Clinical and epidemiological characterization of monkeypox virus infections in a Portuguese hospital

Carlos M. Nogueira, Department of Dermatovenereology, Unidade Local de Saúde de Braga, Braga, Portugal Raquel Azevedo, Department of Infectious Diseases, Unidade Local de Saúde de Braga, Braga, Portugal Teresa Pereira, Department of Dermatovenereology, Unidade Local de Saúde de Braga, Braga, Portugal Luísa Graça, Department of Infectious Diseases, Unidade Local de Saúde de Braga, Braga, Portugal Ana C. Carvalho, Department of Infectious Diseases, Unidade Local de Saúde de Braga, Braga, Portugal

Objective: Monkeypox virus infection was historically described as a zoonotic disease endemic to Africa, characterized by a generalized vesiculopustular rash and prominent systemic symptoms. The 2022 outbreak revealed a distinct clinical pattern, with sustained sexual transmission and atypical presentations. This study aimed to characterize the clinical features of mpox cases diagnosed at a Portuguese hospital. Methods: We conducted a retrospective analysis of patients diagnosed with mpox between May 2022 and October 2023. Diagnosis was confirmed by molecular testing. Data were extracted from electronic medical records. Results: Nineteen patients were identified, predominantly male, with a median age of 32 years. All cases were attributed to sexual transmission, mainly among men who have sex with men. Cutaneous involvement was universal, typically with a limited number of lesions localized to the genital or perianal region. Systemic symptoms were generally mild. Over half developed complications, most commonly proctitis, followed by bacterial superinfection. Two patients required hospitalization. Anal or perianal lesions were significantly associated with proctitis. Sexually transmitted coinfections were frequent. Patients required only symptomatic treatment. Conclusion: This series highlights a shift in mpox phenotype during the recent outbreak, characterized by limited lesion burden, predominant anogenital involvement, and mild systemic manifestations. Complications were frequent, requiring close monitoring, and STI screening is recommended.

Keywords: Mpox. Monkeypox virus. Sexually transmitted diseases. Disease outbreaks.