Pathomorphological Findings and Infectious Diseases in Selected European Brown Hare (Lepus europaeus Pallas, 1778) Populations from Schleswig-Holstein, Germany

In the northernmost German federal state Schleswig-Holstein, populations of European brown hares (Lepus europaeus Pallas, 1778) show diverse densities and varying courses over the years. To examine differences in pathomorphological findings and infectious diseases as possible reasons for varying population dynamics, we assessed 155 hunted hares from three locations in Schleswig-Holstein from 2016 to 2020. We investigated the association of location, year, age, and sex of animals to certain pathomorphological findings and infectious diseases. Frequent pathomorphological findings were intestinal parasites (63.9%), hepatitis (55.5%), nephritis (31.0%), steatitis (23.2%), enteritis (13.5%), and pneumonia (5.2%). Body condition differed significantly between locations, and the prevalence of pneumonia was significantly higher in females. Enteritis was not detected in 2019, when much more juveniles were sampled. Hepatitis and nephritis occurred significantly more often in 2016 and among adults. Additionally, more adults showed hepatitis with concurrent serotitre for European brown hare syndrome virus (EBHSV), while intestinal parasitosis as well as high excretion rates of coccidia were more common in juveniles. Sampled animals showed high infection rates with Eimeria spp. (96.1%), Trichostrongylus spp. (52.0%), Graphidium strigosum (41.2%), and a high seroprevalence (90.9%) for EBHSV, without severe symptoms. This study revealed a low prevalence of infectious pathogens, but a high prevalence of chronic inflammations of unknown origin in the tested brown hare populations. Overall, our results indicate a rather minor importance of infectious diseases for observed population dynamics of analysed hare populations in Schleswig-Holstein.

Molecular Characterization of Mitochondrial Cytochrome c oxidase subunit 1 (Cox1) gene from Trichostrongylus Species (Nematoda: Trichostrongylidae) in Northern Iran

Objective

The objective of the present study was to identify Trichostrongylus species by molecular analysis and also phylogenetic relationships of Trichostrongylus species by mitochondrial Cytochrome c oxidase subunit 1 (Cox1) gene in Guilan province, northern Iran.

Methods

Abomasum and duodenum contents of 144 livestock were collected from sheep, goats, and cattle in Guilan province. Morphological survey was performed for initial screening. Total DNA was extracted, and the partial region of Cox1 gene was amplified and sequenced. Genetic diversity was calculated and phylogenetic analysis of the data on nucleotide sequence was conducted by MEGA7 software.

Results

Three species of Trichostrongylus including T. colubriformis, T. vitrinus, and T. axei were identified by morphological characteristics. The genetic divergence within the species in the present study was observed for T. axei (0-2.5%), T. colubriformis (0.77%), and T. vitrinus (0%). The mean inter-species difference between the three species of Trichostrongylus obtained in this study was 14.4-15.4%.

Conclusion

The Cox1 sequences of the members of Trichostrongylus spp. were highly variable and this could be used as a valuable measure to achieve a proper assessment on biodiversity. Sequence data generation from other species of Trichostrongylus will be needed to reconstruct the phylogenetic relationships of this genus of nematodes.

Status of Infectious Diseases in Free-Ranging European Brown Hares (Lepus europaeus) Found Dead between 2017 and 2020 in Schleswig-Holstein, Germany

The European brown hare (Lepus europaeus) is a quite adaptable species, but populations have been decreasing for several decades in different countries, including Germany. To investigate infectious diseases as possible influences on observed population decline in the German federal state Schleswig-Holstein, 118 deceased free-ranging European brown hares were collected between 2017 and 2020 and underwent detailed postmortem examination with extended sampling. Infectious diseases were a major cause of death (34.7%). The number of juveniles found exceeded the adult ones. The main pathomorphological findings were hepatitis (32.8%), pneumonia (22.2%), nephritis (19.1%), liver necrosis (12.9%), and enteritis (40.7%). An unusual main finding was steatitis (20.9%) of unknown origin. Animals were mainly emaciated and showed high infection rates with Eimeria spp. (91.3%) and Trichostrongylus spp. (36.2%). European Brown Hare Syndrome Virus reached an epidemic status with few fatal infections (4.2%) and high seroprevalence (64.9%), whereas the prevalence of Rabbit Haemorrhagic Disease Virus 2 was very low (0.8%) in hares in Schleswig-Holstein. Pathogens such as Yersinia pseudotuberculosis (5.9%), Pasteurella multocida (0.8%), and Staphylococcus aureus (3.4%) only caused sporadic deaths. This study illustrates the wide distribution of various infectious pathogens with high mortality and even zoonotic potential. Infectious diseases need to be considered as an important influence on population dynamics in Schleswig-Holstein.

Development of resistance to eprinomectin in gastrointestinal nematodes in a goat herd with pre-existing resistance to benzimidazoles

We described a first case of resistance to eprinomectin in goat herd in Poland in which resistance to benzimidazoles had been previously reported. The herd was established in 2011 by purchasing several goats from a single herd in south-eastern Poland. Resistance to benzimidazoles in the herd was first reported in 2017. Shortly after the owner started to signal low effectiveness of the treatment with eprinomectin. In June 2018 the larval development test from pooled faecal sample was performed and the results indicated the presence of resistance to macrocyclic lactones and levamisole. In July 2018 a faecal egg count (FEC) reduction test was performed in 39 animals with levamisole, eprinomectin and one untreated control group. Drugs were used in doses recommended for goats. Three methods of calculation of FEC reduction were compared. After eprinomectin treatment, FEC reduction ranged from 0 to 20%, depending on the method of calculation. FEC reduction following levamisole treatment was 100%. Main species present in the faecal samples after treatment and in larvicidal concentrations in larval development test was Haemonchus contortus. This is the first report of anthelminthic resistance to macrocylic lactones (eprinomectin) in goats in Poland.

Molecular detection of Trichostrongylus species through PCR followed by high resolution melt analysis of ITS-2 rDNA sequences

Polymerase chain reaction followed by high resolution melting (PCR-HRM) analysis is a simple, rapid and accurate method for molecular detection of various nematode species. The objective of the present study was, for the first time, to develop a PCR-HRM assay for the detection of various animal Trichostrongylus spp. A pair of primers targeting the ITS-2 rDNA region of the Trichostrongylus spp. was designed for the development of the HRM assay. DNA samples were extracted from 30 adult worms of Trichostrongylus spp., the ITS-2-rDNA region was amplified using PCR, and the resultant products were sequenced and characterized. Afterwards, the PCR-HRM analysis was conducted to detect and discriminate Trichostrongylus spp. Molecular sequence analysis revealed that 24, 4, and 1 of the samples were T. colubriformis, T. vitrinus and T. capricola, respectively. Results from PCR-HRM indicated that complete agreement was relatively found between speciation by HRM analysis and DNA sequencing for the detection of Trichostrongylus species. The PCR-HRM analysis method developed in the present study is fast and low-cost; the method can be comparable with other molecular detection techniques, representing a reliable tool for the identification of various species within the Trichostrongylus genus.