Rabies is caused by a virus, which is transmitted via saliva of infected animals, usually through a bite in the skin. Rarely, it can be transmitted through a mucous membrane such as the eyes, nose or mouth. After infection, the virus travels from peripheral nerves to the central nervous system, brain and spinal cord. Although initially symptoms are very non-specific (fever, headache and malaise) central infection leads to the classic neurological symptoms of rabies, including
- Insomnia, anxiety, agitation
- Confusion, hallucinations, delirium
- Paralysis, seizure
- Increased salivation
- Hydrophobia (fear of water)
Rabies virus is found only in mammals. More than 90 percent of cases in the U.S. are caused in association with exposure to wild animals; fortunately, animal vaccination programs have dramatically decreased the instance of rabies in domestic animals and livestock. Worldwide, however, 90 percent of cases are associated with bites from stray dogs, an important consideration when traveling internationally. Pre-travel immunization is recommended prior to travel in high-risk areas, particularly in the developing world.
Determining whether an exposure warrants treatment is the critical first step. One must consider the animal source and the type of exposure. The type of exposure is also important. Rabies is most commonly transmitted by animal bites, but transmission through scratches, wounds and mucous membranes is also possible. Casual contact by itself, such as petting a rabid animal, does not constitute a significant exposure.
Further, the rabies virus needs water to live. When dry, the virus is generally harmless. Dry materials containing the virus (e.g., dried feces) are generally non-infectious. Exposure requires that the virus pass from the infected animal’s saliva, blood or other bodily fluid to your bodily fluid through an open scratch or a mucous membrane such as your eyes, mouth or nose. If you are concerned about an exposure, first clean the site of exposure thoroughly. Then contact your doctor or come to the emergency department for urgent evaluation.
If a doctor recommends treatment, you will likely receive an injection of Human Rabies Immune Globulin (HRIG) at the site of the exposure. This shot provides passive protection immediately. You will also receive Human Diploid Cell Vaccine (HDCV) immediately and on subsequent days 3, 7, 14 and 28. Usually in 7-10 days, your body will develop immunity that lasts for approximately 2 years. If you have been previously immunized against rabies, you will likely receive the HDCV booster immediately and again 3 days later.
Avoiding potential exposure is your best protection. Should you be exposed, rapid evaluation and intervention will prevent rabies from developing.
Tips for prevention of rabies:
- Avoid close contact with wild animals, particularly those displaying unusual behavior.
- Immunize domestic pets under the guidance of your veterinarian.
- If traveling in high-risk environments or working in environments with potential exposure, consider pre-vaccination. Internationally the highest risk areas are Africa, Asia and Latin America, where dog vaccination programs have been historically less successful.
- If a potential exposure occurs, seek care immediately.
WASHINGTON – An increasing number of bats found in D.C. homes are testing positive for rabies, and the city health department is urging residents to "bat proof" their homes.
Prince George's County reports finding nine bats that tested positive for rabies since Aug. 1, and says one person who came in contact with an infected bat was treated pre-emptively for rabies.
No humans have reported being bitten yet. D.C. health workers are recommending the public take steps to keep it that way.
Among the city's bat protection suggestions:
- Close windows and doors;
- Fix broken window screens;
- Repair or screen-off points of entry such as loose shingles, vents and chimneys.
The health department says if someone is bitten by a bat or gets infectious material, such as saliva from a bat in the eyes, nose, mouth or a wound, he should wash the affected area thoroughly with soap and water and seek medical advice immediately.
The city warns citizens should not attempt to capture a bat on their own. If a bat is found in a house, animal control should be called immediately at 202-576-6664.
The rabies virus attacks the central nervous system causing convulsions, paralysis and finally death. The virus can affect all warm-blooded animals, but it is most often found in wildlife, such as raccoons, skunks, foxes and bats. Dogs and cats may contract rabies if they have not been vaccinated against it. All mammals, including humans, are susceptible to rabies. Dena Iverson of the D.C. Department of Health says the city's caught 74 bats recently and 13 of those caught tested positive for rabies.