Feasibility of post-exposure-prophylaxis with single-dose rifampicin and identification of high prevalent clusters in villages' hyperendemic for leprosy in Senegal.

INTRODUCTION: Senegal is a leprosy low-endemic country with nine villages known to be hyperendemic with a leprosy incidence rate above 1,000 per million inhabitants. We aim to implement a door-to-door screening strategy associated with the administration of a single-dose-rifampicin (SDR) as post-exposure prophylaxis (PEP) to household and social contacts in these villages and to identify spatial clustering and assess the risk of leprosy in population according to the physical distance to the nearest index-case. METHODS: From October/2020 to February/2022 active door-to-door screening for leprosy was conducted in nine villages. Using an open-source application, we recorded screening results, demographic and geographic coordinate's data. Using Poisson model we analysed clustering and estimated risk of contracting leprosy in contacts according to the distance to the nearest new leprosy patient. RESULTS: In nine villages, among 9086 contacts listed, we examined 7115. Among 6554 eligible contacts, 97.8% took SDR. We found 39(0.64%) new leprosy cases among 6,124 examined in six villages. Among new cases, 21(53.8%) were children, 10(25.6%) were multibacillary and 05(12.8%) had grade 2 disability. The prevalent risk ratio and 95% confidence intervale(95%CI) adjusted by village were 4.2(95%CI 1.7-10.1), 0.97(95%CI 0.2-4.4), 0.87(95%CI 0.2-25), 0.89(95%CI 0.3-2.6) and 0.70(95%CI 0.2-2.5) for the contacts living in the same household of an index case, 1-25m, 26-50m, 51-75m and 76-100m compared to those living at more than 100m respectively. We identified nine high prevalent clusters including 27/39(69%) of new cases in 490/7,850(6%) inhabitants, with relative risks of 46.6(p-value = 0.01), and 7.3, 42.8, 8.2, 12.5, 11.4, 23.5, 22.3, and 14.6 (non-significant p-values). CONCLUSIONS: Our strategy has proved the feasibility of active screening for leprosy in contacts and the introduction of PEP for leprosy under programmatic conditions. Only individuals living in the same household as the leprosy patient had a significant risk of contracting leprosy. We documented nine clusters of leprosy that could benefit from tailored control activities while optimizing resources.

[Leprosy in children in the region of Thiès, Senegal: study determining whether or not it is a signal of recrudescence]. / La lèpre de l'enfant à Thiès/Sénégal: signal d'une recrudescence?

Leprosy is an infectious and transmissible disease. According to the WHO, the number of new cases of leprosy in children in Senegal has risen moderately since 2013. This study aimed to analyze the epidemiological, clinical, therapeutic and evolutionary features of leprosy in children in the geographical areas of two social rehabilitation villages in the region of Thiès. We conducted a retrospective study over a period of 3 years (2013-2015). All new cases of Hansen's disease aged 0 -15 years were included. Over the three year period, 39 children were included in the study, with a boy predominance (n=23, 59%). Among these children, 27 (66.7%) came from a social rehabilitation village for leprosy patients. One family member was affected by leprosy in 27 cases (69.2%). More than half of the children (23 cases, 58.9%) had multibacillary leprosy (lepromatous-lepromatous). All children underwent a 12-month treatment, at the end of which thirty-six (92.3%) children were healed. Leprosy is still present in Senegal despite the efforts made by the national programme to combat leprosy. In the light of these results, it is important to emphasize the role of active screening strategy targeted to children, which seems to have shown its effectiveness in the region. Early detection, contact tracing and early treatment are important factors in the reduction of the contagiousity of leprosy.

[Evaluation of the Senegal leprosy endemic in 2002]. / Evaluation de l'endémie lépreuse au Sénégal en 2002.

UNLABELLED: The authors had for aim to assess the epidemiology of leprosy in Senegal after 7 years of efficient prevention. METHODS: A retrospective study was made on epidemiologic data in Senegal collected between January 1 and December 31, 2002. The indicators of eradication (total number of new cases diagnosed in that year compared to the country's population, expressed in cases per 100,00 inhabitants), the coverage rate (number of cases treated compared to the number of patients recorded for treatment), as well as the cure rate (percentage of patients having complied to the duration of treatment) were all noted. RESULTS: The mean detection rate was 0.5 case per 100,000 inhabitants with 434 new cases reported. The prevalence rate was 0.99 per 10,000 with 981 cases recorded for total management. The coverage rate for total management was 100%. The observed cure rate was 89% and 8% of the patients were lost to follow-up.

Definition of an algorithm for the management of common skin diseases at primary health care level in sub-Saharan Africa.

In order to help primary health care (PHC) workers in developing countries in the care of common skin diseases, an algorithm for the management of pyoderma, scabies, superficial mycoses, contact dermatitis and referral of early leprosy cases (based on the identification of diseases through the presence of objective key signs, and on treatments by generic drugs) was elaborated. One thousand patients were seen by trained dermatologists, who established diagnoses and treatments; in addition, there was systematic recording of each key sign, according to the successive algorithm steps. We compared the diagnostics and treatments obtained for several combinations of diagnostic signs, with those of the dermatologists. Sensitivity, specificity, positive predictive value and negative predictive value of defined combinations were high for pyoderma, scabies and superficial mycoses. Values were less exact for dermatitis and leprosy, but were considered sufficient for the level of health care targeted. The apportionment of treatments between the algorithm and the dermatological approaches was considered appropriate in more than 80% of cases; mismanagement was possible in 7% of cases, with few predictable harmful consequences. The algorithm was found satisfactory for the management of the dermatological priorities according to the standards required at the PHC level.

Fibronectin-binding antigen 85 and the 10-kilodalton GroES-related heat shock protein are the predominant TH-1 response inducers in leprosy contacts.

Peripheral blood mononuclear cells from 27 healthy leprosy contacts were analyzed for lymphoproliferation and TH-1 cytokine secretion (interleukin-2 and gamma interferon) in response to heat shock proteins with molecular masses of 65, 18, and 10 kDa from Mycobacterium leprae and the 30-32-kDa antigen 85 (Ag 85) from Mycobacterium bovis BCG. Cells from 18 and 19 of 19 lepromin-positive contacts proliferated or produced TH-1 cytokines in response to the M. leprae 10-kDa protein and to Ag 85, respectively. Limiting-dilution analysis for two lepromin-positive contacts indicated that about one-third of M. leprae-reactive T cells displayed specificity to the M. leprae 10-kDa protein and Ag 85. The M. leprae 65- and 18-kDa proteins were less potent TH-1 response inducers: gamma interferon and interleukin-2 could be measured in 14 and 19 lepromin-positive contacts, respectively. In contrast, very low or undetectable proliferative and cytokine responses were found for 8 lepromin-negative contacts. Our data demonstrate that the fibronectin-binding Ag 85 and the 10-kDa GroES homolog are powerful mycobacterial TH-1 response inducers in the vast majority of lepromin-positive contacts and suggest that they might be valuable candidates for a future subunit vaccine.

[The frequency of the appearance of perforating foot ulcers in patients with Hansen's disease as a function of treatment with disulone alone or with polychemotherapy]. / Fréquence d'apparition de maux perforants plantaires chez des malades hanséniens en fonction du traitement par disulone seule ou polychimiothérapie.

Between 1986 and 1989, in 5 departments of Senegal, 436 new cases of leprosy were detected, of whom 225 were put under dapsone monotherapy and 211 under multidrug therapy (MDT). Of them, 190 could be followed-up during 2 years by means of annual bacteriological and clinical examination, including neurological assessment. In 2 years, the onset of 10 (5.3%) chronic plantar ulcers (CPU) was observed: 4 (4%) among the 99 patients under dapsone monotherapy and 6 (6.6%) among the 91 under MDT (no significant difference). Of the 10 CPU, 3 (2%) appeared among the 149 patients without any disability at detection while 7 (17%) were observed among the 41 others who presented a grade 1 disability at detection (p < 0.01). Of the 6 CPU appeared in the patients under MDT, 5 (22%) were observed among the 23 who presented a grade 1 disability at detection and 1 (1.5%) among the 68 who did not (p < 0.01). This difference was not noted in the patients under dapsone monotherapy. Our results need to be confirmed by other studies including a higher number of patients followed-up during a longer period of time. Nevertheless, they suggest that MDT could prevent the onset of CPU, but only in patients without any disability at detection. Therefore, they reemphasize the importance of early detection of the disease in leprosy control programmes.

[Characterization of chronic plantar ulcers in former leprosy patients]. / Cancérisation des plaies chroniques plantaires chez les anciens malades de la lèpre.

Between 1988 and 1992, 21 biopsies for pathological examination were taken from 20 Senegalese leprosy patients suffering from chronic plantar ulcers (CPU) suspected of malignant transformation. The diagnosis of squamous cell carcinoma was effectively made in 13 cases and that of pseudoepitheliomatous hyperplasia in the remaining 8 cases. The mean period of time between the onset of CPU and that of malignant transformation was 10 years (range: 1 to 15 years); the mean annual frequency of the malignant transformation was 2 per 1,000 CPU. In countries where pathological examination is not available, below knee amputation could be considered whenever main clinical signs of malignant transformation are present. In countries where pathological examination is available, the therapeutic decision may differ according to the diagnosis: below knee amputation supplemented with block dissection of inguinal lymph nodes whenever possible in cases of carcinoma; below knee amputation depending on the function status of the foot and on the volume of tumor in case of pseudo-epitheliomatous hyperplasia.

[Detecting and monitoring leprosy neuropathy: which test to chose?]. / Dépister et surveiller une neuropathie hansénienne: quel test choisir?

The purpose of the study is to propose a simple and reproducible test for assessing nerve damage in leprosy. It is applied to the sensory branch of the radial nerve of leprosy patients, prior to any treatment. Skin sensitivity is measured by means of a needle, a drop of ether and some calibrated filaments. These three tests are collated and compared with the results of electromyographic examination of the nerve. The filament calibrated to 0.2 grams gives optimum sensitivity (0.79) and excellent specificity (0.95) in relation to the electromyographic test. Its routine use in the field is simple and reproducible and should result in a greater number of patients receiving the treatment they need.

[Epidemiological study of HIV seroprevalence in a leprosy patient population in Senegal]. / Etude épidémiologique de la séroprévalence de l'infection par le VIH dans une population hansénienne au Sénégal.

We report the findings of an epidemiological study conducted between June 1989 and February 1990 on a population of leprosy patients in southern Senegal (Bignona major endemic disease sector). Two types of population were studied: patients living in urban areas and inmates of leprosaria. The global HIV seroprevalence (HIV 2 in all cases) of the leprosy-patient population was 1.15% (3/257): 0.8% (1/130) for the urban group and 1.5% (2/127) for the leprosaria. The seroprevalence rate does not differ significantly from that for the control group studied and for blood donors (1/221). The diagnosis of leprosy in the seropositive subjects had been established before 1980. None of them showed any sign of relapse. The immunodepression associated with the presence of HIV was only moderate: it was reflected in a lowering of the CD4 count and of the CD4/CD8 ratio, but with no clinical sign of AIDS.