Conference abstract
Emergence of Haemophilus ducreyi as a major cause of cutaneous ulcers in yaws endemic areas of Cameroon
Pan African Medical Journal - Conference Proceedings. 2023:18(178).03
Oct 2023.
doi: 10.11604/pamj-cp.2023.18.178.2301
Archived on: 03 Oct 2023
Contact the corresponding author
Keywords: Cutaneous ulcers, Haemophilus ducreyi, environment, flies
Oral presentation
Emergence of Haemophilus ducreyi as a major cause of cutaneous ulcers in yaws endemic areas of Cameroon
Philippe Ndzomo1,&, Serges Tchatchouang1, Mireille Noah1, Theophile Njamnshi2, Rebecca Handley3, Camila Gonzales- Beiras4, Tania Crucitti5, Michael Marks3, Sara Eyangoh1
1Centre Pasteur du Cameroun, Yaoundé, Cameroun, 2National Yaws, Leishmaniasis, Leprosy and Buruli ulcer Control Programme, Yaoundé, Cameroun, 3London School of Hygiene and Tropical Medecine, London, United Kingdom, 4Fundación Lucha contra el Sida, Yaoundé, Cameroun, 5Institut Pasteur de Madagascar, Tananarive 101, Madagascar
&Corresponding author
Introduction: epidemics of cutaneous ulcers in children are regularly reported in tropical and subtropical countries. Although they are frequently attributed to Treponema pallidum pertenue which causes yaws, Haemophilus ducreyi has emerged as a major cause of cutaneous ulcers in yaws-endemic areas and appears to persist after azithromycin mass treatment campaigns. The objective was to determine the prevalence of H. ducreyi cutaneous ulcers and to detect its DNA in non-human samples to improve the understanding of transmission dynamics.
Methods: a cross-sectional study was conducted in thirteen endemic health districts in Cameroon from 2020 to 2022. Swab samples were collected from cutaneous ulcer cases, from critical sites in the environment, and from domestic animals that may be involved in the transmission chain. All samples were transported cold and analyzed at the Centre Pasteur du Cameroun, which is the national reference laboratory for the confirmation of yaws and related ulcers. Before analysis, a nucleic amplification-based test was developed and validated for the differential diagnosis of yaws-like lesions. In addition, a method for screening H. ducreyi DNA on non-human matrices was designed.
Results: analysis performed over the past 3 years confirmed the predominance of H. ducreyi in yaws-like lesions in children with more than 20% (ranging from 0 to 73% in health districts) detection rate. H. ducreyi DNA was not detected in environmental samples analyzed but positive amplifications were obtained in samples collected from clothes and bed linens of patients with H. ducreyi cutaneous ulcers. Flies were the only animal on which we had positive amplification to H. ducreyi, with a detection rate ranging from 15 to 27%.
Conclusion: these data confirm that H. ducreyi is the principal cause of cutaneous ulcers in children in yaw endemic areas in Cameroon and suggest a possible role of flies in the transmission of H. ducreyi under natural conditions. Further investigations are needed to determine whether bacterial DNA in the flies is related to the ubiquity of the organism in the environment or the carriage of live organisms.
Emergence of Haemophilus ducreyi as a major cause of cutaneous ulcers in yaws endemic areas of Cameroon
Philippe Ndzomo1,&, Serges Tchatchouang1, Mireille Noah1, Theophile Njamnshi2, Rebecca Handley3, Camila Gonzales- Beiras4, Tania Crucitti5, Michael Marks3, Sara Eyangoh1
1Centre Pasteur du Cameroun, Yaoundé, Cameroun, 2National Yaws, Leishmaniasis, Leprosy and Buruli ulcer Control Programme, Yaoundé, Cameroun, 3London School of Hygiene and Tropical Medecine, London, United Kingdom, 4Fundación Lucha contra el Sida, Yaoundé, Cameroun, 5Institut Pasteur de Madagascar, Tananarive 101, Madagascar
&Corresponding author
Introduction: epidemics of cutaneous ulcers in children are regularly reported in tropical and subtropical countries. Although they are frequently attributed to Treponema pallidum pertenue which causes yaws, Haemophilus ducreyi has emerged as a major cause of cutaneous ulcers in yaws-endemic areas and appears to persist after azithromycin mass treatment campaigns. The objective was to determine the prevalence of H. ducreyi cutaneous ulcers and to detect its DNA in non-human samples to improve the understanding of transmission dynamics.
Methods: a cross-sectional study was conducted in thirteen endemic health districts in Cameroon from 2020 to 2022. Swab samples were collected from cutaneous ulcer cases, from critical sites in the environment, and from domestic animals that may be involved in the transmission chain. All samples were transported cold and analyzed at the Centre Pasteur du Cameroun, which is the national reference laboratory for the confirmation of yaws and related ulcers. Before analysis, a nucleic amplification-based test was developed and validated for the differential diagnosis of yaws-like lesions. In addition, a method for screening H. ducreyi DNA on non-human matrices was designed.
Results: analysis performed over the past 3 years confirmed the predominance of H. ducreyi in yaws-like lesions in children with more than 20% (ranging from 0 to 73% in health districts) detection rate. H. ducreyi DNA was not detected in environmental samples analyzed but positive amplifications were obtained in samples collected from clothes and bed linens of patients with H. ducreyi cutaneous ulcers. Flies were the only animal on which we had positive amplification to H. ducreyi, with a detection rate ranging from 15 to 27%.
Conclusion: these data confirm that H. ducreyi is the principal cause of cutaneous ulcers in children in yaw endemic areas in Cameroon and suggest a possible role of flies in the transmission of H. ducreyi under natural conditions. Further investigations are needed to determine whether bacterial DNA in the flies is related to the ubiquity of the organism in the environment or the carriage of live organisms.
