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Volume 32, Number 10—October 2026

Research Letter

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

Jianxu Zhang1, Peng Lv1, Teng Zhao, Hanji Jiang, James S. Squire, Martin S. Yonnie, Zikan Koroma, Ibrahim F. Kamara, Abdulai A. Jalloh, Guangqian Pei, Yunfei Wang, Hongling Liu, Mohamed B. JallohComments to Author , and Zhiqiang MiComments to Author 
Author affiliation: Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China (J. Zhang); National Key Laboratory of Advanced Biotechnology, Academy of Military Medical Sciences, Beijing, China (P. Lv); State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing (T. Zhao, H. Jiang, G. Pei, Y. Wang, Z. Mi); University of Sierra Leone, Freetown, Sierra Leone (J.S. Squire); National Public Health Agency, Freetown (J.S. Squire, Z. Koroma, A.A. Jalloh, M.B. Jalloh); Ministry of Health, Bombali DHMT, Makeni, Sierra Leone (M.S. Yonnie); World Health Organization, Health Systems and Services Cluster, Freetown (I.F. Kamara); The Fifth Medical Center of Chinese PLA General Hospital, Beijing (H. Liu); College of Medicine and Allied Health Sciences, University of Sierra Leone, Freetown (M.B. Jalloh)

Main Article

Figure 2

Heatmap of bacterial species investigated from study of Haemophilus ducreyi bacteria causing cutaneous ulcer outbreak in children, Sierra Leone, December 2025. Values are shown as log10(abundance + 0.01)%. Metagenomic analysis based on the DNBSEQ-G99 sequencing platform (MGI Tech, https://www.mgi-tech.com). The heatmap revealed that H. ducreyi, the third most abundant bacterium, was the most suspected causative agent through 22 skin swab samples. The samples were designated as follows: FS, samples collected on November 18, 2025; S, samples collected on December 12, 2025; AS and BS, samples collected on December 18, 2025.

Figure 2. Heatmap of bacterial species investigated from study of Haemophilus ducreyi bacteria causing cutaneous ulcer outbreak in children, Sierra Leone, December 2025. Values are shown as log10(abundance + 0.01)%. Metagenomic analysis based on the DNBSEQ-G99 sequencing platform (MGI Tech, https://www.mgi-tech.com). The heatmap revealed that H. ducreyi, the third most abundant bacterium, was the most suspected causative agent through 22 skin swab samples. The samples were designated as follows: FS, samples collected on November 18, 2025; S, samples collected on December 12, 2025; AS and BS, samples collected on December 18, 2025.

Main Article

1These authors contributed equally to this article.

Page created: September 21, 2026
Page updated: September 28, 2026
Page reviewed: September 28, 2026
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