Dr Thulani Pattiyakumbura/ PG Trainee in Medical Virology
Dr Rohitha Muthugala/ Consultant Virologist, National Hospital Kandy
Currently, monkeypox has gained global attention with an outbreak reported in non-endemic countries; the United States, the United Kingdom, Australia, Austria, Belgium, Canada, Denmark, France, Germany, Israel, Italy, the Netherlands, Portugal, Slovenia, Spain, Sweden, and Switzerland . A total 92 of laboratory-confirmed cases have been reported up to the 26th of May. According to current evidence, cases have been detected mainly, among men who have sex with men (MSM). To date, all cases whose samples were confirmed by PCR as being infected with the West African clade, which has a low fatality rate ,.
Monkeypox is a zoonotic disease caused by an Orthopoxvirus belonging to the family Poxviridea. Variola virus (which causes smallpox), vaccinia virus (used in the smallpox vaccine), and cowpox virus are all members of the Orthopoxvirus genus . Poxvirus viruses are among the largest animal viruses, and when tagged with fluorescent dyes, they can be visualized under light microscopy. The virions appear to be oval or brick-shaped structures of 200 to 400 nm in length, and they carry a double-strand DNA genome . In 1958, outbreaks of two pox-like illnesses in monkey colonies kept for scientific purposes led to the discovery of monkeypox. The infection was later named 'monkeypox’ . The monkeypox virus causes a smallpox-like disease in humans. According to the studies, the discontinuation of universal smallpox vaccination resulted in an increase in human susceptibility to monkeypox virus infection .
The first human case was reported in the Democratic Republic of Congo (DRC) in 1970, where a 9-year-old child acquired a smallpox-like illness that was later proved to be human monkeypox . In 2003, the DRC recorded 11 cases and one fatality, while Sudan reported 10 cases but no deaths in 2005. Two cases were discovered in DRC in 2009. In 2021, two cases were confirmed in the United States. The United Kingdom reported 9 cases of monkeypox in early May 2022, with the first case having recently visited Nigeria. Currently, several non-endemic countries are experiencing an outbreak of monkeypox.
Exposure to rats, rabbits, squirrels, monkeys, porcupines, and gazelles has been related to outbreaks in western and central Africa. Inhabitants of distant tropical rain forests may contract the disease by directly contacting these animals while capturing, butchering, or preparing them for consumption; infection has also been associated with ingestion. Human to human transmission via close contact with lesions, body fluids, respiratory droplets, and contaminated materials . Fortunately, human-to-human transmission seems to be limited. The longest known transmission chain was six generations, meaning the final diseased person in the chain was six links away from the original infected person .
Monkeypox causes a spectrum of clinical diseases that vary from self-limiting infection to severe disease in at-risk individuals, such as children, pregnant women, or people with immunodeficiency. Patients may experience an unexplained acute skin rash, headache, acute onset fever, lymphadenopathy, myalgia, backache, and generalized body weakness . Deforming scars, secondary bacterial skin infection, bronchopneumonia, respiratory distress, keratitis, corneal ulceration, encephalitis, and septicemia are all complications of the monkeypox infection . Monkeypox has two primary clades that cause human infection. Infections with the West African clade appear to induce less severe disease, with a case fatality rate of 3.6 % compared to 10.6 % for the Congo Basin clade.
Polymerase chain reaction (PCR) alone or in combination with sequencing is the main method of detection. Oropharyngeal or nasopharyngeal swab, and skin biopsy of the vesiculopustular rash/root of the intact vesiculopustule collected into VTM can be used to detect the infection. Additionally, serological methods targeting monkeypox specific IgM and IgG also have a role in diagnosis. Electron microscopy can be used to evaluate the sample for a potential poxvirus, but follow-up confirmation by PCR is required.
Monkeypox virus infection currently has no documented, safe treatment. Smallpox vaccine, antivirals (Cidofovir), and vaccinia immune globulin (VIG) can all be used to control an outbreak .
To prevent the infection, precautions such as: avoiding contact with infected animals (including infected or dead monkeys in endemic regions), avoiding contact with infected material (such as bedding), isolating infected patients, when caring for patients, use appropriate personal protection equipment (PPE) and practice good hand hygiene after contact with infected animals or humans, should be practiced .
Rapid diagnostic facilities and surveillance programs are essential to understanding the changing epidemiology of this reemerging zoonotic disease and preventing an impending epidemic.
 P. E. Fine, Z. Jezek, B. Grab, and H. Dixon, “The transmission potential of monkeypox virus in human populations,” Int. J. Epidemiol., vol. 17, no. 3, pp. 643–650, Sep. 1988, doi: 10.1093/ije/17.3.643.
 I. D. Ladnyj, P. Ziegler, and E. Kima, “A human infection caused by monkeypox virus in Basankusu Territory, Democratic Republic of the Congo,” Bull. World Health Organ., vol. 46, no. 5, p. 593, 1972.