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Monkeypox (also called mpox by the
WHO Who or WHO may refer to: * Who (pronoun), an interrogative or relative pronoun * Who?, one of the Five Ws in journalism * World Health Organization Arts and entertainment Fictional characters * Who, a creature in the Dr. Seuss book '' Horton He ...
) is an infectious
viral disease A viral disease (or viral infection) occurs when an organism's body is invaded by pathogenic viruses, and infectious virus particles (virions) attach to and enter susceptible cells. Structural Characteristics Basic structural characteristics, ...
that can occur in humans and some other animals. Symptoms include
fever Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...
,
swollen lymph nodes Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's Tissue (biology), tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels t ...
, and a
rash A rash is a change of the human skin which affects its color, appearance, or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, c ...
that forms blisters and then crusts over. The time from exposure to onset of symptoms ranges from five to twenty-one days. The duration of symptoms is typically two to four weeks. There may be mild symptoms, and it may occur without any symptoms being apparent. The classic presentation of fever and
muscle pains Myalgia (also called muscle pain and muscle ache in layman's terms) is the medical term for muscle pain. Myalgia is a symptom of many diseases. The most common cause of acute myalgia is the overuse of a muscle or group of muscles; another lik ...
, followed by swollen glands, with
lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classif ...
s all at the same stage, has not been found to be common to all outbreaks. Cases may be severe, especially in children, pregnant women or people with suppressed immune systems. The disease is caused by the
monkeypox virus ''Monkeypox virus'' (MPV, MPXV, or hMPXV) is a species of double-stranded DNA virus that causes monkeypox in humans and other mammals. Monkeypox virus is a zoonotic virus belonging to the ''orthopoxvirus'' genus, making it closely related to the ...
, a
zoonotic A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that has jumped from a non-human (usually a vertebrate) to a human. ...
virus in the genus ''
Orthopoxvirus ''Orthopoxvirus'' is a genus of viruses in the family ''Poxviridae'' and subfamily ''Chordopoxvirinae''. Vertebrates, including mammals and humans, and arthropods serve as natural hosts. There are 12 species in this genus. Diseases associated wi ...
''. The variola virus, the causative agent of
smallpox Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) c ...
, is also in this genus. Of the two types in humans, cladeII (formerly West African clade) causes a less severe disease than the Central African (Congo basin) type. It may spread from infected animals by handling infected meat or via bites or scratches. Human-to-human transmission can occur through exposure to infected body fluids or contaminated objects, by small droplets, and possibly through the airborne route. People can spread the virus from the onset of symptoms until all the lesions have scabbed and fallen off; with some evidence of spread for more than a week after lesions have crusted. Diagnosis can be confirmed by testing a lesion for the virus's DNA. There is no known cure. A study in 1988 found that the
smallpox vaccine The smallpox vaccine is the first vaccine to be developed against a contagious disease. In 1796, British physician Edward Jenner demonstrated that an infection with the relatively mild cowpox virus conferred immunity against the deadly smallpox ...
was around 85% protective in preventing infection in close contacts and in lessening the severity of the disease. A newer smallpox and monkeypox vaccine based on
modified vaccinia Ankara Modified vaccinia Ankara (MVA) is an attenuated (weakened) strain of the vaccinia virus. It is being used as a vaccine (called MVA-BN, brand names: Imvanex in the EU, Imvamune in Canada, and Jynneos in the US) against smallpox and monkeypox, havi ...
has been approved, but with limited availability. Other measures include regular hand washing and avoiding sick people and animals. Antiviral drugs,
cidofovir Cidofovir, brand name Vistide, is a topical or injectable antiviral medication primarily used as a treatment for cytomegalovirus (CMV) retinitis (an infection of the retina of the eye) in people with AIDS. Cidofovir was approved for medical u ...
and tecovirimat, vaccinia immune globulin and the
smallpox vaccine The smallpox vaccine is the first vaccine to be developed against a contagious disease. In 1796, British physician Edward Jenner demonstrated that an infection with the relatively mild cowpox virus conferred immunity against the deadly smallpox ...
may be used during outbreaks. The illness is usually mild and most of those infected will recover within a few weeks without treatment. Estimates of the risk of death vary from 1% to 10%, although few deaths as a consequence of monkeypox have been recorded since 2017. Several species of mammals are suspected to act as a natural reservoir of the virus. Although it was once thought to be uncommon in humans, the quantity and severity of outbreaks has significantly increased since the 1980s, possibly as a result of waning immunity since the stopping of routine smallpox vaccination. The first cases in humans were found in 1970 in the
Democratic Republic of the Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...
(DRC). There have been sporadic cases in Central and West Africa, and it is endemic in the DRC. The
2022 monkeypox outbreak An ongoing outbreak of monkeypox, a viral disease, was confirmed in May 2022. The initial cluster of cases was found in the United Kingdom, where the first case was detected in London on 6 May 2022 in a patient with a recent travel his ...
represents the first incidence of widespread
community transmission In medicine, public health, and biology, transmission is the passing of a pathogen causing communicable disease from an infected host individual or group to a particular individual or group, regardless of whether the other individual was previou ...
outside of Africa, which was initially identified in the
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...
in May 2022, with subsequent cases confirmed in at least 74 countries in all continents except Antarctica. On 23 July 2022, the
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of ...
(WHO) declared the outbreak a
Public Health Emergency of International Concern A public health emergency of international concern (PHEIC) is a formal declaration by the World Health Organization (WHO) of "an extraordinary event which is determined to constitute a public health risk to other States through the internatio ...
(PHEIC) with more tha
53,000 reported cases
in 75 countries and territories.


Signs and symptoms

It is possible for a person to be infected with monkeypox without showing any symptoms. Monkeypox symptoms tend to begin 5 to 21 days after infection, with early symptoms including headache,
muscle pains Myalgia (also called muscle pain and muscle ache in layman's terms) is the medical term for muscle pain. Myalgia is a symptom of many diseases. The most common cause of acute myalgia is the overuse of a muscle or group of muscles; another lik ...
,
fever Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...
and fatigue, initially resembling influenza. Within a few days of the fever, lesions characteristically appear on the face before appearing on the trunk then elsewhere such as palms of the hands and soles of the feet. The disease can resemble chickenpox, measles and
smallpox Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) c ...
but is distinguished by the presence of swollen glands which may appear behind the ear, below the jaw, in the neck or in the groin, before the onset of the rash. Many cases in the 2022 monkeypox outbreak presented with genital and peri-anal lesions, fever, swollen lymph nodes, and pain when swallowing, with some patients manifesting only single sores from the disease. Three-quarters of affected people have lesions on the palms and soles, more than two-thirds in the mouth, a third on the genitals and one in five have lesions in the eyes. They begin as small flat spots, before becoming small bumps which then fill with at first clear fluid and then yellow fluid, which subsequently burst and scab over, persisting for around ten days. There may be a few lesions or several thousand, sometimes merging to produce large lesions. After healing, the lesions may leave pale marks before becoming
dark Darkness, the direct opposite of lightness, is defined as a lack of illumination, an absence of visible light, or a surface that absorbs light, such as black or brown. Human vision is unable to distinguish colors in conditions of very low lu ...
scars. An unwell person may remain so for two to four weeks.


Complications

Complications include secondary infections,
pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severi ...
,
sepsis Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...
, encephalitis, and loss of vision with severe eye infection. If infection occurs during pregnancy,
still birth Stillbirth is typically defined as fetal death at or after 20 or 28 weeks of pregnancy, depending on the source. It results in a baby born without signs of life. A stillbirth can result in the feeling of guilt or grief in the mother. The term i ...
or birth defects may occur. The disease may be milder in people vaccinated against smallpox in childhood. Patel and colleagues, in
the BMJ ''The BMJ'' is a weekly peer-reviewed medical trade journal, published by the trade union the British Medical Association (BMA). ''The BMJ'' has editorial freedom from the BMA. It is one of the world's oldest general medical journals. Origi ...
, demonstrate that this virus can produce severe symptoms, particularly in HIV-positive people. The descriptive case series reveal that symptoms can be so severe that hospitalization is required in 10% of cases. The study also shows that 75% of patients (15 out of 20 participants) admitted to the hospital were HIV-positive individuals. Overall, the study depict a new variety of clinical manifestations including proctitis and rectal perforation. The pictures of genital lesions published in
the BMJ ''The BMJ'' is a weekly peer-reviewed medical trade journal, published by the trade union the British Medical Association (BMA). ''The BMJ'' has editorial freedom from the BMA. It is one of the world's oldest general medical journals. Origi ...
show the severity of monkeypox, which is often described as causing moderate symptoms.


In other animals

The disease has also been reported in
dormice A dormouse is a rodent of the family Gliridae (this family is also variously called Myoxidae or Muscardinidae by different taxonomists). Dormice are nocturnal animals found in Africa, Asia, and Europe. They are named for their long, dormant hibe ...
,
tree squirrels Tree squirrels are the members of the squirrel family (Sciuridae) commonly just referred to as "squirrels." They include more than 100 arboreal species native to all continents except Antarctica and Oceania. They do not form a single natural, or ...
, rope squirrels and non human primates. Rodents such as rats and mice are likely susceptible but not known. Signs and symptoms in animals vary among different species. Monkeypox infected
Gambian pouched rat The Gambian pouched rat (''Cricetomys gambianus''), also commonly known as the African giant pouched rat, is a species of nocturnal pouched rat of the giant pouched rat genus ''Cricetomys'', in the family Nesomyidae. It is among the largest m ...
s may have mild symptoms. During the 2003 US outbreak, affected prairie dogs presented with fever, cough,
sore eyes Conjunctivitis, also known as pink eye, is inflammation of the outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may occur. The ...
, poor feeding and rash. Non-human primates present similarly. They may have breathing problems, facial swelling, mouth ulcers and swollen glands. In cynomolgus monkeys, the time from exposure to symptoms was noted to be around a week. Rabbits and rodents typically present with fever, cough, runny nose, sore eyes and swollen glands. They develop small bumps that fill with yellow fluid and may have patches of hair loss and pneumonia. Spread among animals occurs via the fecal-oral route and through the nose, through wounds and eating infected meat. Death is more likely in baby monkeys. The CDC recommend that animals exposed to monkeypox be quarantined for six weeks.


Causes

Monkeypox in both humans and animals is caused by infection with the
monkeypox virus ''Monkeypox virus'' (MPV, MPXV, or hMPXV) is a species of double-stranded DNA virus that causes monkeypox in humans and other mammals. Monkeypox virus is a zoonotic virus belonging to the ''orthopoxvirus'' genus, making it closely related to the ...
– a
double-stranded DNA virus A DNA virus is a virus that has a genome made of deoxyribonucleic acid (DNA) that is replicated by a DNA polymerase. They can be divided between those that have two strands of DNA in their genome, called double-stranded DNA (dsDNA) viruses, and ...
in the genus ''
Orthopoxvirus ''Orthopoxvirus'' is a genus of viruses in the family ''Poxviridae'' and subfamily ''Chordopoxvirinae''. Vertebrates, including mammals and humans, and arthropods serve as natural hosts. There are 12 species in this genus. Diseases associated wi ...
'', family ''
Poxviridae ''Poxviridae'' is a family of double-stranded DNA viruses. Vertebrates and arthropods serve as natural hosts. There are currently 83 species in this family, divided among 22 genera, which are divided into two subfamilies. Diseases associated wit ...
''. The virus was first identified in captive monkeys and is found mainly in
tropical rainforest Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation of at least 60 mm – and may also be referred to as ''lowland equa ...
regions of Central and
West Africa West Africa or Western Africa is the westernmost region of Africa. The United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, M ...
. The two subtypes of virus are cladeI and cladeII (formerly Congo Basin and West African clades, matching the geographical areas). In addition to monkeys, the virus has been identified in
Gambian pouched rat The Gambian pouched rat (''Cricetomys gambianus''), also commonly known as the African giant pouched rat, is a species of nocturnal pouched rat of the giant pouched rat genus ''Cricetomys'', in the family Nesomyidae. It is among the largest m ...
s (''Cricetomys gambianus''),
dormice A dormouse is a rodent of the family Gliridae (this family is also variously called Myoxidae or Muscardinidae by different taxonomists). Dormice are nocturnal animals found in Africa, Asia, and Europe. They are named for their long, dormant hibe ...
(''
Graphiurus The African dormice (genus ''Graphiurus'') are dormice that live throughout sub-Saharan Africa in a variety of habitats. They are very agile climbers and have bushy tails. They eat invertebrates and small vertebrates. Species Genus ''Graphiurus' ...
'' spp.) and African squirrels ('' Heliosciurus'', and '' Funisciurus''). The use of these animals as food may be an important source of transmission to humans.


Transmission

Humans can be infected by an animal via a bite or scratch, bush meat preparation, or by contact with an infected animal’s bodily fluids or lesion material. The virus is thought to enter the body through broken skin, the respiratory tract, or the
mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It i ...
s of the eyes, nose, or mouth. Once a human is infected, transmission to other humans is common, with family members and hospital staff at particularly high risk of infection. The virus can spread by respiratory (airborne) contact or by direct contact with an infected person's bodily fluids or during pregnancy from mother to fetus. There are indications that transmission can occur during sexual contact, with infectious monkeypox virus able to be isolated from semen samples. Prolonged shedding in seminal fluids has raised the possibility of a genital reservoir for monkeypox virus. It is not known if the virus can spread through vaginal fluids. The virus can also spread via
fomite A fomite () or fomes () is any inanimate object that, when contaminated with or exposed to infectious agents (such as pathogenic bacteria, viruses or fungi), can transfer disease to a new host. Transfer of pathogens by fomites A fomite is any ...
s or through indirect contact with lesion material, such as through contaminated bedding, even with standard personal protective equipment, likely through inhalation. Risk factors for transmission include sharing a bed or room, or using the same utensils as an infected person. Increased transmission risk is associated with factors involving the introduction of virus to the
oral mucosa The oral mucosa is the mucous membrane lining the inside of the mouth. It comprises stratified squamous epithelium, termed "oral epithelium", and an underlying connective tissue termed '' lamina propria''. The oral cavity has sometimes been des ...
. It is not yet known if people without symptoms of monkeypox can spread the virus. Further research about the transmission of the strain responsible for the 2022 outbreak is ongoing, but it is not thought to be different from other strains of the cladeII.


People living with HIV

According to a
Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...
(CDC) report, 41% of cases of monkeypox were among HIV-positive patients (136 out of 334 patients) between May and July 2022. ''
The New England Journal of Medicine ''The New England Journal of Medicine'' (''NEJM'') is a weekly medical journal published by the Massachusetts Medical Society. It is among the most prestigious peer-reviewed medical journals as well as the oldest continuously published one. Hi ...
'' (NEJM) also looked at more than 500 cases from different countries and found that 41% of them were among HIV patients. In addition, a study that looked at nearly 200 cases in Barcelona and Madrid discovered that 40% were HIV-positive. Patel and colleagues observed 197 patients from sexual health centres in south London between May and July 2022. They reported 35.5% patients had HIV-1 co-infection. 91.4% of these participants were receiving antiretroviral therapy and 78.6% had an undetectable HIV-1 viral load (<200 copies). The median CD4 count was 664 cells (interquartile range 522-894 cells). The proportion of HIV-positive individuals in these reports is significantly higher than the HIV rate among men who have sex with other men.


Diagnosis

Clinical differential diagnosis must consider other rash illnesses, such as chickenpox, measles, bacterial skin infections, scabies, syphilis and medication-associated allergies. Lymphadenopathy during the
prodromal In medicine, a prodrome is an early sign or symptom (or set of signs and symptoms) that often indicates the onset of a disease before more diagnostically specific signs and symptoms develop. It is derived from the Greek word ''prodromos'', meaning ...
stage of illness can distinguish monkeypox from chickenpox or smallpox. Diagnosis can be verified by testing for the virus.
Polymerase chain reaction The polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) ...
(PCR) testing of samples from skin lesions is the preferred laboratory test. PCR blood tests are usually inconclusive because the virus remains in blood only a short time. To interpret test results, information is required on date of onset of fever, date of onset of rash, date of specimen collection, current stage of rash, and patient age.


Prevention

Vaccination Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating ...
against smallpox is assumed to protect against human monkeypox infection because they are closely related viruses, and the vaccine protects animals from experimental lethal monkeypox challenges. This has not been conclusively demonstrated in humans because routine smallpox vaccination was discontinued following the eradication of smallpox.
Smallpox vaccine The smallpox vaccine is the first vaccine to be developed against a contagious disease. In 1796, British physician Edward Jenner demonstrated that an infection with the relatively mild cowpox virus conferred immunity against the deadly smallpox ...
has been reported to reduce the risk of monkeypox among previously vaccinated persons in Africa. The decrease in immunity to poxviruses in exposed populations is a factor in the prevalence of monkeypox. It is attributed to waning cross-protective immunity among those vaccinated before 1980, when mass smallpox vaccinations were discontinued, and to the gradually increasing proportion of unvaccinated individuals. The United States
Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...
(CDC) recommends 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. However, the CDC does not recommend pre-exposure vaccination for unexposed
veterinarian A veterinarian (vet), also known as a veterinary surgeon or veterinary physician, is a medical professional who practices veterinary medicine. They manage a wide range of health conditions and injuries in non-human animals. Along with this, vet ...
s, veterinary staff, or animal control officers, unless such persons are involved in field investigations. No smallpox or monkeypox vaccine has been approved for use during pregnancy. The CDC recommends that healthcare providers don a full set of
personal protective equipment Personal protective equipment (PPE) is protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury or infection. The hazards addressed by protective equipment include physical, e ...
(PPE) before caring for an infected person. This includes a gown, mask, goggles, and a disposable filtering respirator (such as an N95). An infected person should be isolated in preferably a negative air pressure room or at least a private exam room to keep others from possible contact. Monkeypox prevention cannot be simplified to just providing a vaccine. There are more pressing challenges to address, such as access to treatment, veracity and availability of information, and quality of health care. Public health messaging is perhaps the most important challenge. The multiple levels of interconnectivity and negotiated social meanings inherent to the disease require cooperation between medical professionals and patients to achieve correct public health communication. Therefore, Scalvini argues in
the BMJ ''The BMJ'' is a weekly peer-reviewed medical trade journal, published by the trade union the British Medical Association (BMA). ''The BMJ'' has editorial freedom from the BMA. It is one of the world's oldest general medical journals. Origi ...
that it is necessary a "new ethic of shared responsibility" to educate people about dangers and give people from underprivileged groups the tools they need to make better decisions.


Treatment

In the European Union and the United States, tecovirimat is approved for the treatment of several
poxvirus ''Poxviridae'' is a family of double-stranded DNA viruses. Vertebrates and arthropods serve as natural hosts. There are currently 83 species in this family, divided among 22 genera, which are divided into two subfamilies. Diseases associated wit ...
es, including monkeypox.
BMJ Best Practice BMJ Best Practice is an online decision-support tool for use at the point of care. It was created in 2009 by ''The BMJ''. Development ''The BMJ'' launched BMJ Best Practice in 2009. About BMJ Best Practice Ranked one of the best clinical decisio ...
recommends tecovirimat or the smallpox treatment
brincidofovir Brincidofovir, sold under the brand name Tembexa, is an antiviral drug used to treat smallpox. Brincidofovir is a prodrug of cidofovir. Conjugated to a lipid, the compound is designed to release cidofovir intracellularly, allowing for higher int ...
as the first line antiviral treatment if required, alongside supportive care (including
antipyretic An antipyretic (, from ''anti-'' 'against' and ' 'feverish') is a substance that reduces fever. Antipyretics cause the hypothalamus to override a prostaglandin-induced increase in temperature. The body then works to lower the temperature, which r ...
,
fluid balance Fluid balance is an aspect of the homeostasis of organisms in which the amount of water in the organism needs to be controlled, via osmoregulation and behavior, such that the concentrations of electrolytes ( salts in solution) in the various b ...
and oxygenation). Empirical antibiotic therapy or
aciclovir Aciclovir (ACV), also known as acyclovir, is an antiviral medication. It is primarily used for the treatment of herpes simplex virus infections, chickenpox, and shingles. Other uses include prevention of cytomegalovirus infections following tra ...
may be used if secondary bacterial or varicella zoster infection is suspected, respectively.


Outcome

After healing, the scabs may leave pale marks before becoming darker scars. The risk of death in those infected ranges from 0% to 11%, depending on the type of monkeypox and location in the world. Fatality rates have been reported as around 3.6% in West Africa and 10.6% in Central Africa. Most reported deaths have occurred in young children and people with
HIV infection Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ma ...
.


Epidemiology

In 1970, monkeypox was first associated with an illness as a disease in humans in the
Democratic Republic of the Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...
(formerly Zaire), in the town of
Basankusu Basankusu is a town in Équateur Province, Democratic Republic of the Congo. It is the main town and administrative centre of the Basankusu Territory. In 2004, it had an estimated population of 23,764. It has a gravel airstrip, covered and open ma ...
, Équateur Province. Although it was once thought to be uncommon in humans, cases increased since the 1980s, possibly as a result of waning immunity since the stopping of routine smallpox vaccination. Between 1981 and 1986
WHO Who or WHO may refer to: * Who (pronoun), an interrogative or relative pronoun * Who?, one of the Five Ws in journalism * World Health Organization Arts and entertainment Fictional characters * Who, a creature in the Dr. Seuss book '' Horton He ...
surveillance in DRC/Zaire recorded 338 confirmed cases and 33 deaths (CFR 9.8%). In 1996–1997, a second outbreak of human illness was identified in DRC/Zaire and between 1991 and 1999, 511 cases were reported in DRC/Zaire. CladeI of disease remains endemic in DRC and has a higher CFR than the other genetic clade in Western Africa. By May 2022, the
case fatality rate In epidemiology, case fatality rate (CFR) – or sometimes more accurately case-fatality risk – is the proportion of people diagnosed with a certain disease, who end up dying of it. Unlike a disease's mortality rate, the CFR does not take int ...
(CFR) of past outbreaks was around , while the CFR of the 2022 outbreak remains below 1%. No human-to-human transmission was documented until the
2022 monkeypox outbreak An ongoing outbreak of monkeypox, a viral disease, was confirmed in May 2022. The initial cluster of cases was found in the United Kingdom, where the first case was detected in London on 6 May 2022 in a patient with a recent travel his ...
in Europe. CladeII had an outbreak – the first outbreak of monkeypox outside of Africa – in Midwestern United States among owners of pet prairie dogs in 2003. Seventy-one people were reportedly infected, of whom none died. As of 2018, monkeypox was traditionally restricted to the ecology of
tropical rainforests Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation of at least 60 mm – and may also be referred to as ''lowland equa ...
. although the pattern was broken in 2005, when 49 cases were reported in Sudan (areas now
South Sudan South Sudan (; din, Paguot Thudän), officially the Republic of South Sudan ( din, Paankɔc Cuëny Thudän), is a landlocked country in East Africa. It is bordered by Ethiopia, Sudan, Central African Republic, Democratic Republic of the ...
), with no fatalities. The genetic analysis suggested that the virus did not originate in Sudan but was imported, most likely from DRC. Many more monkeypox cases have been reported in Central and West Africa, and in the Democratic Republic of Congo in particular: 2000 cases per year are known between 2011 and 2014. The collected data is often incomplete and unconfirmed, which hinders realistic estimations of the number of cases of monkeypox over time. Nevertheless, it was suggested that the number of reported monkeypox cases had increased and the geographical occurrence broadened as of 2018.


2003 U.S. outbreak

In May 2003, a young child became ill with fever and rash after being bitten by a prairie dog purchased at a local swap meet near
Milwaukee Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee ...
,
Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...
. In total, 71 cases of monkeypox were reported through 20 June 2003. All cases were traced to Gambian pouched rats imported from Accra,
Ghana Ghana (; tw, Gaana, ee, Gana), officially the Republic of Ghana, is a country in West Africa. It abuts the Gulf of Guinea and the Atlantic Ocean to the south, sharing borders with Ivory Coast in the west, Burkina Faso in the north, and To ...
, in April 2003 by a Texas exotic animal distributor. No deaths resulted. Electron microscopy and serologic studies were used to confirm that the disease was human monkeypox. People with monkeypox typically experienced prodromal symptoms of fever, headaches, muscle aches, chills, and drenching sweats. Roughly one-third of infected people had nonproductive coughs. This
prodromal In medicine, a prodrome is an early sign or symptom (or set of signs and symptoms) that often indicates the onset of a disease before more diagnostically specific signs and symptoms develop. It is derived from the Greek word ''prodromos'', meaning ...
phase was followed 1–10 days later by the development of a papular rash that typically progressed through stages of vesiculation, pustulation, umbilication, and crusting. In some people, early lesions had become ulcerated. Rash distribution and lesions occurred on head, trunk, and extremities. Many of the people had initial and satellite lesions on palms, soles, and extremities. Rashes were generalized in some people. After onset of the rash, people generally manifested rash lesions in different stages. Everyone affected reported direct or close contact with prairie dogs, later found to be infected with the monkeypox virus.


2017–2019 Nigeria outbreak

According to the Nigeria Centre for Disease Control (NCDC), between 1971 and 1978, only 10 human monkeypox infections were reported in the country. In September 2017, human monkeypox re-emerged in Nigeria, 39 years since it had been last reported. The subsequent 2017–18 Nigerian human monkeypox outbreak was, at that time, the largest ever outbreak of cladeII of the virus, with 118 confirmed cases. Unlike previous outbreaks of this clade, infection was predominantly among young male adults and human-to-human transmission appears to have readily occurred. Seven deaths (5 male, 2 female, case fatality rate of 6%) were reported, including a baby and four
HIV/AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ...
patients. Additionally, a pregnant woman in her second trimester had a spontaneous miscarriage due to monkeypox infection. The Niger Delta University Teaching Hospital reported that a substantial number of its young adult cases had concomitant genital ulcers, syphilis and HIV infection. Monkeypox spread around southeast and south Nigeria with some states and the federal government of
Nigeria Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...
seeking ways to contain it. By December 2017 it spread to
Akwa Ibom Akwa Ibom State is a state in the South-South geopolitical zone of Nigeria, bordered on the east by Cross River State, on the west by Rivers State and Abia State, and on the south by the Atlantic Ocean. The state takes its name from the Qua Ib ...
,
Abia Abia or ABIA may refer to: ABIA * Austin-Bergstrom International Airport, in Austin, Texas, United States * Australian Book Industry Awards, national literary and industry awards People * Abia (name) * Abia (mythology), the nursemaid of Glenus ...
,
Bayelsa Bayelsa is one of the states in the South-South region of Nigeria, located in the core of the Niger Delta region. Bayelsa State was created in 1996 and was carved out from Rivers State, making it one of the newest states in the federation. Yena ...
, Benue, Cross River, Delta, Edo, Ekiti, Enugu, Imo,
Lagos Lagos (Nigerian English: ; ) is the largest city in Nigeria and the second most populous city in Africa, with a population of 15.4 million as of 2015 within the city proper. Lagos was the national capital of Nigeria until December 1991 fo ...
,
Nasarawa Nasarawa is a Local Government Area in Nasarawa State, Nigeria. Its headquarters are in the town of Nasarawa, located at 8°32'N 7°42'E, with a population of 30,949 (as of 2016). The local government area has an area of 5,704 km and a populat ...
, Oyo,
Plateau In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides ...
, Rivers and Federal Capital Territory. The outbreak started in September 2017 and remained ongoing across multiple states as of May 2019. The US Centers for Disease Control and Prevention reported cases of American travelers contracting Monkeypox upon return from Lagos and Ibadan. Agam Rao, a medical officer in the Division of Pathogens and High Consequence Pathology at the CDC, said that since 2018 all cases reported outside Africa have come from Nigeria. In a 2021 article Oyewale Tomori pointed out that the number of monkeypox infections in Nigeria through 2021 was likely to be under-represented, because much of the Nigerian population had been avoiding healthcare facilities due to fear of contracting COVID-19. In May 2022, the Nigerian government released a report stating that between 2017 and 2022, 558 cases were confirmed across 32 states and the Federal Capital Territory. The Rivers State was the most affected by monkeypox followed by Bayelsa and Lagos. There were 8 deaths reported, making for a 3.5% Case Fatality Ratio. In 2022, NCDC implemented a National Technical Working Group for reporting and monitoring infections, strengthening response capacity.


2018 and 2019 United Kingdom cases

In September 2018, the
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...
's first case of monkeypox was recorded. The person, a Nigerian national, is believed to have contracted monkeypox in Nigeria before travelling to the United Kingdom. According to
Public Health England Public Health England (PHE) was an executive agency of the Department of Health and Social Care in England which began operating on 1 April 2013 to protect and improve health and wellbeing and reduce health inequalities. Its formation came as a ...
, the person was staying in a naval base in
Cornwall Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic ...
before being moved to the Royal Free Hospital's specialised infectious disease unit. People who had been in contact with the person since he contracted the disease were contacted. A second case was confirmed in the town of Blackpool, with a further case that of a medical worker who cared for the case from Blackpool. A fourth case occurred on 3 December 2019, when monkeypox was diagnosed in a person in
south west England South West England, or the South West of England, is one of nine official regions of England. It consists of the counties of Bristol, Cornwall (including the Isles of Scilly), Dorset, Devon, Gloucestershire, Somerset and Wiltshire. Cities ...
. They were travelling to the UK from Nigeria.


2019 Singapore case

In May 2019, a 38-year-old man who travelled from Nigeria was hospitalised in an isolation ward at the
National Centre for Infectious Diseases The National Centre for Infectious Diseases (Abbreviation: NCID; ms, Pusat Nasional bagi Penyakit Berjangkit; ta, தேசிய தொற்றுநோய் மையம்; Chinese: ), previously known as the Communicable Disease Centre ...
in
Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, bor ...
, after being confirmed as the country's first case of monkeypox. As a result, 22 people were quarantined. The case may have been linked to a simultaneous outbreak in Nigeria.


2021 cases in United Kingdom, United States

In May 2021, in the UK, three cases of monkeypox from a single household were identified by Public Health Wales. The cases were also announced by Health Secretary
Matt Hancock Matthew John David Hancock (born 2 October 1978) is a British politician who served as Minister for the Cabinet Office and Paymaster General from 2015 to 2016, Secretary of State for Digital, Culture, Media and Sport from January to July 201 ...
while addressing MPs. The
index case The index case or patient zero is the first documented patient in a disease epidemic within a population, or the first documented patient included in an epidemiological study. It can also refer to the first case of a condition or syndrome (not n ...
was diagnosed on 24 May after traveling from
Nigeria Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...
. The second case was reported on 2 June, and the third on 24 June. One of the three patients, an adult female, was treated with tecovirimat. On day 7 of tecovirimat, she was discharged from hospital to complete her second week of treatment at home. In July 2021, in the US, an American returning from a trip in Nigeria was diagnosed with monkeypox. Subsequent testing identified the virus as belonging to cladeII. The patient was hospitalized and treated with tecovirimat and was discharged after 32 days, at which time monkeypox virus DNA could no longer be detected in residual skin lesions.


2022 outbreak


History

Monkeypox was first identified as a distinct illness in 1958 among laboratory monkeys in
Copenhagen Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...
, Denmark. The first documented cases in humans was in 1970, in six unvaccinated children during the smallpox eradication efforts; the first being a 9-month old boy in the
Democratic Republic of the Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...
(formerly Zaire). The others, including three who were playmates, were in Liberia and Sierra Leone. It was noted to be less easily transmissible than smallpox. From 1981 to 1986, over 300 cases of human monkeypox were reported in the DRC, the majority being due to contact with animals. In 1996, the disease reemerged in the DRC with 88% of cases resulting from human-to-human transmission. Small viral outbreaks with a death rate in the range of 10% and a secondary human-to-human infection rate of about the same amount occur routinely in equatorial Central and West Africa. In humans, the disease remained confined to the rain forests of Western and Central Africa until 2003, when an outbreak of monkeypox occurred in the US. All cases were traced to sick rodents imported from Ghana. Local prairie dogs caught the infection and passed it onto their owners. The disease was found to be mild and there were no deaths. Between 1970 and 2019 the disease was reported in 10 African countries; mostly in Central and
West Africa West Africa or Western Africa is the westernmost region of Africa. The United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, M ...
. In 2018, cases of monkeypox were diagnosed in the UK in two unrelated travellers from Nigeria. That year the first human-to-human transmission outside of Africa was confirmed in the UK. This person was a healthcare worker who possibly contracted the disease from contaminated bedlinen. Cases were also reported in travellers to Israel and Singapore. The UK saw further cases in 2019 and 2021. On 31 July 2022, the first death from monkeypox was recorded in India: a 22-year-old man who had returned from the UAE died.


Nomenclature

On 28 November 2022, the World Health Organization announced it "will adopt the term ''mpox'' in its communications, and encourages others to follow these recommendations". It expects a transition period of a year during which mpox and monkeypox would be synonyms. The name ''monkeypox'' was criticised for being a misnomer (monkeys are not the main host or reservoir of the virus), for reinforcing stigma about African countries as a source of disease, and encouraging racist stereotypes that compared Black people with primates. The change followed an open letter, by two dozen African scientists, warning that these issues were harming the fight to contain the disease outbreak.


See also

*
2003 Midwest monkeypox outbreak Beginning in May 2003, by July a total of 71 cases of human monkeypox were found in six Midwestern states including Wisconsin (39 cases), Indiana (16), Illinois (12), Kansas (1), Missouri (2), and Ohio (1). The cause of the outbreak was traced ...
*
2022 monkeypox outbreak An ongoing outbreak of monkeypox, a viral disease, was confirmed in May 2022. The initial cluster of cases was found in the United Kingdom, where the first case was detected in London on 6 May 2022 in a patient with a recent travel his ...
* 2022 monkeypox outbreak in Canada * 2022 monkeypox outbreak in the United States * 2022 monkeypox outbreak in the United Kingdom


References


External links


CDC – Monkeypox Fact Sheet

WHO – Monkeypox Fact Sheet

"Could Monkeypox Take Over Where Smallpox Left Off?"
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Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it ...
'', 4 March 2013.
More than 80 cases confirmed in 12 countries
23 May 2022.
MonkeypoxTracker
– Monkeypox statistics visualization site
PoxApp - the monkeypox app
– Assess skin lesions and symptoms with
artificial intelligence Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech r ...
developed by Stanford University {{Authority control Animal viral diseases Poxviruses Virus-related cutaneous conditions Wikipedia medicine articles ready to translate