Exposure to a rabid animal is a life-threatening emergency: rabies is almost always fatal unless postexposure prophylaxis (PEP), which includes wound care, a series of vaccine doses and, depending on prior vaccination, rabies immune globulin, is started promptly. In the United States, cats are the most frequently reported rabid domestic animal, with about 200 to 300 rabid cats reported each year, although more than 90% of animal rabies cases are in wild animals such as raccoons, foxes, bats and skunks. In Maryland, feral cats accounted for 10% of reported rabid animals in 2023. Fewer than 10 people die of rabies in the United States each year.
Feral cats often live in colonies, usually made up of females and their kittens. A managed colony has a caretaker or community program that provides veterinary care, including spaying, neutering and vaccination. An unmanaged colony gets informal care from neighbors or none at all.
The rabid cat
On August 13, 2024, the Cecil County Health Department told the Maryland Department of Health about an aggressive feral cat from an unmanaged urban colony found outside a hotel in northeast Maryland. On August 8 the cat had turned aggressive and bitten or scratched two local residents. Animal control captured and euthanized it on August 8 or 9, and two days later the state laboratory found rabies in its brain tissue. A kitten from the same colony, behaving the same way, had last been seen by hotel staff on August 13, so other cats in the colony may also have been rabid.
Because cats can shed rabies virus for up to 10 days before showing signs, investigators treated July 29 to August 13 as the period when people could have been exposed.
Finding everyone who might have been exposed
The county and state health departments worked with county animal services and emergency services and with CDC. They focused on three groups:
- Hotel guests and staff. Reservation records identified 309 people who were at the hotel during the risk period: 107 (35%) Maryland residents from 10 local health jurisdictions and 202 (65%) from 27 other states and Canada. Local health departments reached Maryland residents by phone or certified letter; health departments in other states were asked to assess their residents; and CDC notified Canadian officials. In all, 197 people (63.8%) completed a risk assessment, and no exposures were found among guests. The two residents with known bites or scratches received PEP at a local emergency department on August 13.
- Local residents. In a novel step, a reverse 911 message went to every mobile phone subscriber in Cecil County, describing the situation and asking anyone who might have been exposed to a cat from the colony, or who knew of an exposed animal, to call the health department. One person called and turned out not to have been exposed, but the calls revealed that neighbors often saw and fed feral cats near the hotel and at a nearby farm. The farm's owners, reached through state dairy inspectors they knew, reported no exposures.
- People experiencing homelessness. Hotel staff and the county's special populations team, which supports marginalized residents, knew of at least three people staying near the hotel. Trusted community partners reached two of them, and one, exposed on August 9, received PEP on August 18. Nearby walk-in clinics were asked to report any patients with recent animal bites or scratches.
In total, three people had been exposed, all received PEP, and none has developed rabies. Of the 29 jurisdictions involved, 17 reported the staff time they spent: 450 hours.
The colony held about 20 cats and kittens, which neighbors fed and sheltered sporadically, so other rabid cats may have gone unreported. Animal services captured three more cats from the colony within three weeks; all were euthanized and tested negative.
Lessons
Feral cats are more likely than pets to meet wildlife that carry rabies and less likely to get veterinary care, and people are more likely to approach a cat than a wild animal, so feral cats pose a greater risk of human exposure than wildlife. CDC estimates that PEP after exposure to rabid or possibly rabid cats costs about $33 million a year. Maryland has reported 109 rabid cats since 2019. National surveillance does not record whether rabid cats had owners, but news reports and state records suggest a substantial share are feral or live in colonies. Mass exposures requiring multistate contact tracing are rarely described.
Managed colonies usually aim for high rabies vaccination coverage and use sterilization so the colony gradually dies out. Unmanaged colonies can pose ongoing risks as long as the cats keep breeding, and can require extensive public health resources. But neighbors who already feed feral cats are an opportunity: they can be drawn into a managed colony program with spaying, neutering and vaccination, and many jurisdictions have organizations that can help.
The investigation needed many kinds of outreach, including international notification, special populations teams, trusted farming contacts and reverse 911, and trusted community partners and dedicated county staff were crucial in getting PEP to people experiencing homelessness. The authors call for better understanding of urban cat ecology and rabies, and for more public education about the risks of unmanaged colonies. Not all states reported how many people they contacted or how much time they spent, so both figures are likely underestimates.
Sources
- Ludmer S, Crum D, Wallace R, Hutson J. Rabies Outbreak in an Urban, Unmanaged Cat Colony — Maryland, August 2024. MMWR Morb Mortal Wkly Rep 74(31). https://www.cdc.gov/mmwr/volumes/74/wr/mm7431a2.htm
- CDC, rabies postexposure prophylaxis guidelines: https://www.cdc.gov/rabies/hcp/clinical-care/post-exposure-prophylaxis.html
- Maryland Department of Health, laboratory-confirmed animal rabies, 2023: https://health.maryland.gov/phpa/OIDEOR/CZVBD/Shared%20Documents/Laboratory%20Confirmed_jurisdiction_species_2023.pdf
Licence: CC0 1.0 (public domain) · Adapted from www.cdc.gov
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