Mammomonogamus nematodes in felid carnivores: a minireview and the first molecular characterization

Evaluation of parasitic infections with histological and molecular detection in Anoles from St. Kitts

Anoles are a widely distributed group of reptiles that are also increasing in popularity as a pet animal. These species have been described as paratenic and intermediate hosts for many parasites of veterinary and medical importance. However, while human and animals such as cats and dogs may often interact with anoles, little research has been conducted in terms of assessing the full potential of anoles to harbor parasites of public and veterinary health significance. The current study analyzed the parasites of anoles captured and dissected in St. Kitts, West Indies, to describe the parasitic population within these reptiles and evaluate the potential role of anoles as intermediate/paratenic hosts. From March until May of 2019, samples from 11 anoles were collected following humane euthanasia and evaluated grossly, histologically, and molecularly for the presence of parasites. Histologic evaluation revealed adult ascarids, oxyurids, and spirurids within the stomach, as well as intraluminal adult ascarids within the intestine, and encysted larval trematodes within the intestinal wall. Molecular analysis based on 18S rRNA and ITS2 DNA markers for nematodes and trematodes, respectively, identified Physaloptera sp. (99.4-99.8% identical with Physaloptera turgida, Physaloptera mirandai, Physaloptera retusa, Physaloptera rara) and Platynosomum illiciens (99.7% identical). Phylogenetic analysis of ITS 2 sequences of P. illiciens from this study cladded monophyletically with the same species from different geographic areas and hosts. Our study highlights the importance of understanding the role anoles play in the life cycles of less well-studied parasites, and the potential of these animals to act as intermediate or paratenic hosts.

Additional characterization of the adult worm Mammomonogamus laryngeus (Railliet, 1899) and the tissue lesions caused by the infection in buffaloes

Mammomonogamus spp. are parasites with curious characteristics, such as the "Y" shape that results from male and female maintaining the permanent copulation position and the controversial presence or absence of spicules. These nematodes are hematophagous and cause damage to the upper respiratory tracts of cattle, sheep, goats, deer, wild yaks, and orangutans. Human infection is rare and most cases until now have been in the Caribbean Islands or in Brazil, and mainly in farmworkers but recently there have been reports affecting tourists. In the present work, the parasites were recovered from the laryngopharynx and larynx region of Bubalus bubalis on the island of Marajó, Pará, Brazil. Different microscopy methodologies were applied (bright field, fluorescence, and scanning electron microscopy) to explore the ultrastructural details of the anterior end, genital structures and the host tissue damage caused by the nematodes. The well-developed mouth is an important structure in the identification of these nematodes and used by the parasite to adhere to the host's tissue. Different methodologies in microscopy and molecular biology contributed to a detailed morphological description and showed the phenotypic position of Mammomonogamus laryngeus. Light and scanning electron microscopy (SEM) showed details of the papillae, amphids, festoons, ribs, and teeth. Fluorescence microscopy enabled a detailed characterization of different structures, such as the bursal rays and SEM enabled the visualization of the specialized features of the cuticle surface in the male and female. Histopathological analyses, cryofracture and environmental SEM experiments of the infected tissues were carried out in order to investigate the lesions resultant from the parasitism. In addition, the parasite couples were submitted to cryofracture and these results revealed details of the reproductive structures of both sexes, including the male spicule.