Detection of mpox virus in ambient air in a sexual health clinic

Abstract

Although transmitted mainly through direct (sexual) contact, mpox virus (MPXV) can be detected in ambient air. We explored the use of air sampling for diagnosis or (genomic) surveillance of mpox in a sexual health clinic. For six out of six patients who were infected with MPXV, all four of our ambient air PCR tests were positive. For 14 uninfected patients, PCR was positive in three ambient air samples, albeit with higher cycle threshold (C_t) values. Genomic sequencing of samples from two positive patients showed matching sequences between air and clinical samples.

Keywords: Air; Monkeypox; Rectum; Saliva; skin.

Fig. 1

Air sampling results. The figure shows the individual qPCR C_t values (y-axis) of all ambient air samples (x-axis), which were collected either in an outpatient examination room in the presence of infected (red) or uninfected (blue) patients or in an unused room (green). The ticks on the x-axis indicate samples taken in the presence of an individual patient. The two collection substrates in each sample cartridge were analyzed separately using both an in-house qPCR assay (D) and an Altona qPCR assay (O). See Supplementary Table S1 for the C_t value obtained with each sample, collection substrate, and PCR test.

Fig. 2

MPXV genome sequencing and SNV analysis. Genome sequences obtained from skin and ambient air samples from cases 1 and 6 matched the United States 2022 sequence (ON563414.3). Bases differing from the reference sequence are shown in green. The positions of genome SNVs relative to the reference genome sequences are indicated at the bottom. The genomic coordinates of the SNVs from skin and ambient air samples and the functional information on each mutation can be found in Supplementary Table S5. The genome sequence alignment file is provided as a separate supplementary file.