The Historical Epidemiology of Human Monkeypox: A Review of Evidence from the 1970 Emergence to the 2022 Outbreak

Abstract

Human Monkeypox (HMPX) outbreak in the year 2022 occurs in many countries outside of the African regions, a common location of such outbreaks, with a considerable rate of human-to-human transmission, which was an uncommon route of infection before. The epidemiological reports also represent a sharping pace of infection spreading between communities rather than in previous outbreaks as the following pace of afflictions is unpredictable. Also, the cautions regarding the sexually transmitted infection of the such virus have been raised in this outbreak. Further, the main reservoirs of the recent outbreaks are yet to be revealed. As a consequence, the World Health Organization (WHO) has declared the 2022 HMPX outbreak as an "Atypical" phenomenon compared to its previous characteristics. To better recognize the properties of this outbreak, herein we systematically described and compared the historical evidence of monkeypox virus outbreaks in the aspects of epidemiological, clinical, and molecular evolutions since its emergence, as well as an explanation of the previous investigations and considerations of WHO and other international health societies over time. The history of human and monkeypox virus interaction during the past 64 years provides viewpoints on preventing strategies and assessing the present and potential future hazards of health implications.

Keywords: epidemiology; monkeypox virus; orthopoxvirus.