Monkeypox: epidemiology, mode of transmission, clinical features, genetic clades and molecular properties

Recently monkeypox cases have been reported from many non-endemic countries. The objective of this article is to bring out the epidemiology, mode of transmission, clinical features, genetic clades, and molecular properties of monkeypox virus.

A detailed literature review was conducted on monkeypox, using databases PubMed/Medline, EMBASE, PMC and Cochrane Library, for the period between 1985 to 2022.

Genetically monkeypox virus can be classified into Central African clade and Western African clades. The sequence similarity between the two strains was found to be 99.5%. However, some significant differences were found in the virulent and nonvirulent genes of the strains, such as BR-203, BR-209, COP-C3L b and COP-H5R, COP-A9L, COP-A50R, and COP-A36R, respectively. Human to human transmission occurs after exposure to respiratory droplets, oral secretions, contact with lesions, fomites, and direct/sexual contact. Monkeypox can also be transmitted from the infected mother to the fetus through the placenta leading to congenital infection. In May 2022 several cases have been reported from Europe, North America, and Australia, particularly from homosexual men.

Monkeypox is a zoonotic disease which was prevalent in Central and Western African countries. Recently, human to human spread was noticed in developed countries of Europe, North America and Australia. Despite with a close genetic similarity between the two clades, the Central African strain is comparatively very virulent with high mortality. Monkeypox should be considered a re-emerging, neglected disease and proper measures like hand hygiene, wearing masks and vaccination to the high-risk groups are advised.