Leishmania species and clinical characteristics of Pacific and Amazon cutaneous leishmaniasis in Ecuador and determinants of health-seeking delay: a cross-sectional study

Abstract

Background Cutaneous Leishmaniasis (CL) affects up to 5.000 people in Ecuador each year. L. guyanensis and L. braziliensis are the most common of the eight CL-causing Leishmania species. Earlier CL research concentrated on the easily accessible Pacific region. This study aims to describe the Leishmania species in Pacific and Amazon ecoregions, to analyze regional differences in CL patient clinical presentation, and to identify determinants of health-seeking delay. Methods All cases in this cross-sectional study were diagnosed using smear slide microscopy, PCR, or both. Cytochrome B gene sequencing was used to identify the causative Leishmania species in qPCR-positive samples. Results This study included 245 patients, with 154 (63%) infected in the Pacific region and 91 (37%) infected in the Amazon. Causative Leishmania species were identified in 135 patients (73% of qPCR positives). L. guyanensis was identified in 76% (102/135) of the samples and L. braziliensis in 19% (26/135). The Pacific region had a low prevalence of 6% (5/89) of L. braziliensis. For the first time, we report L. guyanensis from the central Amazon, L. braziliensis from the northern Pacific, and L. lainsoni from both the central Amazon and northern Pacific. Amazon cases had a longer median health-seeking delay in months (2.0, IQR 3.0) than Pacific cases (1.0, IQR 1.5). Prolonged health-seeking delay was associated with older age, Amerindian ethnicity, infection at lower altitudes, non-ulcerative lesions, and lesions on the lower limbs. Conclusions In the Pacific region, health-seeking delay is relatively short and L. braziliensis prevalence remains low. Limited access to health care and stigma might explain the prolonged health-seeking delay in the Amazon. We recommend larger studies on the distribution of Leishmania species in Amazon CL cases and additional regional research into diagnostic test accuracy. Furthermore, the determinants of health-seeking delay in Ecuador should be investigated further.

Diagnostic accuracy of qPCR and microscopy for cutaneous leishmaniasis in rural Ecuador: A Bayesian latent class analysis

“…Ct values by region and microscopy results are presented in S2 Table . The qPCR detected 1x10 -9 ng/μL of synthetic DNA, which is equivalent to 4 copies of DNA in each 15uL reaction (S1 File). In 135/186 (73%) of the qPCR positive samples (71% Amazon, 74% Pacific) the causative Leishmania species could be determined, or in 46/129 (36%) and 89/185 (48%) of the total number of paired samples investigated in the Amazon and the Pacific, respectively [23]. Table 2 provides information on the species distribution by region, the sample internal control Ct values, and 18SrDNA Ct values by species.…”

“…The convenience sampling technique was used to obtain the study population sample size. A separate publication on this data provides additional details on the sample size calculation [ 23 ]. All centers had the laboratory capacity to perform smear slide microscopy and offered free treatment for CL-confirmed participants (intramuscular meglumine antimoniate for 20 consecutive days) or treatment for alternative diagnoses.…”

“…The geographical location of the participant was recorded to estimate the altitude of the place of infection in meters from the altitude of the airstrip of the nearest village ( http://www.ais.aviacioncivil.gob.ec /) or with topographic-map.com ( https://es-ec.topographic-map.com/maps/6ogw/Ecuador/ ) and was dichotomized as well in the Amazon and the Pacific region. Species determination was done by sequencing Cytochrome B and MPI as described elsewhere [ 23 ]. All the study data were collected on paper forms and entered into an electronic data capture system ( https://www.castoredc.com/ ).…”

“…com/maps/6ogw/Ecuador/) and was dichotomized as well in the Amazon and the Pacific region. Species determination was done by sequencing Cytochrome B and MPI as described elsewhere [23]. All the study data were collected on paper forms and entered into an electronic data capture system (https://www.castoredc.com/).…”

Infecciones tropicales parasitarias. Una revisión sistemática

“…MEDICIENCIAS UTA.2024;8 (2):21-35 predominando las especies L guyanensis y la L braziliensis. La leishmaniasis mucosa, progresa hasta provocar deformidades, aumentando la mortalidad, es más frecuente en sexo masculino (88%), y se caracteriza por la presencia de una úlcera en la mucosa nasal (77%), la edad de afectación más frecuente es a los mayores de 15 años (69%) y los síntomas se mantienen por más de 4 meses (63%), dentro de los exámenes pertinentes y predictores para el diagnóstico se encuentran la PCR, prueba cutánea en Montenegro, histopatología y serología (4,5). Con respecto al tratamiento de la leishmaniasis, se utiliza el antimoniato de meglumina como primera opción terapéutica, a una dosis de 10 -15 mg/kg/día (19).…”