The Massachusetts Department of Public Health on May 18 confirmed a single case of monkeypox virus infection in a man who had recently traveled to Canada.
Massachusetts health authorities said Wednesday that they confirmed a case of
a rare and sometimes serious viral illness called monkeypox — the first
infection identified in the United States this year amid a rash of cases
outside the disease’s typical territory.
Monkeypox, which can be passed to animals and humans, is usually found in
Central and West Africa. But health authorities in Europe have confirmed more
than a dozen cases this month and are investigating dozens more. Some
infections confirmed in the United Kingdom “have no travel links” to a place
where monkeypox is regularly found, officials said, suggesting the virus may
be spreading through the community.
Monkeypox is not known to spread easily between humans. The fact that cases
are emerging in several countries at once — with signs of “sustained”
transmission in people — is striking, said Aris Katzourakis, a professor of
evolution and genomics at the University of Oxford.
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 Congo during a period of intensified effort to
eliminate smallpox. Since then monkeypox has been reported in humans in other
central and western African countries.
Signs and symptoms
In humans, the symptoms of monkeypox are similar to but milder than the
symptoms of smallpox. Monkeypox begins with fever, headache, muscle aches, and
exhaustion. The main difference between symptoms of smallpox and monkeypox is
that monkeypox causes lymph nodes to swell (lymphadenopathy) while smallpox
does not. The incubation period (time from infection to symptoms) for
monkeypox is usually 7−14 days but can range from 5−21 days.
The illness begins with:
• Fever
• Headache
• Muscle aches
• Backache
• Swollen lymph nodes
• Chills
• Exhaustion
Within 1 to 3 days (sometimes longer) after the appearance of fever, the
patient develops a rash, often beginning on the face then spreading to other
parts of the body.
Lesions progress through the following stages before falling off:
• Macules
• Papules
• Vesicles
• Pustules
• Scabs
The illness typically lasts for 2−4 weeks. In Africa, monkeypox has been shown
to cause death in as many as 1 in 10 persons who contract the disease.
Transmission
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 (even if not visible), respiratory
tract, or the 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 through 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 methods of transmission
include direct contact with body fluids or lesion material, and indirect
contact with lesion material, such as through contaminated clothing or linens.
The reservoir host (main disease carrier) of monkeypox is still unknown
although African rodents are suspected to play a part in transmission. The
virus that causes monkeypox has only been recovered (isolated) twice from an
animal in nature. In the first instance (1985), the virus was recovered from
an apparently ill African rodent (rope squirrel) in the Equateur Region of the
Democratic Republic of Congo. In the second (2012), the virus was recovered
from a dead infant mangabey found in the Tai National Park, Cote d’Ivoire.
Treatments
Currently, there is no proven, safe treatment for monkeypox virus infection.
For purposes of controlling a monkeypox outbreak in the United States,
smallpox vaccine, antivirals, and vaccinia immune globulin (VIG) can be used.
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