Causes of admission and outcomes of brown hare (Lepus europaeus) leverets at wildlife rescue centres in the Czech Republic

Background Wildlife rescue centres care for orphaned and injured young as an integral part of their work. However, inappropriate interventions in nature can have a negative effect on the survival of young hares, especially when the care of these young is not very successful. The aim of this study was to assess the number of brown hare leverets admitted to rescue centres in the Czech Republic in the period from 2010 to 2019, the causes of their admission to rescue centres and their outcomes. Results We evaluated the number of brown hare leverets admitted to rescue centres in the Czech Republic in the period from 2010 to 2019 and the outcomes associated with their leaving these rescue centres. We found that the number of brown hare leverets admitted increased during the monitored period (rSp = 0.6364, p < 0.05). The most frequent reasons for admission were the admission of orphaned young (49.15%), leverets brought needlessly (19.60%) and leverets that had been bitten by other animals (18.63%). More (p < 0.05) young admitted to rescue centres died (40.76%) than were reared successfully and released back into the wild (32.40%). Leverets that had been caught needlessly or orphaned and late-born leverets survived and could be released back into the wild (38.56, 34.51 and 52%, respectively), while fatalities were recorded in most leverets bitten by another animal (65.05%) or hit in a collision with a vehicle (97.06%). Most young hares (76.92%) that were exhausted or starved at the time of admission could not be saved. Conclusions Since only a small proportion of hares in a litter survive until adulthood in the wild, young animals being found and taken needlessly to rescue centres may harm the hare population. Our results show that only around one in three healthy young hares admitted to rescue centres are reared successfully. It is, in our opinion, of fundamental importance to the protection of brown hare leverets to inform the public of this issue and prevent needless interventions into natural rearing in the wild.

Potent protease inhibitors of deadly lagoviruses: rabbit hemorrhagic disease virus and European brown hare syndrome virus

Rabbit hemorrhagic disease (RHD) and European brown hare syndrome (EBHS) are highly contagious diseases caused by lagoviruses in the Caliciviridae family and mainly affect rabbits and hares, respectively. These infectious diseases are associated with high mortality and a serious threat to domesticated (farmed and pet) and wild rabbits and hares, including endangered species such as Riparian brush rabbits. In the US, only isolated cases of RHD had been reported until Spring 2020. However, RHD caused by RHD type 2 virus (RHDV2) was unexpectedly reported in April 2020 in New Mexico and has subsequently spread to several US states infecting wild rabbits and hares. Since it is almost impossible to control and eradicate the virus from wild animals, it is highly likely RHD will become endemic in the US. Vaccines are available for RHD, however, there is no specific treatment for these deadly diseases. RHDV and EBHSV encode a 3C-like protease (3CLpro), which is essential for virus replication and a promising target for antiviral drug development. We have previously generated focused small molecule libraries of 3CLpro inhibitors and demonstrated the in vitro potency and in vivo efficacy of some protease inhibitors against viruses that encode 3CLpro including caliciviruses and coronaviruses. Here we established the enzyme assay and cell-based assays for these uncultivable viruses to determine the in vitro activity of 3CLpro inhibitors, including GC376, a protease inhibitor being developed for feline infectious peritonitis, and identified potent inhibitors of RHDV1 and 2 and EBHSV. In addition, structure-activity relationship study and homology modelling of the 3CLpros and inhibitors revealed that lagoviruses share similar structural requirements for 3CLpro inhibition with other caliciviruses.

Phylogenetic Analysis of European Brown Hare Syndrome Virus Strains from Poland (1992–2004)

European brown hare syndrome (EBHS) is lethal to several species of free-living hares worldwide. The genetic characterization of its virus (EBHSV) strains in European circulation and epidemiological knowledge of EBHSV infections is not yet complete. The study determined the nucleotide sequences of the genomes of EBHSV strains from Poland and analyzed their genetic and phylogenetic relationships to a group of hare lagoviruses. The genome of five virus strains detected in Poland between 1992 and 2004 was obtained by RT-PCR and sequencing of the obtained amplicons. The genetic relationships of the EBHSV strains were analyzed using the full genome and VP60 gene sequences. Additionally, the amino acid sequence of the VP60 gene was analyzed to identify mutations specific to recognized EBHSV subgroups. Partial amplification of the virus open reading frame (ORF)1 and ORF2 regions obtained nearly complete nucleotide genome sequences of the EBHSV strains. Phylogenetic analysis placed them in a GII.1 cluster with other European strains related to nonpathogenic hare caliciviruses. VP60 gene analysis allocated these EBHSV strains to the G1.2, G2.2–2.3 or G3 virus genetic groups. The amino acid sequence differences in the entire genome ranged from 1.1 to 2.6%. Compared to a reference French EBHSV-GD strain, 22 variable amino acid sites were identified in the VP60 region of the Polish strains, but only six were in VP10. Single amino acid changes appeared in different sequence positions among Polish and other European virus strains from different genetic groups, as well as in VP10 sequences of nonpathogenic hare caliciviruses. The results of the study showed a high genetic homogeneity of EBHSV strains from Poland despite their different location occurrence and initial detection times. These strains are also phylogenetically closely related to other EBHSV strains circulating in Europe, likely confirming the slow evolutionary dynamics of this lagovirus species.

The distribution of lagomorph syphilis caused by Treponema paraluisleporidarum in Europe

Treponema paraluisleporidarum infects both rabbits (ecovar Cuniculus) and hares (ecovar Lepus). While the occurrence of the bacterium has previously been reported for European brown hares (Lepus europaeus) and domestic rabbits (Oryctolagus cuniculus f. domestica), there are no data available that report infection in the European context. We tested a total of 1,995 serum samples and 287 genital swabs from opportunistically sampled European brown hares (Lepus europaeus; n = 2135), Mountain hares (Lepus timidus; n = 4), European rabbits (Oryctolagus cuniculus; n = 138), and pet rabbits (O. cuniculus f. domestica; n = 5). The samples originated from eight European countries. In case only serum was available, we tested the samples for the presence of anti-treponemal antibodies. For this, we utilized the Treponema pallidum-particle agglutination test (TP-PA), which is suited for the use in lagomorphs due to the antigenic cross-reactivity of anti-T. pallidum and anti-T. paraluisleporidarum antibodies. In addition, the results of 380 sera were confirmed using the fluorescent-Treponema antibody absorption test (FTA-ABS). In all cases where swab samples were available, DNA was extracted and tested using quantitative PCR to test for the presence of the lagomorph syphilis-bacterium. We were able to detect antibodies in 825 of 1,995 lagomorph sera (41.4%; brown hare: 825/1,868; rabbit: 0/127) and obtained positive qPCR results from 182 of 287 swab samples (63.4%; European brown hare: 167/267; mountain hare: 4/4; rabbit: 11/16). While all rabbit sera (n = 127) tested negative for anti-treponemal antibodies, the presence of the bacterium was confirmed in eight wild (n = 8/11) and three domestic rabbits (n = 3/5) from Germany using qPCR.

Viral Disease in Lagomorphs: A Molecular Perspective

Our understanding of molecular biology of the viruses that infect lagomorphs is largely limited to the leporipoxvirus myxoma virus (MYXV) and the lagoviruses rabbit haemorrhagic disease virus (RHDV) and European brown hare syndrome virus (EBHSV) that infect the European rabbit (Oryctolagus cuniculus) and the European brown hare (Lepus europaeus) respectively. Thanks to the great effort of historic surveillance studies and careful sample archiving, the molecular evolution of these viruses is being resolved. Although historically considered viruses that cause species specific diseases recent reports show that several lagomorphs may now face the threat of these maladies. The driving factors behind these changes has not been determined and the effect of these species jumps on lagomorph populations has yet to be seen. Lagomorphs are also affected by several other lesser studied viral diseases. In addition, recent metagenomic studies have led to the identification of novel lagomorph viruses the importance of these to lagomorph health remains to be fully determined. In this chapter we summarize molecular aspects of viruses that infect lagomorphs, paying particular attention to recent interspecies infections.

Hunter estimates of game density as a simple and efficient source of information for population monitoring: A comparison to targeted survey methods

Hunters in Europe gather non-survey game species population estimates to inform wildlife management, however, the quality of such estimates remains unclear. We compared estimates of game density, realized annual intrinsic growth rates, and period mean growth rates between hunter obtained data and data obtained by targeted survey methods for four species in Poland from 1960 to 2014. Raw hunter estimates were strongly positively correlated to spotlight counts of red fox (18 years of monitoring), strip counts of brown hare (21 years) and grey partridge (25 years), male call counts of partridge (24 years), and complete counts of roe deer (49 years), and not related to spotlight counts of brown hare (15 years). Realized annual intrinsic growth rates derived from hunter estimates were strongly positively related to annual intrinsic growth rates derived from strip counts of grey partridge and complete counts of roe deer, but only weakly or not related to strip counts of brown hare, spotlight counts of red fox and brown hare, and male call counts of grey partridge. The period length at which the period mean growth rates derived from hunter estimates and estimates from other methods were strongly correlated was largely variable among methods and species. In the roe deer, correlation between these variables was strong across all years, while in smaller game species the period mean growth rates based on hunter estimates and other methods had the strongest association in period lengths of 6 to 11 years. We conclude that raw hunter estimates convey largely similar information to that provided by other targeted survey methods. Hunter estimates provide a source of population data for both the retrospective and prospective analysis of game population development when more robust estimates are unavailable.

Agri-environment schemes do not support Brown Hare populations due to inadequate scheme application

The goal of many agri-environment schemes (AES) is to increase biodiversity in agroecosystems. AES effects are often measured on invertebrates and birds; mammals as indicator species are infrequently targets of such researches. Our goal was to evaluate the local-scale effects of the Hungarian Agri-Environmental Measures (AEM) on the European brown hare (Lepus europaeus), which shows decreasing population trends across Europe. We compared hare abundances and their dropping numbers in AEM and control agricultural arable and grassland fields of 17 game management units in two seasons. We also examined the quality of arable fields based on their margin width and vegetation cover. We found that margin quality was higher in AEM than in the control fields. Control grasslands had higher vegetation quality than the AEM grasslands. We found a significant difference in hare counts between AEM and control arable fields in spring but no difference in autumn. The dropping densities did not differ in any season, treatment category or agroecosystem type. We conclude that the AEM program (2009-2014) in Hungary was not effective for the hare, and this might have been caused by the inadequate or weak application of AEM practices. We provide recommendations for future AEM programs to enhance biodiversity.

Comparison of spotlighting monitoring data of European brown hare (Lepus europaeus) relative population densities with infrared thermography in agricultural landscapes in Northern Germany

A successful wildlife management requires monitoring. Including non-scientific volunteers into monitoring actions is a common way for obtaining long-term and comprehensive data. Hunters present a valuable target group as they are spread out nationwide in Germany and additionally, they provide a know-how regarding game species. Since 1990s, various German hunting associations established monitoring programs and motivated hunters to join, in order to record population sizes of huntable game species under standardized census methods. The aim of this study was to compare instructed hunters performed spotlight counts of European brown hares with thermography in three federal states (Lower-Saxony, Saxony-Anhalt, North Rhine-Westphalia) in 2015–2018 in Northern Germany. Therefore, we modelled the number of hares counted by both methods with the associated observed area. Moreover, we performed repeated thermographic counts in selected areas and performed distance sampling to test the deviations of estimated population densities within a short time period. Repeated infrared thermographic counts on three consecutive nights show a coefficient of variation from 6.6% to 15.5% with deviations of 2.2–2.7 hares per 100 ha, while the method of distance sampling reveals minor deviations of 0.9–1.7 hares per 100 ha and a coefficient of variation from 3.1–7.4%. The coefficient of variation value between spotlight and infrared thermographic count lies between 0 to 21.4%. Our model confirmed no significant differences between the European brown hare density estimations based on a spotlight count and an infrared thermographic count on the following night. The results provide insight into the dimension of the error margin of density estimations performed by spotlight counts. Therefore, we recommend to take possible counting errors into account and to ideally perform repeated counts to assess the error margin for each counting site. This would help for example to quantify the uncertainty in the calculation of mortality rates. Additionally, our results show that monitoring data generated by instructed hunters can provide reliable and valid data, if implemented and conducted in a standardized scientific way.