ABSTRACT Localized cutaneous leishmaniasis (LCL) is an endemic disease in several Mexican States with the main endemic areas located in the South-Southeast region of the country, where 90% of Leishmania (Leishmania) mexicana cases are registered. The Southeast region is located in the Yucatan Peninsula, including Campeche, Quintana Roo and Yucatan States. Campeche and Quintana Roo register more than 60% of the cases in the country each year, while in Yucatan the reports are of imported cases due to residents traveling to endemic areas. However, since 2015, autochthonous cases have been diagnosed by health authorities in municipalities with no previous transmission records. We aimed to identify Leishmania parasite species involved in autochthonous cases by means of the PCR technique. The present study included 13 autochthonous cases of LCL with clinical and parasitological diagnoses during 2018 and 2019 by health authorities, without specific identification of the causal agent. Tissue samples were taken by scraping the margins of active lesions and then they were spotted onto an FTATM Elute Microcard. Next, DNA was eluted and used for PCR amplification of specific Leishmania genus and L. (L.) mexicana species-specific fragments. Molecular analysis showed evidence that L. (L.) mexicana was the causal agent of LCL in 12 of the 13 patients; in one patient, PCR was not performed due to the patient’s refusal to participate in the study. Identifying Leishmania species that cause LCL is necessary to define efficient treatment schemes and control strategies for the disease in vulnerable and susceptible areas of the Yucatan State’s municipalities.

ABSTRACT A cross-sectional study was conducted with a sample of 40 dogs with clinical signs suggestive of infection by Leishmania spp and Trypanosoma cruzi in the municipality of Lázaro Cárdenas, Quintana Roo, Mexico. Blood, skin and bone marrow samples were taken. Indirect immunofluorescence (IFI) tests for detection of anti-Leishmania infantum and immunochromatic test for the detection of anti-Trypanosoma cruzi antibodies in serum were performed. In addition, molecular analyses were performed using PCR to detect Leishmania spp in bone marrow and skin and T. cruzi in bone marrow. Histopathological analyses of the skin and cytology of the bone marrow were carried out in search of lesions and trypanosomatid agents. The results showed that 3 (7.5%) and 6 (15%) dogs with anti-L. infantum and T. cruzi antibodies were detected, respectively. Molecular analyses detected 17 dogs positive for infection by T. cruzi (42.5%) and none for infection by Leishmania spp. Dogs with low body condition showed greater seropositivity to T. cruzi using Fisher’s exact test (p<0.05). Parasites of the genus Leishmania did not actively participate in the pathological processes of the animals; however, a high frequency of animals infected with T. cruzi was observed.

RESUMEN Se realizó un estudio transversal con una muestra de 40 perros con signos clínicos sugestivos de infección por Leishmania spp y Trypanosoma cruzi en el municipio de Lázaro Cárdenas, Quintana Roo, México. Se tomaron muestras de sangre, piel y médula ósea. Se realizaron las pruebas de inmunofluorescencia indirecta (IFI) para detección de anticuerpos anti-Leishmania infantum e inmunocromática para detección de anticuerpos anti-Trypanosoma cruzi en suero. Además, se realizaron análisis moleculares, mediante PCR para la detección de Leishmania spp en médula ósea y piel y T. cruzi en médula ósea. Se realizaron análisis histopatológicos de piel y citológicos de médula ósea en busca de lesiones y agentes tripanosomátidos. Se detectaron 3 (7.5%) y 6 (15%) perros con anticuerpos anti-L. infantum y T. cruzi, respectivamente. En los análisis moleculares se detectaron 17 perros positivos a la infección por T. cruzi (42.5%) y ninguno a la infección por Leishmania spp. Los perros con baja condición corporal presentaron mayor seropositividad a T. cruzi mediante la prueba exacta de Fisher (p<0.05). Los parásitos del género Leishmania no participaron activamente en los procesos patológicos de los animales estudiados; sin embargo, se observa una alta frecuencia de animales infectados por T. cruzi.

This study longitudinally investigated the association between Triatoma dimidiata infestation, triatomine infection with Trypanosoma cruzi and household/backyard environmental characteristics in 101 homesteads in Molas and Yucatan, Mexico, between November 2009 (rainy season) and May 2010 (dry season). Logistic regression models tested the associations between insect infestation/infection and potential household-level risk factors. A total of 200 T. dimidiata were collected from 35.6% of the homesteads, mostly (73%) from the peridomicile. Of all the insects collected, 48% were infected with T. cruzi. Infected insects were collected in 31.6% of the homesteads (54.1% and 45.9% intra- and peridomiciliary, respectively). Approximately 30% of all triatomines collected were found in chicken coops. The presence of a chicken coop in the backyard of a homestead was significantly associated with both the odds of finding T. dimidiata (OR = 4.10, CI 95% = 1.61-10.43, p = 0.003) and the presence of triatomines infected with T. cruzi (OR = 3.37, CI 95% = 1.36-8.33, p = 0.006). The results of this study emphasize the relevance of chicken coops as a putative source of T. dimidiata populations and a potential risk for T. cruzi transmission.

Investigamos longitudinalmente la asociación entre la infestación por Triatoma dimidiata, su infección con Trypanosoma cruzi y las características ambientales de los domicilios/peridomicilios en 101 viviendas de Molas, Yucatán, México entre Noviembre de 2009 (temporada lluviosa) y Mayo de 2010 (temporada seca). Mediante modelos de regresión logística se probaron asociaciones entre la infestación/infección de T. dimidiatay factores de riesgo potenciales a nivel de las viviendas. Se colectó un total de 200 individuos de T. dimidiata en el 35.6% de las viviendas, mayormente del peridomicilio (73%). De todos los triatominos colectados el 48% se encontraron infectados con T. cruzi. Los triatomas infectados fueron colectados en el 31.6% de las viviendas (54.1% y 45.9% en intra y peridomicilio respectivamente). Aproximadamente el 30% de todos los triatominos colectados, fueron encontrados en gallineros. La presencia de un gallinero en el peridomicilio de una vivienda se asoció significativamante tanto con las posibilidades de encontrar T. dimidiata (OR = 4.10, CI 95% = 1.61-10.43, p = 0.003) como con la presencia de triatominos infectados con T. cruzi (OR = 3.37, CI 95% = 1.36-8.33, p = 0.006). Los resultados de este estudio enfatizan la relevancia de los gallineros como fuente putativa de poblaciones de T. dimidiata y como una fuente potencial de riesgo de transmisión de T. cruzi.