Rabies is a viral, zoonotic disease, meaning that it's spread to humans by other infected animals. Around the world, rabies exposure is most commonly associated with bites from unvaccinated dogs. Thanks to legislation requiring canine rabies vaccinations in the United States, dog bite exposures are rare. Instead, U.S. rabies exposures are most commonly due to bites from infected wildlife, including bats, according to the Centers for Disease Control, or CDC. The symptoms of rabies typically don't develop for a period of one to three months after exposure, during which time prophylactic vaccinations are effective. Once symptoms develop, however, the disease is nearly always fatal.
Flu-like Symptoms
Bat bites, while rare, are small and nearly painless. So, unless the person has seen the bat inflict the bite, he or she might not seek medical treatment. In such a case, if the bat in question was rabid, the infected human will begin to develop flu-like symptoms within weeks. The World Health Organization, or WHO, lists headache, fever, generalized achiness, and malaise as among the early symptoms of rabies in humans.
Irritation at Bite
The rabies virus is unique in the way it's spread: It travels from the site of a bite wound through the nerves toward the salivary glands, and from there spreads to the brain. This salivary gland concentration of the infection is the reason that infected animals spread the disease through their saliva. Further, the symptoms develop in an order that roughly parallels the spread of the disease, starting near the bite, and progressing upward. The Wisconsin Department of Health Services notes that renewed irritation, itching, or burning at the site of the bite are other early symptom of rabies.
Hydrophobia
The classic symptom of rabies, and the one most readily associated with the disease, is hydrophobia, or fear of water. This symptom arises from the concentration of the rabies virus in the salivary glands, which causes painful throat spasms upon swallowing. Over a short period of time, these spasms cause infected humans to begin to fear water, to the point that even the thought of drinking or bathing leads to spasms in the throat. The Wisconsin Department of Health Services notes that spasms can extend to the muscles of respiration as well, making it difficult to breathe.
Mental Changes
The final stage of rabies involves changes in affect and cognition. WHO notes that either agitation and aggression or paralysis can ensue, and is often accompanied by delirium, seizures, and hallucination. Treatment is purely palliative; there is no cure for rabies, but it is possible to make victims a bit more comfortable in the last stages of the disease. Typically, the symptoms of rabies progress completely over a period of about 14 days.
