Monkeypox, which can be passed to animals and humans, is usually found in Central and West Africa. As monkeypox cases rise in Europe and other parts of the globe, health authorities are expressing concern about the unusual uptick. As such, the Centers for Disease Control and Prevention (CDC) recently issued an alert urging doctors and state health departments in the United States to be vigilant.
Monkeypox is a rare disease caused by infection with the monkeypox virus. Monkeypox was first discovered in 1958 when two outbreaks of a pox-like disease occurred in colonies of monkeys kept for research, hence the name “monkeypox.”
The first human case of monkeypox was recorded in 1970 in the Democratic Republic of the Congo during an intensified effort to eliminate smallpox.
The main disease carrier of monkeypox remains unknown. However, African rodents and nonhuman primates (like monkeys) may harbor the virus and infect people.
Monkeypox cases in the United States are very rare. Monkeypox doesn’t occur naturally in the country, but there have been cases associated with international travel or imported animals from areas where the disease is more common.
CDC scientists are collaborating with the Massachusetts Department of Public Health to investigate a situation in which a U.S. resident tested positive for monkeypox on May 18 after returning to the U.S. from Canada.
The CDC is also tracking multiple clusters of monkeypox that have been reported in early to mid-May in several countries that don’t typically report monkeypox, including those in Europe and North America.
It’s not clear how people in those clusters were exposed to monkeypox. Health care providers in the United States are on alert for patients with rash illnesses consistent with monkeypox.
Signs and Symptoms
The symptoms of monkeypox are similar to but milder than the symptoms of smallpox. The main difference between the symptoms of smallpox and monkeypox is that monkeypox causes lymph nodes to swell while smallpox does not. The incubation period from infection to symptoms of monkeypox is usually seven to 14 days, but it can range from five to 21 days.
The illness begins with:
- Muscle aches
- Swollen lymph nodes
Within one to three days (or sometimes longer) after a fever begins, people may develop a rash starting on the face and then spreading to other body parts.
Lesions progress through the following stages before falling off:
The illness typically lasts for two to four weeks. In Africa, monkeypox has been shown to cause death in as many as 1 in 10 people who contract the disease.
Transmission of monkeypox virus occurs when a person comes into contact with the virus from an animal, human or materials contaminated with the virus. The virus enters the body through broken skin, the respiratory tract or mucous membranes (eyes, nose or mouth).
- Animal-to-human transmission may occur by bite or scratch, bush meat preparation, direct contact with body fluids or lesion material, or indirect contact with lesion material, such as contaminated bedding.
- Human-to-human transmission is thought to occur primarily through large respiratory droplets. Respiratory droplets generally cannot travel more than a few feet, so prolonged face-to-face contact is required. Other human-to-human transmission methods include direct contact with body fluids or lesion material and indirect contact with lesion material, such as contaminated clothing or linens.
The main disease carrier of monkeypox is still unknown, although African rodents are suspected of playing a part in transmission.
Several measures can be taken to prevent infection with the monkeypox virus:
- Avoid contact with animals that could harbor the virus (including animals that are sick or found dead in areas where monkeypox occurs).
- Avoid contact with any materials, such as bedding, that have been in contact with a sick
- Isolate infected patients from others who could be at risk for infection.
- Practice good hand hygiene—washing your hands with soap and water or using an alcohol-based hand sanitizer—after contact with infected animals or humans.
- Use personal protective equipment when caring for patients.
Currently, there is no proven, safe treatment for monkeypox virus infection.
To control a monkeypox outbreak in the United States, the smallpox vaccine, antiviral medications and vaccinia immune globulin (VIG) can be used. Learn more about the smallpox vaccine, antivirals and VIG treatments here.