Colorado health officials are currently investigating a suspected case of the plague in a human, underscoring the attention on this rare bacterial infection with a historical reputation for causing devastating pandemics. Despite its historical significance, the plague is now effectively treatable with antibiotics.

The Centers for Disease Control and Prevention (CDC) estimates that approximately seven human cases of the plague are reported each year in the United States. Earlier this year, Oregon officials documented a case in a person likely infected by their sick cat, highlighting potential transmission sources.

Understanding the Plague:

The plague presents primarily in three forms: bubonic, septicemic, and pneumonic. Bubonic plague, identified by painful, swollen lymph nodes called buboes, is the most common form. Without treatment, it can progress into septicemic plague (widespread infection) and pneumonic plague (lung infection), the most lethal form.

Symptoms include sudden high fever, chills, severe headaches, and pain in the abdomen, legs, and arms. Early diagnosis and treatment are critical to prevent progression and life-threatening complications, according to experts from the Cleveland Clinic.

Transmission and Prevention:

Yersinia pestis, the plague bacterium, typically spreads through bites of infected fleas, which transmit the infection among rodents, pets, and humans. Transmission can also occur through direct contact with infected bodily fluids or respiratory droplets from individuals with pneumonic plague.

Health experts advise avoiding contact with sick or deceased animals, especially rodents, and ensuring pets receive regular flea treatments. When in areas endemic to plague, using insect repellents containing DEET helps prevent flea bites and reduces infection risk.

Global and Domestic Presence:

In the U.S., plague cases primarily occur in rural regions of northern New Mexico, northern Arizona, southern Colorado, California, southern Oregon, and far western Nevada, as reported by the CDC. Globally, the disease remains endemic in countries such as the Democratic Republic of the Congo, Madagascar, and Peru, according to the World Health Organization (WHO).

Treatment and Vaccination:

While no specific plague vaccine is available in the U.S. for the general population, WHO recommends vaccination for high-risk groups like laboratory workers and healthcare professionals. Prompt treatment with antibiotics such as streptomycin or gentamicin effectively cures the plague if administered early after symptom onset.

Dr. Lisa Morici, a microbiologist and immunologist from Tulane University School of Medicine, stressed the urgency of early medical intervention, citing pneumonic plague’s nearly 100% fatality rate if untreated. She highlighted ongoing uncertainties regarding vaccine efficacy against pneumonic plague, underscoring the need for further research.

Challenges in Vaccine Development:

Morici identified ethical and logistical challenges in conducting clinical trials for a plague vaccine, particularly due to the rarity of bubonic plague and its responsiveness to antibiotics. Despite these obstacles, she emphasized the importance of advancing vaccine research to protect against all plague forms, particularly in endemic regions.

As Colorado health officials continue investigating the suspected plague case, the incident emphasizes the importance of robust public health measures and ongoing vigilance against infectious diseases like the plague.