► Review compiling current knowledge of African swine fever gross pathogenesis. ► Description and discussion of clinical and pathomorphological correlates. ► Supplementation of wild boar data. ► ...Definition of research gaps.
African swine fever (ASF) is among the most important viral diseases that can affect domestic and feral pigs. Both clinical signs and pathomorphological changes vary considerably depending on strain virulence and host factors. Acute infections with highly virulent virus strains lead to a clinical course that resembles a viral haemorrhagic fever that is characterized by pronounced depletion of lymphoid tissues, apoptosis of lymphocyte subsets, and impairment of haemostasis and immune functions. It is generally accepted that most lesions can be attributed to cytokine-mediated interactions triggered by infected and activated monocytes and macrophages, rather than by virus-induced direct cell damage. Nevertheless, most pathogenetic mechanisms are far from being understood. This review summarizes the current knowledge and discusses implications and research gaps.
Metagenomics is currently the only generic method for pathogen detection. Starting from RNA allows the assessment of the whole sample community including RNA viruses. Here we present our modular ...concerted protocol for sample processing for diagnostic metagenomics analysis of human, animal, and food samples. The workflow does not rely on dedicated amplification steps at any stage in the process and, in contrast to published methods, libraries prepared accordingly will yield only minute amounts of unclassifiable reads. We confirmed the performance of the approach using a spectrum of pathogen/matrix-combinations showing it has the potential to become a commonly usable analytical framework.
We inoculated 6 cattle with severe acute respiratory syndrome coronavirus 2 and kept them together with 3 uninoculated cattle. We observed viral replication and specific seroreactivity in 2 ...inoculated animals, despite high levels of preexisting antibody titers against a bovine betacoronavirus. The in-contact animals did not become infected.
Raccoon dogs might have been intermediate hosts for severe acute respiratory syndrome-associated coronavirus in 2002-2004. We demonstrated susceptibility of raccoon dogs to severe acute respiratory ...syndrome coronavirus 2 infection and transmission to in-contact animals. Infected animals had no signs of illness. Virus replication and tissue lesions occurred in the nasal conchae.
About the Authors: Kevin Ciminski Affiliations Institute of Virology, Medical Center–University of Freiburg, Freiburg, Germany, Faculty of Medicine, University of Freiburg, Freiburg, Germany Florian ...Pfaff Affiliation: Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany ORCID logo http://orcid.org/0000-0003-0178-6183 Martin Beer * E-mail: Martin.Beer@fli.de (MB); martin.schwemmle@uniklinik-freiburg.de (MS) Affiliation: Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany Martin Schwemmle * E-mail: Martin.Beer@fli.de (MB); martin.schwemmle@uniklinik-freiburg.de (MS) Affiliations Institute of Virology, Medical Center–University of Freiburg, Freiburg, Germany, Faculty of Medicine, University of Freiburg, Freiburg, Germany ORCID logo http://orcid.org/0000-0002-2972-6855 Introduction Influenza A viruses (IAVs) circulate among a wide variety of different hosts. IAVs initiate infection via the viral HA surface glycoprotein that binds to sialic acid receptors on host cell glycoproteins (Fig 2A). ...recently, it was thought that sialic acids serve as the universal receptors for all influenza virus strains, thereby facilitating cross-species transmission. H18mut, mutations in H18; HA, hemagglutinin; IAV, influenza A virus; MHC-II, major histocompatibility complex class II; N11trunc, truncated N11; NA, neuraminidase. https://doi.org/10.1371/journal.ppat.1008384.g002 Conventional IAVs and the bat H9N2 virus possess the surface glycoprotein neuraminidase (NA), which removes sialic acid residues from infected cells to facilitate the release of newly formed viral particles (Fig 2A). An exchange of key amino acids in the putative receptor binding site prevents any interaction with sialic acid
biting midges, small hematophagous dipterans, are the demonstrated or putative vectors of multiple arboviruses of veterinary and public health importance. Despite its relevance in disease spread, the ...ceratopogonid genus
is still a largely neglected group of species, predominantly because the major human-affecting arboviruses are considered to be transmitted by mosquitoes. However, when a pathogen is detected in a certain vector species, a thorough search for further vectors often remains undone and, therefore, the relevant vector species may remain unknown. Furthermore, for many hematophagous arthropods, true vector competence is often merely suspected and not experimentally proven. Therefore, we aim to illuminate the general impact of
biting midges and to summarize the knowledge about biting midge-borne disease agents using the order
, the largest and most diverse group of RNA viruses, as an example. When considering only viruses evidentially transmitted by
midges, the Simbu serogroup (genus
) is presumably the most important group within the virus order. Its members are of great veterinary importance, as a variety of simbuviruses, e.g., the species
or
, induces severe congenital infections in pregnant animals. The major zoonotic representative of this serogroup occurs in South and Central America and causes the so-called Oropouche fever, an acute febrile illness in humans.
Domestic cats (
) 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.
Schmallenberg virus (SBV), an orthobunyavirus infecting ruminants, emerged in 2011 in Central Europe, spread very rapidly throughout the continent and established an endemic status, thereby ...representing a constant threat not only to the European livestock population, but also to neighboring countries. Hence, in endemically infected regions, the maintenance and regular verification of diagnostics is needed and in not yet affected regions, suitable diagnostic systems should be established to be prepared for a potential introduction of the disease. In addition, also for the trade of animals into free regions, highly reliable and sensitive diagnostics are of utmost importance. Therefore, a laboratory proficiency trial was initiated to allow for performance evaluations of test systems available for SBV-diagnostics, but also for evaluation of veterinary diagnostic laboratories performing those tests. Ten serum samples (six seropositive, four seronegative) were provided for serological analysis, four of the seropositive samples were provided undiluted, while the remaining samples represented 1/2 and 1/4 dilutions of one of the aforementioned samples in negative serum. Ten further sera (five virus-positive, five negative) were sent to the participants to be analyzed by SBV genome detection methods. A total of 48 diagnostic laboratories from 15 countries of three continents (Europe, Asia, North America) and three kit manufacturers participated in the SBV proficiency test, thereby generating 131 result sets, corresponding to 1310 individual results. The sample panel aimed for serological analysis was tested 72 times; the applied diagnostic methods comprised different commercial ELISAs and standard micro-neutralization tests. The sample set aimed for genome detection was analyzed in 59 approaches by various commercial or in-house (real-time) RT-PCR protocols. Antibody or genome positive samples were correctly identified in every case, independent of the applied diagnostic test system. For seronegative samples, three incorrect, false-positive test results were produced. Virus-negative samples tested false-positive in two cases. Thus, a very high diagnostic accuracy of 99.58% and 99.66% was achieved by the serological and virological methods, respectively. Hence, this ring trial demonstrated that reliable and robust SBV-diagnostics has been established in veterinary diagnostic laboratories in affected and non-affected countries.
Tick-borne encephalitis virus (TBEV) is an important arbovirus, which is found across large parts of Eurasia and is considered to be a major health risk for humans. Like any other arbovirus, TBEV ...relies on complex interactions between vectors, reservoir hosts, and the environment for successful virus circulation. Hard ticks are the vectors for TBEV, transmitting the virus to a variety of animals. The importance of these animals in the lifecycle of TBEV is still up for debate. Large woodland animals seem to have a positive influence on virus circulation by providing a food source for adult ticks; birds are suspected to play a role in virus distribution. Bank voles and yellow-necked mice are often referred to as classical virus reservoirs, but this statement lacks strong evidence supporting their highlighted role. Other small mammals (e.g., insectivores) may also play a crucial role in virus transmission, not to mention the absence of any suspected reservoir host for non-European endemic regions. Theories highlighting the importance of the co-feeding transmission route go as far as naming ticks themselves as the true reservoir for TBEV, and mammalian hosts as a mere bridge for transmission. A deeper insight into the virus reservoir could lead to a better understanding of the development of endemic regions. The spatial distribution of TBEV is constricted to certain areas, forming natural foci that can be restricted to sizes of merely 500 square meters. The limiting factors for their occurrence are largely unknown, but a possible influence of reservoir hosts on the distribution pattern of TBE is discussed. This review aims to give an overview of the multiple factors influencing the TBEV transmission cycle, focusing on the role of virus reservoirs, and highlights the questions that are waiting to be further explored.
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