The human population is currently facing the third and possibly the worst pandemic caused by human coronaviruses (CoVs). The virus was first reported in Wuhan, China, on 31 December 2019 and spread within a short time to almost all countries of the world. Genome analysis of the early virus isolates has revealed high similarity with SARS-CoV and hence the new virus was officially named SARS-CoV-2. Since CoVs have the largest genome among all RNA viruses, they can adapt to many point mutation and recombination events; particularly in the spike gene, which enable these viruses to rapidly change and evolve in nature. CoVs are known to cross the species boundaries by using different cellular receptors. Both animal reservoir and intermediate host for SARS-CoV-2 are still unresolved and necessitate further investigation. In the current review, different aspects of SARS-CoV-2 biology and pathogenicity are discussed, including virus genetics and evolution, spike protein and its role in evolution and adaptation to novel hosts, and virus transmission and persistence in nature. In addition, the immune response developed during SARS-CoV-2 infection is demonstrated with special reference to the interplay between immune cells and their role in disease progression. We believe that the SARS-CoV-2 outbreak will not be the last and spillover of CoVs from bats will continue. Therefore, establishing intervention approaches to reduce the likelihood of future CoVs spillover from natural reservoirs is a priority.

Respiratory tract infections are the primary cause of morbidity and mortality globally. Human bocavirus 1 (HBoV1), a member of the Parvoviridae family causes a wide spectrum of respiratory diseases in children, and gastroenteritis in adults. The mechanisms of latency, persistence, and reinfection of Bocavirus are poorly understood at present due to the lack of permissive cell lines and efficient animal models. Moreover, the dual infections of HBoV and other respiratory viruses further complicate the study of the pathogenicity of Bocaviruses. The data on immunological consequences of Bocavirus infection are sparse. However, the existing data have highlighted the role of CD4 T cells in Bocavirus infection. High titres of HBoV-specific antibodies have been detected in different populations suggesting its ubiquitous prevalence. Interestingly, the mechanism employed by Bocavirus to evade the immune system mostly targets type I IFN pathways and cause pyroptotic cell death of host cells. This review summarizes the immune responses evoked in response to Bocavirus infection, escape mechanism employed by the virus, and the vaccination strategies, including antisense technology to combat Bocavirus infections.

The outbreak of the current global pandemic caused by the spread of a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has posed an unprecedented threat to global health and economy across the whole world. As of today, the number of cases diagnosed with SARS-CoV-2 is exceeding 271 million with over 5.32 million deaths globally. Despite the high throughput technology and considerable advances in sciences, the outbreaks of the COVID-19 pandemic present a colossal challenge to scientific community. Scientists and clinicians all over the world are putting tremendous efforts to develop effective treatments to combat this deadly pathogen, at least to contain it momentarily until an adequate treatment regimen is available. Conventionally, vaccines have been developed as one of the therapeutic strategies to restrict infectious diseases. Although several vaccines are in the pipeline, evaluation of efficacy in animals’ studies and human are time-consuming. On the other hand, several drugs already in clinical use are being employed to test their efficacy against SARS-CoV-2. Some of these drugs have been already used as anti-viral drugs and others have been used for different therapeutic purposes. In this review, we summarize the ongoing efforts to control the dissemination of SARS-CoV-2 and highlight the potential prophylactic and therapeutic measures including the recently developed vaccines in the foreseeable future. Moreover, we emphasize an importance of having a customized strategy that can be easily and quickly employed to overcome possible future outbreaks.

Currently, the standard assay employed to diagnose human orthopneumovirus infection is real-time reverse transcriptase PCR assay (rRT-PCR), a costly and time-consuming procedure that requires the manipulation of infectious viruses. In addition to RT-PCR, serological tests can complement the molecular diagnostic methods and have proven to be important tools in sero-surveillance. In this study, we report the development, optimization, and validation of a novel and rapid in-house diagnostic ELISA kit to detect human orthopneumovirus in clinical samples. We developed three sensitive ELISA formats through the immunization of rats with novel recombinant pPOE-F or pPOE-TF vectors. The two vectors expressed either the full-length (pPOE-F) or the truncated form (pPOE-TF) of the fusion (F) protein. The developed ELISA kits were optimized for coating buffer, capture antibody, blocking buffer, sample antigen, detection antibodies, and peroxidase-conjugated antibody, and validated using 75 rRT-PCR-confirmed nasopharyngeal aspirate (NPA) human orthopneumovirus samples and 25 negative samples collected from hospitalized children during different epidemic seasons between 2014 and 2017. Our results indicate that rats immunized with pPOE-F or pPOE-TF showed significant induction of high levels of MPAs. Validation of the ELISA method was compared to the rRT-PCR and the sensitivity hierarchy of these developed ELISA assays was considered from highest to lowest: indirect competitive inhibition ELISA (93.3%) > indirect antigen-capture ELISA (90.6%) > direct antigen-capture ELISA (86.6%). The development of the rapid in-house diagnostic ELISA kits described in this study demonstrates that a specific, rapid and sensitive test for human orthopneumovirus antigens could be successfully applied to samples collected from hospitalized children during different epidemics and can help in the efficient diagnosis of respiratory syncytial viral infections.