Viruses and Antiviral Agents
John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie in Basic Sciences Endocrine Surgery Rhinology, 2018
Viruses are small acellular infectious agents that can only replicate within cells. They characteristically comprise of genetic material made of nucleic acids (DNA or RNA) encased in a protective capsule of proteins, the nucleoprotein or nucleocapsid (Figure 20.1). Some also contain lipid envelopes. Envelopes originate from the cells in which the virus particle was made (through a process called budding), and are essentially lipid bi-layer vesicles enclosing the virus particle. During budding, the cell’s membrane proteins are replaced with viral proteins, which are important for the virus’s entry into a new host cell. Although they vary in size and shape enormously (range 20 nm to 500 nm), at a mode of around 100 nm in diameter, they are approximately 10 times smaller than bacteria. Viruses are therefore not normally visible by light microscopy. Classifying viruses is done according to three parameters: type of nucleic acid; shape and size of capsid; and presence of a lipid envelope.
Diagnosing Viral Infections
Firza Alexander Gronthoud in Practical Clinical Microbiology and Infectious Diseases, 2020
Viruses can be transmitted through various routes of exposure. Combining this with clinical symptoms and laboratory findings can narrow down the potential viruses involved. Fecal-oral route, i.e. enterovirus, hepatitis AInhalation of aerosols and droplets, i.e. measles, varicella zosterArthropod-borne, i.e. dengue virus, Zika virus and West Nile virusSexually transmitted, i.e. hepatitis B and HIVBlood-borne, i.e. HIV, hepatitis B and C
Biogenic Synthesis of Nanoparticulate Materials for Antiviral Applications
Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji in Viral and Antiviral Nanomaterials, 2022
Various severe viruses have emerged, causing multiple infectious diseases and triggering a global health concern. The current epidemic of atypical pneumonia instigated by the 2019 Coronavirus spread to the entire world, resulting in more than 3 million deaths; an immediate solution is needed to curb this phenomenon. Besides the Coronavirus, many other viruses exist, too, such as human immunodeficiency virus (HIV), human papillomavirus (HPV), norovirus, hepatitis viruses, and many others (Delshadi et al. 2021). Viruses can be transmitted through body fluids and aerosol particles from an infected person to a healthy person. Aerosols show a dynamic role in dispersing viruses in the air, making them more critical and dangerous for humankind. Therefore, many attempts have been made to develop antivirus drugs to curb and tackle the many different viruses present in the atmosphere. However, studies have found that many of these drugs have inevitable side effects on human tissues and cells, particularly for younger people in the community. Thus, the evolution of nanotechnology has created an alternative pathway, and it shows the prevailing ability in improving the effectiveness against virus contagion and imitation (Chaudhuri et al. 2018).
The roles of epidermal growth factor receptor in viral infections
Published in Growth Factors, 2022
Kah Man Lai, Wai Leng Lee
Viruses are submicroscopic infectious agents that reply on living cells to multiply. They are made up of nucleic acid genomes, either DNA or RNA, which are surrounded by a protective protein coat known as capsid (Ryu 2017). Viral infection involves a sequence of events including the attachment and uptake of virus into the host cells, viral gene expression and replication by usurping cellular machinery, assembly of viral proteins and genome to form progeny virions which subsequently egress from the host cells. Newly synthesised virions may infect neighbouring susceptible cells at the site of initial entry and cause localised infection. Alternatively, virus may disseminate to other parts of the body via lymphatic or haematogenous routes and cause systemic infection (Burrell, Howard, and Murphy 2017; Fenner et al. 1987).
Guideline for the management of COVID-19 patients during hospital admission in a non-intensive care setting
Published in European Clinical Respiratory Journal, 2020
Klaus Nielsen Jeschke, Barbara Bonnesen, Ejvind Frausing Hansen, Jens-Ulrik Stæhr Jensen, Therese Sophie Lapperre, Ulla Møller Weinreich, Ole Hilberg
COVID-19 disease is caused by a pulmonary infection with the new coronavirus, severe acute respiratory infection coronavirus 2 (SARS-CoV-2). The virus was first identified during an outbreak of severe respiratory infections in December 2019 in the large Chinese city, Wuhan. The new coronavirus SARS-CoV-2 resembles SARS-CoV and MERS-CoV but has never previously been identified in humans. The virus is transmitted by droplets contact with contaminated surfaces. For SARS-CoV-2 the reproductive value, R0, is around 2.2 according to WHO (R0 is an indication of the transmissibility of a virus, representing the average number of new infections generated by an infectious person in a totally naïve population). The incubation period 2–14 days. Amongst those who contracted COVID-19, 15–20% require hospitalization, with around 15% of cases presenting with severe symptoms and 5% requiring intensive care [2]. ICU mortality differs between studies but seems to be around 26% [3]. The overall Case Fatality Rate (CFR) is around 4% but differs significantly between populations [4].
Influenza A (H1N1) outbreak in the Asokore Mampong Sub – Municipal, Ghana: A case report
Published in Cogent Medicine, 2019
Justice Ofori-Amoah, Reindolf Anokye, Alfred Mensah, Francisca Ahiavih Esinam, John Baffoe Yeboah, Isaac Kofi Kontor
Swine Flu or the Influenza A (H1N1), refers to an acute respiratory disease that originated from pigs. It is known to have been caused by one of several swine influenza A strains and its highly contagious (Dandagi & Byahatti, 2011). It is transmitted like a virus from one person to another in the same way influenza spreads (Fotedar, Fotedar, Sharma, & Bhardwaj, 2013) and it is typically incubated within one (1) to four (4) days averaging two (2) to three (3) days (Fotedar et al., 2013). Symptoms of the virus include sore in the throat, severe headache with chills, coughs, weakness as well as general unpleasant feeling similar to the symptoms of influenza. There have been cases where some persons who had swine flu showed severe respiratory illness such as pneumonia or respiratory failure resulting in death (Fotedar et al., 2013). Those that are at a higher risk for complications from swine flu are usually those suffering from chronic medical conditions such as heart disease, diabetes as well as women who are pregnant (Connecticut State Department of Public Health, 2018).