Human mpox (formerly monkeypox) is an emerging zoonotic disease caused by monkeypox virus (MPXV) (1,2). Since the 1970s, mpox outbreaks in humans have occurred sporadically, mainly in Africa (3). In early May 2022, mpox emerged worldwide, and case numbers increased substantially (4). On July 23, 2022, the World Health Organization (WHO) declared the mpox outbreak a Public Health Emergency of International Concern (5).

Genomic surveillance might be considered a fundamental approach to tracking circulating strains and investigating viral spread (6–8). By October 2022, Brazil had reported 12,378 mpox cases, and the state of Minas Gerais, located in southeast Brazil, reported a total of 838 cases through epidemiologic week 41 (9).

We selected 34 human MPXV-positive samples collected in Minas Gerais during June–September 2022 for whole-genome sequencing at the Central Laboratory of Public Health of Minas Gerais. The selected samples had cycle threshold values <30 and available epidemiologic patient data. The study was approved by the research ethics committee of the Ezequiel Dias Foundation (approval no. 62702222.6.0000.9507).

We extracted viral DNA from lesion exudate and sequenced with the Ion Torrent PGM platform (Thermo Fisher Scientific, https://www.thermofisher.com) using a set of MPXV-specific primers designed for this study by using the primalscheme platform version 1.3.2 (https://pypi.org/project/primalscheme) (Appendix Table 1). We used the MPXV reference genome (GenBank accession no. NC_063383.1) to perform genome assembly by using Burrows-Wheeler Aligner version 0.7.17 (https://github.com/lh3/bwa), SAMtools version 1.11 (https://github.com/samtools), and iVar version 1.0 (https://github.com/andersen-lab/ivar). We used Nextclade version 2.8.1 (Nextstrain, https://clades.nextstrain.org) to assess genome quality and classification.

We used MAFFT version 7.310 (https://mafft.cbrc.jp) to align the 34 genomes obtained from this study with an additional 218 MPXV genomes collected from GISAID (https://www.gisaid.org) until October 3, 2022 (Appendix Table 2). We used BEAST version 1.10.4 (https://beast.community) to infer the Bayesian phylogeny. The Brazilian Ministry of Health Notifiable Diseases Information System provided weekly notified cases of MPXV infection in Minas Gerais.

Epidemiologic data revealed that the highest number (n = 112) of MPXV cases in Minas Gerais were reported during epidemiologic week 31 (Appendix Figure 1). The data also highlight that the metropolitan region of Belo Horizonte had the highest concentration (n = 608) of confirmed cases during June–September (Appendix Figure 2).

Using patients’ clinical records, we found that 55.9% (19/34) were HIV-positive and 23.5% (8/34) reported active sexually transmitted infection. Among the screened samples, 33 were from male patients and 1 was from a female patient; patients were 22–46 (mean 32.5) years of age. The most frequent signs and symptoms were rash (34/34, 100%), lymphadenopathy (22/34, 64.7%), and fever (21/34, 61.8%) (Appendix Figure 3). Among mpox patients, 17 reported no travel history, 15 reported travel history to the state of São Paulo, Brazil, and 1 each reported travel to London and to Portugal.

Using the Ion Torrent PGM platform, we obtained a total number of 34 MPXV genome sequences. Genome coverage was 76.2%–97.5% (mean 87%) and had an average depth of 391× (Table). All the genomes generated in this study belonged to lineages B.1 (n = 13), B.1.1 (n = 19), B.1.2 (n = 1), and B.1.9 (n = 1), which are lineages responsible for the 2022 outbreak (7,8).

Figure

Figure. Bayesian phylogenetic tree of 34 genome sequences generated during genomic surveillance of monkeypox virus, Minas Gerais, Brazil, 2022. The tree also includes 218 reference strains available at GISAID (https://www.gisaid.org...

Our phylogenetic reconstruction revealed that all genomes from the 2022 mpox outbreak grouped together (Figure). Most of the genomes we obtained from Minas Gerais grouped with MPXV genomes isolated from other regions of Brazil (Figure). Our phylogenetic reconstruction revealed that the first mpox case reported in Minas Gerais, isolated from a patient with a travel history to London, UK (GISAID accession no. EPI_ISL_13780332), grouped with a genome sequence from the United Kingdom (GISAID accession no. EPI_ISL_14439774).

We also sequenced a sample from the first confirmed mpox death in Brazil, which was reported in late July 2022. That sample was collected from a patient who resided in Minas Gerais and was in treatment for diffuse large B-cell lymphoma and HIV (10). The genome from that patient’s sample belonged to the B.1.1 lineage, and in our phylogenetic reconstruction, it clustered with genome sequences isolated from Minas Gerais and from other states in Brazil.

Overall, our data revealed that an mpox case detected in Minas Gerais in early 2022 was related to a likely importation event, probably associated with a traveler returning from the United Kingdom, and then sustained MPXV community transmission. The first confirmed death reported in Minas Gerais was associated with a local MPXV infection described in a patient who reported several underlying conditions. These results contribute to genomic MPXV surveillance in Minas Gerais and increase the number of genome sequences from this virus available in GISAID. These findings and the available data can help future studies aiming to improve diagnostic protocols and vaccine development.

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