Dynamics of Infection with Strongylidae of the Przewalski Horse (Equus Przewalskii) Population in the Chernobyl Exclusion Zone
Dynamics of Infection with Strongylidae of the Przewalski Horse (Equus przewalskii) Population in the Chernobyl Exclusion Zone. Zvegintsova N. S., Zharkikh T. L., Yasynetska N. I. — In 1998 and in 1999, several Przewalski horses (PH) from the Reserve Askania Nova were transferred to the Chernobyl Exclusion Zone (CEZ), a free-roaming breeding population was therefore established. Parasitological monitoring of the population was carried out between 1998 and 2006. Before the transportation, PHs were dewormed with Albendazole. On arrival, the PHs were placed in large pasture enclosures for acclimatization, where they were kept between a few weeks and eight months before releasing into the wild. Besides PHs, some domestic working horses were kept in the enclosures. After transportation to CEZ, the level of infection with intestinal helminths in PHs increased. Probably, it was due to the following factors: 1) larvae of helminthes, which survived in intestines after deworming, developed, 2) the pasture in acclimatization enclosures was contaminated with parasites, as PHs shared the enclosures with domestic horses. Over the first three years, the prevalence of Strongylidae were 98.8%, the mean intensities varied from 248.0 ± 51.3 to 612.0 ± 278.2 eggs per gram faeces (epg). A mean intensity in bachelor males was higher than in members of harem groups, as the bachelors had closer contacts with domestic horses. After domestic horses had been transferred outside of CEZ in 2001, the overall intensity in PHs has progressively decreased. During 2004-2006, the mean intensity became stable with range 80.9 ± 25.5 to 138.9 ± 33.2 epg, with prevalence of 93.1%. In 3.5% of faecal samples, Parascaris equorum (Ascarididae) were found; a mean intensity was 29.0 ± 10.7 epg. A few eggs of Anoplocephala perfoliata (Anoplocephalidae) were found in three samples only. Due to negligible contamination of pastures excluded from farming industry long ago, there are comparatively low levels of infection in the free-roaming PHs. The present level of infection is considered harmless to the horses as clinical symptoms of helminthoses were never noticed.
Strongylid Community Structure of the Przewalski's Horses (Equus ferus Przewalskii) from the Biosphere Reserve "Askania-Nova", Ukraine
Species composition and the structure of strongylid community of the Przewalski's horse (Equus ferus przewalskii Poljakov, 1881) semi-free population at the "Askania-Nova" Biosphere Reserve were studied by the in vivo method of diagnostic deworming. After deworming of 24 adult Przewalski's horses by the anthelmintic "Univerm" (0.2% aversectin C, Russia), 25,815 strongylid specimens were collected and identified. Thirty-one strongylid species of 12 genera were found including 6 species of the subfamily Strongylinae and 25 — of Cyathostominae. Nine to 18 strongylid species (average 14.5 ± 2.5) were found per horse. Cyathostomes (Cyathostominae) dominated in the Przewalski's horse strongylid community: 9 species (Cyathostomum catinatum, C. pateratum, Cylicocyclus nassatus, C. insigne, C. leptostomum, C. ashworthi, Cylicostephanus longibursatus, C. goldi and C. minutus) were found in more than 80% of horses examined and composed 94.1% of the total number of strongylid collected. Strongyles (Strongylinae) were found in 100% of the E. ferus przewalskii examined; prevalence of separate species was from 4.2% to 58.3%. The general structure of the strongylid community was multimodal with dominant (9 species), subdominant (4), background (4) and rare (14) species. The list of strongylid species found in the Przewalski'si horses in Ukraine was enlarged to 37 species.
Comparative studies of the intestinal strongylid communities of 14 ponies, 6 donkeys and 9 zebras from the “Askania-Nova” Biosphere reserve (Ukraine) were carried out after deworming the hosts with aversectin drug. Faecal sampling (200 g each) was performed at 24, 36, 48, 60, and 72 hours after treatment; all nematodes expelled were collected and identified. Thirty strongylid species from 12 genera were found; 7 species from the Strongylinae and 23 species from Cyathostominae. In ponies 27 species were found (range 8–23; mean 14 ± 3.8). In donkeys 23 species were found (range 11–15; mean 12 ± 1.3). Cyathostomum tetracanthum a species specific for donkeys was found for the first time in Ukraine. In zebras 17 species were found (range 2–13; mean 7 ± 3.6). The results obtained confirmed the specificity of the intestinal strongylid fauna of different equid species grazing on the same pastures in the “Askania-Nova” reserve.
Analysis of the species composition and community structure of helminths in saiga antelope (Saiga tatarica) was performed using multi-year (1979-2013) data collected from the “Askania Nova” Biosphere Reserve, Ukraine. During this period, 31 saiga antelopes of different ages (7 calves, 24 adults) were examined; totally, more then 63,900 helminth specimens were collected and identified by morphological criteria. Levels of saiga infection by nematodes were from 39 to 671 EPG (207±132 SD); seasonal fluctuations in saiga infections were insignificant (Mann-Whitney test; p>0.05).
Nineteen helminth species were found in saigas in the “Askania Nova”: 3 species of Cestoda (Avitellina centripunctata, Moniezia expansa and Taenia hydatigena) and 16 species of Nematoda (Chabertia ovina, Haemonchus contortus, Marshallagia marshalli, Cooperia oncophora, Camelostrongylus mentulatus, Aonchotheca bovis, Skrjabinema ovis, Oesophagostomum venulosum, Trichostrongylus axei, T. colubriformis, T. probolorus, Ostertagia ostertagi, O. circumcincta, O. trifurcata, Nematodirus spp., Trichurus ovis). From 2 to 13 species per one host were observed. Nematodes dominated within the parasite community and composed more then 99 % of the total helminths found. Significant differences were found in helminth diversity between young and adult saigas (p<0.05). Prevalence- frequency distribution revealed multimodal structure of helminth community with dominant, subdominant, background and rare species. The highest number of helminthes (14 species and 50 % of the total amount) inhabited the small intestine; 11 species (45 %) were found in the abomasum and 9 species (5 %) in the large intestine. The Bray-Curtis cluster analysis revealed significant differences within the helminth communities in saigas from the “Askania Nova” Biosphere Reserve and saigas from Kazakhstan, Dagestan and Kalmykia.
More than 30 species of exotic ungulates are currently kept in the Askania-Nova Biosphere Reserve (Kherson Region, Ukraine). During the years 1978–2014, 146 ungulates of 24 species (16 species of Bovidae, 4 — Cervidae, 4 — Camelidae) were examined by partial helminthological dissection; more than 402,700 specimens of helminths were collected and identified. The purpose of the present study was to summarize these data and analyze the species diversity in exotic ungulates. Totally, 38 species of helminths: 3 species of Trematoda, 6 — Cestoda, 29 — Nematoda were found. Ungulates from the family Bovidae were the most infected; they harbored 36 species of helminths, 1–18 species per host. In Camelidae, 15 species were found; 3–10 species per host. Cervidae harbored 9 species; 1–6 species per host. The highest species diversity was detected in the ungulates introduced from regions with climatic conditions similar to those in southern Ukraine: saiga antelope (19 species), European mouflon (18), Barbary sheep (18), and markhor (17). Ten species typical for domestic ruminants (Haemonchus contortus, Nematodirus sp., Aonchotheca bovis, Moniezia expansa, Oesophagostomum venulosum, Ostertagia circumcincta, Trichostrongylus axei, T. colubriformis, T. probolurus and Trichuris ovis) dominated in the parasite communities. Our results indicated reduction in the species diversity and alteration of the parasite community structures in these exotic ungulates kept in the Askania-Nova Reserve compared to their natural habitats.
The Przewalski’s horse (Equus ferus przewalskii, Poljakov, 1881) is an endangered subspecies of wild horses (Equus ferus) native to steppes of Central Asia. In 2015, the Program of Establishing of a Semi-Free Population of the Przewalski’s Horse in the Orenburg Reserve was launched by FGFI “Orenburg Reserves”. The first group of 6 Przewalski’s horses (2 males and 4 females) born in the semi-reserve Le Villaret, France, was transported to the Orenburg Reserve. Th e aim of this work was to investigate the species composition of the intestinal parasite community and to monitor the dynamics of the parasite infection of the newly established Przewalski’s horse population. The level of infection by gastrointestinal parasites within the horses was examined by the McMaster method. Gastrointestinal parasites were collected in vivo after deworming of the horses with macrocyclic lactone drug “Univerm” (0.2 % aversectin C, PharmBioMed, Russia). Totally, 20 species of parasites were found: 19 species of nematodes (species of the family Strongylidae and Habronema muscae) and one species of botflies from the genus Gasterophilus. Th e widest species diversity (18 species from 8 genera) was observed in strongylids: 2 species from the subfamily Strongylinae and 16 species from Cyathostominae. Distribution of strongylid species between ten prevalence classes revealed a bimodal structure (“core-satellite” mode) of the strongylid community. Th e results obtained in this study are to be considered as the initial data for the further parasitological monitoring of Przewalski’s horses at the Orenburg State Reserve.
Species composition and structure of strongylid (Nematoda: Strongylidae) community were examined in 15 plains zebras (Equus burchelli) and 8 Grevy’s zebra (Equus grevyi) kept in the “Askania-Nova” Biosphere Reserve (Ukraine). Strongylids were collected from zebras in vivo following deworming with the “Univerm” (0.2 % aversectin C, Russia). Twenty-two strongylid species (3 species of subfamily Strongylinae and 19 — of Cyathostominae) were found. In plains zebras, 21 strongylid species were found; from 3 to 14 species per host. In Grevy’s zebras, 18 strongylid species were recorded; from 4 to 14 species per host. Cyathostominae dominated in the communities of both zebra species; they composed more then 99 % of strongylid number. Comparison of strongylid biodiversity in plains zebras from the “Askania-Nova” reserve with data collected from four African countries showed low similarity of strongylid faunas in zebras from Ukraine and Africa; the strongylid community was similar to those of domestic ponies from the same area.