A prospective cohort study of Cutaneous Leishmaniasis due to Leishmania major: Dynamics of the Leishmanin skin test and its predictive value for protection against infection and disease

Abstract

Background Leishmanin Skin Test (LST) is considered as a useful indicator of past infection by Leishmania parasites. However, the temporal dynamics of a positive LST under different epidemiologic scenarios and whether it relates to the protection against the recurrence of an overt disease are not fully documented. Methodology/Principal findings We report here on a population based prospective study conducted on 2686 individuals living in two foci located in Central Tunisia, to assess over a one-year epidemiologic season, the incidence of Leishmania (L.) major infection and disease and changes in LST reactivity. The two foci were both endemic for Cutaneous Leishmaniasis (CL) due to L. major, but contrasted in their history for this disease (ie: an old focus versus a recent focus). We found that most infections occurred in the new focus (290/1000; 95% CI: 265-315 person-years) with an incidence rate of CL lesions 2.4 times higher than in the old focus. Likewise, the rates of LST reactivity reversion and loss, in the new focus, were 99/1000[38-116] person-years and 14/1000[8-21] person-years, respectively. Loss of LST reactivity was not noticed in the old focus. Interestingly, the incidence rates of symptomatic infection did not differ significantly according to the LST status at enrolment (negative versus positive) between the combined foci and the new one.

Comparison between cutaneous leishmaniasis patients with facial and non‐facial lesions

“…Additionally, we recognize the possibility of selection bias, as all cases were collected from the in‐hospital setting and probably include patients with a more severe perception of their symptoms. Finally, we have not looked at the possibility of recurrence; however, this has been described previously, 19‐21 and further studies with long‐term surveillance are needed to allow real appreciation of relapse rate in both facial and non‐facial CL. Our study’s main points of strength include the relatively large number of cases with documented follow‐up treatment and the fact that all CL diagnoses were made by PCR.…”

Cytokine expression in the delayed-type hypersensitivity response of Peromyscus yucatanicus infected by Leishmania (Leishmania) mexicana that healed spontaneously / Expressão de citocinas na resposta de hipersensibilidade de tipo retardado de Peromyscus yucatanicus infectado por Leishmania (Leishmania) mexicana que curou espontaneamente

“…The resolution of cutaneous lesions caused by Leishmania spp., either spontaneously or after treatment with meglumine antimoniate, has been associated with the development of a protective immune response (Bettaieb et al, 2020). This protection is characterized by a strong DTH reaction, assessed by the leishmanin skin test (LST), that indicates a cellular immune response and memory developed after Leishmania infection (Alimohammadian et al, 2012).…”

“…It has been generally accepted that patients who resolve their lesions either spontaneously or after treatment develop a protective immune response that makes them resistant to reinfection (Bettaieb et al, 2020). This protection is evidenced through a delayed-type hypersensitivity (DTH) reaction that indicates the cellular immune response and memory developed after Leishmania infection.…”

Estudio clínico y epidemiológico de Leishmaniasis Cutánea en un Hospital Nivel II Del Perú

“…además, de afectar primordialmente a poblaciones de muy baja economía de países en vías de desarrollo (Bettaieb et al, 2020;Han et al, 2021;Karimkhani et al, 2017;Samir-Cubas et al, 2019). La leishmaniasis describe una enfermedad causada por una infección con un parásito protozoario del género Leishmania, que puede manifestarse en tres formas: cutánea, mucocutánea y visceral.…”