In 2011, an unidentified disease in cattle was reported in Germany and the Netherlands. Clinical signs included fever, decreased milk production, and diarrhea. Metagenomic analysis identified a novel orthobunyavirus, which subsequently was isolated from blood of affected animals. Surveillance was initiated to test malformed newborn animals in the affected region.

S evere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, at the end of 2019. Researchers have identified close relatives to SARS-CoV-2 in bats (1) and pangolins (order Pholidota) (2,3). Whether the pandemic was initiated by direct transmission from bats or through an intermediate mammalian host is still under debate (4). During the 2002-2004 severe acute respiratory syndrome pandemic, researchers documented the causative virus in raccoon dogs (Nyctereutes procyonoides) in China, indicating that these animals might have been intermediate hosts for the virus (5). Fur producers in China own >14 million captive raccoon dogs, accounting for ≈99% of the global share of raccoon dogs (6) (Appendix Figure 1, panel A, https:// wwwnc.cdc.gov/EID/article/26/12/20-3733-App1. pdf). However, whether these animals are susceptible to SARS-CoV-2 is unknown. Using our established study design (7), we characterized susceptibility, viral shedding, transmission potential, serologic reactions, and pathologic lesions of raccoon dogs after experimental SARS-CoV-2 infection.

A fter spilling over from an unknown animal host to humans, a novel betacoronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in December 2019 (1,2) and induced a global pandemic. This virus, which causes coronavirus disease, was first identified in humans in Wuhan, China (3). The role of livestock and wildlife species at the human-animal interface in disease emergence and dynamics was extensively discussed, focusing on the identification of susceptible species, potential reservoirs, and intermediate hosts. Natural or experimental infections have demonstrated the susceptibility of fruit bats (Rousettus aegyptiacus), ferrets, felids, dogs, and minks to the virus; however, pigs, chicken, and ducks are not susceptible (4-6). Besides ducks, chicken, and pigs, other major livestock species, including >1.5 billion cattle (Bos taurus), live with close contact with humans. Non-SARS-CoV-2 betacoronaviruses are widespread in bovines (7); seroprevalences reach up to 90% (8), but these infections are usually subclinical (7). However, whether any ruminant species are susceptible to SARS-CoV-2 infection or whether there is any cross-reactivity of antibodies against bovine coronaviruses (BCoVs) and SARS-CoV-2 is unknown. We examined the susceptibility of cattle to SARS-CoV-2 infection and characterized the course of infection.

Domestic cats (Felis catus) are popular companion animals that live in close contact with their human owners. Therefore, the risk of a trans-species spreading event between domestic cats and humans is ever-present. Shortly after the emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its rapid spread around the world, the role of domestic cats in the transmission cycle was questioned. In the present study, the first large-scale survey of antibody occurrence in the domestic cat population in Germany was conducted, in order to assess the incidence of naturally occurring human to cat transmission of SARS-CoV-2. A total of 920 serum samples, which were collected from April to September of 2020, were screened by an indirect multispecies ELISA. Positive samples were verified using an indirect immunofluorescence test (iIFT) and additionally tested for neutralizing antibodies. Furthermore, serum samples were screened for antibodies against feline coronavirus (FCoV), in order to rule out cross-reactivity in the described test systems. Overall, 0.69% (6/920) of serum samples were found to be positive for antibodies against SARS-CoV-2 by ELISA and iIFT. Two of these reactive sera also displayed neutralizing antibodies. No cross-reactivity with FCoV-specific antibodies was observed. The finding of SARS-CoV-2 antibody-positive serum samples in the domestic cat population of Germany, during a period when the incidence of human infection in the country was still rather low, indicates that human-to-cat transmission of SARS-CoV-2 happens, but there is no indication of SARS-CoV-2 circulation in cats.

Recently, a novel atypical porcine pestivirus (APPV) with significant distribution was described in the USA. Subsequent screening of the German pig sector showed a high prevalence of APPV with high variability among strains. First indication of a cell culture isolate is provided which will allow further investigations like pathogenesis studies.

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Orthobunyaviruses (OBVs) form a distinct genus of arthropod-borne bunyaviruses that can cause severe disease upon zoonotic transmission to humans. Antigenic drift or genome segment re-assortment have in the past resulted in new pathogenic OBVs, making them potential candidates for causing emerging zoonoses in the future. Low-resolution electron cryo-tomography studies have shown that OBV particles feature prominent trimeric spikes, but their molecular organization remained unknown. Here we report X-ray crystallography studies of four different OBVs showing that the spikes are formed by an N-terminal extension of the fusion glycoprotein Gc. Using Schmallenberg virus, a recently emerged OBV, we also show that the projecting spike is the major target of the neutralizing antibody response, and provide X-ray structures in complex with two protecting antibodies. We further show that immunization of mice with the spike domains elicits virtually sterilizing immunity, providing fundamental knowledge essential in the preparation for potential newly emerging OBV zoonoses.

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