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.

Atypical colorations occur in different groups of vertebrates. The loss of melanin in the skin, hair and eyes is the result of an autosomal recessive genetic entity. It causes individuals to present with a white coloration of the skin and hair, as well as red eyes, known as albino. This manuscript documents the first record in Mexico of complete albinism in a marsupial, Didelphis virginiana, captured in the Yucatan peninsula.

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.

Summary: Virginia opossum, Didelphis virginiana , is a synanthropic mammal associated with peridomestic areas of Yucatán, However, little is known about the gastrointestinal parasite infections of this species. The infection prevalence, mean abundance and mean intensity of eggs and oocysts of gastrointestinal parasites, in opossums captured in the peridomestic areas were estimated in six rural localities of Yucatán, Mexico. Eighty-four faecal samples were processed by flotation technique. McMaster test was used to estimate the number of helminth eggs and protozoa oocysts per gram of feces. Seven genera of gastrointestinal parasites were identified, and then infection prevalence was estimated as follows: Protozoa Eimeria sp. (51.9 %) and Sarcocystis sp. (1 %); nematodes Ancylostoma sp. (80.56 %), Cruzia sp. (62.04 %), Trichuris sp. (60.19 %), Capillaria sp. (29.63 %), Turgida sp. (23.15 %), Toxocara sp. (11.11 %), and Ascaris sp. (1.85 %); and one acanthocephalan: Oligacanthorhynchus sp. (14.81 %). This is the first study on the diversity of gastrointestinal parasites in Virginia opossums, and first evidence about the potential role of opossums in the transmission of zoonotic gastrointestinal parasites in peridomestic areas of Yucatán, Mexico.

The American opossum Didelphis virginiana is the marsupial species with the largest geographic distribution in North America, a very important natural host and key to the maintenance and transmission of many zoonotic pathogenic microorganisms of importance in public health, and one of the wild mammals with the greatest adaptation to the human environment, but despite all that very little is known about some physiological aspects in their free-ranging populations. In the present study, basic haematological parameters of 201 opossums from a synanthropic population of D. virginiana in a rural locality of the state of Yucatan, are first described. The average values of haemoglobin, packed cell volume, red blood cells, and eosinophils were higher in males and adults (except eosinophils) than in females and juveniles, respectively, and juvenile opossums had higher values of lymphocytes, neutrophils, and platelets than males. Non-pregnant females had significantly higher values of mean corpuscular volume, lymphocytes and platelets than pregnant ones, while red blood cell count and segmented neutrophils showed higher values in pregnant females. The establishment of the basic haematological parameters for free-ranging populations of D. virginiana is a very useful reference for both the health monitoring of the populations and further studying the host-parasite relationship of some zoonotic pathogens present in the Yucatan Peninsula.