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Washington Luis Conrado Dossantos - One of the best experts on this subject based on the ideXlab platform.
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associations among immunological parasitological and clinical parameters in canine visceral leishmaniasis emaciation spleen parasitism specific antibodies and Leishmanin Skin Test reaction
Veterinary Immunology and Immunopathology, 2008Co-Authors: Washington Luis Conrado Dossantos, E E V Jesus, M Paranhossilva, Andrea Mendes Pereira, J C Santos, C O Baleeiro, Eliane Goes Nascimento, Edson D Moreira, Geraldo Gileno De Sa Oliveira, Lain PontesdecarvalhoAbstract:Associations among parameters commonly used as markers of infection by Leishmania sp., or of susceptibility to visceral leishmaniasis, were investigated in 325 stray dogs from an area where this disease is endemic. Evidence of infection (presence of Leishmania in splenic cultures, positive Leishmanin Skin Test (LST) or detection of anti-Leishmania antibody activity in the serum) was found in 57% of the animals. Both evidence of weight loss (x2-Test, P = 0.0005) and presence of specific antibody activity in the serum (x2-Test, P < 0.0001) were directly associated with positive splenic culture. The frequencies of animals with positive splenic culture were directly correlated with the intensities of antibody activity in the serum as measured by ELISA (relative risk of 3.4 for animals with moderate antibody levels and relative risk of 8.43 for animals with high-antibody levels). A negative association was observed between positive Leishmanin Skin Test results and emaciation (x2, P = 0.0089). Furthermore, animals with positive splenic cultures and negative Leishmanin Skin Test results had higher levels of total serum IgG (Kruskal–Wallis Test, P = 0.001) and IgG2 (Kruskal–Wallis Test, P = 0.05) than animals with negative splenic cultures, and were more emaciated than animals with negative LST results and positive splenic cultures. The data presented herein suggest that associating these common parameters may improve their performance in predicting susceptibility to canine visceral leishmaniasis.
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Inflammation and structural changes of splenic lymphoid tissue in visceral leishmaniasis: a study on naturally infected dogs.
Parasite immunology, 2007Co-Authors: C. C. Santana, Geraldo Gileno De Sa Oliveira, José Vassallo, L. A. R. De Freitas, Lain Pontes-de-carvalho, Washington Luis Conrado DossantosAbstract:The aim of this study was to identify splenic immuno-inflammatory patterns associated with natural infection by Leishmania chagasi. Spleen samples were obtained from 72 stray dogs from an endemic area of visceral leishmaniasis. The animals were grouped into four categories as follows: (i) potentially resistant to visceral leishmaniasis, with a positive Leishmanin Skin Test result, and negative splenic culture for Leishmania parasites (ii) potentially susceptible to visceral leishmaniasis, with a negative Leishmanin Skin Test and positive splenic culture for Leishmania (iii) infected with undefined susceptibility status, with a positive Leishmanin Skin Test and positive splenic culture for Leishmania, and (iv) noninfected, with a negative Leishmanin Skin Test, negative splenic culture for Leishmania, and negative serology for anti-Leishmania antibodies. Histopathological analyses showed that there was a higher frequency of perisplenitis (18/25, P < 0.0001), granuloma (7/25, P = 0.0102), structural disorganization (14/25, P < 0.0001), and atrophy of the lymphoid follicles (20/25, P = 0.0036) and of the marginal zone (15/25, P = 0.0025) in the potentially susceptible group than in the other groups. The data presented here show changes in the white pulp of the spleen that are associated with naturally acquired visceral leishmaniasis.
Sadok Chlif - One of the best experts on this subject based on the ideXlab platform.
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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.
PLoS neglected tropical diseases, 2020Co-Authors: Jihene Bettaieb, Amine Toumi, Adel Gharbi, Sadok Chlif, Wissem Ghawar, Mariem Nouira, Nabil Belhaj-hamida, Nissaf Ben-alaya, Dhafer Laouini, Hechmi LouzirAbstract: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.
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Prevalence and determinants of Leishmania major infection in emerging and old foci in Tunisia
Parasites & vectors, 2014Co-Authors: Jihene Bettaieb, Bilel Chelghaf, Aicha Boukthir, Amine Toumi, Adel Gharbi, Sadok Chlif, Afif Ben SalahAbstract:Background Zoonotic Cutaneous Leishmaniasis (ZCL) due to Leishmania major (L. major) is still a serious public health problem in Tunisia. This study aimed to compare the prevalence and risk factors associated with L. major infection in old and new foci using Leishmanin Skin Test (LST) in central Tunisia.
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Prevalence and determinants of Leishmania major infection in emerging and old foci in Tunisia
Parasites and Vectors, 2014Co-Authors: Jihene Bettaieb, Bilel Chelghaf, Aicha Boukthir, Amine Toumi, Adel Gharbi, Sadok Chlif, Afif Ben SalahAbstract:Background: Zoonotic Cutaneous Leishmaniasis (ZCL) due to Leishmania major (L. major) is still a serious public health problem in Tunisia. This study aimed to compare the prevalence and risk factors associated with L. major infection in old and new foci using Leishmanin Skin Test (LST) in central Tunisia. Methods: A cross sectional household survey was carried out between January and may09 on a sample of 2686 healthy individuals aged between 5 and 65 years. We determined the prevalence of L. major infection using the LST. Risk factors of LST positivity were assessed using a logistic regression model. Results: The overall prevalence of LST positivity was 57% (95% CI: 53-59). The prevalence of L. major infection was significantly higher in the old focus (99%; 95% CI: 98-100) than in the emerging foci (43%; 95% CI: 39-46) (p =
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The predictive validity of naturally acquired delayed-type hypersensitivity to Leishmanin in resistance to Leishmania major-associated cutaneous leishmaniasis.
Journal of Infectious Diseases, 2005Co-Authors: Afif Ben Salah, Sadok Chlif, Hechmi Louzir, Mourad Mokni, Amor Zaatour, Mohamed Raouene, Riadh Ben Ismail, Koussay DellagiAbstract:To accurately quantify the different outcomes of Leishmania major infection and to evaluate the fraction of zoonotic cutaneous leishmaniasis (ZCL) cases prevented by naturally acquired Leishmanin Skin Test (LST) reactivity, a cohort of 470 children was followed up in 2 endemic foci, Remada and Dhiba, in southern Tunisia. During May 1997, before the ZCL emergence season, LST was performed, and results were reassessed 12 months later. Active case detection during the ZCL emergence season showed a high incidence of ZCL: 57.0% in Remada and 13.7% in Dhiba. The preventive fraction of ZCL conferred by LST reactivity increased proportionally with the reaction size before the emergence season, revealing a dose-response effect of approximately 70%. In addition, asymptomatic L. major infection appeared to be a significant form of natural immunization, particularly in the context of relatively low transmission. These findings may help in the design and evaluation of vaccines.
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The Predictive Validity of Naturally Acquired Delayed-Type Hypersensitivity to Leishmanin in Resistance to Leishmania major–Associated Cutaneous Leishmaniasis
The Journal of infectious diseases, 2005Co-Authors: Afif Ben Salah, Sadok Chlif, Hechmi Louzir, Mourad Mokni, Amor Zaatour, Mohamed Raouene, Riadh Ben Ismail, Koussay DellagiAbstract:To accurately quantify the different outcomes of Leishmania major infection and to evaluate the fraction of zoonotic cutaneous leishmaniasis (ZCL) cases prevented by naturally acquired Leishmanin Skin Test (LST) reactivity, a cohort of 470 children was followed up in 2 endemic foci, Remada and Dhiba, in southern Tunisia. During May 1997, before the ZCL emergence season, LST was performed, and results were reassessed 12 months later. Active case detection during the ZCL emergence season showed a high incidence of ZCL: 57.0% in Remada and 13.7% in Dhiba. The preventive fraction of ZCL conferred by LST reactivity increased proportionally with the reaction size before the emergence season, revealing a dose-response effect of approximately 70%. In addition, asymptomatic L. major infection appeared to be a significant form of natural immunization, particularly in the context of relatively low transmission. These findings may help in the design and evaluation of vaccines.
Adel Gharbi - One of the best experts on this subject based on the ideXlab platform.
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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.
PLoS neglected tropical diseases, 2020Co-Authors: Jihene Bettaieb, Amine Toumi, Adel Gharbi, Sadok Chlif, Wissem Ghawar, Mariem Nouira, Nabil Belhaj-hamida, Nissaf Ben-alaya, Dhafer Laouini, Hechmi LouzirAbstract: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.
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Prevalence and determinants of Leishmania major infection in emerging and old foci in Tunisia
Parasites & vectors, 2014Co-Authors: Jihene Bettaieb, Bilel Chelghaf, Aicha Boukthir, Amine Toumi, Adel Gharbi, Sadok Chlif, Afif Ben SalahAbstract:Background Zoonotic Cutaneous Leishmaniasis (ZCL) due to Leishmania major (L. major) is still a serious public health problem in Tunisia. This study aimed to compare the prevalence and risk factors associated with L. major infection in old and new foci using Leishmanin Skin Test (LST) in central Tunisia.
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Prevalence and determinants of Leishmania major infection in emerging and old foci in Tunisia
Parasites and Vectors, 2014Co-Authors: Jihene Bettaieb, Bilel Chelghaf, Aicha Boukthir, Amine Toumi, Adel Gharbi, Sadok Chlif, Afif Ben SalahAbstract:Background: Zoonotic Cutaneous Leishmaniasis (ZCL) due to Leishmania major (L. major) is still a serious public health problem in Tunisia. This study aimed to compare the prevalence and risk factors associated with L. major infection in old and new foci using Leishmanin Skin Test (LST) in central Tunisia. Methods: A cross sectional household survey was carried out between January and may09 on a sample of 2686 healthy individuals aged between 5 and 65 years. We determined the prevalence of L. major infection using the LST. Risk factors of LST positivity were assessed using a logistic regression model. Results: The overall prevalence of LST positivity was 57% (95% CI: 53-59). The prevalence of L. major infection was significantly higher in the old focus (99%; 95% CI: 98-100) than in the emerging foci (43%; 95% CI: 39-46) (p =
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Risk factors of Leishmanin-Skin Test positivity in transmission of Leishmania infantum in the center of Tunisia
Archives de l'Institut Pasteur de Tunis, 2003Co-Authors: A. Ben Salah, Adel Gharbi, Sadok Chlif, A Zaatour, N. Ben Alaya Bouafif, N. Bel Haj Hamida, K. DellagiAbstract:Dans le but d'estimer la prevalence et d'etudier les facteurs de risque de positivite au Test cutanee a la Leishmanine (TCL), une etude transversale a ete menee dans les gouvernerats de Kairouan et Kasserine entre les mois de juin 2000 et Avril 2001 sur un echantillon de 3190 volontaires sains. Le taux de prevalence standardise sur l'âge de la positivite au TCL est de 45,9% (IC 95% = [43,9-47,9]) ce qui confirme l'hyper endemicite de la zone etudiee. Ce taux varie en fonction des delegations; il est le plus eleve dans le village de Zaghdoud (Kairouan) ou il atteint 75,9% (IC 95% = [71,9-79,5]) et le moins eleve dans le village de Abdeladhim (Kasserine) avec un taux de prevalence de 6,5% (IC 95% = [3,7-11,0]). l'absence de difference significative entre les deux sexes suggere une exposition similaire entre les hommes et les femmes. l'etude de la prevalence en fonction de l'âge montre un profil different en fonction de la situation epidemiologique des differentes delegations. En effet, dans les delegations de Zaghdoud, Sidi Amor, El Hajeb et chbika, le taux de prevalence augmente rapidement avec l'âge atteignant un plateau a plus de 80% a partir de 15 ans. Pour les autres delegations, le taux de prevalence augmente progressivement avec l'âge partant d'un niveau faible pour les moins de 5 ans et atteignant plus de 70% a partir de 45 ans. L'analyse multivariee des facteurs de risque de la positivite au TCL montre que seules la delegation et l'âge sont des determinants de cette infection.
Afif Ben Salah - One of the best experts on this subject based on the ideXlab platform.
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Prevalence and determinants of Leishmania major infection in emerging and old foci in Tunisia
Parasites and Vectors, 2014Co-Authors: Jihene Bettaieb, Bilel Chelghaf, Aicha Boukthir, Amine Toumi, Adel Gharbi, Sadok Chlif, Afif Ben SalahAbstract:Background: Zoonotic Cutaneous Leishmaniasis (ZCL) due to Leishmania major (L. major) is still a serious public health problem in Tunisia. This study aimed to compare the prevalence and risk factors associated with L. major infection in old and new foci using Leishmanin Skin Test (LST) in central Tunisia. Methods: A cross sectional household survey was carried out between January and may09 on a sample of 2686 healthy individuals aged between 5 and 65 years. We determined the prevalence of L. major infection using the LST. Risk factors of LST positivity were assessed using a logistic regression model. Results: The overall prevalence of LST positivity was 57% (95% CI: 53-59). The prevalence of L. major infection was significantly higher in the old focus (99%; 95% CI: 98-100) than in the emerging foci (43%; 95% CI: 39-46) (p =
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The predictive validity of naturally acquired delayed-type hypersensitivity to Leishmanin in resistance to Leishmania major-associated cutaneous leishmaniasis.
Journal of Infectious Diseases, 2005Co-Authors: Afif Ben Salah, Sadok Chlif, Hechmi Louzir, Mourad Mokni, Amor Zaatour, Mohamed Raouene, Riadh Ben Ismail, Koussay DellagiAbstract:To accurately quantify the different outcomes of Leishmania major infection and to evaluate the fraction of zoonotic cutaneous leishmaniasis (ZCL) cases prevented by naturally acquired Leishmanin Skin Test (LST) reactivity, a cohort of 470 children was followed up in 2 endemic foci, Remada and Dhiba, in southern Tunisia. During May 1997, before the ZCL emergence season, LST was performed, and results were reassessed 12 months later. Active case detection during the ZCL emergence season showed a high incidence of ZCL: 57.0% in Remada and 13.7% in Dhiba. The preventive fraction of ZCL conferred by LST reactivity increased proportionally with the reaction size before the emergence season, revealing a dose-response effect of approximately 70%. In addition, asymptomatic L. major infection appeared to be a significant form of natural immunization, particularly in the context of relatively low transmission. These findings may help in the design and evaluation of vaccines.
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Analysis of granzyme B activity as a surrogate marker of Leishmania-specific cell-mediated cytotoxicity in zoonotic cutaneous leishmaniasis.
Journal of Infectious Diseases, 2004Co-Authors: Thouraya Bousoffara, Afif Ben Salah, Hechmi Louzir, Koussay DellagiAbstract:The purpose of this study was to analyze Leishmania-specific cell-mediated cytotoxicity in individuals with active or healed zoonotic cutaneous leishmaniasis (ZCL). The (51)Cr-release assay revealed a significant cytotoxicity against L. major-infected autologous macrophages in individuals with active or healed ZCL. As a surrogate marker of cytotoxic response, a Test based on the measure of granzyme B activity in parasite-stimulated peripheral blood mononuclear cells was optimized and evaluated in 88 individuals. Increased granzyme B activity was found in 62.5% of patients with active ZCL and in only 30% of individuals with healed ZCL. In both groups, granzyme B activity was significantly higher than in healthy, Leishmanin Skin Test-negative control subjects (P
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Leishmanin Skin Test lymphoproliferative responses and cytokine production after symptomatic or asymptomatic Leishmania major infection in Tunisia.
Clinical and Experimental Immunology, 1999Co-Authors: A. Sassi, Afif Ben Salah, H. Louzir, M. Mokni, A. Ben Osman, Koussay DellagiAbstract:Resistance to Leishmania parasite infection requires the development of a cellular immune response that activates macrophage leishmanicidal activity. In this study we have investigated the lymphoproliferative responses and in vitro cytokine production of peripheral blood mononuclear cells (PBMC) from individuals living in an endemic area for L. major infection in Tunisia. The results were compared with the DTH reaction of the Leishmanin Skin Test (LST). Sixty-seven individuals were included in the study: 22 persons (age range 9-60 years) who developed, 2 years before the present study, a parasitologically confirmed localized cutaneous leishmaniasis (LCL) that healed spontaneously, and 45 individuals (age range 18-20 years) born and living in the same area, with no previous history of LCL. LST was positive (Skin induration > or = 5 mm) in 20/22 cured cases of LCL and in 75% of healthy individuals without history of LCL. LST+ individuals expressed vigorous Leishmania-specific lymphoproliferative responses associated with in vitro production of interferon-gamma (IFN-gamma) but not IL-4. Interestingly, IL-10 was detected in parallel with the highest levels of IFN-gamma in PBMC supernatants from 3/20 cured LCL and 8/25 individuals without history of LCL. Our results showed a 98% concordance between the DTH reaction assessed by LST and the in vitro proliferative assay induced by soluble leishmanial antigens. Moreover, proliferative assays as well as cytokine analysis did not show any significant difference of the immune memory to parasite antigens developed by patients who had overt cutaneous leishmaniasis and those who had apparently asymptomatic infection.
Jihene Bettaieb - One of the best experts on this subject based on the ideXlab platform.
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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.
PLoS neglected tropical diseases, 2020Co-Authors: Jihene Bettaieb, Amine Toumi, Adel Gharbi, Sadok Chlif, Wissem Ghawar, Mariem Nouira, Nabil Belhaj-hamida, Nissaf Ben-alaya, Dhafer Laouini, Hechmi LouzirAbstract: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.
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Prevalence and determinants of Leishmania major infection in emerging and old foci in Tunisia
Parasites & vectors, 2014Co-Authors: Jihene Bettaieb, Bilel Chelghaf, Aicha Boukthir, Amine Toumi, Adel Gharbi, Sadok Chlif, Afif Ben SalahAbstract:Background Zoonotic Cutaneous Leishmaniasis (ZCL) due to Leishmania major (L. major) is still a serious public health problem in Tunisia. This study aimed to compare the prevalence and risk factors associated with L. major infection in old and new foci using Leishmanin Skin Test (LST) in central Tunisia.
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Prevalence and determinants of Leishmania major infection in emerging and old foci in Tunisia
Parasites and Vectors, 2014Co-Authors: Jihene Bettaieb, Bilel Chelghaf, Aicha Boukthir, Amine Toumi, Adel Gharbi, Sadok Chlif, Afif Ben SalahAbstract:Background: Zoonotic Cutaneous Leishmaniasis (ZCL) due to Leishmania major (L. major) is still a serious public health problem in Tunisia. This study aimed to compare the prevalence and risk factors associated with L. major infection in old and new foci using Leishmanin Skin Test (LST) in central Tunisia. Methods: A cross sectional household survey was carried out between January and may09 on a sample of 2686 healthy individuals aged between 5 and 65 years. We determined the prevalence of L. major infection using the LST. Risk factors of LST positivity were assessed using a logistic regression model. Results: The overall prevalence of LST positivity was 57% (95% CI: 53-59). The prevalence of L. major infection was significantly higher in the old focus (99%; 95% CI: 98-100) than in the emerging foci (43%; 95% CI: 39-46) (p =