Tick-borne encephalitis (TBE) is the most important viral tick borne zoonosis in Europe. In Germany, about 250 human cases are registered annually, with the highest incidence reported in the last years coming from the federal states Bavaria and Baden-Wuerttemberg. In veterinary medicine, only sporadic cases in wild and domestic animals have been reported; however, a high number of wild and domestic animals have tested positive for the tick-borne encephalitis virus (TBEV) antibody. In May 2015, a five-month-old lamb from a farm with 15 Merino Land sheep and offspring in Nersingen/Bavaria, a TBEV risk area, showed impaired general health with pyrexia and acute neurological signs. The sheep suffered from ataxia, torticollis, tremor, nystagmus, salivation and finally somnolence with inappetence and recumbency. After euthanasia, pathological, histopathological, immunohistochemical, bacteriological, parasitological and virological analyses were performed. Additionally, blood samples from the remaining, healthy sheep in the herd were taken for detection of TBEV antibody titres. At necropsy and accompanying parasitology, the sheep showed a moderate to severe infection with Trichostrongylids, Moniezia and Eimeria species. Histopathology revealed mild to moderate necrotising, lymphohistiocytic and granulocytic meningoencephalitis with gliosis and neuronophagia. Immunohistochemistry for TBEV was negative. RNA of a TBEV strain, closely related to the Kumlinge A52 strain, was detected in the brain by quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) and subsequent PCR product sequencing. A phylogenetic analysis revealed a close relationship to the TBEV of central Europe. TBEV was cultured from brain tissue. Serologically, one of blood samples from the other sheep in the herd was positive for TBEV in an enzyme-linked immunosorbent assay (ELISA) and in a serum neutralisation test (SNT), and one was borderline in an ELISA. To the authors’ knowledge this is the first report of a natural TBEV infection in a sheep in Europe with clinical manifestation, which describes the clinical presentation and the histopathology of TBEV infection.

The significance of hemotrophic mycoplasma in cattle remains unclear. Especially in Europe, their epidemiological parameters as well as pathophysiological influence on cows are lacking. The objectives of this study were: (1) to describe the prevalence of ‘Candidatus Mycoplasma haemobos’ (‘C. M. haemobos’) and Mycoplasma wenyonii (M. wenyonii) in Bavaria, Germany; (2) to evaluate their association with several blood parameters; (3) to explore the potential of vertical transmission in Simmental cattle; and (4) to evaluate the accuracy of acridine-orange-stained blood smears compared to real-time polymerase chain reaction (PCR) results to detect hemotrophic mycoplasma. A total of 410 ethylenediaminetetraacetic acid-blood samples from cows from 41 herds were evaluated by hematology, acridine-orange-stained blood smears, and real-time PCR. Additionally, blood samples were taken from dry cows of six dairy farms with positive test results for hemotrophic mycoplasma to investigate vertical transmission of infection. The period prevalence of both species was 60.24% (247/410), C. M. haemobos 56.59% (232/410), M. wenyonii 8.54% (35/410) and for coinfection 4.88% (20/410). Of the relevant blood parameters, only mean cell volume (MCV), mean cell hemoglobin (MCH), and white blood cell count (WBC) showed differences between the groups of infected and non-infected individuals. There were lower values of MCV (P < 0.01) and MCH (P < 0.01) and higher values of WBC (P < 0.05) in ‘C. M. haemobos’-infected cows. In contrast, co-infected individuals had only higher WBC (P < 0.05). In M. wenyonii-positive blood samples, MCH was significantly lower (P < 0.05). Vertical transmission of ‘C. M. haemobos’ was confirmed in two calves. The acridine-orange-method had a low sensitivity (37.39%), specificity (65.97%), positive predictive value (63.70%) and negative predictive value (39.75%) compared to PCR. ‘Candidatus Mycoplasma haemobos’ was more prevalent than M. wenyonii in Bavarian Simmental cattle, but infection had little impact on evaluated blood parameters. Vertical transmission of the infection was rare. Real-time PCR is the preferred diagnostic method compared to the acridine-orange-method.

Viral diseases remain a major concern for animal health and global food production in modern agriculture. In chickens, avian leukosis virus subgroup J (ALV-J) represents an important pathogen that causes severe economic loss. Until now, no vaccine or antiviral drugs are available against ALV-J and strategies to combat this pathogen in commercial flocks are desperately needed. CRISPR/Cas9 targeted genome editing recently facilitated the generation of genetically modified chickens with a mutation of the chicken ALV-J receptor Na⁺/H⁺ exchanger type 1 (chNHE1). In this study, we provide evidence that this mutation protects a commercial chicken line (NHE1ΔW38) against the virulent ALV-J prototype strain HPRS-103. We demonstrate that replication of HPRS-103 is severely impaired in NHE1ΔW38 birds and that ALV-J-specific antigen is not detected in cloacal swabs at later time points. Consistently, infected NHE1ΔW38 chickens gained more weight compared to their non-transgenic counterparts (NHE1W38). Histopathology revealed that NHE1W38 chickens developed ALV-J typical pathology in various organs, while no pathological lesions were detected in NHE1ΔW38 chickens. Taken together, our data revealed that this mutation can render a commercial chicken line resistant to highly pathogenic ALV-J infection, which could aid in fighting this pathogen and improve animal health in the field.

The syndrome of arachnomelia is an inherited malformation mainly of limbs, back and head in cattle. At present the arachnomelia syndrome has been well known mainly in Brown Swiss cattle. Nevertheless, the arachnomelia syndrome had been observed in the Hessian Simmental population during the decade 1964–1974. Recently, stillborn Simmental calves were observed having a morphology similar to the arachnomelia syndrome. The goal of this work was the characterization of the morphology and genealogy of the syndrome in Simmental to establish the basis for an effective management of the disease.

Enteric viral infections represent a major concern for poultry production, causing growth retardation, impaired feed conversion, and increased mortality, particularly in young birds. To investigate the involvement of RNA and DNA enteric viruses in flocks exhibiting growth problems, seven poultry farms in southern Germany, including broiler, pullet, and breeder operations, were examined for the presence of chicken astrovirus (CAstV), avian reovirus (ARV), and fowl adenovirus-1 (FAdV-1) by means of RT-PCR. All farms exhibited growth retardation, diarrhea, and enteritis-associated lesions. Histopathology revealed features of runting–stunting syndrome in most of the broiler farms and depletion of lymphatic tissue in most of the pullet farms. CAstV was detected in all flocks, ARV in six, and FAdV-1 in four farms. To further characterize the viral agents, metagenomic sequencing of cecal tonsils from one severely affected broiler flock confirmed the presence of a CAstV strain identical (100%) to CAV/Belgium/4134_001/2019. In addition, the complete genome of avian Sicinivirus was assembled for the first time in Germany, showing 96.8% nucleotide identity with a Dutch strain (Chicken/NLD/2019/V_M_056_picorna_2). These findings demonstrate the widespread circulation and co-infection of enteric viruses on German poultry farms and underline the transboundary nature of these infections, emphasizing the need for enhanced surveillance and biosecurity measures to mitigate their impact on poultry health and productivity.