Monkeypox Virus: Structure, Genome, Symptoms, Hosts, Spread and Identification

What is Monkeypox virus?

After the severe zoonotic pandemic caused by COVID-19, the world is facing another threat today. Monkeypox virus member of the family Poxviridae, subfamily Chordopoxvirinae, and genus Orthopoxvirus is appearing as a pandemic to the human population. Some of the common viruses’ variola, cowpox, camelpox, and vaccinia viruses share the genus Orthopoxvirus with Monkeypox virus. Since smallpox eradication, the MP virus is the first Orthopoxvirus affecting human populations, confirmed by the World Health Organization in 1980. There are two types of monkeypox, clade I and clade II. The ongoing global outbreak that started in 2022 has been caused by clade II.

Structure and Genome of Monkeypox Virus

Monkeypox virus is a large, enveloped virus. When seen in an electron microscope, it highlighted their distinctive brick-like, ovoid, and rectangular shape. The genome is linear, double-stranded DNA (dsDNA), making up two hundred kilobase pairs encoding around 200 proteins, including the different enzymes needed for viral assembly, replication, host range management, and pathogenicity. This genome is encapsulated in the core of each virion. The cytoplasm of infected cells is the only site where the viral cycle occurs. Two lipoprotein envelopes are present in the virion: one is exterior and covers the viral surface proteins necessary for attachment to the cell surface, while the other is internal and encloses the capsid.

What are the possible hosts for the monkeypox virus?

Initially, the virus was isolated from monkeys, thus the name monkeypox virus; however, it has also some other natural hosts, including a variety of squirrel and rat species found in the rainforests of Central and West Africa. It is still unclear where the monkeypox virus is primarily found.

How does the monkeypox virus spread?

The monkeypox virus is spread via contact between the index patient, a person, and the biological fluids, lesions, or both of a reservoir animal or an unintentionally infected host, such as a monkey. According to reports, the virus can also be spread by direct touch, respiratory droplets, and contact with contaminated objects, including bedding and towels.

What are the symptoms of a monkeypox infection?

The signs and symptoms are less severe but resemble those of smallpox, which include a typical rash led by minor prodromal symptoms (such as lymphadenopathy, fever, and flu-like symptoms). Cases in the present outbreak have been atypical, with the characteristic rash that begins in the perianal and vaginal areas and may or may not spread to other parts of the body.

Vaccination for Monkeypox Virus

Evidence showed that the smallpox vaccine has a potential protective effect against the monkeypox virus, as well as an improvement in infection symptoms.

Laboratory Identification of Monkeypox Virus

Identification of viral DNA in swabs collected from crusts of vesicles or ulcers constitutes the preferred technique for diagnosing active monkeypox cases. Because the virus can cause diseases that are clinically identical to other pox-like disorders, like smallpox and chickenpox, laboratory identification is crucial.

Unlike variola viruses, however, MPV can infect a wide range of animals, which has prevented human immunization from eradicating it worldwide and allowed it to continue as a reservoir in wild animals while occasionally causing human disease.

References

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Likos, A. M., Sammons, S. A., Olson, V. A., Frace, A. M., Li, Y., Olsen-Rasmussen, M., … & Damon, I. K. (2005). A tale of two clades: monkeypox viruses. Journal of General Virology, 86(10), 2661-2672.

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Anwar, F., Haider, F., Khan, S., Ahmad, I., Ahmed, N., Imran, M., … & Ji, X. Y. (2023). Clinical manifestation, transmission, pathogenesis, and diagnosis of monkeypox virus: a comprehensive review. Life, 13(2), 522.