Severe Neurologic Disease in a Horse Caused by Tick-Borne Encephalitis Virus, Austria, 2021

As evidenced by sero-epidemiological studies, infections of horses with the tick-borne encephalitis virus (TBEV) occur frequently in TBEV-endemic areas. However, there are only very few reports of clinical cases. A possible underreporting may be due to a variety of diagnostic challenges. In this study, ELISA and neutralization tests were applied to serum samples. Brain tissue samples were investigated for the presence of nucleic acids of TBEV, Equid alphaherpesvirus 1, Borna disease virus 1, West Nile and Usutu viruses, rustrela virus, as well as Eastern, Western, and Venezuelan equine encephalitis viruses with RT-qPCR, RT-PCR, and qPCR, respectively. TBEV-specific amplification products were subjected to Sanger sequencing. In addition, a direct fluorescent antibody test for rabies was performed. Clinical and patho-histological findings are reported. Using specific RT-qPCR and RT-PCR assays, TBEV nucleic acids were demonstrated in brain tissue samples. Sequencing revealed the Western (formerly Central) European subtype of TBEV as the etiological agent. A high titer of TBEV-specific neutralizing antibodies was found in the serum. RNAscope in situ hybridization revealed TBEV RNA confined to neuronal cell bodies and processes. No other pathogens or nucleic acids thereof could be detected. Diagnostic procedures need to be carried out early after the onset of neurological signs to allow for a final etiological diagnosis of acute TBEV infections in horses.

Tick-Borne Encephalitis Virus (TBEV) Infection in Two Horses

A final diagnosis in a horse with clinical signs of encephalopathy can be challenging despite the use of extensive diagnostics. Clinical signs are often not pathognomonic and need to be interpreted in combination with (specific) laboratory results and epidemiological data of the geographical region of the origin of the case(s). Here we describe the diagnostic pathway of tick-borne encephalitis virus infection in two horses using established molecular diagnostic methods and a novel in situ hybridization technique to differentiate between regionally important/emerging diseases for central Europe: (i) hepatoencephalopathy, (ii) Borna disease virus, and (iii) West Nile virus infections.

A Systematic Approach to Dissection of the Equine Brain-Evaluation of a Species-Adapted Protocol for Beginners and Experts

Introduction of new imaging modalities for the equine brain have refocused attention on the horse as a natural model for ethological, neuroanatomical, and neuroscientific investigations. As opposed to imaging studies, strategies for equine neurodissection still lack a structured approach, standardization and reproducibility. In contrast to other species, where adapted protocols for sampling have been published, no comparable guideline is currently available for equids. Hence, we developed a species-specific slice protocol for whole brain vs. hemispheric dissection and tested its applicability and practicability in the field, as well as its neuroanatomical accuracy and reproducibility. Dissection steps are concisely described and depicted by schematic illustrations, photographs and instructional videos. Care was taken to show the brain in relation to the raters' hands, cutting devices and bench surface. Guidance is based on a minimum of external anatomical landmarks followed by geometric instructions that led to procurement of 14 targeted slabs. The protocol was performed on 55 formalin-fixed brains by three groups of investigators with different neuroanatomical skills. Validation of brain dissection outcomes addressed the aptitude of slabs for neuroanatomical studies as opposed to simplified routine diagnostic purposes. Across all raters, as much as 95.2% of slabs were appropriate for neuroanatomical studies, and 100% of slabs qualified for a routine diagnostic setting. Neither autolysis nor subfixation significantly affected neuroanatomical accuracy score, while a significant negative effect was observed with brain extraction artifacts. Procedure times ranged from 14 to 66 min and reached a mean duration of 23.25 ± 7.93 min in the last of five trials in inexperienced raters vs. 16 ± 2.83 min in experts, while acceleration of the dissection did not negatively impact neuroanatomical accuracy. This protocol, derived analogously to the consensus report of the International Veterinary Epilepsy Task Force in dogs and cats, allows for systematic, quick and easy dissection of the equine brain, even for inexperienced investigators. Obtained slabs feature virtually all functional subcompartments at suitable planes for both diagnostic and neuroscientific investigations and complement the data obtained from imaging studies. The instructive protocol and brain dissection videos are available in Supplementary Material.

Emergence of West Nile virus lineage 2 in Europe: Characteristics of the first seven cases of West Nile neuroinvasive disease in horses in Austria

We report details of the first seven equine cases of confirmed West Nile neuroinvasive disease in Austria. The cases presented during summer and autumn of 2016 (n = 2), 2017 (n = 3) and 2018 (n = 2). All horses showed gait abnormalities and 6 of 7 horses exhibited fasciculations and/or tremors, and we provide video recordings of these. Three horses also showed cranial nerve involvement. Following rapid improvement, three horses were discharged. Four horses were euthanized due to the severity of clinical signs and subjected to neuropathological examination. West Nile virus (WNV) lineage 2 nucleic acid was detected in 5 of 7 horses, and WNV‐specific neutralizing antibodies in all 7 horses. In addition, serologic evidence of WNV infection was found in two out of fourteen in‐contact horses. Horses may be considered a sentinel species for human WNV infections, integrating human and veterinary medicine and thus contributing to the one health concept.

Genetic and spatial characterization of the red fox (Vulpes vulpes) population in the area stretching between the Eastern and Dinaric Alps and its relationship with rabies and canine distemper dynamics

Information on the population dynamics of a reservoir species have been increasingly adopted to understand and eventually predict the dispersal patterns of infectious diseases throughout an area. Although potentially relevant, to date there are no studies which have investigated the genetic structure of the red fox population in relation to infectious disease dynamics. Therefore, we genetically and spatially characterised the red fox population in the area stretching between the Eastern and Dinaric Alps, which has been affected by both distemper and rabies at different time intervals. Red foxes collected from north-eastern Italy, Austria, Slovenia and Croatia between 2006–2012, were studied using a set of 21 microsatellite markers. We confirmed a weak genetic differentiation within the fox population using Bayesian clustering analyses, and we were able to differentiate the fox population into geographically segregated groups. Our finding might be due to the presence of geographical barriers that have likely influenced the distribution of the fox population, limiting in turn gene flow and spread of infectious diseases. Focusing on the Italian red fox population, we observed interesting variations in the prevalence of both diseases among distinct fox clusters, with the previously identified Italy 1 and Italy 2 rabies as well as distemper viruses preferentially affecting different sub-groups identified in the study. Knowledge of the regional-scale population structure can improve understanding of the epidemiology and spread of diseases. Our study paves the way for an integrated approach for disease control coupling pathogen, host and environmental data to inform targeted control programs in the future.

Mycobacterium caprae Infection of Red Deer in Western Austria-Optimized Use of Pathology Data to Infer Infection Dynamics

Austria is officially bovine tuberculosis (TB) free, but during the last decade the west of the country experienced sporadic TB cases in cattle. Free-ranging red deer are known to be the maintenance host of Mycobacterium (M.) caprae in certain areas in Austria, where cattle can become infected on alpine pastures shared with deer. The epidemiology of TB in deer in alpine regions is still poorly understood. To inform decisions on efficient interventions against TB in deer, a method is needed to better capture the infection dynamics on population level. A total of 4,521 free-ranging red deer from Austria's most western Federal state Vorarlberg were TB-tested between 2009 and 2018. M. caprae was confirmed in samples from 257 animals. Based on descriptions of TB-like lesions, TB positive animals were categorized with a newly developed lesion score called “Patho Score.” Analyses using this Patho Score allowed us to distinguish between endemic, epidemic and sporadic TB situations and revealed different roles of subgroups of infected deer in infection dynamics. Overall, deer in poor condition, deer of older age and stags were the subgroups that were significantly more often TB positive (p = 0.02 or smaller for all subgroups). Deer in poor condition (p < 0.001) and stags (p = 0.04) also showed more often advanced lesions, indicating their role in mycobacterial spread. TB was never detected in fawns, while hinds were the subgroup that showed the fewest advanced lesions. Analysis of outbreaks of TB and lesion development in yearlings provided some evidence for the role of winter feeding as a source for increased infection transmission. Sporadic cases in TB-free areas appear to precede outbreaks in these areas. These currently TB-free areas should receive particular attention in sampling schemes to be able to detect early spreading of the infection. The Patho Score is a quick, easy-to-apply and reproducible tool that provides new insights on the epidemiology of TB in deer at population level and is flexible enough to relate heterogeneous wildlife monitoring data collected following different sampling plans. This lesion score was used for systematic assessment of infection dynamics of mycobacterial infections.

Bartonella DNA in heart tissues of bats in central and eastern Europe and a review of phylogenetic relations of bat-associated bartonellae

Background

Bats are among the most widely distributed mammals worldwide and can represent hosts or reservoirs for a number of different pathogens. Bartonella spp. are opportunistic bacterial pathogens, which are transmitted by a large variety of arthropods. The aim of this study was to investigate the presence and host-associations of these Gram-negative bacteria in heart tissues of bats collected in four different countries from eastern and central Europe and to analyze their phylogenetic relationship with other bat-associated bartonellae.

Results

The results of this study show for the first time the presence of Bartonella spp. DNA in heart tissues of bats from central and eastern Europe. The overall prevalence of the infection was 1.38%. Phylogenetic analysis identified four new Bartonella spp. sequences, which were closely related with other Bartonella previously isolated from bats in Europe and North America.

Conclusions

The gltA sequences of Bartonella spp. showed considerable heterogeneity in the phylogenetic analysis resulting in six different clades. Our study demonstrated the presence of Bartonella spp. only in heart tissues of bats from Romania, with two new bat species recorded as hosts (Myotis cf. alcathoe and Pipistrellus pipistrellus).

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3070-7) contains supplementary material, which is available to authorized users.

Efficacy of live attenuated porcine reproductive and respiratory syndrome virus 2 strains to protect pigs from challenge with a heterologous Vietnamese PRRSV 2 field strain

Background

Effective vaccines against porcine reproductive and respiratory syndrome virus (PRRSV), especially against highly pathogenic (HP) PRRSV are still missing. The objective of this study was to evaluate the protective efficacy of an experimental live attenuated PRRSV 2 vaccine, composed of two strains, against heterologous challenge with a Vietnamese HP PRRSV 2 field strain. For this reason, 20 PRRSV negative piglets were divided into two groups. The pigs of group 1 were vaccinated with the experimental vaccine, group 2 remained unvaccinated. All study piglets received an intranasal challenge of the HP PRRSV 2 on day 0 of the study (42 days after vaccination). Blood samples were taken on days 7 and 21 after vaccination and on several days after challenge. On day 28 after challenge, all piglets were euthanized and pathologically examined.

Results

On days 7 and 21 after vaccination, a PRRSV 2 viraemia was seen in all piglets of group 1 which remained detectable in seven piglets up to 42 days after vaccination. On day 3 after challenge, all piglets from both groups were positive in PRRSV 2 RT-qPCR. From day 7 onwards, viral load and number of PRRSV 2 positive pigs were lower in group 1 than in group 2. All pigs of group 1 seroconverted after PRRSV 2 vaccination. PRRSV antibodies were detected in serum of all study pigs from both groups from day 14 after challenge onwards. In group 2, moderate respiratory symptoms with occasional coughing were seen following the challenge with HP PRRSV 2. Pigs of group 1 remained clinically unaffected. Interstitial pneumonia was found in four piglets of group 1 and in all ten piglets of group 2. Histopathological findings were more severe in group 2.

Conclusions

It was thus concluded that the used PRRSV 2 live experimental vaccine provided protection from clinical disease and marked reduction of histopathological findings and viral load in pigs challenged with a Vietnamese HP PRRSV 2 field strain.

Babesia vesperuginis, a neglected piroplasmid: new host and geographical records, and phylogenetic relations

BACKGROUND

Babesia spp. are hemoparasites which infect the red blood cells of a large variety of mammals. In bats, the only known species of the genus is Babesia vesperuginis. However, except a few old reports, the host range and geographical distribution of this bat parasite have been poorly studied. This study aimed to investigate the presence of piroplasms in tissues of bats collected in four different countries from eastern and central Europe: Austria, Czech Republic, Hungary and Romania.

METHODS

A total of 461 bat carcasses (24 species) were collected between 2001 and 2016 from caves, mines and buildings. PCR was performed using specific primers targeting a portion of the 18S rDNA nuclear gene and cytochrome c oxidase subunit 1 mitochondrial gene, followed by sequencing.

RESULTS

The results of this study show for the first time the presence of B. vesperuginis in bats in central and eastern Europe. The phylogenetic analysis of the 18S rDNA nuclear gene revealed no variability between the sequences and the phylogenetic analysis of the cox1 mitochondrial gene proved that B. vesperuginis could be divided into two subclades.

CONCLUSION

Our study showed a broad geographical distribution of B. vesperuginis in European bats, reporting its presence in five new host species (M. cf. alcathoe, M. bechsteinii, M. myotis, Pi. nathusii and V. murinus) and three new countries.

Infections of horses and shrews with Bornaviruses in Upper Austria: a novel endemic area of Borna disease

Borna disease, a lethal infection with Borna disease virus-1 (BoDV-1), was diagnosed in four horses from Upper Austria in 2015 and 2016. All cases occurred in winter (two cases in February 2015 and two cases in December 2016), and the maximal distance of the affected stables was 17 km. To demonstrate whether the causative agent was also harbored by its reservoir host, the bicolored white-toothed shrew (Crocidura leucodon), 28 shrews from this geographic area were collected in 2015 and investigated for the presence of BoDV-1. The shrew species were identified according to taxonomic clues and molecular barcodes. Affected horses and all shrews were investigated using histology, immunohistochemistry (IHC) and reverse transcription PCR. The horses exhibited severe nonpurulent encephalitis. Large amounts of BoDV-1 antigen were identified in their CNS. Among the 28 shrews, nine were identified as C. leucodon and 13 as Sorex araneus (Common shrew; Eurasian shrew). Six C. leucodon (66.7%) and one S. araneus (7.7%) had BoDV-1 infections. In accordance with previous findings, the IHC of C. leucodon exhibited a high amount of viral antigen in many neural and extraneural tissues. By contrast, the single positive S. araneus had an exclusively neural staining pattern. Of all positive samples, whole-genome BoDV-1 sequences were generated. The acquired sequences of the affected shrews were not identical to each other and clustered around the sequences of the diseased horses belonging, surprisingly, to the German ‘strain V’ cluster.

Comparison of clinical and immunological findings in gnotobiotic piglets infected with Escherichia coli O104:H4 outbreak strain and EHEC O157:H7

Background

Shiga toxin (Stx) producing Escherichia coli (E. coli) (STEC) is the most frequent cause of diarrhoea-positive haemolytic uraemic syndrome (D + HUS) in humans. In 2011, a huge outbreak with an STEC O104:H4 strain in Germany highlighted the limited possibilities for causative treatment of this syndrome. The responsible STEC strain was found to combine Stx production with adherence mechanisms normally found in enteroaggregative E. coli (EAEC). Pathotypes of E. coli evolve and can exhibit different adhesion mechanisms. It has been shown previously that neonatal gnotobiotic piglets are susceptible for infection with STEC, such as STEC O157:H7 as well as for EAEC, which are considered to be the phylogenetic origin of E. coli O104:H4. This study was designed to characterise the host response to infection with the STEC O104:H4 outbreak strain in comparison to an STEC O157:H7 isolate by evaluating clinical parameters (scoring) and markers of organ dysfunction (biochemistry), as well as immunological (flow cytometry, assessment of cytokines/chemokines and acute phase proteins) and histological alterations (light- and electron microscopy) in a gnotobiotic piglet model of haemolytic uraemic syndrome.

Results

We observed severe clinical symptoms, such as diarrhoea, dehydration and neurological disorders as well as attaching-and-effacing lesions (A/E) in the colon in STEC O157:H7 infected piglets. In contrast, STEC O104:H4 challenged animals exhibited only mild clinical symptoms including diarrhoea and dehydration and HUS-specific/severe histopathological, haematological and biochemical alterations were only inconsistently presented by individual piglets. A specific adherence phenotype of STEC O104:H4 could not be observed. Flow cytometric analyses of lymphocytes derived from infected animals revealed an increase of natural killer cells (NK cells) during the course of infection revealing a potential role of this subset in the anti-bacterial activity in STEC disease.

Conclusions

Unexpectedly, E. coli O104:H4 infection caused only mild symptoms and minor changes in histology and blood parameters in piglets. Outcome of the infection trial does not reflect E. coli O104:H4 associated human disease as observed during the outbreak in 2011. The potential role of cells of the innate immune system for STEC related disease pathogenesis should be further elucidated.

Occurrence, morphological characterization and antigen localization of felid herpesvirus-induced pneumonia in cats: a retrospective study (2000-2006)

The pathological findings in nine cases of pneumonia associated with infection by felid herpesvirus-1 (FeHV-1) are presented. The animals affected were five kittens, two subadult cats and two adult cats. The microscopical changes included fibrinonecrotic pneumonia and severe necrosis of the bronchial and bronchiolar epithelium. FeHV-1 antigen was detected immunohistochemically in pneumocytes, alveolar macrophages and necrotic bronchial and bronchiolar epithelial cells. In the youngest kitten viral antigen was also found in the liver. FeHV-1 infection should therefore be considered as a differential diagnosis in cats with fibrinonecrotic pneumonia and demonstration of viral antigen by immunohistochemistry is a useful diagnostic procedure in such cases.

Spontaneously occurring alimentary osteofluorosis associated with proliferative gastroduodenopathy in rabbits

Growing rabbits from two rabbitries, fed with commercial concentrates and hay, developed painful thickenings of the extremities. Four rabbits from each farm were clinically examined and necropsied. All animals showed multiple moderate to severe osseous proliferations of extremities and mandibles and a mild to severe proliferative gastroduodenopathy. Histologically, periosteal and endosteal hyperostosis and a mild to severe proliferation of the gastric and duodenal mucosa were noted. Bone analyses revealed 12,700 and 15,000 microg fluoride per gram of bone ash in affected rabbits, compared with 550 microg fluoride in a control animal. A highly elevated fluoride content was found in concentrates. Vitamin A levels were moderately increased only in one concentrate, and copper levels were normal. Results indicate that alimentary fluoride intoxication caused prominent bony proliferations in the examined rabbits. Whether the proliferative gastroduodenopathy is related to the elevated fluoride intake or represents an incidentally occurring secondary disease remains to be determined.

A human case of travel-related rabies in Austria, September 2004

A young male Austrian tourist, aged 23 years and unvaccinated against rabies, was bitten by a dog in Morocco in July 2004. One month later he was hospitalised in Ceuta with symptoms compatible with rabies. He died on 23 September in an Austrian hospital after a diagnosis of rabies was confirmed by FAT, IHC and RT-PCR (including sequencing) of the neck skin and the RT-PCR (including sequencing) of the pharyngeal swab. This Austrian case of laboratory confirmed rabies highlights the urgent need for reinforcement of the international recommendations for travel vaccinations.

Travel-associated rabies in Austrian man

Rabies developed in an Austrian man after he was bitten by a dog in Agadir, Morocco. Diagnosis was confirmed by reverse transcription–polymerase chain reaction and immunohistochemistry. The patient's girlfriend was bitten by the same dog, but she did not become ill.

Clinical and pathological features of the Porcine Ulcerative Dermatitis Syndrome (PUDS)

The nomenclature of ulcerative dermatitis as used in literature is somehow confusing because on the one hand this skin disorder is associated with bacterial growth and on the other hand it is a synonym for a chronic sporadic disease of adult sows with unknown aetiology. Thus, we propose the terminus 'Porcine Ulcerative Dermatitis Syndrome (PUDS)' for the latter to distinguish between these two disease complexes. This syndrome could be identified by clinical and pathological examinations in six sows, that were submitted to the clinic. Epidermal ulcers could be found nearly all over the body, but teats were always spared. Haematological examination showed a slight anaemia but physiological leucocyte counts. However, lymphopenia (x = 44.8%), granulocytosis (x = 42.0%) and an increased number of monocytes (x = 13.1%) could be found. Histologically, a lymphoplasmacytic and granulohistiocytic infiltration in the corium was most prominent. In some cases, a moderate leucocytoclastic vasculitis and perivasculitis could be seen at the dermo-epidermal border. Additionally, a multifocal interstitial nephritis with lymphoplasmacytic infiltration was a prominent feature in all animals. Participation of an immune complex associated disorder can be assumed when regarding histological findings as skin lesions in combination with glomerulonephritis are a common feature of such diseases. Also, IgG levels were elevated two- to fourfold in all affected sows when compared with healthy control pigs. This supports the hypothesis that not only T cells, as shown previously, but also the humoral branch of the immune system is involved in the aetiology of PUDS.

Leberegelbedingte Photodermatitis beim Rind

Zwei Fleckviehkühe wurden wegen Hauterkrankungen nach Weidegang an die II. Medizinische Universitätsklinik für Klauentiere der Veterinärmedizinischen Universität Wien überwiesen. Bei der klinischen Untersuchung waren die Veränderungen auf die unpigmentierten Bereiche der Haut begrenzt. Die Haut des Rückens, des Flotzmaules, der Augen und der Zitzen war am stärksten betroffen. Die Tiere zeigten Alopezie, Erythem, Schuppen- und Krustenbildung, seröse Exsudation, Hautverdickungen, Hautablösungen und Narbenbildung. Signifikante Abweichungen der klinischchemischen Parameter bestanden in einer erhöhten Serumenzymaktivität der GGT und GLDH. Das klinische Erscheinungsbild erwies sich als durch eine Leberschädigung bedingte Photodermatitis solaris. Die parasitologische Untersuchung einer Kotprobe und des Gallenblasenpunktats ergab einen hochgradigen Leberegelbefall. Mittels Ultraschalluntersuchung konnten massive Leberveränderungen wie Gallengangsverkalkungen und Abszesse diagnostiziert werden. Bei der pathomorphologischen Untersuchung wurde bei beiden Tieren eine Fasziolose in Verbindung mit hepatogener Photodermatitis festgestellt. Die Symptomatik sowie klinische und pathologische Befunde werden beschrieben und Differenzialdiagnosen diskutiert.

[Isoimmune haemolytic icterus in neonatal calves as a consequence of vaccination against piroplasmosis]

The article refers about several cases of isoimmunohaemolytic icterus in neonatal calves from different farms, whose dams had all been vaccinated against piroplasmosis. Clinical signs of immunomediated icterus neonatorum gravis, results of blood chemistry (with special regard to liver-specific parameters in the neonatal calf and results of haematology) as well as gross pathology and pathohistology are to be discussed. It is summarized, that the most relevant indicators for a hepatopathy in the newborn calf are total-bilirubin and the glutamate-dehydrogenase. Today, the production of piroplasmosis-vaccines out of blood of splenectomized animals is referred to as the only practicable method of harvesting sufficient amounts of vaccine-antigen.

[Calcinosis in goats]

Death, abortion, decreased milk yield and emaciation in dairy goats occurred due to calcinosis in a goat operation on 1100 meter sea level in Tyrol. This could be diagnosed by the clinical, sonographical and pathomorphological investigation. In the basic fodder yellow oat grass proportion was present with 40%. Clinically the apathic goats showed reduced appetite, emaciation, dyspnea, anaemic mucous membranes, heart noises and less activity to move. The blood-chemical examination of one goat revealed an increased activity of AP (199 U/l), calcium and phosphor-concentrations were in normal range. Sonographically liquidothorax and -perikard, calcified pulmonary and aortic valves and a thickened aortic orifice as well as calcification of kidneys, enlargment of liver and ascites could be diagnosed in this goat. The sonographical findings were confirmed by pathomorphological examination.