Monkeypox (mpox) virus: Classification, origin, transmission, genome organization, antiviral drugs, and molecular diagnosis

Abstract

Monkeypox virus (MPXV) is a double-stranded DNA virus belonging to the Poxviridae family of the genus Orthopoxvirus with two different clades known as West African and Congo Basin. Monkeypox (MPX) is a zoonosis that arises from the MPXV and causes a smallpox-like disease. The endemic disease status of MPX was updated to an outbreak worldwide in 2022. Thus, the condition was declared a global health emergency independent of travel issues, accounting for the primary reason for its prevalence outside Africa. In addition to identified transmission mediators through animal-to-human and human-to-human, especially sexual transmission among men who have sex with men came to prominence in the 2022 global outbreak. Although the severity and prevalence of the disease differ depending on age and gender, some symptoms are commonly observed. Clinical signs such as fever, muscle and headache pain, swollen lymph nodes, and skin rashes in defined body regions are standard and an indicator for the first step of diagnosis. By following the clinical signs, laboratory diagnostic tests like conventional polymerase chain reaction (PCR) or real-time PCR (RT-PCR) are the most common and accurate diagnostic methods. Antiviral drugs such as tecovirimat, cidofovir, and brincidofovir are used for symptomatic treatment. There is no MPXV-specific vaccine; however, currently available vaccines against smallpox enhance the immunization rate. This comprehensive review covers the MPX disease history and the current state of knowledge by assessing broad topics and views related to disease origin, transmission, epidemiology, severity, genome organization and evolution, diagnosis, treatment, and prevention.

Keywords: Diagnosis; Genome; Monkeypox virus; Mpox; Susceptibility; Transmission.

Fig. 1

The number of confirmed MPX or mpox cases globally. (a) The top 20 countries have the highest cases as of 16 January 2023. The death tolls are indicated in parenthesis (the World Health Organization, 2022 Mpox Outbreak [8]) (b) Weekly distribution of the global cases from the beginning of the outbreak (OurWorldInData [12]). Note: For the WHO European region, confirmed and probable cases are included within confirmed case counts.

Fig. 2

The transmission of the MPXV is animal-to-animal, animal-to-human, and human-to-human.

Fig. 3

The structure of the MPXV and its genome.