Strongylids of Domestic Horses in Eastern Slovakia: Species Diversity and Evaluation of Particular Factors Affecting Strongylid Communities.

PURPOSE: This study aimed to examine the species diversity and structure of the strongylid community in domestic horses in Eastern Slovakia. Also, an analysis of the impact of age, sex, and collection location factors on the strongyid communities was performed. METHODS: Twenty-seven horses 1.5-21 years old from two farms in eastern Slovakia with different horse-management conditions were studied. Strongylids were collected after horse treatments with Noromectin (0.2 mg ivermectin); 66,170 specimens were collected and identified. Faecal egg count reduction test (FECRT) was performed following fenbendazole (FBZ) and ivermectin (IVM) treatments. RESULTS: Twenty-four strongylid species were found; horses were infected with 6 to 16 (average = 11.7) species. Six cyathostomin species (Cylicocyclus nassatus, Cyathostomum catinatum, C. pateratum, Cylicostephanus longibursatus, C. goldi, C. calicatus) were the most prevalent; C. catinatum was the dominant species in both farms (Berger-Parker index 0.34 and 0.42). The structure of the strongylid community was multimodal with dominant, subdominant, background, and rare species. The Mantel test showed that horse age and sex did not significantly affect the nematode infracommunity composition (p > 0.05), while the impact of the collection location (farm) was significant (p = 0.03). Additionally, C. longibursatus was identified as the species contributing significantly to the observed farm differences. Strong resistance to FBZ was documented on both farms (FECRT was 36.4% and 22.7%); IVM resistance was not observed (FECRT = 100%). CONCLUSION: This study presents the first report on the strongylids parasitizing domestic horses in Eastern Slovakia and gives basic information for further studies of horse parasites and their control in the region.

US-wide equine strongylid egg count data demonstrate seasonal and regional trends.

Equine strongylid parasites are ubiquitous around the world and are main targets of parasite control programmes. In recent years, automated fecal egg counting systems based on image analysis have become available allowing for collection and analysis of large-scale egg count data. This study aimed to evaluate equine strongylid fecal egg count (FEC) data generated with an automated system over three years in the US with specific attention to seasonal and regional trends in egg count magnitude and sampling activity. Five US regions were defined; North East, South East, North Central, South Central and West. The data set included state, region and zip code for each FEC. The number of FECs falling in each of the following categories were recorded: (1) 0 eggs per gram (EPG), (2) 1 ⩽ 200 EPG, (3) 201 ⩽ 500 EPG and (4) >500 EPG. The data included 58 329 FECs. A fixed effects model was constructed fitting the number of samples analysed per month, year and region, and a mixed effects model was constructed to fit the number of FECs falling in each of the 4 egg count categories defined above. The overall proportion of horses responsible for 80% of the total FEC output was 18.1%, and this was consistent across years, months and all regions except West, where the proportion was closer to 12%. Statistical analyses showed significant seasonal trends and regional differences of sampling frequency and FEC category. The data demonstrated that veterinarians tended to follow a biphasic pattern when monitoring strongylid FECs in horses, regardless of location.

Characterization of the complete mitochondrial genomes of the zoonotic parasites Bolbosoma nipponicum and Corynosoma villosum (Acanthocephala: Polymorphida) and the molecular phylogeny of the order Polymorphida.

Acanthocephalans of the order Polymorphida mainly parasitic in birds and mammals, are of veterinary, medical and economic importance. However, the evolutionary relationships of its 3 families (Centrorhynchidae, Polymorphidae and Plagiorhynchidae) remain under debate. Additionally, some species of Polymorphida (i.e. Bolbosoma spp. and Corynosoma spp.) are recognized as zoonotic parasites, associated with human acanthocephaliasis, but the mitochondrial genomes for representatives of Bolbosoma and Corynosoma have not been reported so far. In the present study, the complete mitochondrial genomes B. nipponicum and C. villosum (Acanthocephala: Polymorphidae) are reported for the first time, which are 14 296 and 14 241 bp in length, respectively, and both contain 36 genes [including 12 PCGs, 22 tRNA genes and 2 rRNA genes] and 2 non-coding regions (NCR1 and NCR2). The gene arrangement of some tRNAs in the mitogenomes of B. nipponicum and C. villosum differs from that found in all other acanthocephalans, except Polymorphus minutus. Phylogenetic results based on concatenated amino acid (AA) sequences of the 12 protein-coding genes (PCGs) strongly supported that the family Polymorphidae is a sister to the Centrorhynchidae rather than the Plagiorhynchidae, and also confirmed the sister relationship of the genera Bolbosoma and Corynosoma in the Polymorphidae based on the mitogenomic data for the first time. Our present findings further clarified the phylogenetic relationships of the 3 families Plagiorhynchidae, Centrorhynchidae and Polymorphidae, enriched the mitogenome data of the phylum Acanthocephala (especially the order Polymorphida), and provided the resource of genetic data for diagnosing these 2 pathogenic parasites of human acanthocephaliasis.

Efficacy of a single-dose albendazole against lancet liver fluke Dicrocoelium dendriticum and liver enzymes activity in naturally infected sheep.

Infections with D. dendriticum are distributed worldwide and mostly associated with ruminant livestock. Depending on the length and strength of the infection it can be manifested with losses in milk production, reductions in milk and wool quality, decreased weight gains, reproductive performance and poor carcass quality. The objective of this study was to determine the efficacy of albendazole (ABZ) against the lancet liver fluke Dicrocoelium dendriticum in naturally infected sheep using parasitological methods. Twenty-four sheep were divided into four groups: two untreated control groups (C1, C2) and two treated groups (T1, T2), with six animals in each group. The sheep in the treated groups were administered a single oral dose (15 mg/kg bwt) of ABZ suspension. After ABZ treatment the animals were slaughtered on Day 14 (groups C1, T1) and Day 30 (groups C2, T2) and were necropsied. Coprological therapeutic ABZ efficacy reached 92.4% on Day 14 (P < 0.001) and 88.5% on Day 30 (P < 0.001). On Day 30, the serum activities of hepatic and cholestatic enzymes including serological analysis of total protein concentration (TP) and protein fractions were evaluated. Significant decrease of aspartate aminotransferase (AST) (P < 0.01) and gamma-glutamyltransferase (GGT) (P < 0.05) activity by 36.9% and 34.6%, respectively, were detected for sheep in T2 group. These enzymes showed a strong positive correlation to fluke burden: AST (r = 0.654) and GGT (r = 0.768), respectively (P < 0.05). Additionally, the electrophoretic analysis of serum total protein and protein fraction concentrations revealed minimal hypoproteinemia and hyperalbuminemia after ABZ treatment. The decrease of liver enzyme activities and their correlation with fluke burden may indicate recovery of hepatocellular and biliary damage following the reduction of fluke burdens after ABZ therapy. A decline in AST and GGT activity could serve as a valuable adjunct bioindicator of liver damage and fluke reduction after treatment of dicrocoeliosis in naturally infected sheep.

Equine tapeworm (Anoplocephala spp.) infection: evaluation of saliva- and serum-based antibody detection methods and risk factor analysis in Slovak horse populations.

A lack of accurate information on the prevalence and distribution of Anoplocephala spp. infections on horse farms has led to insufficient attention to tapeworm control and increasing horse anoplocephaloses in Europe. Our study aimed to examine the occurrence of Anoplocephala spp. infection using coprological, serum- and saliva-based antibody detection methods and to analyze the risk factors associated with tapeworm infection in domestic horses in Slovakia. Fecal, serum, and saliva samples were collected from 427 horses from 31 farms in Slovakia. Additionally, a questionnaire study was conducted to collect information on tapeworm distribution on horse farms and analyze risk factors associated with infection. Fecal samples were examined by the mini-FLOTAC and the double centrifugation/combined sedimentation-flotation techniques. Serum and saliva samples were analyzed by ELISA to determine antibody levels against Anoplocephala spp. The effects of variables associated with an individual horse were tested for the positive result of the saliva ELISA test on Anoplocephala spp. Cestode eggs were detected in 1.99% of fecal samples (farm prevalence 12.90%), with no differences between the two coprological methods. Serum-based tapeworm ELISA results revealed that 39.39% of horses tested positive (farm prevalence 83.87%); while saliva-based tapeworm ELISA results revealed 56.95% positive horses (farm prevalence 96.77%). Binary logistic regression analysis revealed four meaningful predictors that significantly impacted the likelihood of detecting tapeworm infection in horses: horse age, pasture size, anthelmintic treatment scheme, and access to pasture. The influences of other variables associated with an individual horse were not significantly associated with detecting tapeworm infection.

Infection patterns of helminth community in black rockcod Notothenia coriiceps in West Antarctica over a 6-year term.

Patterns of the rockcod Notothenia coriiceps infection with helminths were analysed to understand the dynamics of parasite communities in this Antarctic fish and to test their stability over time. The study was performed using helminth samples collected from 183 N. coriiceps in 2014-2015 and 2020-2021 in the vicinity of the Ukrainian Antarctic station (UAS) "Akademik Vernadsky", Galindez Island, Argentine Islands, West Antarctica. Overall, 25 helminth taxonomical categories (nine trematodes, four cestodes, five nematodes, and seven acanthocephalans) were subjected to analysis. A direct comparison of the helminth population characteristics showed that nine species significantly changed their infection parameters during the 6 years between the samples. Seven of them (Pseudoterranova sp., Contracaecum sp., Ascarophis nototheniae, monolocular metacestodes, bilocular metacestodes, Metacanthocephalus rennicki, and Diphyllobothrium sp.) were found to have a significant impact on the differences between helminth infracommunities in 2014-2015 and 2020-2021. Most studied patterns of helminth component community appeared to show a stable tendency, and observed fluctuations were close to the steady trend. Slight but significant changes in the infection patterns observed in this study might have been caused by changes in the populations of intermediate, paratenic, and definitive hosts of helminths (marine invertebrates, mammals, and birds), which participate in helminth transmission in Antarctic ecosystems.

Effect of sainfoin (Onobrychis viciifolia) on cyathostomin eggs excretion, larval development, larval community structure and efficacy of ivermectin treatment in horses.

Alternative strategies to chemical anthelmintics are needed for the sustainable control of equine strongylids. Bioactive forages like sainfoin (Onobrychis viciifolia) could contribute to reducing drug use, with the first hints of in vitro activity against cyathostomin free-living stages observed in the past. We analysed the effect of a sainfoin-rich diet on cyathostomin population and the efficacy of oral ivermectin treatment. Two groups of 10 naturally infected horses were enrolled in a 78-day experimental trial. Following a 1-week adaptation period, they were either fed with dehydrated sainfoin pellets (70% of their diet dry matter) or with alfalfa pellets (control group) for 21-days. No difference was found between the average fecal egg counts (FECs) of the two groups, but a significantly lower increase in larval development rate was observed for the sainfoin group, at the end of the trial. Quantification of cyathostomin species abundances with an ITS-2-based metabarcoding approach revealed that the sainfoin diet did not affect the nemabiome structure compared to the control diet. Following oral ivermectin treatment of all horses on day 21, the drug concentration was lower in horses fed with sainfoin, and cyathostomin eggs reappeared earlier in that group. Our results demonstrated that short-term consumption of a sainfoin-rich diet does not decrease cyathostomin FEC but seems to slightly reduce larval development. Consumption of dehydrated sainfoin pellets also negatively affected ivermectin pharmacokinetics, underscoring the need to monitor horse feeding regimes when assessing ivermectin efficacy in the field.

Morphology, molecular characterization and phylogeny of Bolbosoma nipponicum Yamaguti, 1939 (Acanthocephala: Polymorphidae), a potential zoonotic parasite of human acanthocephaliasis.

Human acanthocephaliasis is a rare parasitic zoonosis mainly caused by acanthocephalans belonging to the genera Acanthocephalus, Bolbosoma, Corynosoma, Macracanthorhynchus, and Moniliformis. In the present paper, the juveniles of Bolbosoma nipponicum Yamaguti, 1939 collected from the northern fur seal Callorhinus ursinus (Linnaeus) (Mammalia: Carnivora) in Alaska, USA were precisely identified based on morphological characters and genetic data. Their detailed morphology was studied using light and, for the first time, scanning electron microscopy. The molecular characterization of the nuclear genes [small ribosomal subunit (18S) and large ribosomal subunit (28S)] and the mitochondrial cytochrome c oxidase subunit 1 (cox1) sequence data of B. nipponicum are provided for the first time. Moreover, in order to clarify the phylogenetic relationships of the genus Bolbosoma and the other genera in the family Polymorphidae, phylogenetic analyses were performed integrating different nuclear (18S + ITS+28S) and mitochondrial (cox1) sequence data using maximum likelihood (ML) and Bayesian inference (BI). The phylogenetic results showed that Bolbosoma has a sister relationship with Corynosoma, and also revealed that Southwellina is sister to Ibirhynchus + Hexaglandula. Our molecular phylogeny also indicated a possible host-switch pattern during the evolution of the polymorphid acanthocephalans. The ancestors of polymorphid acanthocephalans seem to have originally parasitized fish-eating waterfowl in continental habitats, then extended to fish-eating marine birds in brackish water and marine habitats, and finally, opportunistically infected the marine mammals.

First morphological and molecular characterization of cystacanths of Corynosoma evae Zdzitowiecki, 1984 (Acanthocephala: Polymorphidae) from Antarctic teleost fishes.

Cystacanths of the polymorphid acanthocephalan Corynosoma evae Zdzitowiecki, 1984 were examined and redescribed based on newly collected material from teleost fishes from coastal waters of the Galindez Island (Argentine Islands, West Antarctica). Detailed morphological data, measurements and photomicrographs, including scanning electron microscopy images, are presented. Our morphological and morphometrical analyses confirmed the validity of C. evae; however, three key characteristics of taxonomic importance (i.e., the number of rows of hooks on the proboscis, and the number and arrangement of genital spines in males) showed significant morphological variability. In addition, a genital spine in the posterior body end of a female is reported for the first time. This study provides the first sequences of the small and large subunits nuclear ribosomal RNA genes (SSU and LSU) and the mitochondrial cytochrome c oxidase subunit 1 (cox1) for C. evae. Maximum likelihood and Bayesian inference analyses of the SSU + LSU + cox1 and the cox1 datasets placed C. evae as a sister lineage to a clade formed by C. validum Van Cleave, 1953 and C. villosum Van Cleave, 1953, although with low support. In contrast, the position of C. evae in the phylogenetic analysis of the SSU + LSU dataset remained unresolved. Finally, C. arctocephali Zdzitowiecki, 1984 from pinnipeds from the subantarctic and Antarctic regions is considered as a valid species.

Trematodes from Antarctic teleost fishes off Argentine Islands, West Antarctica: molecular and morphological data.

In 2014-2015 and 2019-2021, teleost fishes off Galindez Island (Antarctic Peninsula) were examined for trematodes. Combined morphological and molecular analyses revealed the presence of eight trematode species of four families (Hemiuridae, Lecithasteridae, Opecoelidae, Lepidapedidae) from five fish species. Only adult trematodes were found and all of them are Antarctic endemics with their congeners occurring on other continents. The hemiuroids, Elytrophalloides oatesi (Leiper & Atkinson, 1914), Genolinea bowersi (Leiper & Atkinson, 1914), and Lecithaster macrocotyle Szidat & Graefe, 1967 belong to the most common Antarctic species and together with Lepidapedon garrardi (Leiper & Atkinson, 1914) and Neolebouria georgiensis Gibson, 1976 they were recorded as the least host-specific parasites. The originally sub-Antarctic Neolepidapedon macquariensis Zdzitowiecki, 1993 is a new record for the Antarctic Peninsula and Parachaenichthys charcoti (Vaillant), is a new host record. Neolebouria terranovaensis Zdzitowiecki, Pisano & Vacchi, 1993 is considered a synonym of N. georgiensis because of identical morphology and dimensions. The currently known phylogenetic relationships within the studied families are supported, including the polyphyly of Macvicaria Gibson & Bray, 1982 with the future need to accommodate its Antarctic species in a new genus. The validity of M. georgiana (Kovaleva & Gaevskaja, 1974) and M. magellanica Laskowski, Jezewski & Zdzitowiecki, 2013 needs to be confirmed by further analyses. Genetic sequence data are still scarce from Antarctica, and more studies applying integrative taxonomic approaches and large-scale parasitological examinations of benthic invertebrates are needed to match sequences of larval stages to those of well-characterised adults and to elucidate trematode life-cycles.

World association for the advancement of veterinary parasitology (WAAVP): Third edition of guideline for evaluating the efficacy of equine anthelmintics.

This guideline have been developed to assist in the design, execution, and interpretation of studies to assess the efficacy of anthelmintic drugs against internal parasites of equines, including nematodes, cestodes, and larval instars of Gasterophilus spp. The design and execution of critical and controlled studies are outlined, and their advantages and disadvantages are discussed. Unique considerations for specific target parasites are included. Information is also provided on selection of animals, procedures for randomization, housing, feeding, dosage titration, dosage confirmation and field studies, record keeping and necropsy procedures. Finally, this document includes guidance for group size determination and statistical analysis of study results. This guideline should assist investigators in the evaluation of anthelmintic drugs in horses by using comparable and standardized procedures in studies with appropriate numbers of animals.

Helminth Assemblages of the Antarctic Black Rockcod, Notothenia coriiceps (Actinopterygii: Nototheniidae) in Coastal Waters near Galindez Island (Argentine Islands, West Antarctic): Temporal Changes in the Endoparasite Community.

PURPOSE: Analysis and comparison of the helminth assemblages in Antarctic rockcod Notothenia coriiceps collected near the UAS "Akademik Vernadsky" (Argentine Islands, West Antarctica) in 2002 and 2014-2015 were performed to characterise the parasite community and investigate the temporal changes in helminth assemblages and infection parameters. METHODS: All specimens of N. coriiceps (n = 194) were caught at depths of 10-30 m. Parasites (22,856 helminth specimens and 15,057 cysts) were collected manually and identified based on their morphology. Statistical analysis of the quantitative data was performed using the Quantitative Parasitology 3.0 (QP 3.0), Paleontological Statistics (PAST v. 3.1), and PRIMER 6 software. RESULTS: Twenty-seven species of four taxonomic groups were recorded: trematodes (8 species), cestodes (4), nematodes (5), and acanthocephalans (10). Helminth samples collected in 2002 and 2014-2015 showed a rather high similarity in species composition. The species richness was higher in the sample collected in 2014-2015, while the evenness and diversity in the two samples were similar. The dissimilarity between helminth infracommunities in the two samples appeared to be statistically significant. Larval cestodes Diphyllobotrium sp., the acanthocephalan Metacanthocephalus rennicki, and the trematode Neoleoburia antarctica were found to make the most significant impact on the dissimilarity. CONCLUSIONS: The analysis of the composition and structure of helminth community in N. coriiceps revealed the changes that have happened during the last decade. At least some of the changes are attributed to the changes in marine ecosystems in Western Antarctica.

Molecular Study of Echinococcus granulosus Cestodes in Ukraine and the First Genetic Identification of Echinococcus granulosus Sensu Stricto (G1 Genotype) in the Country.

INTRODUCTION: Cystic echinococcosis is a globally distributed zoonotic disease of great medical and veterinary importance, which is caused by the cestode Echinococcus granulosus sensu lato. In Ukraine, two areas of the prominent circulation of the parasite are established, the southern steppe zone with sheep as the main transmitter, and the northern forest-steppe zone and Polissia, where pigs are mainly responsible for maintaining the E. granulosus transmission. METHODS: Given that only a few studies have so far addressed the genetic diversity of the parasite in Ukraine, we have sequenced partial mitochondrial genes of cytochrome c oxidase 1 (789 bp), NADH dehydrogenase 1 (602 bp) and 12S rRNA (333-334 bp) in pig metacestodes from the Sumy region (farms close to Sumy, northeastern Ukraine) and the Kyiv region (a farm in Bila Tserkva, central Ukraine). RESULTS: Four isolates from four pigs in the Sumy region were identified as E. canadensis (G7 genotype), the major E. granulosus s.l. species circulating in Eastern Europe, including the three microvariants (G7A, G7B, G7C). Three isolates from the two pigs in the Kyiv region were classified as E. granulosus s.s. (G1 genotype), including one microvariant (G1A). CONCLUSION: To our knowledge, this is the first genetic record of E. granulosus s.s. with the presumed highest infectivity and virulence among the E. granulosus s.l. species in Ukraine. The finding has implications for public health as local control programmes should take into consideration different development rate of this parasite in dogs and the greater risk of the species for human infection.

Helminths of the Antarctic dragonfish, Parachaenichthys charcoti (Perciformes, Notothenioidei, Bathydraconidae) Studied near Galindez Island (Argentine Islands, West Antarctica).

PURPOSE: The Antarctic dragonfish, Parachaenichthys charcoti is a notothenioid teleost fish endemic to the Southern Ocean surrounding Antarctica. It is a relatively rare fish species; therefore, published data on the parasite communities of P. charcoti are limited. The present study was performed on the Ukrainian Antarctic Station "Akademik Vernadsky", Argentine Islands, West Antarctica and the purpose was to examine the species diversity of the parasites of P. charcoti and to identify the parameters of helminth infection and helminth component community. METHODS: Fifteen specimens of P. charcoti were caught at a depth of 10-30 m and examined using standard parasitological techniques. All helminths (6251 specimens) were collected manually, fixed in 70% ethanol and identified based on their morphology. RESULTS: All examined specimens of P. charcoti were found to be infected with helminths; each fish harboured 10-20 helminth species (mean 13.2; median 13) and 237-804 helminth specimens (mean 417; median 401). Twenty-seven helminth species were found, including nine species of trematodes, 4 of cestodes, 4 of nematodes and 10 of acanthocephalans. P. charcoti is the definitive host for 11 out of 27 helminth species recorded. In the helminth component community, the diversity indices were 2.03 (Shannon's index) and 0.79 (Simpson's index); Pielou evenness index was 0.61, and Berger-Parker dominance index was 0.38. CONCLUSIONS: Our results indicate a high species diversity and complex structure of the helminth community in Antarctic dragonfish P. charcoti in the Argentine Islands.

Diphyllobothrium sprakeri n. sp. (Cestoda: Diphyllobothriidae): a hidden broad tapeworm from sea lions off North and South America.

BACKGROUND: The systematic of several marine diphyllobothriid tapeworms of pinnipeds has been revised in recent years. However, 20 species of Diphyllobothrium from phocids and otariids are still recognized as incertae sedis. We describe a new species of Diphyllobothrium from the intestine of California sea lions Zalophus californianus (Lesson) (type-host) and South American sea lions Otaria flavescens (Shaw). METHODS: Zalophus californianus from the Pacific coast of the USA and O. flavescens from Peru and Argentina were screened for parasites. Partial fragments of the large ribosomal subunit gene (lsrDNA) and the cytochrome c oxidase subunit 1 (cox1) mitochondrial gene were amplified for 22 isolates. Properly fixed material from California sea lions was examined using light and scanning electron microscopy. RESULTS: A total of four lsrDNA and 21 cox1 sequences were generated and aligned with published sequences of other diphyllobothriid taxa. Based on cox1 sequences, four diphyllobothriid tapeworms from O. flavescens in Peru were found to be conspecific with Adenocephalus pacificus Nybelin, 1931. The other newly generated sequences fall into a well-supported clade with sequences of a putative new species previously identified as Diphyllobothrium sp. 1. from Z. californianus and O. flavescens. A new species, Diphyllobothrium sprakeri n. sp., is proposed for tapeworms of this clade. CONCLUSIONS: Diphyllobothrium sprakeri n. sp. is the first diphyllobothriid species described from Z. californianus from the Pacific coast of North America, but O. flavescens from Argentina, Chile and Peru was confirmed as an additional host. The present study molecularly confirmed the first coinfection of two diphyllobothriid species in sea lions from the Southern Hemisphere.

Genetic variability, cryptic species and phylogenetic relationship of six cyathostomin species based on mitochondrial and nuclear sequences.

Cyathostomins are important intestinal nematode parasites of equines and include 50 accepted species. Their taxonomy has been frequently revised and the presence of cryptic species suggested. Furthermore, usually molecular- and morphology-based phylogenetic analyses give divergent results. In this study, the nucleotide sequences of the nuclear second internal transcribed spacer (ITS-2) and the mitochondrial partial cytochrome c oxidase subunit I (COI) were determined for adults of six cyathostomin species (Coronocyclus coronatus, Coronocyclus labiatus, Cylicocyclus nassatus, Cylicostephanus calicatus, Cylicostephanus longibursatus, Cylicostephanus minutus) collected from different equine species within two geographic regions. Maximum likelihood trees were calculated for ITS-2, COI, and concatenated data. No obvious differentiation was observed between geographic regions or equine host species. As previously reported, Coronocyclus coronatus and Cylicostephanus calicatus revealed a close relationship. Cryptic species were detected in Cylicostephanus minutus and Cylicostephanus calicatus. Cylicocyclus nassatus and Coronocyclus labiatus showed diverse mitochondrial and nuclear haplotypes occurring in different combinations, while Cylicostephanus longibursatus was comparatively homogenous. In conclusion, a combined analysis of nuclear and mitochondrial haplotypes improved resolution of the phylogeny and should be applied to the remaining cyathostomin species and across additional equine host species and geographic regions.

Review of metazoan parasites of the northern fur seal (Callorhinus ursinus) and the analysis of the gastrointestinal helminth community of the population on St. Paul Island, Alaska.

The northern fur seal (NFS), Callorhinus ursinus (Mammalia: Otariidae), is a marine mammal species included into the IUCN Red List as the vulnerable species which population is dramatically declining. A significant amount of parasitological data collected previously and our recent data allowed us to clarify the list of NFS metazoan parasites and to perform a comprehensive analysis of the gastrointestinal helminth community. Gastrointestinal tracts from 756 NFSs (3- to 4-year-old males) were collected during the annual Aleut subsistence harvests in July-August of 2011-2014 from five separate rookeries on St. Paul Island, Alaska. Totally, 27,625 specimens of helminths and approximately 1000 nasal mites were collected and identified. Detailed analysis of the previously published and newly obtained data revealed 32 species of metazoan parasites, including trematodes (6 species), cestodes (4), nematodes (9), acanthocephalans (9) and arthropods (4). The gastrointestinal helminth community of newly studied NFSs comprised 19 species including trematodes (4), cestodes (3), nematodes (5) and acanthocephalans (7). Temporal changes in the helminth community structure were small but statistically significant. Gastrointestinal helminth infracommunities comprised from 1 to 10 species (average of 4). Small but significant correlation was found between the abundances of acanthocephalans (Corynosoma similis and C. strumosum), nematodes (Contracaecum osculatum, Pseudoterranova spp.) and cestode Diphyllobothrium tetrapterum.

Effects of life history stage and climatic conditions on fecal egg counts in plains zebras (Equus quagga) in the Serengeti National Park.

In wildlife, endoparasite burden can be affected by host life history stage, environmental conditions, host abundance, and parasite co-infections. We tested the effects of these factors on gastrointestinal parasite infection in plains zebras (Equus quagga) in the Serengeti ecosystem, Tanzania, using fecal egg counts of two nematode families (Strongylidae and Ascarididae) and the presence/absence of cestode (Anoplocephalidae) eggs. We predicted higher egg counts of Strongylidae and Ascarididae, and increased likelihood of Anoplocephalidae infection in individuals (1) during energetically costly life history stages when resource allocation to immune processes may decrease and in young zebras after weaning because of increased uptake of infective stages with forage, (2) when climatic conditions facilitate survival of infective stages, (3) when large zebra aggregations increase forage contamination with infective stages, and (4) in individuals co-infected with more than one parasite group as this may indicate reduced immune competence. Strongylidae egg counts were higher, and the occurrence of Anoplocephalidae eggs was more likely in bachelors than in band stallions, whereas Ascarididae egg counts were higher in band stallions. Strongylidae and Ascarididae egg counts were not increased in lactating females. Strongylidae egg counts were higher in subadults than in foals. Regardless of sex and age, Ascarididae infections were more likely under wet conditions. Co-infections did not affect Strongylidae egg counts. Ascarididae egg counts in adult females were higher when individuals were co-infected with Anoplocephalidae. We present evidence that parasite burdens in plains zebras are affected by life history stage, environmental conditions, and co-infection.

Causes of mortality in northern elephant seal pups on San Miguel Island, California.

In February 2015, we conducted a field study of causes of mortality of northern elephant seal (Mirounga angustirostris) pups on San Miguel Island, California. Autopsies were performed on 18 freshly dead pups. Ages of pups ranged from stillborn to 6-8 wk. Gross and histologic lesions included trauma (9 of 18 pups), multifocal necrotizing myopathy (8 of 18), starvation with emaciation (7 of 18), congenital anomalies (3 of 18), bacterial infections (3 of 18), and perinatal mortality (stillbirths and neonates; 2 of 18). Trauma and emaciation or starvation were the most significant contributors to death. Bacterial infections included hemolytic Escherichia coli isolated from the lungs of 2 pups with pneumonia. Additionally, non-hemolytic Streptococcus sp. and hemolytic E. coli were isolated from the liver of an emaciated pup that had mild multifocal suppurative hepatitis. Other lesions, including a previously described necrotizing myopathy, congenital anomalies, and bacterial infections, were detected concurrently in cases with starvation and/or emaciation or trauma.

Concurrent Proteomic Fingerprinting and Molecular Analysis of Cyathostomins.

Rapid, cost-effective, efficient, and reliable helminth species identification is of considerable importance to understand host-parasite interactions, clinical disease, and drug resistance. Cyathostomins (Nematoda: Strongylidae) are considered to be the most important equine parasites, yet research on this group is hampered by the large number of 50 morphologically differentiated species, their occurrence in mixed infections with often more than 10 species and the difficulties associated with conventional identification methods. Here, MALDI-TOF MS, previously successfully applied to identify numerous organisms, is evaluated and compared with conventional and molecular genetic approaches. A simple and robust protocol for protein extraction and subsequent DNA isolation allowing molecular confirmation of proteomic findings is developed, showing that MALDI-TOF MS can discriminate adult stages of the two closely related cyathostomin species Cylicostephanus longibursatus and Cylicostephanus minutus. Intraspecific variability of proteomic profiles within morphospecies demonstrated an identification of morphospecies with an accuracy of close to 100%. In contrast, three genospecies within C. minutus and sex-specific profiles within both morphospecies could not be reliably discriminated using MALDI-TOF MS. In conclusion, MALDI-TOF MS complemented by the molecular protocol is a reliable and efficient approach for cyathostomin species identification.