Earlier this week, a California man was confirmed to have contracted the plague, the 5th case of the infamous disease in the US this year.The man from South Lake Tahoe resident, was the California’s first case of plague in 5 years, according to the health department of El Dorado County. Colorado also saw its 1st case in 5 years in July, when a southwestern region resident, who has since then recovered, was infected, according to Colorado Department of Public Health and Environment. In late July, a case was documented in Arizone by Navajo County public health officials. Also two cases were reported this year in New Mexico, including a man who died.
Such reports on plague may sound scary, but the experts say that bacterial infection is not something to worry about.
A professor of ecology, evolution and behavior, Susan Jones at the University of Minnesota College of Biological Sciences said,“Bubonic plague in the U.S. is not the same scenario as the historical Black Death, and we do not need to be afraid of it in the same way,”.
Although tragic, the cases this year aren’t unusual, she informed.
The average rate of cases in United States has reported seven human cases of plague every year, as per the Centers for Disease Control and Prevention. Cases reached a high of 17 in 2006.
Jones said, Whether there are more yearly cases than average can depend on what’s going on in rodents. Plague is caused by bacteria called Yersinia pestis, which are carried by fleas that live on rodents including prairie dogs and squirrels. Humans are more likely to become infected with plague when there is an outbreak of the bacterial infection in local wild rodent populations.
“Plague waxes and wanes in the rodents. When a lot of rodents are infected and dying, plague can more easily spill over into nearby humans,” she said. With just five human cases reported so far this year, the US is still well within the normal range, though fatalities are rare.
A spokesperson for the New Mexico Department of Health, Dave Morgan told NBC via email that, “It is unusual to have more than one plague-related death in the same year, and few cases result in death,”. Earlier when plague was caught and was treated with antibiotics, the chance of death declined to nearly 10 percent.
According to CDC, there had not been a plague fatality in United States since 2015, which had total number of 16 cases, four out of which resulted in deaths.
However, there is limited information about the death of the man in Rio Arriba County on the New Mexico-Colorado border, as health department of New Mexico reported that the case as septicemic plague, rather than the much more common bubonic plague.
According to the Mayo clinic, both septicemic plague and bubonic plague are caused by the same bacteria, these name refers to what part of the body is affected. Bubonic plague occurs when the symptoms causing large, swollen lymph nodes, called buboes. Septicemic plague is an infection in the blood and can be the first sign of infection or develop from untreated bubonic plague. Neither is contagious, said CDC.
The third form of plague, pneumonic plague only can be spread from person to person. It occurs when the infection gets into the lungs, either through untreated bubonic or septicemic plague, or from inhaling infected droplets of another person. It is the most serious form of the disease, says CDC.
“Early diagnosis is very important,” said Jones, also added that in some parts of the U.S. where plague is common, “physicians and veterinarians are on alert for symptoms of plague.”
She stated that various symptoms of plague including fever, chills and headache, can be confused with other illnesses also. However, every year, epidemiologists develops maps to track the reports on plague in rodents in the western US. If a person has spent time outdoors in these areas and found to have these symptoms, doctors may consider it as plague.
The majority of the plague cases occurred in the Arizona, Colorado, New Mexico and Utah where Four Corners area meet, while plague is identified in rodents across the West. According to Jones, this is due to the squirrels and prairie dogs that live in these areas and the harbor plague carrying fleas. These fleas can make their way to humans just by latching onto pets that roam in rural areas.
Susan Jones said, “When you are outdoors in areas known to harbor plague, do not touch any wild rodents or rabbits. Don’t let your pets roam around. Apply flea control to pets, and repellent to yourself if you are walking or camping in the wilderness. Stay away from areas that harbor rodents, such as prairie dog towns, hay bale storage and wood piles,”. “And if you are concerned that you or your pet may have been exposed to plague, contact your physician and your veterinarian.”