US CDC Lowers Annual Plague Estimate to Five Cases

By Staff, Agencies

The US Centers for Disease Control and Prevention (CDC) has revised its estimate of annual human plague infections in the United States, lowering the figure from seven to five cases per year.

The CDC updated its Plague Maps and Statistics page on Wednesday, stating that an average of five human plague cases are reported annually in the US.

The previous version, dated March 2025, cited seven cases, although the agency’s own yearly data showed an average of approximately five. The CDC has not explained the reason for the revision.

Current CDC data show 131 plague cases were recorded across the US between 2000 and 2025, including 17 deaths.

The highest annual totals were recorded in 2006, with 17 cases, and 2015, with 16 cases. Four people died in 2015, the highest annual death toll during that period.

The earlier estimate of seven cases may have been based on a different period. A CDC study published in April 2026 found 196 human plague cases between 1991 and 2018, an average of seven cases per year.

According to the CDC, plague first reached the US in 1900 aboard rat-infested steamships and subsequently caused outbreaks in port cities.

Since the last urban epidemic in Los Angeles in 1924–1925, cases have largely been reported in rural western states, particularly New Mexico, Arizona and Colorado, as well as parts of California, Oregon and Nevada.

The disease is caused by the Yersinia pestis bacterium, which circulates among rodents and fleas. More than 80% of US cases are bubonic plague, which generally does not spread directly between people.

Pneumonic plague, which affects the lungs, can spread through respiratory droplets following close contact.

At least two additional US cases were recorded in 2026, according to provisional CDC data. One patient in Arizona recovered after treatment, while a woman in New Mexico died in June. Early diagnosis and antibiotic treatment are critical, as untreated plague can rapidly become fatal.

The CDC update comes amid international attention over the reported death of a laboratory worker in Russia’s Irkutsk Region.

Russian authorities said extensive testing found no evidence linking her death to pathogens handled at her workplace and maintained that there was no epidemic risk. Kremlin spokesman Dmitry Peskov also said most media reports about the incident were “false information.”

Rospotrebnadzor separately offered the US assistance in responding to infectious disease outbreaks, citing Russia’s epidemiological expertise and offering specialists, laboratory equipment and diagnostic and preventive tools.