Three case reports of human rabies recently appeared in the MMWR. Reading each one served as a reminder of just how horrifying this infection is when it strikes — which very fortunately is quite rare in our country.
Two cases were domestic and followed recognized direct bat exposures with no post-exposure preventive measures taken. Here are the exposure summaries:
Case 1: In July 2024, a Minnesota woman who lived alone reported to family members that a bat or bird had been trapped in her house for several days. After discovering a bat in the sink, she reportedly killed it with a hammer and disposed of it. A bite was not mentioned; however, the method reportedly used to kill the bat could have produced splatter resulting in inoculation of infectious nervous tissue onto broken skin or mucous membranes. In addition, family members reported that the patient wore a hearing aid, was a deep sleeper who used a continuous positive airway pressure machine, and routinely consumed alcohol, factors that might have reduced her awareness of having had direct bat contact.
Case 2: In October 2024, a woman living in California told family members that she had recently found a bat indoors at her worksite. Although the bat initially appeared to be dead, when she handled it with her bare hands, she felt movement and a possible bite. She discarded the bat, and in the absence of any apparent wound, did not consult a medical provider or public health officials, and the bat was not tested for rabies.
Symptom onset was 3 weeks after bat exposure in the first case and 1 month in the second. Both individuals died.
The discussion emphasized the importance of the CDC’s recommendation to give the rabies vaccine after any direct bat contact. North American bats are small, and bites might not be apparent, causing trivial injuries. This is especially critical when the patient has conditions that make them less likely to notice a bite, as in the first case. As a result, any direct contact with a bat should warrant preventive intervention.
The third case was imported, with the patient’s exposure in Haiti 7 months before clinical presentation. (You read that right.) A prolonged delay in diagnosis led to a large number of healthcare workers potentially exposed, though fortunately none developed rabies. After a 10-day hospitalization at one hospital, he was transferred to another where the diagnosis was ultimately confirmed; he died approximately 6 weeks after initial symptom onset.
Key to solving the origin of this case was the phylogenetic analysis of the patient’s rabies virus, which showed it derived from a strain known to be endemic in canines and wild mongooses in Haiti — and distinct from the bat variant most commonly identified in U.S. cases.
These cases serve as a reminder that rabies remains an almost universally fatal condition. A case report of a 15-year-old girl who survived has led to some adoption of the treatment she received — the “Milwaukee Protocol” — though there is debate about its specific effectiveness versus advances in the critical care of patients with coma. Regardless, even survivors often have serious neurological sequelae — this is a terrible disease.
The challenge for us clinicians here in the United States, with only a few cases reported annually, is to assess the risk of exposures in scenarios quite different from those outlined in these recent case reports. We’d all recommend post-exposure prophylaxis and vaccination for patients who directly handled a bat or were bitten by a dog in Haiti.
But what about the bat flying around the house, or in a garage, but with no apparent bite? Canada dropped recommending rabies preventive measures for that scenario, with no reported increase in rabies cases. Or a dog bite in a foreign country with an established rabies vaccine protocol for dogs?
Consider the following cases:
Case 1: A man awoke from a sound sleep to find a bat flying around his room. He opened his windows and left the room. He returned in an hour, and the bat was gone. There was no apparent contact with the bat.
Case 2: A 12-year-old boy sustained a dog bite from a neighbor’s dog while visiting family in rural Brazil. The bite occurred while they were playing with a tennis ball, breaking his skin and causing slight bleeding. The neighbors said the dog had received most of its scheduled rabies vaccines and had exhibited no abnormal behavior.
Go ahead and vote! And let’s hear your thoughts in the comments section!
(Image: Two Bats Flying, by Hokusai Katsushika, 1830. National Library of Congress.)
Rabies prophylaxis is like buying a lottey ticket exept your life is the Powerball.
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Well said! But no unanimity in the responses, that’s for sure.
-Paul
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Sometimes I don’t know why they call us for advice. Unless it obvious that the risk is zero, how could we say not to give the vaccine?
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Another mitigating factor in safe rabies risk management is inappropriate care in some health care settings. About 15yrs ago my wife woke me to say a bat had just flown across the ceiling above us in the bedroon of a rural cabin where we were vacationing. Their was no obvious contact with our bodies; however, we elected to drive an hour away to an ED in northern Wisconsin seeking rabies vaccine and post exposure prophylaxis. The ED physician tried to reassure us there was no need for this & was very reluctant to order it. I then felt I needed to invoke the fact that I was a physician and we were not leaving until we received treatment. He acquiesed reluctantly . Two days later, we located the bat in the house; captured it and brought it to the county health officer, who sent it to Madison for testing which turned out negative obviating the need to complete the prophylaxis course. If I was not an MD, the ER doc may not have given into my insistance and sadly, may have put others at risk in similar situations.
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Interestingly enough you do not mention the rabies antibodies so often touted in academic settings . What is your take on the antibodies given there is no RCT that I can find on the matter. Do you think it actually works?
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Almost the exact same situation occurred with me and my partner after a scratch from a rabid raccoon in the midwest. It felt like the downplay culture/pressure was intense. I would not let them discharge her until she had vaccines and Ig around the scratches despite several attempts at reassurance from the provider. And I eventually felt I had to invoke being a physician. A scary time.
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I live in Brazil and here there is a public health protocol for several years in cases of dog bites. If the domestic animal (dog or cat) could be observed for the next 10 days, there is not recommendation for prophylaxis. Of course it is independent of animal vaccination status. If the domestic animal has infeccted with rabies, it dies no more than 5 days.
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Yes, this is why I chose Brazil! Thanks for confirming.
-Paul
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10 or 15 years ago, there was a shortage of rabies vaccine, and the Public Health Department required that we get their approval for every series. We discovered was that about half of the vaccine was being given to people who didn’t have an indication for it – typically exposure to a low-risk animal, like a cat, rat, squirrel, or a pet dog that could be observed. After the shortage resolved, we asked the injection clinic to call ID whenever a patient came in for PEP. This reduced inappropriate use (without any cases of rabies), even though we were pretty liberal about approving the shots.
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The bat case 100% should get vaccinated. The dog bite just needs to have the dog quarantined for 10 days and examined by a veterinarian 10 days post-bite. If the neurological exam that day is normal then it is not possible that the dog could have had rabies in his salivary glands at the time of the bite. Ten days is well within the incubation period for rabies and if the dog did develop signs of rabies it could be euthanized and tested and if positive, the child could then get prophylaxis.
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I’m a public health nurse in a local (county) health department. We are tasked with approving animal brains for rabies testing. We also provide evidence-based risk assessment guidance to medical providers and community members with concern about rabies exposure. (We always direct community members to consult with their medical provider but also try to provide them with some context for risk and rationale for rabies PEP.) For high-risk exposures we strongly encourage people to seek PEP and then we follow the case throughout the PEP series, sometimes communicating with involved medical providers. In the process we have seen some common errors in PEP administration that may affect efficacy and prompt re-administration of rabies biologics. 1. Rabies vaccine and HRIG (administered with dose 1 of the vaccine series) should never be given in the same anatomical location. These products can decrease the efficacy of each other when given together. 2. A rabies vaccine dose is not considered valid if administered in the gluteal area and must be repeated. 3. A 5th dose in the vaccine series and rabies antibody titers should be considered in immunocompromised persons who have had a potentially high-risk exposure.
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Thanks for this very helpful information!
-Paul
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Given that the 10-day quarantine protocol for dog bites relies on the assumption that the virus is only present in saliva shortly before symptoms appear, how should public health officials adjust their risk assessment and post-exposure prophylaxis (PEP) recommendations if the biting animal is a species with a less predictable incubation period or if the victim is immunocompromised, potentially altering the window for effective intervention?
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My understanding is that a bat is diseased if flying in a house or structure. Their sonar ability is that precise/accurate.
I also understand that infected bat guano is a source of rabies transmission if aerosolized and inspired.
I also have friends who have homes in northern Wisconsin where hordes of bats aggregate under hot tub tarpaulins. And I have wondered about their risk of rabies acquisition via the aerosolized bat guano, especially if a “diseased” bat is found flying in their house and they can’t catch it.
I have gone so far as to suggest that they get/consider preexposure prophylaxis with rabavert.
But I could be completely wrong about my approach/understanding. What do you think?
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Decision making was cruder when I was bitten by a rabid cat, as a 5 year old (cat was killed, and it’s brain examined). All that I can recall, was crying each afternoon for the next 21 days when being taken to our family doctor’s house for my rabies shot (intensively painful due to the large quantity of vaccine injected SQ). The rest of the story I put together from family lore learned much later, plus learning a bit about rabies in medical school (just as the transition to HDCV was coming online). Two adults, our mailman and a neighbor, who were bitten by the same cat and both died. One during or shortly after completing the vaccine series – presumably due to immune encephalitis from the vaccine produced in brain tissue cultures. The other adult became ill and died many months later, presumably from rabies. The personal experience left me, after entering ED practice, with a bit of bias (certainly not evidence based) towards PEP treating at a lower threshold of concern.
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Many years ago I was working as a vet student in a veterinary pathology lab. I was working in the isolation room, gowned, masked and gloved dissecting the brain from a submitted bat. The pathologist came to the door to talk with me while I was working. The scalpel blade slipped and flicked a tiny piece of bat brain into his eye. He looked at me and scowled “That bat better not be rabid!” Fortunately for both of us it was not.
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