Monkeypox outbreak in Madrid (Spain): Clinical and virological aspects

Abstract

Background: Monkeypox is the most prevalent Orthopoxvirus zoonosis infection since the eradication of smallpox. The current multi-country outbreak involves five WHO regions affecting mainly Europe. Accurate clinical and virological aspects of the disease outside endemic areas are needed.

Methods: We performed an observational study of cases diagnosed in Madrid (Spain) (May/June 2022). Confirmation from vesicular lesions swabs, Orthopoxvirus real-time PCR, sequencing, phylogenetic analysis, and direct detection by Electron microscopy was performed. In addition, a structured epidemiological questionnaire was completed systematically to gather sociodemographic, clinical, and behavioral data from all confirmed cases.

Findings: We extracted data from 48 patients, all cisgender men. The median age was 35 years (IQR 29 - 44), and 87.5% were MSM. The most prevalent symptoms were the presence of vesicular-umbilicated and pseudo-pustular skin lesions (93.8%), asthenia (66.6%), and fever (52.1%). In addition, the location of the lesions in the genital or perianal area was related to the role in sexual intercourse (p<0.001). Sequencing analysis indicated the virus circulating in Spain belongs to the western African clade. Like the other European cases in the outbreak, the Spanish isolates are a direct descendant of viruses previously detected in Nigeria, the UK, Singapore, and Israel in 2017-2018.

Conclusions: Monkeypox is an emerging infectious disease in Europe where community transmission is reported, mainly in MSM. The first symptom was skin lesions instead of classical fever and rash. The disease follows a self-limited course, and there have been no cases with a serious presentation or severe complications.

Keywords: Communicable diseases; Emerging; Monkeypox.

Fig 1

Distribution of Monkeypox cases, by symptom onset during May/2022. Bars indicate the date of onset and the date of sampling. The Ct is also indicated in a green scale for each patient whose identification is also shown. Red stars indicate the participation in different chemsex events.

Fig. 2

Pictures of inguinal lymphadenopathies and vesicular-umbilicated genital lesions (A); perianal (B) and perioral lesions (C).

Fig 3

Image of the virus obtained by negative staining from a clinical sample by electron microscopy.

Fig. 4

Phlylogenetic tree obtained with sequence samples and representative Monkeypox genomes downloaded from NCBI and those sequenced in this work. Accession numbers, country of origin and years are indicated. Sequences from the current outbreak are shown by a red bar. Phylogenetic analysis was performed by using Iqtree v. 2.1.4-beta using predicted model K3Pu+F+I and 1000 bootstraps replicates.