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==Abstract==

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A helminthological study of six adult Siberian roe deer (''Capreolus pygargus'' ) individuals from Primorsky Krai was performed. The abomasa and small intestine contents were assessed. All animals were infected with nematodes, and the intensity of infection ranged from tens to hundreds of specimens. ''Spiculopteragia spiculoptera''  was the dominant species, and ''Mazamastrongylus dagestanica''  and ''Nematodirus filicollis''  were also detected. ''Ostertagia antipini''  and a minor morph of ''S. spiculoptera'' , “''Rinadia mathevossiani'' ”, were observed for the first time in Primorsky Krai. In addition, the Spirurida nematode ''Pygarginema skrjabini''  was detected in one roe, and the trematode ''Dicrocoelium dendriticum''  was found in the small intestines of two roes.  

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==Keywords==

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Capreolus pygargus ; Primorsky Krai ; Helminths ; Spiculopteragia spiculoptera ; Rinadia mathevossiani ; Mazamastrongylus dagestanica ; Ostertagia antipini ; Nematodirus filicollis ; Pygarginema skrjabini ; Dicrocoelium dendriticum

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==Introduction==

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Among Russian zoologists, the Siberian roe deer ''Capreolus pygargus''  Pallas, 1771 has been considered a subspecies of the European roe deer ''Capreolus capreolus''  Linnaeus, 1758 — ''Capreolus capreolus pygargus''  for the major part of the 20th century ( [[#bb0005|Flerov, 1952]]  ;  [[#bb0010|Geptner ''et al'' ., 1961                            ]] ). This fact affected the data presentation of the helminth fauna of the roe. Extensive information about the roe helminth fauna, which was collected during the 20th century, did not distinguish between the two roe species (''C. pygargus''  and ''C. capreolus'' ) ( [[#bb0035|Pryadko, 1976]] ).      

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The Siberian roe is a widespread species, and there are mixed populations of ''C. pygargus''  and ''C. capreolus'' . According to the results of molecular-genetic studies, 80% of the roes in the Moscow and adjacent regions have “Siberian” mitochondrial genomes ( [[#bb0045|Zvychaynaya et al., 2011]] ). In connection with that, a helminthological study of the Siberian roe is quite important.      

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There is poor helminthological information about the Siberian roe deer that inhabits the Russian Far East. A study by [[#bb0030|Oshmarin and Parukhin (1963)]]  can be considered as the only report. The authors presented the results of a roe helminthological study in Primorsky Krai, but there was no data on the quantitative rate of infection.      

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Our objective was to gain information about the ''C. pygargus''  helminth fauna. Our research focused on the helminth species composition and uppermost nematodes that parasitise the abomasum and small intestine. Interest in these helminths is based on the high rates of infection and species diversity. A high degree of community for the nematode species composition of different ruminant species is typical. Therefore, a study of Siberian roe deer helminth fauna is important to identify the helminth exchange process between different species of wild and domestic ruminants.      

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==Materials and Methods==

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Helminthological autopsy of the abomasum and small intestine of six ''C. pygargus''  adult individuals was carried out according to conventional methodology ( [[#bb0020|Ivashkin et al., 1971]] ). Data collection occurred in the Terneysky District of Primorsky Krai (Russian Far East) during the snow period (November–February) from 2010 to 2013.      

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We collected the contents from the abomasum and first 50 cm of the small intestine connected with the abomasum. The samples were placed in a container and covered with water in a 1:1 ratio. We also scraped off the mucous tunic of the abomasum and small intestine and placed it in a container with the contents. After 10–15 min, we decanted the supernatant and recovered the sediment with water. We repeated this procedure 3–5 times until the supernatant became transparent. Then, we fixed the sediment with 96% ethanol at a 1:1 ratio.

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In the laboratory, we picked out the nematodes from the sediment using a binocular loupe. Species identification of the nematodes was made using males only because of unreliability of precise diagnostics based on females. Male species were cleared with 10% aqueous solution of glycerine in temporary whole mounts. Species identification was based on morphology, specifically on the reproductive system according to [[#bb0040|Skryabin ''et al'' ., 1954                            ]] ; [[#bb0035|Pryadko, 1976]]  ;  [[#bb0015|Govorka ''et al'' ., 1988                            ]] , and [[#bb0025|Kusnetsov, 2006]] . Because of the scarcity of data on the morphology of ''Nematodirus''  spp., we used our own keys for this genus (unpublished).      

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==Results and Discussion==

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All studied individuals of ''C. pygargus''  had the nematode species ''Spiculopteragia spiculoptera''  Guschanskaja, 1931, ranging from 26 to 392 males per animal, with an average of 173 specimens per animal. One of the roe deer had two males of the minor morph ''S. spiculoptera''  species, “''Rinadia mathevossiani'' ” (Ruchliadev, 1948). Morph ''R. mathevossiani''  was found in Primorsky Krai for the first time. We also found males of ''Mazamastrongylus dagestanica''  (Altaev, 1952), ranging from one to 25 specimens in three roe deer, with an average of nine specimens per animal. Two roe deer had one and 12 specimens of ''Nematodirus filicollis''  (Rudolphi, 1802) males. One roe had 10 specimens of ''Ostertagia antipini''  Matschulsky, 1950, and this species was observed for the first time in Primorsky Krai.      

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The total number of nematode females found in the abomasum and small intestine contents of ''C. pygargus''  ranged from 32 to 476 specimens, with an average of 238 nematode females per roe deer.      

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In addition to the nematodes listed above, which are similar in size and morphology, we found 112 nematodes of the species ''Pygarginema skrjabini''  Kadenazii, 1948 in the abomasum of one roe deer. These nematodes belong to the order Spirurida. They are relatively large at 2–2.5 cm in length. In contrast to all mentioned nematodes, which have a direct life cycle, the ''P. skrjabini''  cycle includes an intermediate host, dung beetles.      

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In addition to nematodes, the trematode ''Dicrocoelium dendriticum''  (Rudolphi, 1819) was found in the small intestine contents of two roe deer, with two and 20 specimens per animal.      

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Information about the taxonomical composition of the roe deer helminths was collected from the same area over a half of century ago ([[#bb0030|Oshmarin and Parukhin, 1963]] ). Those results consist with our results for only one species, ''D. dendriticum''  (= ''Dicrocoelium lanceatum'' ). In addition to this species,  [[#bb0030|Oshmarin and Parukhin (1963)]]  reported five species of roe deer helminths in the Sikhote-Alin Reserve, ''Skrjabinotrema ovis'' , ''Oesophagostomum venulosum'' , ''Spiculopteragia shulzi'' , ''Dictyocaulus eckerti'' , and ''Setaria altaica'' .

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==Acknowledgement==

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This study was supported by the RFBR  grant No. [[#gts0005|13-04-00341a]]  and the Wildlife Conservation Society  (USA).

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==References==

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