Dataset Information

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. CONCLUSIONS/SIGNIFICANCE:Our findings confirm LST as a good tool for assessing L. major cryptic infection. However, the instability of the LST positivity in new foci should be considered as an important confounder of the outcome of this infection when developing a research protocol for vaccine trial.

SUBMITTER: Bettaieb J

PROVIDER: S-EPMC7473511 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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.

Bettaieb Jihène J Toumi Amine A Ghawar Wissem W Chlif Sadok S Nouira Mariem M Belhaj-Hamida Nabil N Gharbi Adel A Ben-Alaya Nissaf N Laouini Dhafer D Louzir Hechmi H Dellagi Koussay K Ben Salah Afif A

PLoS neglected tropical diseases 20200825 8

<h4>Background</h4>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.<h4>Methodology/principal findings</h4>We report here on a population based prospective study conducted on 2686 individuals living in two foci located in Central Tunisia, to ass ...[more]

PMID: 32841284

Similar Datasets

Project description:BackgroundRecent circumstantial evidence suggests that an increasing number of Iranian patients with cutaneous leishmaniasis are unresponsive to meglumine antimoniate (Glucantime), the first line of treatment in Iran. This study was designed to determine whether the clinical responses (healing, or non-healing) were correlated with the susceptibility of Leishmania parasites to Glucantime.Methods and findingsIn vitro susceptibility testing was first performed on 185 isolated parasites in the intracellular mouse peritoneal macrophage model. A strong correlation between the clinical outcome and the in vitro effective concentration 50% (EC50) values was observed. Parasites derived from patients with non-healing lesions had EC50 values at least 4-fold higher than parasites derived from lesions of healing patients. A selection of these strains was typed at the molecular level by pulsed-field gels and by sequencing the pteridine reductase 1 (PTR1) gene. These techniques indicated that 28 out of 31 selected strains were Leishmania tropica and that three were Leishmania major. The L. major isolates were part of a distinct pulsed-field group, and the L. tropica isolates could be classified in three related additional pulsed-field groups. For each pulsed-field karyotype, we selected sensitive and resistant parasites in which we transfected the firefly luciferase marker to assess further the in vitro susceptibility of field isolates in the monocyte cell line THP1. These determinations confirmed unequivocally that patients with non-healing lesions were infected with L. tropica parasites resistant to Glucantime. Additional characterization of the resistant isolates showed that resistance is stable and can be reversed by buthionine sulfoximine, an inhibitor of glutathione biosynthesis.ConclusionsTo the authors' knowledge, this is the first report of proven resistant parasites contributing to treatment failure for cutaneous leishmaniasis and shows that primary Glucantime-resistant L. tropica field isolates are now frequent in Iran.

Project description:BACKGROUND:In Ethiopia, visceral leishmaniasis (VL) is caused by Leishmania donovani. The estimated country-wide incidence of VL in Ethiopia is 3700-7400 cases/year. The balance between anthroponotic and zoonotic transmission is still unknown even though most authors believe that visceral leishmaniasis in East Africa is anthroponotic. Asymptomatic leishmania infections occur more frequently than clinically apparent visceral leishmaniasis cases. The aim of this study was to determine the prevalence of asymptomatic VL infection and assess the degree of exposure among residents in Raya Azebo Woreda villages where cases of VL were recently reported. METHODS:A community based cross-sectional survey was conducted in 2013 between 1st of May and 25th of July. A total of 1099 individuals living in 314 households were included in the study. Socio-demographic and clinical data were collected from each of the participants and venous blood was also collected for the detection of antibodies to visceral leishmaniasis using Direct Agglutination Test. Leishmanin skin test was performed to detect the exposure to the parasite. Data was entered into excel and exported to SPSS version 17 for statistical analysis. Chi-square and the corresponding p-values were used to determine the statistical significance of the proportions/ratios obtained from the cross tabulated data. A p-value < 0.05 was considered statistically significant. RESULT:A total of 1099 study subjects comprising 401 males and 698 females were included in the study. The overall positive leishmanian skin test and sero-prevalence rates respectively were 9.08% and 0.87%. The difference in LST positivity by age group and sero-prevalence by sex were statistically significant (P <0.01 and P<0.05 respectively). Out of the 9 sero-positive individuals, 7 had no history of travel to visceral leishmaniasis endemic areas out of Raya Azebo. CONCLUSION:In general our results suggest occurrence of VL in the study area is, very low. Our survey also indicates that due to the low incidence of the disease, and lack of awareness, some patients remain under diagnosed.

Dataset Information

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.

Publications

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.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets