In brain tissue of three harbor seals of the German North Sea coast, high virus loads of highly pathogenic avian influenza virus (HPAIV) H5N8 were detected. Identification of different virus variants indicates high exposure to HPAIV circulating in wild birds, but there is no evidence for H5 specific antibodies in healthy seals. Replication of avian viruses in seals may allow HPAIV to acquire mutations needed to adapt to mammalian hosts as shown by PB2 627K variants detected in these cases.

Raccoon dogs (Nyctereutes procyonoides) and raccoons (Procyon lotor) are invasive alien species originating from East Asia and North America, respectively. They are discussed as vectors and reservoirs for various infectious diseases, including vector-borne and zoonotic pathogens, and are therefore a potential threat to human and domestic animal health, as well as to biodiversity and conservation. In the years 2021 and 2022, 110 raccoon dogs (Nyctereutes procyonoides) and 30 raccoons (Procyon lotor) were screened via qPCR for the presence of Leptospira spp., Rickettsia spp. and Borreliella spp. in the German federal state of Schleswig-Holstein as part of a health and risk assessment study. Borreliella spp. were confirmed in one raccoon dog and one raccoon, identified as Borreliella afzelii in the raccoon. Leptospira spp. were found in 21 (19.44%) raccoon dogs and 2 (6.90%) raccoons. In five raccoon dogs, Leptospira spp. were identified as Leptospira borgpetersenii, Leptospira kirschneri and Leptospira interrogans.

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.

Sarcoptic mange was detected in five free-ranging raccoon dogs (Nyctereutes procyonoides) in the federal state of Schleswig-Holstein, Germany, during a health assessment study of invasive species, including raccoon dogs, carried out between 2021 and 2022. Four raccoon dogs showed severe lesions, including extensive alopecia with thickening and hyperpigmentation of the skin (lichenification). The fifth animal was less affected, showing only thinning of the hair coat in multiple body locations. Skin scrapings were performed and confirmed the presence of Sarcoptes scabiei. Histopathology of the skin revealed diffuse epidermal hyperplasia and hyperkeratosis, mild eosinophilic dermatitis, and varying amounts of intralesional mites. Staphylococcus pseudintermedius and Corynebacterium auriscanis were detected in the skin samples of the affected animals, indicating a secondary bacterial infection. The source of sarcoptic mange remains unclear; interspecies transmission via direct or indirect contact seems likely. Raccoon dogs are therefore a potential vector for sarcoptic mange, and their behaviour could contribute to disease spread and persistence.

The bacterium Treponema paraluisleporidarum causes syphilis in lagomorphs. In a set of 1,095 samples from four species—European brown hare, mountain hare, Corsican hare, and European rabbit—we tested for infection and genotyped the strains that infect wild lagomorphs. Samples originate from Sweden, the Netherlands, the United Kingdom, Germany, the Czech Republic, and Italy. The phylogenetic analyses of two informative gene targets ( tp0488 and tp0548 ) showed high genetic diversity among the lagomorph-infecting treponemes. More specifically, we found a high number of nucleotide variants and various short repeat units in the tp0548 locus that have not been described for human syphilis and primate yaws causing Treponema pallidum . While the functional aspect of these short repeat units remains subject to ongoing investigations, it likely enables the pathogen to better survive in its lagomorph host. Our data did not support any geographic clustering, which is equally reflected in the host population genetics as shown by mitochondrial genome data corresponding to the sampled lagomorph populations. This is unexpected and in contrast with what has been shown for nonhuman primate infection with T. pallidum . In the future, the combination of multi-locus sequence typing and whole genome data from modern and ancient samples from a wide geographic range and multiple lagomorph species will contribute to a better understanding of the epidemiology and evolutionary path of lagomorph-infecting treponemes. In conclusion, our current study demonstrates widespread infection and a high genetic variation of the syphilis-causing pathogen in a higher number of positively PCR-tested European lagomorphs ( n = 302/1,095). IMPORTANCE: Syphilis is an ancient disease of humans and lagomorphs caused by two distinct but genetically closely related bacteria (>98% sequence identity based on the whole genome) of the genus Treponema . While human syphilis is well studied, little is known about the disease in the lagomorph host. Yet, comparative studies are needed to understand mechanisms in host–pathogen coevolution in treponematoses. Importantly, Treponema paraluisleporidarum –infected hare populations provide ample opportunity to study the syphilis-causing pathogen in a naturally infected model population without antibiotic treatment, data that cannot be obtained from syphilis infection in humans. We provide data on genetic diversity and are able to highlight various types of repetitions in one of the two hypervariable regions at the tp0548 locus that have not been described in the human syphilis-causing sister bacterium Treponema pallidum subsp. pallidum .

The cestode Echinococcus multilocularis parasitizes small intestines of carnivores such as foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) as definitive hosts and represents an important zoonotic threat. This study aimed to determine whether E. multilocularis DNA detection methods by real-time PCR involving easy-to-collect sample types, such as intestinal swabs could represent alternatives to traditional parasitological techniques. Three analytes from foxes and raccoon dogs were tested. i. Swabs taken immediately during necropsy (in situ) from the small intestinal mucosa (FastMucSwab), ii. swabs from scraped-off small intestinal mucosa (IsolMucSwab), collected for the sedimentation-counting-technique (SCT) and for comparative reasons iii. feces from the Ampulla recti. Only minor differences in E. multilocularis DNA detection, independent of sample type, were observed. High levels of concordance between PCR results were noted in the comparison of results on FastMucSwabs, IsolMucSwabs or feces. The agreement between FastMucSwab and IsolMucSwab was excellent (Kappa 0.86 [95 % CI: 0.79-0.92]). If inconclusive PCR results were excluded, PCR on FastMucSwabs had a diagnostic sensitivity of 92.7 % (95 % CI: 83.0-97.3 %) and a specificity of 91.5 % (95 % CI: 88.4-93.9 %) relative to SCT. Compared with SCT, Feces real-time PCR had a diagnostic sensitivity of 82.8 % (95 % CI: 63.5-93.5 %) and a specificity of 90.9 % (95 % CI: 81.4-95.9 %). Segmental swabbing had no diagnostic advantages. Overall, there was evidence that the DNA detection methods used here had a higher diagnostic sensitivity than SCT did. Results suggest that simple alternative methods, such as PCR on FastMucSwabs represent an efficient tool for performing larger-scale epidemiological studies.