Rabies: What you need to know
Human rabies in the United States is rare — only one case was reported to the CDC in 2012. However, the disease is nearly always fatal, and its vectors can be found across the country.
Infectious Disease News spoke with experts about the causes of human rabies and how to recognize and treat the infection. Click here to read the full story.
Based on these interviews and the latest clinical data, here is what you need to know.
Vaccination programs in the US have successfully eliminated rabies in domestic dogs. However, other vectors — including bats, skunks, raccoons and foxes — serve as reservoirs of the virus.
“There has been an expansion of skunk rabies in Colorado, but on the East Coast, raccoon rabies is the major concern,” Jesse Blanton, MPH, an epidemiologist in the CDC’s poxvirus and rabies branch, told Infectious Disease News. “But on top of that, there are 12 to 15 variants of bat rabies, which is a concern for everyone, everywhere in the United States.”
The time it takes to develop rabies after exposure depends on a variety of factors, but the typical incubation period for humans is 60 days, according to Blanton.
Symptoms include pain and itching and myoclonic jerks involving the bitten limb. Strange and unusual behavior due to cerebral dysfunction is also common with infection.
“Rabies tends to wax and wane,” said Rodney Willoughby, MD, a pediatric infectious disease specialist at Children’s Hospital of Wisconsin and professor at the Medical College of Wisconsin. “You can be highly abnormal, but then be normal minutes later. Very few other infections do that. These are helpful diagnostic clues.”
People who are potentially exposed to rabies should seek treatment as soon as possible.
“The longer you go without treatment, the higher your odds are of developing the disease because the virus has a longer time to access the central nervous system,” Charles Rupprecht, VMD, MS, PhD, professor of epidemiology and public health at Ross University School of Veterinary Medicine, St. Kitts, West Indies, told Infectious Disease News. “Even though it may take long for symptoms to develop, there is a narrow window to intervene.”
Postexposure prophylaxis involves administration of rabies immunoglobulin to a patient at the site of the wound after proper washing and then four doses of the rabies vaccine given for 14 days.
After symptoms set in, survival is rare. Aggressive supportive treatment with mineralocorticoids within the first 5 days of hospitalization can increase a patient’s chance for survival, according to Willoughby.
International travelers may want to consider rabies vaccination, but introducing the rabies vaccine into the child immunization schedule would not be cost-effective in the US because canine rabies is no longer a threat.
“It makes sense in places where there is much less money being spent to prevent rabies in animals,” Willoughby said. “The problem is that this is a disease of dogs and livestock, which is part of agriculture. Agriculture agencies don’t want to spend money on preventing human diseases, and the human agencies don’t want to spend money on something that can be prevented by addressing issues with dogs and livestock.”