Biology subjects

Grund, C.

Publications and source records attributed to Grund, C..

4 recordsLinked to original sources

bioRxiv2024

Red knots in Europe - a dead end host species or a new niche for highly pathogenic avian influenza?

The 2020/2021 epidemic in Europe of highly pathogenic avian influenza virus (HPAIV) of subtype H5 surpassed all previously recorded European outbreaks in size, genotype constellations and reassortment frequency and continued into 2022 and 2023. The causative 2.3.4.4b viral lineage proved to be highly proficient with respect to reassortment with cocirculating low pathogenic AIV and seems to establish an endemic status in northern Europe. A specific HPAIV reassortant of the subtype H5N3 was detected almost exclusively in red knots (Calidris canutus islandica) in December 2020. It caused systemic and rapidly fatal disease leading to a singular and self-limiting mass mortality affecting about 3.500 birds in the German Wadden Sea, roughly 1% of the entire flyway population of islandica red knots. Phylogenetic analyses revealed that the H5N3 reassortant very likely had formed in red knots and remained confined to this species. While mechanisms of virus circulation in potential reservoir species, dynamics of spill-over and reassortment events and the roles of environmental virus sources remain to be identified, the year-round infection pressure poses severe threats to endangered avian species, and prompts adaptation of habitat and species conservation practices. One-Sentence SummaryHigh red knot mortality in Europe (December 2020) was associated with infection of a unique genotype of HPAIV H5N3 clade 2.3.4.4b.

ecology↗

bioRxiv2023

Pathogen-prey-predator relations of avian raptors during epizootics of highly pathogenic avian influenza virus HPAIV H5N1 (clade 2.3.4.4b) in Germany

Transition of highly pathogenic clade 2.3.4.4b H5 avian influenza virus (HPAIV) from epizootic to enzootic status in Northern European countries was associated with severe losses and even mass mortalities among various wild bird species. Both avian and mammalian raptors hunting infected debilitated birds or scavenging on virus-contaminated avian carcasses contracted HPAIV infection. This precarious pathogen-prey-predator relation further worsened when in 2021 and 2022 outbreaks in Germany overlapped with the hatching season of avian raptor species. Retro- and prospective surveillance revealed avian raptors as important indicators of HPAIV and its genetic diversity on the one hand. On the other hand, their role as victims of HPAIV is stipulated. The first case of an HPAIV H5N1-related death of a white-tailed sea eagle (Haliaeetus albicilla; WTSE) hatch in Germany, 2021, followed by several such cases in 2022, and a low overall seropositivity rate of 5.0-7.9% among WTSE nestlings, raised fears of a serious negative impact on reproduction rates of WTSEs and other birds of prey when HPAIV becomes enzootic in an ecosystem. However, comparably stable breeding success of WTSE in the study area in 2022 and a potentially evolving natural immunity raises hope for a less severe long-term impact. Article impact statementAdapted surveillance measures were developed to assess risks for the conservation of avian raptors due to the panzootic spread of HPAIV.

microbiology↗

bioRxiv2023

Oral immunization of goats and foxes with a recombinant NDV vectored rabies vaccine

Vaccination of the reservoir species is a key component in the global fight against rabies. For wildlife reservoir species and hard to reach spillover species (e. g. ruminant farm animals), oral vaccination is the only solution. In search for a novel potent and safe oral rabies vaccine, we generated a recombinant vector virus based on lentogenic Newcastle disease virus (NDV) strain Clone 30 that expresses the glycoprotein G of rabies virus (RABV) vaccine strain SAD L16 (rNDV_GRABV). Transgene expression and virus replication was verified in avian and mammalian cells. To test immunogenicity and viral shedding, in a proof-of-concept study six goats and foxes, representing herbivore and carnivore species susceptible to rabies, each received a single dose of rNDV_GRABV (108.5 TCID50/animal) by direct oral application. For comparison, three animals received the similar dose of the empty viral vector (rNDV). All animals remained clinically inconspicuous during the trial. Viral RNA could be isolated from oral and nasal swabs until four (goats) or seven days (foxes) post vaccination, while infectious NDV could not be re-isolated. After four weeks, three out of six rNDV_GRABV vaccinated foxes developed RABV binding and virus neutralizing antibodies. Five out of six rNDV_GRABV vaccinated goats displayed RABV G specific antibodies either detected by ELISA or RFFIT. Additionally, NDV and RABV specific T cell activity was demonstrated in some of the vaccinated animals by detecting antigen specific interferon {gamma} secretion in lymphocytes isolated from pharyngeal lymph nodes. In conclusion, the NDV vectored rabies vaccine rNDV_GRABV was safe and immunogenic after a single oral application in goats and foxes, and highlight the potential of NDV as vector for oral vaccines in mammals. Author SummaryOral vaccination of rabies reservoir and spill-over species is the key to control the disease and prevent human rabies. In the past, baits containing live-attenuated rabies vaccines decreased significantly carnivore-mediated rabies in Central and Western Europe as well as North America. However, certain susceptible species are refractory to the oral immunization using so far licensed vaccines. Our vector vaccine based on avian Newcastle disease virus (NDV) has the potential to contribute to the targeted rabies eradication as it was safe and immunogenic after oral administration in goats and foxes. A single vaccine application elicited a rabies virus (RABV) specific systemic humoral immune response in the majority of the vaccinated animals as well as RABV specific T cells in some of the vaccinated animals. NDV can be manufactured at low-cost using already existing infrastructure of influenza vaccines, opening new possibilities especially for middle- and low-income countries that suffer under the economically burden of rabies.

microbiology↗

bioRxiv2023

Many morphs: parsing gesture signals from the noise

Parsing signals from noise is a general problem for signallers and recipients, as well as for researchers studying communicative systems. Substantial research efforts have been invested in comparing how other species encode information and meaning in their signals, and how signalling is structured. However, our ability to do so depends on identifying and discriminating signals that represent meaningful units of analysis. Early approaches to defining signal repertoires applied top- down approaches, classifying cases into predefined signal types. Recently, more labour-intensive methods have taken a bottom-up approach describing the features of each signal in detail and clustering cases into types based on patterns of similarity between them in multi-dimensional feature-space that were previously undetectable. Nevertheless, it remains essential to assess whether the resulting repertoires are composed of relevant units from the perspective of the species using them, and redefining repertoires when additional data makes more detailed analyses feasible. In this paper we provide a framework that takes data from the largest set of wild chimpanzee (Pan troglodytes) gestures currently available, splitting gesture types at a fine scale based on modifying features of gesture expression and then determining whether this splitting process increases the information content of the communication system. Our method allows different features of interest to be incorporated into the splitting process, providing substantial future flexibility across - for example - species, populations, and levels of signal granularity. In doing so we provide a powerful tool allowing researchers interested in gestural communication to establish repertoires of relevant units for subsequent analyses within and between systems of communication.

animal behavior and cognition↗