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🔗 United States 🔗 Disaster management 🔗 Medicine 🔗 Viruses 🔗 Korea 🔗 COVID-19 🔗 Europe 🔗 China/Chinese history 🔗 Iran 🔗 North America 🔗 Medicine/Pulmonology 🔗 Italy 🔗 China 🔗 East Asia

The 2019–20 coronavirus pandemic is an ongoing pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The outbreak was first identified in Wuhan, Hubei, China, in December 2019, and was recognized as a pandemic by the World Health Organization (WHO) on 11 March. As of 28 March 2020, more than 663,000 cases of COVID-19 have been reported in over 190 countries and territories, resulting in approximately 30,800 deaths. More than 141,000 people have since recovered.

The virus is mainly spread during close contact and via respiratory droplets produced when people cough or sneeze. Respiratory droplets may be produced during breathing but the virus is not considered airborne. People may also catch COVID-19 by touching a contaminated surface and then their face. It is most contagious when people are symptomatic, although spread may be possible before symptoms appear. The time between exposure and symptom onset is typically around five days, but may range from 2 to 14 days. Common symptoms include fever, cough, and shortness of breath. Complications may include pneumonia and acute respiratory distress syndrome. There is no known vaccine or specific antiviral treatment. Primary treatment is symptomatic and supportive therapy. Recommended preventive measures include hand washing, covering one's mouth when coughing, maintaining distance from other people, and monitoring and self-isolation for people who suspect they are infected.

Efforts to prevent the virus spreading include travel restrictions, quarantines, curfews, workplace hazard controls, event postponements and cancellations, and facility closures. These include the quarantine of Hubei, national or regional quarantines elsewhere in the world, curfew measures in China and South Korea, various border closures or incoming passenger restrictions, screening at airports and train stations, and outgoing passenger travel bans. Schools and universities have closed either on a nationwide or local basis in more than 160 countries, affecting more than 1.5 billion students.

The pandemic has led to severe global socioeconomic disruption, the postponement or cancellation of sporting, religious, and cultural events, and widespread fears of supply shortages which have spurred panic buying. Misinformation and conspiracy theories about the virus have spread online, and there have been incidents of xenophobia and racism against Chinese and other East and Southeast Asian people.

🔗 Viruses

Sputnik virophage (from Russian cпутник "satellite", Latin "virus" and Greek φάγειν phagein "to eat") is a subviral agent that reproduces in amoeba cells that are already infected by a certain helper virus; Sputnik uses the helper virus's machinery for reproduction and inhibits replication of the helper virus.

Viruses like Sputnik that depend on co-infection of the host cell by helper viruses are known as satellite viruses. At its discovery in a Paris water-cooling tower in 2008 Sputnik was the first known satellite virus that inhibited replication of its helper virus and thus acted as a parasite of that virus. In analogy to the term bacteriophage it was called a virophage. However, the usage of this term and the relationship between virophages and classical satellite viruses remain controversial.

Sputnik virophages were found infecting giant viruses of Mimiviridae group A. However, they are able to grow in amoebae infected by Mimiviridae of any of the groups A, B, and C.

🔗 Medicine 🔗 Viruses

Original antigenic sin, also known as antigenic imprinting or the Hoskins effect, refers to the propensity of the body's immune system to preferentially utilize immunological memory based on a previous infection when a second slightly different version of that foreign pathogen (e.g. a virus or bacterium) is encountered. This leaves the immune system "trapped" by the first response it has made to each antigen, and unable to mount potentially more effective responses during subsequent infections. Antibodies or T-cells induced during infections with the first variant of the pathogen are subject to a form of original antigenic sin, termed repertoire freeze.

The phenomenon of original antigenic sin has been described in relation to influenza virus, dengue fever, human immunodeficiency virus (HIV) and to several other viruses.

This phenomenon was first described in 1960 by Thomas Francis Jr. in the article "On the Doctrine of Original Antigenic Sin". It is named by analogy to the theological concept of original sin. According to Francis as cited by Richard Krause:

"The antibody of childhood is largely a response to dominant antigen of the virus causing the first type A influenza infection of the lifetime. [...] The imprint established by the original virus infection governs the antibody response thereafter. This we have called the Doctrine of the Original Antigenic Sin."