Monkeypox is a viral zoonotic disease caused by the monkeypox virus belonging to the genus Orthopoxvirus of the family Poxviridae. Monkeypox typically presents clinically with fever, rash, and swollen lymph nodes and may lead to a range of medical complications. The case fatality ratio of Monkeypox is around 3–6%.
A clinical differential diagnosis of monkeypox includes other rash-forming illnesses such as chickenpox, measles, bacterial skin infections, scabies, syphilis, and medication-associated allergies.
Monkeypox causes lymphadenopathy (swollen lymph nodes) during the prodromal stage of illness, this clinical feature helps to distinguish monkeypox from chickenpox or smallpox.
Monkeypox virus carries many similarities to the smallpox virus but it causes a mild, self-limiting disease. Monkeypox is usually less contagious than smallpox.
Smallpox was a serious disease caused by the variola virus. In 1980, the World Health Assembly declared smallpox eradication of smallpox disease. The only remnant of this virus is the stocks held at the Centers for Disease Control and Prevention (USA) and at the State Research Centre of Virology and Biotechnology (Russia).
Get answers about frequently asked questions (FAQs) about Monkeypox
Chickenpox is a highly contagious viral skin infection caused by the varicella-zoster virus belonging to the family Herpesviridae. Primary infection of varicella-zoster virus is called chickenpox. Reactivation of the virus later in life causes herpes zoster (shingles).
Chickenpox and monkeypox share some symptoms but there are some major differences between these two diseases. Some major differences (and similarities) between monkeypox and chickenpox are tabulated below;
|Monkeypox is caused by the monkeypox virus, a member of the Orthopoxvirus genus in the family Poxviridae.
|Chickenpox is caused by the varicella-zoster virus, one of the members of the Herpesvirus family.
|Monkeypox is a viral zoonotic disease. Animal hosts include a range of rodents and non-human primates.
Humans are the only reservoir
|Humans get monkeypox through close contact with an infected person or animal (such as contact with lesions, body fluids, or respiratory droplets), or with material contaminated with the virus such as bedding.
|Transmission of chickenpox occurs via droplets, aerosols, or direct contact with respiratory secretions of infected individuals.
|Structure of the virus
|An enveloped double-stranded DNA virus
|An enveloped double-stranded DNA virus
|The incubation period of monkeypox is usually from 6 to 13 days but can range from 5 to 21 days.
|Distribution of rash
|Monkeypox rash tends to be more concentrated on the face and extremities rather than on the trunk.
|The rash in chickenpox is denser over the trunk and almost never found on the palms or soles (centripetal distribution of rashes).
|Appearance of rash
|Monkeypox rash evolves sequentially from macules (lesions with a flat base) to papules (slightly raised firm lesions), vesicles (lesions filled with clear fluid), pustules (lesions filled with yellowish fluid), and crusts that dry up and fall off.
|Chickenpox rashes appear in multiple crops such as maculopapular, vesicles (fluid-filled blisters), and scabs can be found in one area at the same time. The vesicle is surrounded by an erythematous halo that has been poetically described as a “dewdrop on a rose petal”.
|Detection of monkeypox virus from skin lesions (vesicles and pustules, and dry crusts) using Polymerase chain reaction (PCR).
|Detection of VZV in skin lesions (vesicles, scabs, maculopapular lesions) using polymerase chain reaction (PCR).
|Case fatality rate
|The case fatality ratio (CFR) of monkeypox has historically ranged from 0 to 11 % in the general population. Currently, the CFR has been around 3-6%.
|The fatality rate for varicella was approximately 1 per 100,000 cases among children aged 1 through 14 years.
|Smallpox vaccination is 85% effective at preventing monkeypox. Prior smallpox vaccination may result in milder illness.
|Varicella vaccine is available to prevent chickenpox. Two doses of chickenpox vaccines are 90% effective at preventing chickenpox.
References and further reading