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Yaws, a neglected tropical disease caused by the bacterium Treponema pallidum subspecies pertenue, manifests as ulcerative skin lesions. Nucleic acid amplification tests, like loop-mediated isothermal amplification (LAMP), are versatile tools to distinguish yaws from infections that cause similar skin lesions, primarily Haemophilus ducreyi. We developed a novel molecular test to simultaneously detect T. pallidum and H. ducreyi based on mediator displacement LAMP. We validated the T. pallidum and H. ducreyi LAMP (TPHD-LAMP) by testing 293 clinical samples from patients with yaws-like lesions. Compared with quantitative PCR, the TPHD-LAMP demonstrated high sensitivity and specificity for T. pallidum (84.7% sensitivity, 95.7% specificity) and H. ducreyi (91.6% sensitivity, 84.8% specificity). This novel assay provided rapid molecular confirmation of T. pallidum and H. ducreyi DNA and might be suitable for use at the point of care. TPHD-LAMP could support yaws eradication by improving access to molecular diagnostic tests at the district hospital level.
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http://dx.doi.org/10.3201/eid2602.190505 | DOI Listing |
BMC Infect Dis
July 2025
Department for Disease, Epidemics and Pandemics Control, Yaounde, Cameroon.
Background: In September 2023, fifty cases of chronic limb ulcers of unknown origin were reported in six Health Districts (HDs) in Northern Cameroon. This disease, locally called "Ladde", was described as of mystical origin, transmitted by insect bites. We aimed to describe the cases, identify the cause and socio-anthropological considerations.
View Article and Find Full Text PDFInt J STD AIDS
July 2025
Unidad de ITS y VIH Drassanes - H. Universitari Vall d'Hebron, Barcelona, Spain.
A 64 year old cisgender man attended to our genito-urinary clinic with a 1 week history of a painful genital ulcer after travelling to Madagascar. On physical examination, we observed two small ulcers, each with a fibrinous base and erythematous borders, without associated lymphadenopathy. The initial diagnosis was a genital herpes outbreak.
View Article and Find Full Text PDFPLoS Negl Trop Dis
May 2025
Scientific Direction, Centre Pasteur du Cameroun, Yaounde, Cameroon.
Background: Children in parts of Africa, the South Pacific, and Southeast Asia frequently develop cutaneous ulcers caused by two bacteria: Haemophilus ducreyi (HD) and Treponema pallidum subspecies pertenue (causative agent of yaws). The World Health Organization (WHO) aims to eradicate yaws using mass administration of azithromycin. This also leads to a temporary decrease in ulcers caused by HD followed by a rebound suggesting an ongoing reservoir of infection.
View Article and Find Full Text PDFClin Infect Dis
March 2025
UNC Project Malawi, Lilongwe, Malawi.
Background: As syphilis rates have increased globally, chancroid has dramatically declined as a cause of genital ulcer disease (GUD).
Methods: We recruited patients ≥18 years presenting to an STI clinic with GUD from Lilongwe, Malawi from November 2019 - April 2022. Lesion exudates were tested by darkfield microscopy (DFM) and polymerase chain reaction (PCR) for Treponema pallidum (TP), and by PCR for Haemophilus ducreyi (HD), herpes simplex virus (HSV) and Chlamydia trachomatis (CT).
Lancet Glob Health
November 2024
Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Hospital for Tropical Diseases, London, UK; Division of Infection and Immunity, University College London, London, UK.
Background: To meet the WHO target of eradicating yaws by 2030, highly sensitive and specific diagnostic tools are needed. A multiplex Treponema pallidum-Haemophilus ducreyi loop-mediated isothermal amplification (TPHD-LAMP) test holds promise as a near-patient diagnostic tool for yaws and H ducreyi. We conducted a prospective evaluation in Cameroon, Côte d'Ivoire, Ghana, and the Republic of the Congo to determine the diagnostic accuracy of the TPHD-LAMP test, as well as to assess its acceptability, feasibility, and cost.
View Article and Find Full Text PDF