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Monkeypox is a rare viral disease that occurs mainly in the rain forest
countries of central and west Africa. The disease was first discovered
in laboratory monkeys in 1958. Blood tests of animals in Africa later
found evidence of monkeypox infection in a number of African rodents.
The virus that causes monkeypox was recovered from an African squirrel.
Laboratory studies showed that the virus 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.
is the cause of monkeypox?
Monkeypox is caused by Monkeypox virus, which belongs to
the orthopoxvirus group of viruses. Other orthopoxviruses that cause
infections in humans include variola (smallpox), vaccinia (used for
smallpox vaccine), and cowpox viruses.
are the clinical features of monkeypox?
In humans, monkeypox is similar to smallpox, although it is often
milder. Unlike smallpox, monkeypox causes lymph nodes to swell (lymphadenopathy).
The incubation period for monkeypox is about 12 days (range 7 to 17
days). 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
long does monkeypox last?
The illness typically lasts for 2 to 4 weeks.
Studies of human monkeypox in rural central and west Africa –
where people live in remote areas and are medically underserved –
have reported case-fatality ratios of 1% to 10%.
do people get monkeypox?
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. 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.
there a treatment or vaccine for monkeypox?
Currently, there is no proven, safe treatment for monkeypox. Smallpox
vaccine has been reported to reduce the risk of monkeypox among previously
vaccinated persons in Africa. CDC is recommending that persons investigating
monkeypox outbreaks and involved in caring for infected individuals
or animals should receive a smallpox vaccination to protect against
monkeypox. Persons who have had close or intimate contact with individuals
or animals confirmed to have monkeypox should also be vaccinated.
These persons can be vaccinated up to 14 days after exposure. CDC
is not recommending preexposure vaccination for unexposed veterinarians,
veterinary staff, or animal control officers, unless such persons
are involved in field investigations. For more information about CDC
recommendations for the use of smallpox vaccine to protect against
monkeypox, see the Monkeypox
in the United States
has human monkeypox been reported in the United States?
For current information about the number of human monkeypox cases
under investigation in the United States, see the CDC
case count page. Check the CDC Web site for the monkeypox
case definition and other current information about the outbreak.
did these people become infected with monkeypox virus?
On the 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 also had contact
with other persons with monkeypox in a household setting. No cases
of monkeypox that could be attributed exclusively to person-to-person
contact have been confirmed.
evidence is there that monkeypox virus causes these illnesses?
The 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 one of the first patients and a prairie dog. Using
an electron microscope, they found that the virus had the size and
appearance of a poxvirus (see the electron microscopy images at http://research.marshfieldclinic.org/crc/prairiedog.asp).
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. Many of the reported cases have had laboratory
evidence of monkeypox virus. For current information about the number
of human monkeypox cases under investigation in the United States,
see the CDC case
monkeypox previously been reported in the United States?
No. Prior to the recent report of the disease in the United States,
community-acquired monkeypox had never been reported outside of Africa.
was monkeypox introduced in the United States?
Traceback investigations have implicated a shipment of animals from
Ghana that was imported to Texas on April 9 as the probable source
of introduction of monkeypox virus into the United States. The shipment
contained approximately 800 small mammals of nine different species,
including six genera of African rodents. These rodents included rope
squirrels (Funiscuirus sp.), tree squirrels (Heliosciurus
sp.), Gambian giant rats (Cricetomys sp.), brush-tailed
porcupines (Atherurus sp.), dormice (Graphiurus sp.),
and striped mice (Hybomys sp.).
rats from this shipment were kept in close proximity to prairie dogs
at an Illinois animal vendor implicated in the sale of infected prairie
dogs. CDC laboratory testing of some animals by using PCR and virus
isolation demonstrated that one Gambian giant rat, three dormice,
and two rope squirrels from the April 9 importation were infected
with monkeypox virus. Evaluation of other animals associated with
the shipment is ongoing. Evidence of infection was found in some animals
that had been separated from the rest of the shipment on the day of
their arrival into the United States, indicating early and possibly
widespread infection among the remaining animals in the shipment.
The laboratory investigation confirmed that multiple animal species
are susceptible to infection with monkeypox virus.
should people do if they think they have been exposed to an animal
or person with monkeypox?
Persons 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.
I have monkeypox?
It appears that most people who are ill with monkeypox in the United
States got sick after close contact with infected prairie dogs that
had been purchased as pets. Some patients may have been infected through
contact with other infected animals. If you have not had close contact
with a wild or exotic animal, then the risk that you might have monkeypox
if very low.
measures have been taken to control the outbreak?
CDC and the public health departments in the affected states, together
with the US Department of Agriculture, the Food and Drug Administration,
and other agencies, are participating in a variety of activities to
prevent further spread of monkeypox and identify the source of the
outbreak. To assist with the investigation and outbreak response,
CDC has taken the following steps:
its Emergency Operations Center.
teams of medical officers, epidemiologists, and other experts to
several states to assist with the investigation.
extensive laboratory testing on specimens from humans and animals
thought to have been exposed to monkeypox.
interim U.S. case definitions for human monkeypox and for animal
interim guidelines on infection control and exposure management
for patients in the health care and community settings.
an immediate embargo and prohibition on the importation, interstate
transportation, sale, and release into the environment of certain
rodents and prairie dogs.
ongoing assistance to state and local health departments in investigating
possible cases of monkeypox in both humans and animals the United
with state and federal agencies to trace the origin and distribution
of potentially infected animals.
an interim guidance on the use of smallpox vaccine, cidofovir,
and vaccinia immune globulin in the setting of an outbreak of monkeypox.
interim guidelines for veterinarians.
interim guidance for persons who have frequent contact with animals,
including pet owners, pet shop employees, animal handlers, and
animal control officers.
information will be posted on CDC’s Web
site as it becomes available.
is monkeypox spread from animals to humans?
People can get monkeypox from an infected animal if they are bitten
or touch the animal’s blood, body fluids, or its rash. It is
possible that the virus also might be spread through contact with
respiratory droplets from an infected animal during close contact
or with objects (for example, the animal’s bedding) contaminated
with the virus.
kinds of animals can get monkeypox?
There is not enough information to determine all the types of animals
that may become ill with monkeypox. Until more is known about this
disease, it should be assumed that any mammal – including common
household pets (e.g., dogs, cats) and “pocket pets” (e.g.,
hamsters or gerbils) – could get monkeypox if exposed to another
animal that is infected.
are the signs of monkeypox in animals?
In the current U.S. outbreak, illness in animals has been reported
to include fever, cough, discharge from the eyes, and enlarged lymph
nodes, followed by a bumpy or blister-like rash. Pets that have monkeypox
also may appear to be very tired and may not be eating or drinking.
It is possible that some animals may have only minimal signs of illness.
Some animals have died and others have recovered.
my pet get the smallpox vaccine to protect it from monkeypox?
No, smallpox vaccination is not recommended for pets.
should I do if I think my pet might have monkeypox?
If your pet could have been exposed to a sick animal and is showing
the symptoms of monkeypox, follow these instructions:
the animal from people and other animals immediately. Lock it in
a room or put it in a cage or cardboard box well apart from others,
such as in the garage.
your hands well with soap and hot water after contact with the
animal and any object that may be contaminated with virus.
should be changed after feeding or caring for the animal. Laundry
(e.g., towels, clothing) may be washed in a standard washing machine
with hot water and detergent. The use of chlorine bleach during
hot water washing can provide an added measure of safety. Care
should be used when handling soiled laundry to avoid direct contact
with contaminated material. Soiled laundry should not be shaken
or moved around a lot. Infectious particles could be spread and
your state or local health department that you think you have a
pet with monkeypox. The health department may pick up the animal,
or they may tell you to take the animal to a vet.
not release your pet into the wild. If
it is infected, this could spread the disease to other animals
not leave your pet at a shelter. Again,
this could spread the disease.
not take your pet to a vet without calling
first. The vet must take precautions to receive your pet.
my pet has monkeypox, what will happen to it?
If your vet determines that your pet has monkeypox, he or she will
probably recommend that the animal be humanely euthanized to prevent
further spread of this disease. This decision may be difficult for
you, but it is the best step for the safety of family, friends and
community. If monkeypox were to establish itself in the United States,
many animals and people could become ill.
and Prohibition of Certain Rodents and Prairie Dogs
action have CDC and FDA taken?
On June 11, 2003, CDC and FDA issued a joint order announcing an immediate
embargo on the importation of all rodents from Africa due to the potential
that these rodents can spread monkeypox virus infection to other animal
species and to humans. The joint order also banned within the United
States any sale, offering for distribution, transport, or release
into the environment, of prairie dogs and six specific genera of African
rodents implicated in the current monkeypox outbreak. On November
4, 2003, the joint order was replaced by an interim final rule which
maintains the bans on importation of African rodents and the sale,
distribution, transport, and release into the environment as previously
animals are subject to the interim final rule?
The interim final rule prohibits the importation of all rodents from
Africa. In addition, prairie dogs and the following types of rodents
from Africa may not be distributed, sold, transported, or released
into the environment within the United States: tree squirrels (Heliosciurus
sp.), rope squirrels (Funisciurus sp.), dormice (Graphiurus
sp.), Gambian giant pouched rats (Cricetomys sp.), brush-tailed
porcupines (Atherurus sp.), and striped mice (Hybomys
sp.). The interim final rule applies to animals that are living
the rule apply to African rodents that do not come directly from Africa?
Yes, the rule covers any rodents that were caught in Africa and then
shipped directly to the United States or shipped to other countries
before being imported to the United States. The prohibition also applies
to rodents whose native habitat is in Africa, even if those rodents
were born elsewhere. A broad import ban on African rodents is necessary
because there is no quick, practical method for determining whether
a specific animal was born in a particular geographic region.
the rule apply to dead animals and animal products?
Yes, the monkeypox virus can remain infectious in bushmeat (a term
used to describe meat obtained from animals taken in the wild or the
"bush") and CDC is unaware of data demonstrating the safety of raw
or even prepared bushmeat. Preparation methods such as smoking, salting,
or brining bushmeat may slow down bushmeat's decay, but may not render
bushmeat free of infectious agents. Therefore, CDC's rule applies
to live and dead African rodents and also to products derived from
there any exceptions to the rule?
Yes, the rule recognizes that there are limited circumstances warranting
exemptions from some prohibitions, such as the need to transport an
animal for scientific, exhibition, or educational purposes. Consequently,
under the CDC rule, an individual may seek written permission from
CDC to import any rodents that were obtained, directly or indirectly,
from Africa, or whose native habitat is Africa, or any other kind
of animal whose importation the Director has prohibited by order.
The interim final rule describes the procedures for seeking written
permission from CDC and the information that should be submitted with
any request and also states that the request must be limited to scientific,
exhibition (such as exhibition of an animal at a zoo), or educational
purposes. CDC will respond, in writing, to all requests.
there any exceptions for processed products, such as taxidermied animals
or animal trophies?
Yes, some individuals have asked whether they could import taxidermied
animals or animal trophies, while other questions have involved products
derived from animals, such as brushes that use animal hair and animal
skins. If these products are properly processed to render them non-infectious,
they pose no disease risk. Such processes would include: (1) inactivation
by Heat (heated to an internal temperature of 70°C or placed in
boiling water for a minimum of 30 minutes); (2) preservation in 2%
formaldehyde; chemically treating in acidic or alkaline solutions
(soaking in a solution below pH 3.0 or above pH 11.5 for 24 hours);
or (3) the use of hypertonic salt. Products derived from African rodents,
if treated using one of these methods, are not subject to the import
prohibition at § 71.56(a)(1) and may be imported without written permission
from CDC. Similarly, fully taxidermied African rodents and completely
finished trophies present no disease risk and therefore may be imported
without written permission from CDC.
I take my animal to the veterinarian or animal control as directed
by my state or local health department?
Individuals may transport prairie dogs and the six specified genera
of rodents from Africa to veterinarians or animal control officials
or other entities pursuant to guidance or instructions issued by Federal,
state, or local government authorities. All other transports, distributions,
or sales within the United States of prairie dogs and the six specified
genera of rodents from Africa are prohibited, , unless written permission
is obtained from the FDA.
I release my prairie dog or one of the specified rodents from Africa
into the wild?
No, under no circumstances may individuals release prairie dogs or
one of the specified genera of rodents from Africa into the wild or
any other public or private environment. This prohibition includes
the wilderness, as well as any public or private lands, parks, prairies,
or sanctuaries. Individuals who are apprehensive about retaining these
animals should contact their state animal control office for information
regarding appropriate disposition.
I take my prairie dog or one of the specified rodents from Africa
to a pet “swap meet” (pets for sale or exchange)?
No, individuals may not transport, sell, distribute, or offer for
sale or distribution, prairie dogs and the six specified genera of
rodents from Africa at pet “swap meets.”
I take my prairie dog or one of the specified rodents from Africa
to a school "show and tell" or to a friend's house?
No. CDC and FDA have issued a joint order banning the transport of
prairie dogs and six other types of animals, including tree squirrels,
rope squirrels, dormice, Gambian giant pouched rats, brush-tailed
porcupines, and striped mice. This ban includes all transport of any
of these animals, even if the animal is healthy or acquired before
April 15, 2003.
have a prairie dog, or one of the animals listed above, you can take
it to the veterinarian or to animal control as instructed by your
state or local health department. No other transport is allowed. Nor
is the distribution, or sale of these animals allowed within the United
who violate the joint order may be subject to criminal and/or civil
is HHS' authority for taking this action?
Section 361 of the Public Health Service Act (PHS Act) (42 U.S.C.
264) serves as the principal legal authority for both the CDC and
FDA Rules. Section 361 of the PHS Act gives the Secretary of Health
and Human Services the authority to make and enforce regulations to
prevent the introduction, transmission, and spread of communicable
diseases from foreign countries into the United States or from one
State to another State. CDC's portion of the rule focuses on imported
animals while FDA's portion focuses on animals moving between and
does this action affect the role of state and local health departments?
In order to implement and enforce the joint order, CDC, FDA, and other
involved federal agencies will work collaboratively with state and
local veterinary, agriculture, and public health authorities. HHS
has authority to assist state and local authorities in the prevention
and suppression of communicable diseases and to accept state and local
assistance in the enforcement of federal communicable disease control
regulations. In addition, the interim final rule does not supercede
any action that may be lawfully undertaken by state or local authorities
except to the extent that any such state or local action conflicts
with the interim final rule. Some states involved in the outbreak,
such as Wisconsin and Illinois, have already taken regulatory action.
We expect that other states and local jurisdictions may do likewise.
will enforce the provisions of the order?
A number of federal agencies have authorities related to the animals
involved. FDA will work with the Department of Agriculture, State
and local health authorities, and CDC to make sure that people who
trade in prairie dogs and the listed rodent species as well as other
people who may own these animals are aware of the ban and follow it.
CDC and FDA will work with other appropriate federal agencies, such
as the Bureau of Customs and Border Protection of the Department of
Homeland Security, and the United States Fish and Wildlife Service
of the Department of Interior, who have statutory responsibility for
enforcing the importation embargos.
are the consequences of violating the joint order?
CDC and FDA are most concerned with bringing individuals into compliance
with the joint order as a means of preventing the spread of monkeypox
virus infection to humans and other animals. However, individuals
who violate the joint order may be subject to criminal and/or civil