Haemophilus ducreyi Bacteria Causing Cutaneous Ulcer Outbreak in Children, Sierra Leone, December 2025

In October 2025, an outbreak of cutaneous ulcers on lower limbs began in the Kayassie community in Sierra Leone, predominantly affecting approximately 403 schoolchildren. Initially suspected to be caused by Bacillus anthracis, laboratory testing confirmed that Haemophilus ducreyi bacteria was the causative agent. The number of cases increased progressively: 266 cases by December 24, 2025, 386 cases by January 13, 2026, and 403 cases by February 10, 2026. Patients exhibited progressive skin ulcers with irregular borders occurring mainly on lower limbs. Haemophilus ducreyi is a bacterium traditionally associated with a sexually transmitted infection but has recently been recognized as an emerging cause of cutaneous ulcers in tropical regions. Patients recovered following treatment and management.