Rhinebothrium reydai: A new species of Tapeworm from a Caribbean Stingray.

The Potamotrygonidae are a unique group of Freshwater Stingrays found in the rivers of South America. They were originally thought to have colonised the continent from the Atlantic, since they are found only in rivers that drain into that ocean. However genetic studies have suggested that these Rays are in fact more closely related to Pacific species, and that the species found furthest west (i.e. upstream) are more closely related to marine species than those further downstream, suggesting that the first colonists had come from the Pacific, and that the invasion of South America must therefore have occurred before the rise of the Andes Mountains. This was a surprising conclusion, and provoked scientists to look for more evidence. One place where this was found was in the Tapeworms (Cestoda) that infect the intestines of these Rays, which were found to follow the same genetic pattern, with species found furthest from the sea most closely related to their marine relatives.  Because these Rays appeared to have invaded the continent before the rise of the Andes, they were for a long time presumed to have no close relatives in the seas, however, recent studies of the Indo-Pacific Stingsay genus Himantura revealed that two species previously assigned to it were in fact more closely related to the Freshwater Stingrays of South America; so closely related, in fact, that they were placed in a new genus, Styracura within the family Potamotrygonidae, the first marine Rays assigned to this group.

In a paper published in the journal Zootaxa on 3 August 2017, Bruna Trevisan and Fernando Marques of the Laboratório de Helmintologia Evolutiva at the Universidade de São Paulo describe a new species of Cestode Tapeworm from the intestine of the Caribbean Whiptail Stingray, Styracura schmardae, one of the two species of marine Potamotrygonid.

Tapeworms are parasitic Flatworms that live in the digestive tracts of Vertebrate hosts, attaching themselves to the intestine wall and absorbing nutrients through their skins. Adult Tapeworms engage in sexual reproduction, producing eggs which are passed out of the host in its feces. Juvenile Tapeworms often inhabit one or more intermediate hosts before reaching their final adult stage, growing in the gut till they reach a certain size, then migrating to other tissues where they form cysts, becoming dormant till the animal dies and is eaten by the next host in the life-cycle. 

The new species is placed in the genus Rhinebothrium, which is found in a wide range of Batoids, and given the specific name reydai, in honour of Florian Reyda, an expert on Cestodes who took part in the expedition to the Caribbean coast of Panama that recovered the Stingrays from which this species was first discovered. The species was found living in five Stingrays caught off the coast of Almirante in Bocas Del Toro Province. The Worms were up to 7.4 mm in length with as many s 64 segmants, and were attached to the lining of the intestine by s scolex ('head') with four stalked, bilobed bothridia (suckers).

Scanning electron micrograph showing the scolex of Rhinebothrium reydai. Trevisan &Marques (2017).

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Parasite infections in German soldiers from the Kilianstollen First World War archaeological site.

The science of palaeoparasitology involves the study of parasite remains from palaeontological and archaeological sites. This rarely involves the recovery of whole parasite fossils; the presence of parasites being more commonly determined from eggs, biomarkers or pathological alteration of the remains (i.e. damage caused to the living host of the parasite that is visible in the preserved body). As such identifying specific parasites takes considerable skill, but is considered worthwhile for the insight it gives into the lives of both the parasite and the host.

In a paper published in the journal PLoS One on 15 October 2014, MatthieuLe Bailly of Chrono-Environment at the University of Franche-Comte, Michaël Landolt of Pôle d’Archéologie Interdépartemental Rhénan and Leslie Mauchamp and Benjamin Dufour, also of Chrono-Environment at the University of Franche-Comte, describe the presence of parasites in bodies from the Kilianstollen First World War archaeological site in the Alsace Region of France.

The Killianstollen was a gallery built by German soldiers for use as a refuge during enemy attacks during the winter of 1915/16. It was 125 m long and between 3.5 and 6 m beneath the surface. At about 1.30 pm on 18 March 1918 the southern part of the gallery collapsed following heavy shelling by French artillery, trapping 34 reservist soldiers from the German 94^th Infantry Company. Thirteen of these soldiers were able to escape, but the remaining 21 were left for dead, eventually being excavated by archaeologists in 2011.

Le Bailly et al. took sediment samples from the abdomen regions of three bodies, a 20-year-old soldier, a 22-year-old corporal and a 35-year-old sergeant. These were solid samples, which were rehydrated, then crushed and sieved to extract parasite eggs.

The soldiers recovered during the excavations of ‘‘Kilianstollen’’ in Carspach. Michaël Landolt in Le Bailly et al. (2014).

No eggs were recovered from the body of the corporal. The body of the sergeant yielded two eggs of the Human Whipworm, Trichuris trichiura (a parasitic infection, the eggs of which have been recovered from a wide range of archaeological sites), and one egg of an unknown Capillariid (parasitic nematode).

Egg of Trichuris trichiura (53.19 by 27.45 mm) recovered in individual #1019 in Carspach Alsa‘‘Kilianstollen’’. Scale bar is 20 μm. Matthieu Le Bailly in Le Bailly et al. (2014).

The body of the soldier yielded 5 eggs considered to be from the same unknown Capillariid as the one from the sergeant. It also yielded one Tapeworm egg, Taenia sp. (there are three known species of Taenia that  infect humans, all of which could potentially be present at Kilianstollen), and 180 eggs from the Human Roundworm, Ascaris lumbricoides.

 

 Egg of Ascaris lumbricoides (66.57 by 53.04 mm) recovered in individual # 1018 in Carspach ‘‘Kilianstollen’’.Scale bar is 20 μm. Matthieu Le Bailly in Le Bailly et al. (2014).

A wide range of Capillariid Nematodes infect both human and animal hosts. Le Bailly et al. compared the specimens from Kilianstollen to a wide range of these, but were unable to make a positive identification. However they were most similar to the eggs of Eucoleus gastricus, a species which infects Rats rather than humans. This is quite plausible, as Rats are known to have been a problem at Kilianstollen and most similar First World War sites, with soldiers recording problems with Rat infestations, food being contaminated with Rat faeces and even instances of hungry soldiers eating Rats in both official records and private correspondence. If the eggs do come from Eucoleus gastricusor a similar Rat-infesting species then it cannot be determined that the soldiers were actually suffering from a Nematode infection or whether they had inadvertently consumed eggs from Rat faeces that were actually incapable of causing disease in a Human host.

Egg of Capillariid (65.036 by 28.38 μm) recovered in individual # 1018 in Carspach ‘‘Kilianstollen’’. Scale bar is 20 μm. Matthieu Le Bailly in Le Bailly et al. (2014).

Finally Le Bailly et al. note a considerable difference between the parasite load carried by the non-commissioned ranks and the common soldier at Kilianstollen, with no eggs recovered from the corporal, three belonging to two species from the sergeant and 186 eggs from three species from the common soldier. It is possible that this is simply an artefact of the small sample size, but it is also possible that it is the result of social stratification in the trenches, with non-commissioned ranks having access to better food, hygiene or information than common soldiers.

 Egg of Taenia sp. (34.95 by 32.25 mm) recovered in individual # 1018 in Carspach ‘‘Kilianstollen’’. Scale bar is 20 μm. Matthieu Le Bailly in Le Bailly et al. (2014).

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A preserved bladder stone from a medieval burial in Gdańsk, Poland.

Biological organisms often produce a variety of mineralized tissues, such...

Evidence of parasite infection in a medieval Korean mummy.

Parasite infections have been a fact of life for most humans throughout history, with the medical developments needed to fight them only becoming widely available since the Second World War. Studying the infections found in pre-modern populations is however difficult. Attempts to diagnose infections based upon historical records made by people who lacked the modern medical knowledge to record diagnostic symptoms accurately are an interesting parlour game, but not very...

Fossil Tapeworm eggs from the Permian.

 Tapeworms (Cestoda) are parasitic Flatworms that live in the digestive tracts of Vertebrate hosts, attaching themselves to the intestine wall and absorbing nutrients through their skins. Adult Tapeworms engage in sexual reproduction, producing eggs which are passed out of the host in its feces. Juvenile Tapeworms often inhabit...

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Fossil Tapeworm eggs from the Permian.

Tapeworms (Cestoda) are parasitic Flatworms that live in the digestive tracts of Vertebrate hosts, attaching themselves to the intestine wall and absorbing nutrients through their skins. Adult Tapeworms engage in sexual reproduction, producing eggs which are passed out of the host in its feces. Juvenile Tapeworms often inhabit one or more intermediate hosts before reaching their final adult stage, growing in the gut till they reach a certain size, then migrating to other tissues where they form cysts, becoming dormant till the animal dies and is eaten by the next host in the life-cycle.

In a paper published in the journal PLoS One on 30 January 2013, a team of scientists led by Paula Dentzien-Dias of the Laboratório de Paleontologia e Paleoceanografia at the Instituto de Oceanografia at the Universidade Federal do Rio Grande, announce the discovery of a number of fossilized tapeworm eggs in a coprolite (fossil feces) from the Mid to Late Permian Rio do Rasto Formation in the

municipality of São Gabriel in southern Brazil.

The coprolite is interpreted to have come from a Shark, due to its distinctive spiral shape, which is still seen in the feces of modern Sharks. The eggs are smooth shelled, ovoid structures 145–155 μm long, grouped together in a 1 × 4 mm cluster. This arrangement is typical of modern Tapeworms, who periodically shed clusters of eggs inside cast off body segments (proglottids).

The cluster of eggs from the Permian Shark coprolite in thin section. Dentzien-Dias et al. (2013).

Some of the eggs appear broken, and one has a developing embryo preserved. This egg only possesses part of the outer capsule, but retains a multi-layered inner capsule surrounding the embryo. Dentzien-Dias et al. theorize that the outer capsule has undergone apoptosis as modern Tapeworm eggs do.

Cestode eggs. (Top) The perfect oval shape hole were formed after the filling were reaped out from the coprolite during the lamination, the arrows show the operculum. (Bottom left) Egg with a developing embryophore. (Bottom right). Partial reconstruction of egg in (Bottom left). Abbreviations: C = capsule or shell; E = embryophore (ochosphere); H= putative developing hooklets; I = inner envelope; M= oncospheral membrane; O= outer envelope; P = putative polar thickening; Op = operculum; S = somatic cells. Dentzien-Dias et al. (2013).

The coprolite contains pyrite inclusions, which suggests it almost certainly sank into anoxic waters; the fossil bed it was found in is thought to have formed at the bottom of a freshwater lake. Coprolites with pyrite and preserved Tapeworm eggs have previously been found at neolithic sites, supporting this method of preservation, but nothing remotely as ancient as this find, which is thought to be around 270 million years old. Since it is more-or-less impossible to tell modern Tapeworm eggs apart visually, no attempt at lower level classification of the eggs is made.

Spiral heteropolar coprolite with cestode eggs. Dentzien-Dias et al. (2013).

See also The effect of parasitic Nematodes on European Eels, Two new species of terrestrial Flatworm from Brazil, An invasive Serpulid Worm in the La Encrucijada Biosphere Reserve, Mexico, Blue Flatworms invade Menorca and Evidence of fungal parasites modifying the behavior of ants from the Eocene Messel Shale.

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