{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T03:39:43Z","timestamp":1789616383195,"version":"build-2803163510"},"reference-count":29,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2025,1,30]],"date-time":"2025-01-30T00:00:00Z","timestamp":1738195200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Italian Ministry of Health","award":["871029"],"award-info":[{"award-number":["871029"]}]},{"name":"European Virus Archive\u2014GLOBAL","award":["871029"],"award-info":[{"award-number":["871029"]}]},{"name":"Valentino s.p.a.","award":["871029"],"award-info":[{"award-number":["871029"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Mpox, caused by the Monkeypox virus (MPV), is a global public health threat. Virus isolation is the gold standard to confirm MPV infection, but this process can face many challenges. As an alternative, a new method was developed in in vitro settings using 50 \u00b5M of propidium monoazide (PMAxx, a DNA-binding agent) coupled with digital droplet PCR (ddPCR). Frozen clinical samples analyzed by PMAxx-ddPCR had a median of 0.8 copies\/\u00b5L, while untreated samples had a median of 29.8 copies\/\u00b5L. Since a substantial percentage of reduction was observed in these samples (&gt;80%), it was verified whether this reduction could be due to the freezing process. This hypothesis was confirmed both in vitro and using clinical samples. A gradual increase in the mean percentage of reduction was observed after freezing\u2013thawing cycles of MPV-isolate (59.5\u221281.4%). Moreover, a different percentage of reduction was observed before (68.2%) and after freezing (97.4%) the specimens, suggesting that the freezing process could reduce the number of complete viral particles. Our study shows strong evidence of the usefulness of PMAxx in clinical settings. PMAxx ensures the detection of intact MPV particles, which improves the accuracy of MPV load measurements. This method not only increases the reliability of MPV diagnosis but also overcomes virus isolation limitations.<\/jats:p>","DOI":"10.3390\/ijms26031195","type":"journal-article","created":{"date-parts":[[2025,1,30]],"date-time":"2025-01-30T04:01:39Z","timestamp":1738209699000},"page":"1195","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Measurement of the Infection and Integrity of Monkeypox Virus: A New Method Using PMAxx-ddPCR"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0955-2074","authenticated-orcid":false,"given":"Giuseppe","family":"Sberna","sequence":"first","affiliation":[{"name":"Laboratory of Virology and Biosafety Laboratories, National Institute for Infectious Diseases Lazzaro Spallanzani\u2014IRCCS, 00149 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5277-3417","authenticated-orcid":false,"given":"Eliana","family":"Specchiarello","sequence":"additional","affiliation":[{"name":"Laboratory of Virology and Biosafety Laboratories, National Institute for Infectious Diseases Lazzaro Spallanzani\u2014IRCCS, 00149 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cosmina","family":"Mija","sequence":"additional","affiliation":[{"name":"Laboratory of Virology and Biosafety Laboratories, National Institute for Infectious Diseases Lazzaro Spallanzani\u2014IRCCS, 00149 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1952-5117","authenticated-orcid":false,"given":"Fabrizio","family":"Carletti","sequence":"additional","affiliation":[{"name":"Laboratory of Virology and Biosafety Laboratories, National Institute for Infectious Diseases Lazzaro Spallanzani\u2014IRCCS, 00149 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sara","family":"Belladonna","sequence":"additional","affiliation":[{"name":"Laboratory of Virology and Biosafety Laboratories, National Institute for Infectious Diseases Lazzaro Spallanzani\u2014IRCCS, 00149 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8182-5896","authenticated-orcid":false,"given":"Enrico","family":"Girardi","sequence":"additional","affiliation":[{"name":"Scientific Direction, National Institute for Infectious Diseases Lazzaro Spallanzani\u2014IRCCS, 00149 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0240-7504","authenticated-orcid":false,"given":"Valentina","family":"Mazzotta","sequence":"additional","affiliation":[{"name":"Clinical and Research Department, National Institute for Infectious Diseases Lazzaro Spallanzani\u2014IRCCS, 00149 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7489-5271","authenticated-orcid":false,"given":"Fabrizio","family":"Maggi","sequence":"additional","affiliation":[{"name":"Laboratory of Virology and Biosafety Laboratories, National Institute for Infectious Diseases Lazzaro Spallanzani\u2014IRCCS, 00149 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,1,30]]},"reference":[{"key":"ref_1","unstructured":"(2024, November 09). 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