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Fibropapillomatosis (FP) is a tumor disease that affects all sea turtle species but is mainly seen in green turtles Chelonia mydas. The pathology of FP has been described extensively, but its dynamics in populations over time have been less studied. We analyzed the dynamics of FP in a population of green turtles in Akumal Bay on the central coast of the Mexican Caribbean. A total of 475 green turtles were captured over 15 yr (2004-2018). The highest prevalence of FP was found in the largest turtles, and there was a positive relationship between FP prevalence and size of turtles. FP was first detected in 2008 at a prevalence of 1.6%, and annual prevalence increased markedly from 17.9% in 2015 to 54% by 2018. Likewise, severity of FP increased over time, with most turtles falling into moderately to severely diseased categories (tumor score 2). The average size of turtles with FP was significantly larger than the size of individuals without FP. Regression of tumors was seen in 21% of turtles, tumor score was higher in smaller individuals, and only tumor score 2 was present in the largest sea turtles. An increase in the prevalence and tumor score of FP coincided with the massive arrival of Sargassum in 2015, suggesting that altered environmental conditions may have played a role. The increased prevalence of FP in Akumal Bay prompts the need to explain what might be driving this phenomenon and how widespread it is in the Caribbean.

Dendritic cells form the link between the innate and adaptative immune response, particularly on mucosal and epidermal surfaces. The Langerhans, an epidermal dendritic cell subpopulation, play a key role in the skin immune response across several species. Scarse immune cell subpopulations, including Langerhans-like cells, have been identified in endangered green turtles thereby complicating the understanding of the pathogenesis of diseases such as fibropapillomatosis, which induces skin tumours in this species worldwide. In biopsies from green turtle skin, we demonstrated that the polyclonal anti-human Langerin antibodies strongly stained a Langerin+ cell population in epidermal sheets, the suprabasal layer of the epidermis in cryosections and in cells from cytospin preparation of migration assays. The morphology of these cells was round to amoeboid in normal skin; however, in skin with ulcerative dermatitis, Langerin+ cells aggregated around ulcers and adopted a more pleomorphic morphology. To our knowledge, this is the first identification of Langerin+ cells with a molecular marker in a reptile species.

Rhipicephalus microplus (formerly Boophilus microplus) ticks are potential vectors of several pathogens of livestock especially in tropical and subtropical regions where may have substantial effects on economic development. Among tick-borne pathogens, Anaplasma marginale is considered one of the most important in domestic and wild ruminants worldwide. Different molecular mechanisms have been employed by both ticks and these intracellular pathogens, in order to be able to adapt and survive. Subolesin, originally called 4D8, is an evolutionarily well-preserved protein among ixodid tick species. This new antigen was found to be protective against tick infestations when used as a vaccine, as it has an essential role in tick blood digestion, development and infection of host cells by A. marginale. Recent studies have demonstrated that infection of both tick and vertebrate host cells with this microorganism changed gene expression. Therefore, the main objective of this study was to investigate subolesin expression in uninfected and A. marginale-infected R. microplus salivary glands by real-time reverse transcriptase (RT)-PCR. To analyze the differential expression of the recombinant protein subolesin, the gene was previously expressed from ticks infected with A. marginale. Results from this study revealed that, the expression of subolesin was significantly higher in salivary glands of infected R. microplus in comparison to uninfected ones., This work was supported by the Project CB-2015-01-255205: “Caracterización proteómica de Rhipicephalus microplus, R. annulatus y Amblyomma cajenennse para el control de infestaciones en bovinos”. Authorization DICB/C1000/3284/2016 funded by SEP-CONACYT.

Loggerheads ( Caretta caretta ) are endangered marine turtles and basic research is an essential component of conservation. In an attempt to provide further information in this field, we aimed to identify the microscopic morphological and histochemical features of the small intestine in the loggerhead turtle. Four loggerhead turtle hatchlings were used in this study; due to the loggerhead’s endangered status, this study was performed with dead animals. During necropsy, the cranial and caudal portions of the small intestine were obtained. The samples were embedded in paraffin and stained using the following techniques: Hematoxylin and Eosin, Gomori’s trichrome, Periodic acid-Schiff reactive (PAS), Alcian blue (pH 1.0 and pH 2.5), PAS-Alcian blue, Toluidine blue (pH 4.5 and pH 3.5), Giemsa, colloidal iron, Perl’s blue, Wilder’s impregnation, Methenamine silver, Grimelius and Masson-Fontana. The intestinal mucosa present plicae featuring a pseudostratified columnar epithelium with abundant blood vessels and abundant lymphatic vessels in the submucosa; both of these observations represent the main histological findings. The secretory granules in the goblet cells demonstrated the following characteristics: in the cranial portion, neutral mucopolysaccharides, sulfated acid mucopolysaccharides and mucopolysaccharides with sialic acid were found. In the caudal portion, neutral mucopolysaccharides and mucopolysaccharides with sialic acid were observed. Argentaffin cells were detected along the small intestine, primarily in the cranial portion. There are morphological differences, both histological and histochemical, between the cranial and caudal portion in the small intestine of C. caretta. These characteristics are correlated with possible functions in tissue physiology.

"La tortuga caguama ( Caretta caretta ) es una especie amenazada, por tanto la [investigación básica] es esencial para complementar los esfuerzos de con - servación. Con el objeto de generar información en este campo, este trabajo se orientó a la identificación de la morfología microscópica y los aspectos histoquímicos del intestino delgado en crías de tortuga caguama. Debido a su estatus como especie amenazada, se analizaron 4 especímenes muertos. Durante la necropsia, se obtuvieron muestras del intestino delgado en las porciones craneal y caudal. Las muestras se procesaron por el método de inclusión en parafina y se tiñeron por las siguientes técnicas: hematoxilina y eosina, tricrómica de Gomori, ácido peryódico-reactivo de Schiff (PAS), azul alciano (pH 1.0 y pH 2.5), PAS-azul alciano, azul de toluidina (pH 4.5 y pH 3.5), Giemsa, hierro coloidal, azul de Perls, impregnación de Wilder, me - tenamina de plata, Grimelius y Masson-Fontana. Entre los hallazgos histológicos, los principales fueron: la mucosa intes - tinal presentó plicas revestidas por un epitelio cilíndrico pseudoestratificado con vasos sanguíneos y en la submucosa se observaron abundantes vasos linfáticos. Los gránulos de secreción de las células caliciformes presentaron las siguientes características: en la porción craneal se observó la presen - cia de mucopolisacáridos neutros, ácidos sulfatados y con ácido siálico. En la porción caudal se detectó la presencia de mucopolisacáridos neutros y con ácido siálico. A lo largo del intestino se observaron células argentafines, principalmente en la porción craneal. Existen diferencias morfológicas, tan - to histológicas como histoquímicas, entre la porción craneal y caudal en el intestino de C. caretta . Estas características se correlacionaron con posibles funciones dentro de la fisiología tisular."