My husband and I recently had dinner with some good friends. Over pizza and beer, our friend Drew comically related to us a story about how he was “attacked” by a stray dog while out for a jog one morning. He then asked for some medical advice “Do I need a rabies shot?” he asked me. After making several jokes about The Office episode where Michael Scott carbo loads on fettuccine alfredo and then runs a 5k race advocating rabies awareness, I asked “are those scratches on your leg or bites”? He didn’t know- due to the apparent chaos of the attack he was uncertain of the actual mechanism of injury. I told him I thought he would be OK and that he did not need a rabies immunization (I made sure to let him know we won’t be certain for a few years given the lengthy rabies incubation period). Despite the flippant mood of our conversation, some animal bites do warrant rabies immunizations. When do animal bite victims need rabies immunizations?
How Many People Actually Contract the Rabies Virus?
When a patient presents with an animal bite, reassure them that contracting rabies in the United States is extremely rare. Only one case of rabies was reported among humans in 2001 and three cases among humans in 2002. 55 cases of rabies have been reported in humans in the United States since 1990. Incidence of rabies among humans is highest in Asia and Africa but is still rare. Rabies is most common among wild animals such as raccoons, skunks and bats. Victims of domestic animal bites do not need to be as concerned about rabies as those of wild animals.
What are Symptoms of Rabies?
Incubation period of the rabies virus is typically 1 to 3 months however can be up to several years. The rabies virus affects the central nervous system. Early symptoms include headache, fever and generalized weakness. As the disease progresses, victims suffer from insomnia, hallucinations, partial paralysis and the famous hydrophobia (fear of water) and hypersalivation. Rabies has the highest fatality rate of any infectious disease and death usually occurs within days of symptom onset.
Who Needs a Rabies Immunization?
Although extremely rare, rabies is lethal and therefore post exposure prophylaxis by immunization should be considered. When a patient presents with an animal bite, the affected area should always be cleaned thoroughly and an animal bite report should be submitted to your local animal control agency. If the animal inflicting the bite has been vaccinated for rabies, no rabies vaccine is necessary. If the patient reports that the animal appeared rabid (I find that most patients who have recently been bitten by an animal understandably report that the animal appeared rabid so asking specific questions is helpful) and has not been vaccinated then the rabies vaccine should be initiated. Animal control should be contacted to place the animal under 10 day observation if possible (i.e. they may be able to place your neighbor’s dog under observation but not a bat). The vaccine series may be discontinued if the animal does not exhibit any signs of rabies during the observation period. If the animal cannot be observed, the complete rabies vaccine series must be completed.
How Is the Rabies Vaccine Administered?
Upon presentation with an animal bite, patients who meet the rabies vaccine criteria above should be administered both rabies immune-globulin and a rabies vaccine. The rabies immune-globulin is placed at the site of the bite, the vaccine is administered IM in the deltoid. Then, the rabies vaccine (not the immune-globulin) must be administered on days 3, 7 and 14 after the initial immunization. The CDC offers a great handout you can give to patients to educate them about the rabies vaccine and also remind yourself of the rabies vaccine schedule. Primary care clinics and urgent care clinics do not offer the rabies vaccine; patients must go to their local emergency department or health department.
The likelihood of your patients contracting rabies is nearly zero, however given the aggressive nature of this disease, always err on the side of caution and begin vaccination if your patient meets the rabies vaccine requirement recommendations.