Morphology and molecular phylogeny of a new Myxidium species (Cnidaria: Myxosporea) infecting the farmed turtle Podocnemis expansa (Testudines: Podocnemididae) in the Brazilian Amazon
Graphical abstract
Introduction
Myxozoans correspond to a diverse group of diminutive endoparasitic cnidarians found associated with vertebrates and invertebrates hosts throughout the world [1]. Their adaptive success can be related to endoparasitic life style, but also in the range of exploited hosts, such as annelids and bryozoans (i.e. definitive hosts), fishes, amphibians, reptiles, waterfowl and small mammal (i.e. intermediate hosts), apart from adapting spread by marine, freshwater and terrestrial environments [1], [2]. Despite their evolutionary and ecological interest, myxozoans can also cause important diseases in wild and farmed hosts, sometimes with economic implications [1], [3]. Among the myxozoans, species of the genus Myxidium Bütschli, 1882, are typically coelozoic parasites whose myxospores develop in the gallbladder, urinary bladder, or tubules of the urinary system of their vertebrate hosts [4], [5], [6], [7]. Even though more than 850 Myxidium species are known worldwide, little is known about these myxosporeans to infect reptiles and only six species have been described parasitizing turtles from Asia, Europe and North America [6], [8], [9], [10].
Testudines encompasses the tortoises and turtles in a monophyletic taxon composed by species with a remarkable body plan [11] and almost half of the species have been considered as threatened [12], mainly due to exploitation and unregulated trade [13], [14]. In the Amazon watershed, one of the global regions with a higher stock of turtles [13], the use of these organisms by local populations, for consumption of meat, eggs, and ornamentation is historical and has contributed to the turtles population decline. This decline is especially true for the Giant South American river turtle, Podocnemis expansa Schweigger, 1812, a semi-aquatic species endemic to Amazon basin with an adult capable of being 1 m in length [14], [15]. Several strategies have been implanted to protect species of Podocnemis in South America. Public policies have established illegality of hunting, created conservation areas (especially for the nesting beaches), and legalized the trade of turtles in captivity [15]. In Brazil, Sá et al. [16] estimated the existence of 92 turtle farms, either for commercial purposes or conservation of the species, and these businesses have largely contributed in reducing the threatening of natural populations of P. expansa, a species currently considered of low risk of extinction [12].
This study describes, based on morphologic, molecular, and ultrastructural data, a new Myxidium species parasitizing the gallbladder of South American turtle P. expansa farmed in Brazilian Amazon.
Section snippets
Parasite sampling and microscopic examination
During field research conducted in the municipality of Manacapuru (3°18′52.41″S/ 60°35′25.75″W), Amazonas State, Brazil in December 2015, we had the opportunity to do parasitological exams in an adult farmed specimen of P. expansa. The turtle was obtained from a semi-intensive farming system, where the animals are caged in a density of about one turtle/m2. All organs and body fluids were examined for myxosporeans using light microscopy. Preliminary observations revealed myxosporeans myxospores
Results
An unknown Myxidium species was found floating in the bile of one specimen of P. expensa. The parasite was not found in any other organs, and no pathological signs were observed in the parasitized gallbladder.
Discussion
Of the some 2400 myxozoans known [36], six species of the genus Myxidium have been reported from reptilians, all parasitizing freshwater/terrestrials chelonians [4], [10] but none from Neotropical Region. The present study report the occurrence of new Myxidium infecting the gallbladder of Giant South American river turtle (P. expansa) from a turtle farm in the Brazilian Amazon. The features of this new species were consistent with those of the genus Myxidium[2], and the comparison of M.
Acknowledgments
This study was supported by the São Paulo Research Foundation — FAPESP (grant number 2013/21374-6). Mathews P.D. and Aguiar J.C. were supported by doctoral scholarships from FAPESP (grant number 2013/14656-5 and 2013/20770-5 respectively). E.A. Adriano received a research productivity grant from the National Council of Scientific and Technological Development (CNPq) (grant number 305630/2013-0). The authors thank the business Raimundo and Fabio Chico, owners of the turtle farm, by kindly
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2022, Parasitology InternationalCitation Excerpt :Myxozoans are a prominent group of cnidarian micro-parasites, which infect aquatic organisms. These obligate endoparasites infect vertebrate (primarily fish) and invertebrate hosts, in both freshwater and marine environments [12–15]. A number of new myxozoan species have been described in Brazil in recent years, primarily in the Amazon region, although in most cases, the species represent a few, relatively common genera, in particular Henneguya and Myxobolus [16–21].
A new Myxidium species (Myxozoa: Myxosporea) infecting the gallbladder of the turtle Podocnemis unifilis (Testudines: Podocnemididae) from Peruvian Amazon
2017, Acta TropicaCitation Excerpt :Indeed, only seven species belonging to Myxidiidae family have been reported infecting them (Eiras, 2005; Helke and Poynton, 2005; Garner et al., 2005; Roberts et al., 2008; Aguiar et al., 2017). In the same way, in the Amazon watershed, one of the global regions with a highest stock of turtles, to our knowledge there is only one report of Myxidium species in an adult Arrau turtle (Podocnemis expansa) from the Brazilian Amazon (Aguiar et al., 2017). However, in the Peruvian Amazon, despite of being the second largest portion of the Amazon rainforest, information about myxosporean infection is still scarce or even nothing is known about this group of parasites infecting vertebrate hosts.