitted by saliva, the rabies virus usually enters the body through a bite by an infected animal. Although rabies was once most commonly linked to dog bites, more cases in the United States are now associated with bites from bats and other animals.

rabies causes and risk factors
© Verywell, 2018

Common Risk Factors

Thanks to widespread animal vaccines (given to people at high risk and those who may have been exposed to rabies), the number of rabies-related human deaths in the United States has steadily declined since the 1970s.

According to a study published in the Journal of the American Veterinary Medical Association, of the 4,910 animal rabies cases reported in the U.S. in 2016, the breakdown was as follows:

  • bats (33.5 percent)
  • raccoons (28.6 percent)
  • skunks (21.0 percent)
  • foxes (6.4 percent)
  • cats (5.2 percent)
  • cattle (1.4 percent)
  • dogs (1.2 percent)

Following an animal bite, the risk of developing rabies is especially high when: 

  • the bite takes place in a geographic area where rabies is still present
  • the animal looks ill or displays abnormal behavior
  • the animal’s saliva comes in contact with a wound or mucous membrane 

In some cases, rabies is caused by a scratch from an infected animal.

There have also been reports of rabies being transmitted by infected saliva that has entered the air, usually in bat caves. These cases are very rare.

In theory, it’s possible that human-to-human rabies transmission could occur through bites. However, this theory has never been confirmed. 

Outside the United States

Rabies is far more common In developing countries, where dog bites remain a common cause. According to the World Health Organization (WHO), countries in Africa and Asia account for 95 percent of rabies deaths worldwide. WHO estimates that rabies infection causes tens of thousands of deaths each year.

In Australia and Western Europe, bat rabies is a growing public health threat.

While rabies can affect both domestic and wild animals, bites from domestic dogs are responsible for virus transmission in 99 percent of human rabies cases. Wild animals, such as jackals and mongooses, also have the potential to spread the rabies virus.

Although rare, there have been case reports of rabies transmitted through organ transplantation.

Reducing Your Risk

Behavioral Strategies

Even though rabies is usually transmitted through unprovoked animal bites, it’s a good idea to brush up on behavior that might provoke a bite. To that end, you should never approach or pet an unfamiliar dog. It’s also smart to put a safe distance between yourself and a dog displaying such signals as a tensed body, stiff tail, pulled-back head and/or ears, or an intense stare.

You should also keep your pet from coming in contact with any wild animals.

Vaccinations

Although rabies in domestic dogs is now considered under control in the United States, the CDC estimates that up to 70 dogs and more than 250 cats are reported rabid each year. Most of these animals were unvaccinated and became infected by rabid bats, raccoons, skunks, and other forms of wildlife.

Given these statistics, it’s essential to vaccinate your pets in order to reduce rabies risk for yourself, your family, and the people in your community. If you’re unsure whether your pet has received the proper immunizations, talk to your veterinarian immediately.

In addition, you can lower your risk of contracting rabies by getting vaccinated, especially if you work with pets or in another high-risk occupation or travel to countries with a high rate of rabies.

How Rabies Is Diagnosed
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