Viral Zoonoses

Stem cell therapy: a novel approach against emerging and re-emerging viral infections with special reference to SARS-CoV-2

The past several decades have witnessed the emergence and re-emergence of many infectious viral agents, flaviviruses, influenza, filoviruses, alphaviruses, and coronaviruses since the advent of human deficiency virus (HIV). Some of them even become serious threats to public health and have raised major global health concerns. Several different medicinal compounds such as anti-viral, anti-malarial, and anti-inflammatory agents, are under investigation for the treatment of these viral diseases. These therapies are effective improving recovery rates and overall survival of patients but are unable to heal lung damage caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, there is a critical need to identify effective treatments to combat this unmet clinical need. Due to its antioxidant and immunomodulatory properties, stem cell therapy is considered a novel approach to regenerate damaged lungs and reduce inflammation. Stem cell therapy uses a heterogeneous subset of regenerative cells that can be harvested from various adult tissue types and is gaining popularity due to its prodigious regenerative potential as well as immunomodulatory and anti-inflammatory properties. These cells retain expression of cluster of differentiation markers (CD markers), interferon-stimulated gene (ISG), reduce expression of pro-inflammatory cytokines and, show a rapid proliferation rate, which makes them an attractive tool for cellular therapies and to treat various inflammatory and viral-induced injuries. By examining various clinical studies, this review demonstrates positive considerations for the implications of stem cell therapy and presents a necessary approach for treating virally induced infections in patients.

Variant influenza: connecting the missing dots

BACKGROUND

In June 2009, the World Health Organization declared a new pandemic, the 2009 swine influenza pandemic (swine flu). The symptoms of the swine flu pandemic causing strain were comparable to most of the symptoms noted by seasonal influenza.

AREA COVERED

Zoonotic viruses that caused the swine flu pandemic and its preventive measures.

EXPERT OPINION

As per Centers for Disease Control and Prevention (CDC), the clinical manifestations in humans produced by the 2009 H1N1 'swine flu' virus were equivalent to the manifestations caused by related flu strains. The H1N1 vaccination was the most successful prophylactic measure since it prevented the virus from spreading and reduced the intensity and consequences of the pandemic. Despite the availability of therapeutics, the ongoing evolution and appearance of new strains have made it difficult to develop effective vaccines and therapies. Currently, the CDC recommends yearly flu immunization for those aged 6 months and above. The lessons learned from the A/2009/H1N1 pandemic in 2009 indicated that readiness of mankind toward new illnesses caused by mutant viral subtypes that leap from animals to people must be maintained.

A Review on SARS-CoV-2 Genome in the Aquatic Environment of Africa: Prevalence, Persistence and the Future Prospects

The COVID-19 pandemic (Coronavirus disease 2019) remains problematic in all its manifestations on the global stage where countless events of human-to-human exposure have led to fatal cases; thus, the aftermath being an unprecedented public health concern, with inaccessible health care and the instability of economies and financial institutions. These pose massive obstacles that can insatiably devour existing human resources causing negative impacts, especially in developing countries. Tracking the origin, dissemination and mutating strains of the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) on population-wide scales is a somewhat overwhelming task, with the urgent need to map the dissemination and magnitude of SARS-CoV-2 in near real-time. This review paper focuses on the poor sanitation of some waterbodies and wastewater management policies in low-income African countries, highlighting how these contribute to the COVID-19 pandemic on the continent. Since the outbreak of the novel coronavirus pandemic, there has been an upsurge in scientific literature and studies concerning SARS-CoV-2 with different opinions and findings. The current paper highlights the challenges and also summarizes the environmental aspects related to the monitoring and fate of the SARS-CoV-2 genomes in the aquatic milieu of Sub-Saharan Africa.

A comprehensive review of viruses in terrestrial animals from the Caribbean islands of Greater and Lesser Antilles

Viruses pose a major threat to animal health worldwide, causing significant mortalities and morbidities in livestock, companion animals and wildlife, with adverse implications on human health, livelihoods, food safety and security, regional/national economies, and biodiversity. The Greater and Lesser Antilles consist of a cluster of islands between the North and South Americas and is habitat to a wide variety of animal species. This review is the first to put together decades of information on different viruses circulating in companion animals, livestock, and wildlife from the Caribbean islands of Greater and Lesser Antilles. Although animal viral diseases have been documented in the Caribbean region since the 1940s, we found that studies on different animal viruses are limited, inconsistent, and scattered. Furthermore, a significant number of the reports were based on serological assays, yielding preliminary data. The available information was assessed to identify knowledge gaps and limitations, and accordingly, recommendations were made, with the overall goal to improve animal health and production, and combat zoonoses in the region. This article is protected by copyright. All rights reserved.

Plant-Derived Recombinant Vaccines against Zoonotic Viruses

Emerging and re-emerging zoonotic diseases cause serious illness with billions of cases, and millions of deaths. The most effective way to restrict the spread of zoonotic viruses among humans and animals and prevent disease is vaccination. Recombinant proteins produced in plants offer an alternative approach for the development of safe, effective, inexpensive candidate vaccines. Current strategies are focused on the production of highly immunogenic structural proteins, which mimic the organizations of the native virion but lack the viral genetic material. These include chimeric viral peptides, subunit virus proteins, and virus-like particles (VLPs). The latter, with their ability to self-assemble and thus resemble the form of virus particles, are gaining traction among plant-based candidate vaccines against many infectious diseases. In this review, we summarized the main zoonotic diseases and followed the progress in using plant expression systems for the production of recombinant proteins and VLPs used in the development of plant-based vaccines against zoonotic viruses.

The Complex Epidemiological Relationship between Flooding Events and Human Outbreaks of Mosquito-Borne Diseases: A Scoping Review

BACKGROUND

Climate change is expected to increase the frequency of flooding events. Although rainfall is highly correlated with mosquito-borne diseases (MBD) in humans, less research focuses on understanding the impact of flooding events on disease incidence. This lack of research presents a significant gap in climate change-driven disease forecasting.

OBJECTIVES

We conducted a scoping review to assess the strength of evidence regarding the potential relationship between flooding and MBD and to determine knowledge gaps.

METHODS

PubMed, Embase, and Web of Science were searched through 31 December 2020 and supplemented with review of citations in relevant publications. Studies on rainfall were included only if the operationalization allowed for distinction of unusually heavy rainfall events. Data were abstracted by disease (dengue, malaria, or other) and stratified by post-event timing of disease assessment. Studies that conducted statistical testing were summarized in detail.

RESULTS

From 3,008 initial results, we included 131 relevant studies (dengue n = 45 , malaria n = 61 , other MBD n = 49 ). Dengue studies indicated short-term (< 1  month ) decreases and subsequent (1-4 month) increases in incidence. Malaria studies indicated post-event incidence increases, but the results were mixed, and the temporal pattern was less clear. Statistical evidence was limited for other MBD, though findings suggest that human outbreaks of Murray Valley encephalitis, Ross River virus, Barmah Forest virus, Rift Valley fever, and Japanese encephalitis may follow flooding.

DISCUSSION

Flooding is generally associated with increased incidence of MBD, potentially following a brief decrease in incidence for some diseases. Methodological inconsistencies significantly limit direct comparison and generalizability of study results. Regions with established MBD and weather surveillance should be leveraged to conduct multisite research to a) standardize the quantification of relevant flooding, b) study nonlinear relationships between rainfall and disease, c) report outcomes at multiple lag periods, and d) investigate interacting factors that modify the likelihood and severity of outbreaks across different settings. https://doi.org/10.1289/EHP8887.