Monkeypox (MPX) is a viral zoonotic disease with symptoms like smallpox, with less clinical severity. MPX was first discovered in 1958 in colonies of monkeys kept for research, hence the name ‘monkeypox.’ It is a disease of global public health importance as it not only affects countries in West and Central Africa, but the rest of the world. The true burden of disease is not known.
Monkeypox was first identified in humans in 1970 in the Democratic Republic of the Congo in a 9- year-old boy in a region where smallpox had been eliminated in 1968. Since 1970, cases of monkeypox were reported in 11 African countries and in 2003, the first monkeypox outbreak outside of Africa was reported in the United States of America and was linked to contact with infected pet prairie dogs.
Monkeypox virus (MPXV) is an enveloped double- stranded DNA virus that belongs to the genus Orthopoxvirus and family Poxviridae. There are two distinct genetic clades of the monkeypox virus – the Central African (Congo Basin) clade and the West African clade. The Congo Basin clade has historically caused more severe disease and was thought to be more transmissible. As per the recent literature, the latest strain of monkeypox virus is from West African clade and has about 50 genetic variations compared to related viruses that circulated in 2018-2019. The virus is continuing to evolve during the current outbreak, including several small changes in the genetic code, minor gene variants and a deleted gene.
Natural reservoir is yet unknown. However, certain rodents (including rope squirrels, tree squirrels, Gambian pouched rats, dormice) and non-human primates are known to be naturally susceptible to infection of monkeypox virus.
The incubation period (interval from infection to onset of symptoms) of monkeypox is usually from 6 to 13 days but can range from 5 to 21 days.
Period of communicability
1-2 days before the rash to until all the scabs fall off/gets subsided.
Mode of transmission:
Human-to-human transmission is known to occur through large respiratory droplets generally requiring a prolonged close contact. It can also be transmitted through direct contact with body fluids or lesion material, and indirect contact with lesion material, such as through contaminated clothing or linens of an infected person. Transmission between sexual partners, due to intimate contact during sex with infectious skin lesions seems the more likely mode of transmission among men who have sex with men (MSM). The mode of transmission is evolving.
Animal-to-human transmission of MPXV may occur by bite or scratch of infected animals like small mammals including rodents (rats, squirrels) and non-human primates (monkeys, apes) or through bush meat preparation.
A person of any age having history of travel to affected countries within last 21 days presenting with an unexplained acute rash AND one or more of the following signs or symptoms
A person meeting the case definition for a suspected case, clinically compatible illness and has an epidemiological link (face-to-face exposure, including health care workers without appropriate PPE; direct physical contact with skin or skin lesions, including sexual contact; or contact with contaminated materials such as clothing, bedding or utensils is suggestive of a strong epidemiological link).
A case which is laboratory confirmed for monkeypox virus (by detection of unique sequences of viral DNA either by polymerase chain reaction (PCR) and/or sequencing).
Monkeypox is usually a self-limited disease with the symptoms lasting from 2 to 4 weeks. Severe cases occur more commonly among children and are related to the extent of virus exposure, patient health status and nature of complications. The extent to which asymptomatic infection occurs is unknown. Case fatality ratio of monkeypox has historically ranged from 0 to 11% in the general population and has been higher among young children. In recent times, the case fatality ratio has been around 3-6%.
Common symptoms and signs
Prodrome (0-5 days)
Skin involvement (rash)
Treatment of Monkeypox is primarily supportive.
Principles of Management include:
Raising awareness of risk factors and educating people about the measures they can take to reduce exposure to the virus is the main prevention strategy
for monkeypox. There are number of measures that can be taken to prevent infection with monkeypox virus:
IPC at home
Duration of Isolation Procedures
Affected individuals should avoid close contact with immunocompromised persons and pregnant women until all crusts are gone. Isolation precautions should be continued until all lesions have resolved and a fresh layer of skin has formed.
Vaccination against smallpox was demonstrated through several observational studies to be about 85% effective in preventing monkeypox. Based on currently assessed risks and benefits and regardless of vaccine supply, mass vaccination is not required nor recommended for monkeypox at this time.
Last Modified : 8/7/2023