Environmental changes triggered by deforestation, urban expansion and climate change are present-day drivers of the emergence and reemergence of leishmaniasis. This review describes the current epidemiological scenario and the feasible influence of environmental changes on disease occurrence in the state of Yucatan, Mexico. Relevant literature was accessed through different databases, including PubMed, Scopus, Google, and Mexican official morbidity databases. Recent LCL autochthonous cases, potential vector sandflies and mammal hosts/reservoirs also have been reported in several localities of Yucatan without previous historical records of the disease. The impact of deforestation, urban expansion and projections on climate change have been documented. The current evidence of the relationships between the components of the transmission cycle, the disease occurrence, and the environmental changes on the leishmaniasis emergence in the state shows the need for strength and an update to the intervention and control strategies through a One Health perspective.

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 FTA^TM 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.

In type 1 diabetes, a failure in the regulation of either innate or acquired immunity may be the cause of autoimmune response. A cell population that may have a regulatory role of the immune response are the Natural Killer T (NKT) cells, which are a population expressing T lymphocyte antigen receptor (TCR), and a common marker for NK cells. A distinctive characteristic in NKT cells is their capacity to produce large amounts of immune-modulating cytokines. A decrease in the number and/or functional incapability of NKT cells is associated with progression of type 1 diabetes and with other self-immune diseases. However, the relevance of such findings is not completely understood. Limitations of the current studies include the existing methods to measure NKT activation and the lack of assessment of the expression of genes affected by NKT action. Nevertheless, the study of NKT cells may be a new clinical approach to detect individuals at risk for having type 1 diabetes. Additional studies are needed to evaluate the clinical value of this new predictive tool.

This study evaluated the effect of three feeding levels on the pathogenesis and establishment of H. contortus upon the first infection of parasite-naïve Pelibuey hair sheep lambs. Forty-two 6-month-old hair sheep lambs (24 ± 4 kg) raised parasite free from birth were used. The lambs were assigned to 3 groups (n = 14), and each was fed a diet designed for different daily weight gain (DWG): 75 g/d (Diet 1), 125 g/d (Diet 2) and 200 g/d (Diet 3). After four weeks of diet adaptation, 10 lambs/group were infected with 450 L₃H. contortus/kg BW (infected), and 4 lambs/group were kept parasite-free (NInf). DWG, hematocrit (Ht), hemoglobin (Hb), peripheral eosinophils (EOS), IgG concentration against H. contortus, and eggs per gram (EPG) of feces were measured in each lamb from day 14 before infection until day 29 postinfection (PI). On day 29 PI, the lambs were slaughtered to determine the total number of adult parasites (TAW), the length of the female worms, and the number of eggs in utero (EIU). Each group reached the expected DWG (P = 0.001), and there was no effect of infection or the diet × infection interaction. Ht was lower in infected lambs than in NInf lambs, and this difference was significant for animals on Diets 1 and 2 (P = 0.044). From day 14 PI onward, Hb was lower in the infected lambs than in the NInf lambs (P = 0.001). Furthermore, compared with NInf lambs, the infected lambs had higher EOS from day 7 PI and higher IgG from day 14 PI. Neither EOS nor IgG were affected by diet. Lambs on Diet 3 had lower EPG during patency than those fed Diets 1 or 2 (days 25 and 28 PI; P = 0.002). Furthermore, lambs fed Diet 3 had lower TAW (Diet 1 vs 3 P = 0.037; Diet 2 vs 3 P = 0.049) and EIU (P = 0.004) than lambs fed Diet 1 or 2. Lambs were resilient to infection regardless of diet. Although EOS and IgG were higher in all infected animals than in Ninf animals, EPG, TAW and EIU decreased only in lambs fed Diet 3. Thus, a diet targeting a DWG of 200 g/d can significantly limit the establishment of H. contortus in Pelibuey lambs infected for the first time.

In the present study, helminths from six Didelphis virginiana and one Philander vossi are reported using morphological techniques (clearing, staining, and scanning electron microscopy). Additionally, the 28S rRNA sequences of individuals from nine helminth taxa are provided. Phylogenetic analyses were performed with the new 28S rRNA sequences to confirm the identification and the genealogical relationships of the parasites. Thirteen helminth taxa were identified, comprising the trematodes Brachylaima sp. and Platynosomum illiciens, the cestode Mathevotaenia sp., the nematodes Cruzia americana, Cruzia tentaculata, Viannaia arriaguensis, Viannaia sp., Travassostrongylus sp., Strongyloides sp., Turgida turgida, Trichuris minuta, and Trichuris sp., and the acanthocephalan Oligacanthorhynchus microcephalus. All opossums were infected with at least four helminth taxa. In total, 17 new 28S rRNA sequences from nine helminth taxa were provided. These data, combined with previous records in Mexico, increase the number of helminth taxa parasitizing D. virginiana and P. vossi to 41 and 29, respectively. However, these reports are incompletes and concentered in localities of some states. It is possible that new surveys in the Nearctic and even Neotropical regions will reveal a higher helminth diversity in these mammals in the country.

La enfermedad de Chagas, causada por Trypanosoma cruzi, es una zoonosis endémica en América que afecta a millones de personas y circula en una amplia variedad de especies animales. En México, si bien se ha documentado su presencia en animales domésticos y silvestres, no existían registros de infección en bovinos. Este estudio reporta un caso en Sayula de Alemán, Veracruz, donde se investigó la muerte súbita de tres bovinos en un corral de engorda. A través de exámenes clínicos, hematológicos y pruebas moleculares (PCR), se detectó la presencia de T. cruzi en dos de cinco bovinos analizados, ambos con alteraciones hematológicas graves, compatibles con una forma aguda de la enfermedad. La identificación molecular del parásito, junto con los signos clínicos observados y la respuesta positiva al tratamiento, proporciona evidencia de la infección activa en bovinos. Estos hallazgos sugieren que el ganado puede actuar como reservorio del parásito en contextos peridomésticos, lo que representa un riesgo potencial para la salud humana en zonas rurales endémicas. Además, se destaca la necesidad de incluir a los bovinos en programas de vigilancia epidemiológica, considerando la diversidad genética de T. cruzi y su impacto clínico variable. El estudio subraya la importancia del diagnóstico temprano, el control de vectores y mejoras en las prácticas veterinarias como medidas clave para mitigar la transmisión y los impactos de esta enfermedad en la salud pública y la producción animal.