US: Confirmed monkeypox (mpox) cases reported in Chicago, Ill., through May

Event

Public health officials have reported elevated monkeypox (mpox) activity in Chicago, Illinois, with seven confirmed cases reported April 17-May 5. This is compared to one confirmed case reported Feb. 1-April 16. Health officials urge anyone who is at risk for mpox and has not been previously vaccinated to get vaccinated as soon as possible. As disease surveillance and contact tracing continue, officials will likely identify additional cases in the coming weeks. This report represents the most up-to-date information as of May 9.

Context

Human-to-human transmission occurs among people in close physical contact, with the increase in recent cases linked to sexual contact suggesting that the virus linked to the disease can be sexually transmitted. The current outbreak highlights the importance of vigilant safe sexual practices and suggests mpox can be transmitted while the infected person displays few or no symptoms; however, the risk is currently assessed as low for individuals not routinely engaging with multiple or anonymous sexual partners.

Mpox does not naturally occur in North America; most cases are reported in West and Central Africa, primarily in the DRC, Nigeria, and Cameroon, among individuals who report contact with wild primates or other mammals that may harbor the disease.

Mpox is caused by a virus belonging to the same family as the one that causes smallpox. However, mpox is not the same as smallpox and does not have the same capacity for rapid human-to-human transmission. Mpox is mainly transmitted to humans through direct contact with the bodily fluids of infected rodents or primates. Human-to-human transmission primarily occurs through close personal contact with an infected individual via respiratory droplets, direct contact with bodily fluids, or indirect contact with lesion material (e.g., contaminated clothing or bedding). Symptoms typically appear 6-16 days after exposure but can develop up to 21 days after exposure. Symptoms generally include fever, headache, muscle aches and backaches, swollen lymph nodes, chills, exhaustion, and a distinctive rash characterized by lesions that progress through several stages before falling off.

Advice

Practice basic health precautions, including frequent handwashing with soap and water, covering the nose and mouth when coughing, and avoiding obviously ill individuals. Avoid overcrowded areas such as nightclubs and consider using safe sexual practices such as physical barriers (condoms) in countries reporting mpox transmission. Seek medical attention if symptoms develop within two weeks of being in affected areas, especially if you have had one or more new sexual partners. Vaccines are available but limited.