Human coronaviruses in the 'One Health' context

Seven human coronaviruses have been identified so far: four seasonal coronaviruses (HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1) and three novel coronaviruses (SARS-CoV, MERS-CoV, SARS-CoV-2). While seasonal coronaviruses cause only mild symptoms, novel coronaviruses cause severe and potentially fatal infections. All known coronaviruses originated in animals. Bats are considered as an origin for the majority of coronaviruses capable of infecting humans;however, rodents are proposed as natural hosts for HCoV-OC43 and HCoV-HKU1. Different animal species could serve as intermediate hosts including alpacas (HCoV-229E), livestock (HCoV-OC43), civet cats (SARS-CoV), camels (MERS-CoV), and pangolins (SARS-CoV-2). In Croatia, SARS-CoV-2 was detected in humans, pet animals, wildlife, and the environment. The COVID-19 pandemic has highlighted the role of the 'One Health' approach in the surveillance of zoonotic diseases.Copyright © 2022, University Hospital of Infectious Diseases. All rights reserved.

VHH DIMER P559-R45L NEUTRALIZES SARS-CoV-2 BY STABILIZING SPIKE IN UP CONFORMATION

Background: SARS-CoV-2 Omicron subvariants are highly resistant to vaccineinduced immunity and therapeutic monoclonal antibodies. We previously reported anti-SARS-CoV-2 spike alpaca nanobodies (VHHs) P86 and P17 that potently neutralize the wild type and VOCs from Alpha to Omicron BA.1 and BA.2, but not Omicron subvariants after that such as BA.4/5. Thus, we tried to establish a new VHH that can neutralize all the variants including BA.4/5. Method(s): We developed VHH trimers and heterodimers based on the structural and computational analysis of Delta spike-immunized alpaca VHH library. We tested representative VHHs against SARS-CoV-2 spike by pseudovirus assays and generated VHH heterodimers. We further obtained Cryo-EM structure of Spike trimer and VHH monomer or heterodimer. Result(s): First, we generated series of P86 mutants to counteract L452R mutation in Delta or Omicron BA.5 subvariants and found that P86 R45L was most potent against D614G with an IC50 of 0.03 mug/mL. From the Delta spike-immunized VHH library, we also identified that homo-trimer of a new clone P559 neutralized SARS-CoV-2 Delta and Omicron BA.5 variants with an IC50 of 0.077 and 0.54 mug/mL, respectively. We finally generated P559-R45L heterodimer that neutralized all the variants so far including Omicron BA.5 with an IC50 of 0.39 mug/mL. Cryo-EM structure revealed that three molecules of P559- R45L heterodimer bridged two RBD molecules in the spike trimer and stabilized spike timers with RBD in the up conformation. Conclusion(s): We developed VHH P559-R45L heterodimer that potently neutralized all the variants including Omicron subvariants through unique structural interaction.

Fifty Years of Research on Camelids and the Contribution of Genetics and Genomics: A Scientometrics Evaluation

The population and importance of camels in human life have improved in recent years. As genetics and genomics are becoming a more comprehensive section of life sciences, studying genetic/genomic aspects of the camelid nutrition, milk production, reproduction, immunity, disease and racing ability has become common in recent years. This study was conducted based on text mining and scientometrics techniques. To employ relevant information from Web of Science (WoS), a search strategy was developed to retrieve the "genetics or genomics” and words/phrases related to "camelids”. The statistical population of this study included 3830 publications over a period of 50 years (1971–2020). A total of 3830 publications were retrieved that included 3269 research articles (85.35% of the publications) and 224 review articles (5.85% of the publications). The most frequent subject groups were "Veterinary Sciences” including 862 publications. In total, articles on camelid genomics were published in 1345 journals. Moreover, 127 countries contributed to these 3830 publications, with the USA being the leading country both in number of publications and international collaboration. During the 1971–2010 time period, the phrases "MERS-CoV” and "coronavirus” did not exist in the literature at all, while in the last decade, with 140 and 63 times (5.36% and 2.41%, respectively), they were the most frequent keywords. In general, the most important topics studied from the perspective of camelid genomics have been population genetics and pathogens and their diagnosis, as well as camelid immunity. Future studies should pay special attention to the specificity of camelid genomics for hosting the coronavirus. Furthermore, the special structure of humoral immunity in camels makes this section attractive in immunogenetics research. © 2023, University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering. All rights reserved.

Evaluation of alpaca tracheal explants as an ex vivo model for the study of Middle East respiratory syndrome coronavirus (MERS-CoV) infection.

Middle East respiratory syndrome coronavirus (MERS-CoV) poses a serious threat to public health. Here, we established an ex vivo alpaca tracheal explant (ATE) model using an air-liquid interface culture system to gain insights into MERS-CoV infection in the camelid lower respiratory tract. ATE can be infected by MERS-CoV, being 103 TCID50/mL the minimum viral dosage required to establish a productive infection. IFNs and antiviral ISGs were not induced in ATE cultures in response to MERS-CoV infection, strongly suggesting that ISGs expression observed in vivo is rather a consequence of the IFN induction occurring in the nasal mucosa of camelids.

SCIENCE CALLS. RESEARCH IN ANIMAL PRODUCTION AND TRANSLATIONAL MEDICINE

South American camelids are an autochthonous productive resource used by the Andean peoples since pre-Inca times. As a consequence of the Spanish colonization, they were replaced by other mammals of productive interest, being displaced to the present day. Regarding the scientific field, knowledge of the physiology of these animals also lagged behind that of other species. This was probably due to the distance between research centers and the camelid location. The current search for sustainable production generated a renewed interest in these species, which grew as their production capacity in ecologically and economically marginal areas became more and more valuable, and their physiological particularities led to the discovery of molecules with medicinal applications. Our research group began contributing to the knowledge of the reproductive physiology of the llama and alpaca, describing mechanisms such as the sperm reservoirs formation in the oviduct, and the process of embryo implantation. We report the existence of specific molecules and their role in these events. We advanced towards the improvement of semen cryopreservation and the search for molecular markers of early pregnancy. We explored the recycling of llama manure as fertilizer through composting, vermicomposting, and combined composting and vermicomposting. We initiated studies on the llama milk quality, seeking to include it in the Argentine food code in order to contribute to the food sovereignty of the Andean peoples. Finally, we took on the challenge of finding solutions to the COVID-19 pandemic by generating a platform for the production of llama nanobodies, in consortium with members of the UNT, CONICET, and SIPROSA.

Susceptibility of livestock to SARS-CoV-2 infection.

We report pilot studies to evaluate the susceptibility of common domestic livestock (cattle, sheep, goat, alpaca, rabbit, and horse) to intranasal infection with SARS-CoV-2. None of the infected animals shed infectious virus via nasal, oral, or faecal routes, although viral RNA was detected in several animals. Further, neutralizing antibody titres were low or non-existent one month following infection. These results suggest that domestic livestock are unlikely to contribute to SARS-CoV-2 epidemiology.