Investigation of chronic limb ulcers in Northern Cameroon: a socio-anthropological and clinical perspective

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.

We conducted a mixed descriptive cross-sectional study in November 2023. A case was any person that had presented a skin ulcer on any of the four limbs for at least 4 weeks any time during the study period, suspected of infectious cause or contamination, associated or not to other conditions and residing in the study area from January 2018 to October 2023. After active case-finding in health facilities and within the community, we featured sociodemographic (sex, age, occupation), clinical (location, signs/symptoms, ulcer occurrence), and therapeutic data (itinerary, treatment and outcome). We collected blood samples, ulcer swabs and skin biopsies to test for pathogens (Haemophilus ducreyi, Treponema pallidum, Mycobacterium ulcerans, Mycobacterium leprae, Leishmania), performed an entomological survey to search for potential vectors and conducted a socio-anthropological survey (individual interviews and focus group discussions) to explore community perceptions.

We identified 153 cases in total: 119 (77.8%) were men. The median age was 38.5 years (9 months to 94 years). Farmers (n = 63, 41.2%), followed by housewives (n = 24, 15.7%) were the most affected. The lower limbs (n = 138, 90.2%) were the preferred location. Pain (n = 130, 85.0%), swelling (n = 113, 73.9%), ulceration (n = 43, 28.1%) and fever (n = 42, 27.5%) were the most frequent signs/symptoms at the beginning. In 79 (51.6%) cases, the ulcers occurred spontaneously and 67 (43.8%) after trauma (road injuries, blunt objects ulcers). For treatment, 129 (84.3%) cases visited a traditional healer who ordered decoctions (n = 98, 64.1%) and poultices (n = 95, 62.1%) using powder; 81 (52.9%) cases visited a health facility and received Cloxacillin (n = 78, 51%) and diclofenac (n = 70, 45.8%). Ten (6.5%) cases were completely cured. Six out of ninety-four (6.4%) cases tested were HIV positive, 8 (8.5%) were syphilis positive, all referred for appropriate care. Dermohypodermatitis (n = 14 out of 28, 50%) and pyogenic granuloma (n = 12 out of 28, 43%) were the main anatomopathological findings. No patient was positive for Mycobacterium ulcerans, Haemophilus ducreyi or Treponema pallidum pertenue. The entomological investigation did not reveal any potential insect vectors for leishmaniasis. Socio-anthropological survey mostly reported that "Ladde" is a disease of diabolic origin caused by a spirit which comes from a demon-possessed animal or tree.

Posttraumatic leg ulcers and dermohypodermatitis were the predominant clinical and anatomopathological patterns. Traditional practitioners were the main point of care. Strengthening the capacity of health and laboratory personnel in the diagnosis and management of chronic skin ulcers pathogens is recommended to improve the outcome of chronic ulcers.