Credit CDC
#16,193
Plague in the United States is rare, but it isn't unheard of, at least in states west of the Mississippi (see map below). The last major urban outbreak of plague in the United States occurred in 1924-25 in Los Angeles. Since then, only scattered cases have been reported, with about 7-15 cases each year in the U.S..
Most of the world's plague activity today is in Africa, Asia, and South America. Madagascar is currently dealing with what has become an almost yearly resurgence of Bubonic and Pneumonic Plague. The WHO reports:
On 31 August 2021, the preliminary results of the investigation showed a total of 30 suspected cases of pulmonary plague, including seven deaths (four community deaths and three health facility-based), giving a case fatality ratio of 23%. Twenty laboratory samples (12 blood and eight sputum) were collected and sent to the Pasteur Institute of Madagascar for analysis. Of these 20 samples, 12 (60%) were PCR positive, confirming the outbreak of pneumonic plague in the country.
Two months ago, in Colorado Health Department: Plague Activity Alert, we learned of the death of a 10 y.o. boy in La Plata County, Colorado from Bubonic plague. Plague - which is caused by the bacteria Yersinia pestis - is treatable by antibiotics if caught early enough, so deaths in the United States are rare.
Plague can present in three forms: bubonic, septicemic and pneumonic. If untreated, bubonic plague can evolve to a more transmissible pneumonic plague.
- Bubonic Plague (Yersinia Pestis) - carried by rats, squirrels, and other small rodents, and transmitted by fleas - sets up in the lymphatic system, resulting in the tell-tale buboes, or swollen lymph glands in the the groin, armpits, and neck.
- Less commonly Pneumonic Plague may develop, when the infected individual develops a severe pneumonia, with coughing and hemoptysis (expectoration of blood), which may spread the disease by droplets from human-to-human.
In the United States, 80% of cases are of the less worrisome Bubonic plague, and further transmission is rare. Today we have a report of an unusual case of Pneumonic Plague from Wyoming.
Wyoming Detects Rare Human Case of Pneumonic Plague
September 15, 2021
The Wyoming Department of Health (WDH) announced today the detection of a rare but serious case of pneumonic plague in a northern Fremont County resident.
Plague is a bacterial infection that can be deadly to humans and other mammals, including pets, if not treated promptly with antibiotics. This disease can be transmitted to humans from sick animals or by fleas coming from infected animals; in this case, the person had contact with sick pet cats.
Plague can also be transmitted from person to person through close contact with someone who has pneumonic plague. Individuals with a known exposure to plague require post-exposure treatment with antibiotics to help prevent illness. WDH is notifying individuals who may need this kind of treatment.
Plague symptoms depend on how the patient is exposed. The most common form is bubonic plague, where patients develop the sudden onset of fever, headache, chills, and weakness and one or more swollen, painful lymph nodes called buboes. This form usually results from the bite of an infected flea. Individuals with septicemic plague develop fever, chills, extreme weakness, abdominal pain, shock, and possible bleeding into the skin and other organs. Septicemic plague can occur as the first symptom of plague or may develop from untreated bubonic plague and can be caused by the bite of an infected flea or the handling of an infected animal. Individuals with pneumonic plague develop fever, headache, weakness, and a rapidly developing pneumonia with shortness of breath, chest pain, and sometimes watery or bloody mucous.
Pneumonic plague is the most serious form and is the only form that can be spread from person to person. Pneumonic plague can develop from inhaling infectious droplets or may develop from untreated bubonic or septicemic plague.
Dr. Alexia Harrist, state health officer and state epidemiologist with WDH, said while the risk for humans to contract plague is very low in Wyoming, the disease has been documented throughout the state in domestic and wild animals.
“It’s safe to assume that the risk for plague exists all around our state,” Harrist said. “While the disease is rare in humans, it is important for people to take precautions to reduce exposure and to seek prompt medical care if symptoms consistent with plague develop.”
To reduce the risk of plague, WDH recommends:This human plague case is the seventh thought to be acquired in Wyoming since 1978. Other recorded Wyoming cases include a 1978 out-of-state case acquired in Washakie County, a 1982 Laramie County case, a 1992 Sheridan County case that resulted in death, a 2000 Washakie County case, a 2004 out-of-state case acquired in Goshen County, and a 2008 out-of-state case acquired in Teton County.
- Reducing rodent habitats around the home, workplace, and recreational areas by removing brush, rock piles, junk, cluttered firewood, and possible rodent food supplies.
- Wear gloves if handling or skinning potentially infected animals to prevent contact between your skin and the plague bacteria.
- Use repellent if exposure to fleas is possible during activities such as camping, hiking, or working outdoors. Products containing DEET can be applied to the skin as well as clothing.
- Keep fleas off indoor and outdoor pets by applying flea control products. Animals that roam freely outdoors are more likely to come into contact with plague-infected animals or fleas.
- If pets become sick, seek care from a veterinarian as soon as possible.
- Do not allow dogs or cats that roam free to share beds with people.
Modern medicine, particularly the advent of effective antibiotics, makes plague far less fearsome than it once was, but Madagascar's recent epidemics, and a large 1994 India outbreak that infected more than 5,000 people (see WHO Summary), show that large urban outbreaks are still possible.
In 2019's CDC: The 8 Zoonotic Diseases Of Most Concern In The United States, we looked at a joint CDC, USDA, DOI report on the top (n=56) zoonotic diseases of national concern for the United States.
While Zoonotic Influenzas (avian, swine, etc.) were at the top of the list, Plague ranked 4th, and novel coronaviruses (MERS, SARS, etc.) ranked 5th.
I confess to having a particular interest in Plague, which stems from my working as a paramedic in Phoenix, Arizona where Bubonic plague cases are still occasionally found, and my reading – around the age of 11 – of James Leasor’s The Plague and The Fire which recounts two incredible years in London’s history (1665-1666) - which began with the Great plague, and ended with the Fire of London.
A fascinating read (if you can find a copy) for both history and epidemic aficionados.
