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5 People Died From Rabies in the U.S. in 2021
Highest Total in a Decade
BY ETHAN COVEY
Five people died from rabies last year in the United States—the highest total in a decade. Four of the deaths were linked to bat exposure.
Three of the deaths, which occurred in Idaho, Illinois and Texas, were included in a CDC report. They took place over a five-week period from Sept. 28 to Nov. 10, 2021 (MMWR Morb Mortal Wkly Rep 2022;71[2]:31-32).
The cases included two adults and one child, all of whom had direct contact with a bat, by either collision or biting, within three to seven weeks before symptom onset. Three bat species were involved: • Lasionycteris noctivagans (silver-haired bat) • Tadarida brasiliensis (Mexican free-tailed bat) • Eptesicus fuscus (big brown bat)
All three are common in the United States and have been linked to the spread of rabies.
None of the patients received postexposure prophylaxis (PEP): two because they did not realize the risk for rabies infection associated with bat exposure, and the third due to anti-vaccination beliefs. The patients died within two to three weeks of developing symptoms.
“This report is a sad and important reminder that direct contact with bats is a leading cause of rabies deaths in the U.S.,” said Amber Kunkel, ScD, a CDC Epidemic Intelligence Service officer.
“Rabies transmission from bats to humans can be prevented,” Dr. Kunkel said. “People should avoid contact with bats whenever possible. People who have contact with a bat should consult their local health department to determine if they should receive postexposure prophylaxis and to have the bat tested for rabies, if possible.”
One of the other cases was in an immunocompromised Minnesota man who was bitten by a bat and received PEP but still died because he could not mount an immune response to the PEP. The final case was a man who was bitten by a rabid dog while traveling and died upon return to the United States.
(Left)Tadarida Brasiliensis; (below from top) Eptesicus fuscus; and Lasionycteris noctivagans
Is Rabies Risk Increasing?
The number of cases is raising questions about whether rates of rabies are increasing in the United States.
Although the three deaths investigated in the report match the total number recorded during the preceding 48 months, and the total of five is more than reported since 2011, there are differing opinions regarding whether the risk for rabies is increasing.
“Although these all happened in a short time, they occurred in different states and involved different bat species,” Dr. Kunkel said. “The number of bats tested for rabies and the proportion that test positive have been relatively stable over recent years. (About 24,000 bats were tested for rabies in 2020, and about 1,400 were positive.) These data are not yet available for 2021, but so far we have not noticed any
indication that rabies in bats is increasing.”
Stephen J. Scholand, MD, an infectious disease specialist in Meriden, Conn., disagreed.
“Definitely, it seems the risks of contracting rabies from bats is increasing,” he told Infectious Disease Special Edition. “This is what was recognized—what came to the attention of public health authorities. There are probably a number of other cases that are occurring but remain undiagnosed and unknown, because almost two-thirds of the time, the doctors never figure out what causes a case of encephalitis. The number of rabies cases, therefore, could be higher.”
According to Charles E. Rupprecht, MD, PhD, the CEO of Lyssa Inc. in Lawrenceville, Ga., the inconsistencies in CDC reports are indicative of failures with current rabies surveillance.
“The state of our surveillance is not ideal,” he said. “You’d think that in the age of COVID we’d have more real-time reporting.
“The bottom line,” he added, “is we don’t really have a gauge.
“We don’t know whether there are five cases or 50 cases [in the United States],” he continued, pointing out autopsies are not performed on most people who die in the United States, so the true cause of many deaths might be incorrect.
Part of the challenge of preventing rabies deaths, particularly those associated with bat contact, is that people may not know that exposure to a bat is a risk for rabies transmission. Bites and scratches also can be very small, and it can be difficult to determine what requires medical attention.
“What if you wake up and there is a bat in your bedroom?” Dr. Scholand said. “What if you open your child’s bedroom door and there is a bat?
Dr. Rupprecht stressed that additional efforts are needed, a difficult task in America’s already-constrained healthcare system where prioritizing and maintaining education and increasing the size of the public health workforce are challenges. According to the CDC, healthcare professionals should be aware of the risks associated with bat exposure, and can turn to health departments for detailed information regarding local risk. “Rabies epidemiology varies geographically inside the United States,” Dr. Kunkel said. “Local and state health departments are very familiar with rabies dynamics in their area, and healthcare providers should not hesitate to contact them for advice on evaluating individuals for postexposure prophylaxis. Rabid bats are present in all states except Hawaii, and any person who has direct contact with a bat should be evaluated for postexposure prophylaxis.” Ryan Wallace, DVM, a veterinarian and rabies expert in the CDC’s Division of HighConsequence Pathogens and Pathology, also noted that recent cases should not overshadow progress that has been made in reducing human rabies cases. “We have come a long way in the U.S. toward reducing the number of people who become infected each year with rabies, but this recent spate of cases is a sobering reminder that contact with bats poses a real health risk,” he said. ■
Dr. Scholand reported a relationship with Grifols. Drs. Kunkel and Rupprecht reported no relevant financial relationships.
