Monkeypox virus, infectious in aerosols for more than 90 hours

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Monkeypox is a zoonotic viral disease caused by monkeypox virus (MPXV) infection. The disease is mainly endemic in Central and West Africa, but since May 2022, monkeypox cases have also been reported in some non-endemic countries, with community transmission. As of June 17, global monkeypox cases reached 2,166.

The virus has spread so fast, but its route of transmission has always been confusing. "Body fluids," "droplets," "pathogenic variants," and even "sexual behavior" don't seem to be enough to explain. Recently, researchers from the University of Leicester in the United Kingdom published an article in the top medical journal "The Lancet", saying that the possibility of monkeypox virus transmission through "aerosol" cannot be ruled out.

Aerosols are gaseous dispersion systems composed of solid or liquid particles suspended in a gaseous medium. The density of these solid or liquid particles can differ from the density of the gaseous medium by a small amount, or it can be very different. Viral aerosols can have a major impact on public health and infectious dynamics. Once aerosolized, the virus is exposed to various stressors, and its integrity and infectious potential are altered accordingly.

For the study, the scientists used a 10.7-liter spin chamber in a tertiary biological cabinet. The equipment consists of an aluminum cylinder with a length of 45.7 cm and an inner diameter of 17.8 cm, and the chamber rotates at a speed of 0.8-1.0 rpm (cycles per minute) on a horizontal axis.

The researchers then aerosolized the monkeypox virus in a rotating chamber. Virus infectivity and concentration in aerosols were detected by viral plaque assay culture and quantitative polymerase chain reaction (qPCR) within 90 hours of virus aging. It was found that the concentration of monkeypox virus in the aerosol remained stable for 18-90 hours, and at the same time, the virus remained infectious in the aerosol for more than 90 hours.

Previous studies have demonstrated that poxviridae can remain infectious for long periods of time in the environment, but little is known about the long-term stability of these viruses in aerosols. The experiment sheds some light on the spread of monkeypox in aerosols, but the process of nebulization and sampling may damage the virus, resulting in the inactivation of some virus particles, thereby making monkeypox virus aerosol stable and contagiousness may be underestimated.

At present, the specific research has been published in "The Lancet".