A child in Elmore County, Idaho, is in recovery after the contracting an infection of the Yersinia pestis bacteria – a disease so infamous that it is simply called the plague; though you may know it from its other memorable title, the Black Death.
The announcement, issued by the state’s Central District Health Department (CDHD), marks the first confirmed case of plague in Idaho in 26 years.
Having evolved to live inside rodents, Yersinia pestis is primarily transmitted to new hosts – including us humans – via flea bites. Because rats and mice have been following traveling humans to new settlements and civilizations for thousands of years, it was difficult to pinpoint where the bacteria first arose until DNA sequencing came onto the scene. We now know that the microbe is native to the mountainous steppe region of central Asia, yet is currently circulating, at various levels, in rodent populations across the world.
One of the more significant plague reservoirs is the western United States, which is why many parks in this region post signs warning visitors to keep their distance from wild rodents and to wear protective clothing and/or insect repellent. But despite its lurking presence, the number of human infections reported annually in the US is very low – only about 1 to 17 for the past several decades, according to the Centers for Disease Control and Prevention.
Per the Idaho CDHD press release, the unnamed child had taken a recent trip to Oregon. Because the infection can incubate for a few days, it is impossible to determine where he or she came into contact with a Y. pestis-carrying flea. Since 1990, there have been eight confirmed cases in Oregon and two in Idaho.
Christine Myron, the CDHD spokesperson, told the Washington Post that the child became ill late last month, and was treated with antibiotics at an Elmore area hospital. Earlier this week, laboratory test results came back that confirmed it was a case of bubonic plague – the most common of the three forms of the disease.
Bubonic plague occurs when Y. pestis introduced into the body travels through lymphatic vessels to a lymph node, where it employs multiple devious tricks to evade the immune system while rapidly replicating. As it accumulates in the lymph node, the bacterium secretes toxic chemicals that induce the symptoms of fever, weakness, and headache. Eventually, nearby tissue begins to die off, leading to the characteristic swollen, blue-black lymph nodes called “buboes”.
If quickly treated with antibiotics, most cases of bubonic plague will resolve. If it goes too long without intervention, however, the infection can progress to the bloodstream, turning into the far more lethal septicemic form.
To protect yourself and your pets (who can also get sick or pass it on to you) against exposure to Y. pestis, the CDHD recommends:
- Don’t touch or handle wild rodents or their carcasses
- Keep your pets from roaming and hunting rodents
- Use a veterinarian approved flea control product on your cats and dogs
- Don’t feed rodents in campgrounds, picnic areas, or near your home
- Prevent rodents from coming near your home by removing accessible food sources and nest locations, such as pet food or wood piles
- If you find a group of dead ground squirrels, report it to that state’s Department of Fish and Game