The rustrela virus (RusV) was recently described as a novel pathogen in a circumscribed area of northern Germany close to the Baltic Sea. Up to now, the virus has been detected in cases of fatal non-suppurative meningoencephalitis in zoo animals of different species and a single wild carnivore as well as in apparently healthy yellow-necked field mice ( Apodemus flavicollis). Data regarding the background of this previously undiscovered pathogen, including clinical presentation of the disease, host range, and distribution of the virus, are still limited. Here, three euthanized red-necked wallabies ( Macropus rufogriseus) from zoos of different areas in northeastern Germany were submitted for necropsy after presenting with apathy and therapeutically unresponsive neurological symptoms. A moderate to severe, non-suppurative meningoencephalitis was diagnosed in all three cases. RusV was consistently detected via RT-qPCR and RNA in situ hybridization in the brains of all wallabies. Other, commonly known neuropathogens could not be detected. Overall, red-necked wallabies appear to be highly susceptible to RusV as novel neuropathogen, which is broader distributed in northeastern Germany.
Infection with African swine fever virus (ASFV) causes a highly lethal hemorrhagic disease in domestic and Eurasian wild pigs. Thus, it is a major threat to pig populations worldwide and a cause of substantial economic losses. Recently, less virulent ASFV strains emerged naturally, which showed higher experimental virulence in wild boar than in domestic pigs. The reason for this difference in disease progression and outcome is unclear but likely involves different immunological responses. Unfortunately, besides the importance of CD8α+ lymphocytes, little is known about the immune responses against ASFV in suids. Against this background, we used a multicolor flow cytometry platform to investigate the T-cell responses in wild boar and domestic pigs after infection with the moderately virulent ASFV strain “Estonia2014” in two independent trials. CD4–/CD8α+ and CD4+/CD8α+ αβ T-cell frequencies increased in both subspecies in various tissues, but CD8α+ γδ T cells differentiated and responded in wild boar only. Proliferation in CD8α+ T cells was found 10 days post infectionem only. Frequencies of T-bet+ T cells increased in wild boar but not in domestic pigs. Of note, we found a considerable loss of perforin expression in cytotoxic T cells, 5 and 7 dpi. Both subspecies established a regulatory T-cell response 10 dpi. In domestic pigs, we show increasing levels of ICOS+ and CD8α+ invariant Natural Killer T cells. These disparities in T-cell responses might explain some of the differences in disease progression in wild boar and domestic pigs and should pave the way for future studies.