The Centers for Disease Control and Prevention (CDC) on Wednesday confirmed a rare case of monkeypox in Massachusetts.
The case was discovered in a patient who had returned from a trip to Canada after CDC officials had expressed concerns about rising cases of monkeypox that appeared in the United Kingdom.
Most cases of monkeypox are contracted in central and west Africa, and U.S. health officials maintain that the risk to the general public from the disease is low.
Here are several things to know about the disease and the degree to which it does present a threat.
What is monkeypox?
Monkeypox, a type of orthopoxvirus, is a disease related to smallpox — or variola — though monkeypox is typically less severe.
It was first discovered in 1958 in monkeys that were being kept for research.
The virus was first found in humans in 1970 in the Democratic Republic of the Congo in a child located in a rural rainforest region where smallpox had since been eradicated, according to the World Health Organization (WHO).
The disease is typically only found in west and central African nations or in people who have frequently traveled to those regions.
Symptoms of monkeypox
Monkeypox typically presents seven to 14 days after exposure, and symptoms include fever, headache, muscle ache, backache, chills, exhaustion and swollen lymph nodes — which is the main distinguishing symptomatic factor between smallpox and monkeypox. Smallpox does not typically cause swollen lymph nodes.
One to three days after the onset of fever, patients develop a rash that typically begins on the face and then spreads to other areas of the body. The lesions then progress through different stages before falling off.
Monkeypox usually lasts two to four weeks, according to the CDC.
The disease can be fatal.
In Africa, the mortality rate is as high as 10 percent in those infected with the more severe Congo strain of monkeypox.
The West African strain, in contrast, has a fatality rate of about 1 percent.
Transmission of monkeypox
Monkeypox is typically transmitted by a person coming into contact with the virus via another person, animal or material that is contaminated with monkeypox viral matter, according to the CDC.
The virus can enter the body through contact with broken skin — even if the broken skin is not visible to the naked eye — the respiratory tract, or mucous membranes such as the eyes, nose and mouth.
In animal-to-human transmission, the virus can infect a person through a bite, contact with fluid from an infected animal or contact with the animal’s monkeypox lesions.
In human-to-human transmission, the disease is spread primarily through respiratory droplets; however, the CDC notes that usually large droplets are needed to spread the virus from one person to another, so prolonged face-to-face exposure is likely required to become infected with monkeypox.
Humans can also spread the disease through contaminating linens with which another person may come into contact.
The main host carrier of monkeypox, referred to as the disease reservoir, is not known for certain, but speculation has focused on it being initially spread by African rodents.
Treatment and prevention of monkeypox
There is no known specific treatment to target and effectively treat monkeypox. However, some antivirals, vaccines and vaccinia immune globulin can be used to try to treat the virus and manage symptoms.
First generation smallpox vaccinia vaccines have been shown to be 85 percent effective in preventing monkeypox, according to the WHO. Vaccination with smallpox in childhood is likely to prevent severe outcomes with monkeypox infection.
The original smallpox vaccine is not publicly available, but an updated smallpox and monkeypox vaccine was approved in 2019. It is not publicly available either, but it has been approved by the Food and Drug Administration.
Those in the U.S. who work in conditions where they may be exposed to monkeypox, or who are entering an area of high exposure risk, can receive the 2019 vaccinia vaccine, according to the CDC.
Reuters reports that the United Kingdom began offering health care workers and those exposed to monkeypox the smallpox vaccine Thursday amid the recent U.K. monkeypox outbreak.