Pathogenesis and virulence of coronavirus disease: Comparative pathology of animal models for COVID-19.

Animal models that can replicate clinical and pathologic features of severe human coronavirus infections have been instrumental in the development of novel vaccines and therapeutics. The goal of this review is to summarize our current understanding of the pathogenesis of coronavirus disease 2019 (COVID-19) and the pathologic features that can be observed in several currently available animal models. Knowledge gained from studying these animal models of SARS-CoV-2 infection can help inform appropriate model selection for disease modelling as well as for vaccine and therapeutic developments.

Assessment of Immune Responses to a Trivalent Pichinde Virus-Vectored Vaccine Expressing Hemagglutinin Genes from Three Co-Circulating Influenza A Virus Subtypes in Pigs.

Pichinde virus (PICV) can infect several animal species and has been developed as a safe and effective vaccine vector. Our previous study showed that pigs vaccinated with a recombinant PICV-vectored vaccine expressing the hemagglutinin (HA) gene of an H3N2 influenza A virus of swine (IAV-S) developed virus-neutralizing antibodies and were protected against infection by the homologous H3N2 strain. The objective of the current study was to evaluate the immunogenicity and protective efficacy of a trivalent PICV-vectored vaccine expressing HA antigens from the three co-circulating IAV-S subtypes: H1N1, H1N2, and H3N2. Pigs immunized with the trivalent PICV vaccine developed virus-neutralizing (VN) and hemagglutination inhibition (HI) antibodies against all three matching IAV-S. Following challenge infection with the H1N1 strain, five of the six pigs vaccinated with the trivalent vaccine had no evidence of IAV-S RNA genomes in nasal swabs and bronchoalveolar lavage fluid, while all non-vaccinated control pigs showed high number of copies of IAV-S genomic RNA in these two types of samples. Overall, our results demonstrate that the trivalent PICV-vectored vaccine elicits antibody responses against the three targeted IAV-S strains and provides protection against homologous virus challenges in pigs. Therefore, PICV exhibits the potential to be explored as a viral vector for delivering multiple vaccine antigens in swine.

Recent Discoveries of Novel Mammarenaviruses Infecting Humans and Other Mammals in Asia and Southeast Asia.

Mammarenaviruses, a genus of the family Arenaviridae, are capable of infecting mammals and are primarily found in rodent reservoirs worldwide. Mammarenaviruses can be transmitted to humans through contact with infected rodents, and though infection is often asymptomatic, some members of this genus can cause viral haemorrhagic fever which has mortality rates ranging from 1% to 50%. These viruses are typically restricted geographically, based on the geographical range of their host reservoirs. Lymphocytic choriomeningitis virus (LCMV) was previously thought to be the only mammarenavirus found across the globe. However, recent discoveries of two novel human mammarenaviruses, Wenzhou Virus (WENV) and Plateau Pika Virus (PPV), in Asia and Southeast Asia show that mammarenaviruses are more widespread than previously thought. This editorial article aims to raise awareness about these emerging viruses, their genetic and ecological diversities, and clinical significance, and to encourage further study of these emerging viruses.