*Monkeypox facts written by Melissa Conrad Stöppler, MD
- Monkeypox is a rare disease that occurs primarily in the rainforest
countries of Central and West Africa.
- Monkeypox is similar to smallpox, and the monkeypox virus causes monkeypox.
- Health researchers have identified the viral infection in
laboratory monkeys, African tree squirrels, mice, rats, and rabbits.
can spread to humans. Early symptoms include fever, headache, muscle
aches, backache, swollen lymph nodes, a general feeling of discomfort, and
- Later symptoms occur one to three days or more after the appearance of fever and include a rash with raised bumps, often first developing on the face.
Monkeypox can spread to humans from an infected animal through an animal bite or
direct contact with the animal's lesions or bodily fluids.
- The disease can spread from person to person, although it is not as contagious as smallpox.
Monkeypox can be fatal in up to 10% of cases.
- There is currently no available
treatment for monkeypox.
Monkeypox Symptoms and Signs
The first symptoms that occur are nonspecific -- fever, sweating, malaise, and some patients may develop a cough, nausea, and shortness of breath. About two to four days after fever develops, a rash with papules and pustules develops most often on the face and chest, but other body areas may eventually be affected, including mucus membranes inside the nose and mouth. These skin and mucus membrane pox lesions can ulcerate, crust over, and then begin to heal in about 14-21 days. In addition, lymph nodes usually swell during this time. Some pox lesions may become necrotic and destroy sebaceous glands, leaving a depression or pox scar that, with monkeypox, may gradually become less pronounced over a few years. The toxemia that was seen with smallpox is not seen with monkeypox.
What is monkeypox?
is a rare smallpox-like disease that occurs primarily in the rain forest
countries of central and west Africa. The disease was discovered in
laboratory monkeys in 1958. Studies of animals in Africa later found
evidence of orthopoxvirus infection in a number of African rodents. The
virus has been isolated from an African tree squirrel, which may be the
natural host. Laboratory studies showed that monkeypox also could infect
mice, rats, and rabbits. In 1970, monkeypox was reported in humans for the
first time. In June 2003, monkeypox was reported in prairie dogs and
humans in the United States.
What is the cause of monkeypox?
is caused by Monkeypox virus, which belongs to the orthopoxvirus
group of viruses. Other members of this group of viruses that cause
infections in humans include variola (smallpox), vaccinia (used for
smallpox vaccine), and cowpox viruses.
What are the clinical features of monkeypox?
monkeypox is similar to smallpox, except that enlargement of lymph nodes
(lymphadenopathy) is associated with monkeypox. About 12 days after
exposure, the illness begins with fever, headache, muscle aches, backache,
swollen lymph nodes, a general feeling of discomfort, and exhaustion.
Within 1 to 3 days (sometimes longer) after the appearance of fever, the
patient develops a papular rash (i.e., raised bumps), often first on the
face but sometimes initially on other parts of the body. The lesions
usually develop through several stages before crusting and falling off.
How long does monkeypox last?
illness typically lasts for 2 to 4 weeks.
Is monkeypox fatal?
human monkeypox in rural central and west Africa - where people live in
remote areas and are medically underserved - have reported case-fatality
ratios of as high as 10%.
How do people get monkeypox?
can spread to humans from an infected animal through an animal bite or
direct contact with the animal's lesions or body fluids. The disease
also can be spread from person to person, although it is much less
infectious than smallpox. In human transmission, the virus is thought to
be transmitted by respiratory droplets during direct and prolonged
face-to-face contact. In addition, it is possible monkeypox can be spread
by direct contact with body fluids of an infected person or with
virus-contaminated objects, such as bedding or clothing.
Is there a treatment for monkeypox?
no treatment is available for monkeypox. Smallpox vaccine has been
reported to reduce the risk of monkeypox among previously vaccinated
persons in Africa. CDC is assessing the potential role of postexposure use
of smallpox vaccine as well as therapeutic use of the antiviral drug
Monkeypox in the United States
Where has human monkeypox been reported in the United States?
As of June
9, a total of 33 persons with suspected monkeypox had been reported in
Wisconsin (18), Illinois (10), and Indiana (5). Monkeypox had been
confirmed by laboratory tests in four persons. Seven of the people with
suspected monkeypox had been hospitalized for their illness; there have
been no deaths related to the outbreak. The number of cases and states
involved in the outbreak will likely change as the investigation
continues. For recent information on cases, please see the
Monkeypox Information Update Center.
How did these people become infected with monkeypox virus?
basis of preliminary investigations, it appears that most of the patients
became ill after having close contact with infected prairie dogs that had
been purchased as pets. Some patients may have been infected though
contact with other infected animals, including a Gambian giant rat
(purchased as an exotic pet) and a rabbit. In addition, the possibility of
human-to-human transmission in some cases cannot be excluded at this time.
What evidence is there that monkeypox virus causes these illnesses?
clinical features of the illness in U.S. patients - fever, headache,
muscle aches, and rash - are consistent with those of monkeypox. There
is also strong laboratory evidence of monkeypox. Scientists at the
Marshfield Clinic in Marshfield, Wisconsin, recovered viral isolates from
a patient and a prairie dog. Using an electron microscope, they found that
the virus had the size and appearance of a poxvirus. Laboratory tests at CDC - including
several PCR-based assays, serologic tests, electron microscopy,
immunohistochemistry, and gene sequencing - confirmed these results and
showed that the virus is Monkeypox virus.
Has monkeypox previously been reported in the United States?
to the recent report of the disease in the United States,
community-acquired monkeypox had never been reported outside of Africa.
How was monkeypox introduced in the United States?
not enough information to determine with certainty how monkeypox arrived
in the United States. One hypothesis is that the prairie dogs contracted
the virus from infected Gambian giant rats, which were housed in the same
animal-holding facility or pet shop as the prairie dogs. The Gambian giant
rats were likely imported into the United States from Africa. Studies have
shown that Gambian rats and other rodents in Africa have evidence of
monkeypox virus infection.
What should people do if they think they have been exposed to an animal or
person with monkeypox?
who think they may have been exposed to a person or an animal (e.g., pet
prairie dog) with monkeypox should contact their health care provider and
their state or local health department.
What measures are being taken to control the outbreak?
the public health departments in the affected states, together with the US
Department of Agriculture and other agencies, are participating in a
variety of activities to prevent further spread of monkeypox and identify
the source of the outbreak. CDC has recommended a number of interim
prevention and infection-control measures.
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This information has been provided with the kind permission of Centers for
Disease Control and Prevention (http://www.cdc.gov/). June 10, 2003.