Human Coronavirus (கொரோனாவைரசு) What you need to know

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Coronaviruses are a large group of viruses that are common among animals. In rare cases, they are what scientists call zoonotic, meaning they can be transmitted from animals to humans, according to the US Centers for Disease Control and Prevention.

Figure 

Schematic diagram of the SARS coronavirus structure (reproduced from ref. 20).The viral surface proteins (spike, envelope and membrane) are embedded in a lipid bilayer envelope derived from the host cell. Unlike group 2 coronaviruses, SARS-CoV does not possess a hemagglutinin esterase glycoprotein. The single-stranded positive-sense viral RNA is associated with the nucleocapsid protein. 

History

Coronavirus disease was first described in 1931, with the first coronavirus (HCoV-229E) isolated from humans in 1965. Until the outbreak of severe acute respiratory syndrome in late 2002, only two human coronaviruses (HCoV) were known – HCoV-229E and HCoV-OC43. Once the SARS coronavirus (SARS-CoV) had been identified, two further human coronaviruses were identified. Three groups of coronaviruses exist: group 1 (HCoV-229E and HCoV-NL63), group 2 (HCoVOC43 and HCoV-HKU1), group 3 (no human CoVs as yet). SARS-CoV is an outlier to all three groups, although some place it in group 2.

Human Coronavirus Types

Coronaviruses are named for the crown-like spikes on their surface. There are four main sub-groupings of coronaviruses, known as alpha, beta, gamma, and delta.

Human coronaviruses were first identified in the mid-1960s. The seven coronaviruses that can infect people are:

Common human coronaviruses

1. 229E (alpha coronavirus)
2. NL63 (alpha coronavirus)
3. OC43 (beta coronavirus)
4. HKU1 (beta coronavirus)

Other human coronaviruses

5. MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome, or MERS)
6. SARS-CoV (the beta coronavirus that causes a severe acute respiratory syndrome, or SARS)
7. 2019 Novel Coronavirus (2019-nCoV)

People around the world commonly get infected with human coronaviruses 229E, NL63, OC43, and HKU1.

Sometimes coronaviruses that infect animals can evolve and make people sick and become a new human coronavirus. Three recent examples of this are 2019-nCoV, SARS-CoV, and MERS-CoV.

2019 Novel Coronavirus (2019-nCoV)

On January 9, 2020, the World Health Organization reported that a novel (new) coronavirus was identified by Chinese authorities. The virus is associated with an outbreak of pneumonia in Wuhan City, Hubei Province, China.

SARS-CoV

Severe acute respiratory syndrome coronavirus (SARS-CoV) was first recognized in China in November 2002. It caused a worldwide outbreak in 2002-2003 with 8,098 probable cases including 774 deaths. Since 2004, there have not been any known cases of SARS-CoV infection reported anywhere in the world.

MERS-CoV

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) was first reported in Saudi Arabia in 2012. It has since caused illness in people from dozens of other countries. All cases to date have been linked to countries in or near the Arabian Peninsula. CDC continues to closely monitor MERS globally and work with partners to better understand the risks of this virus, including the source, how it spreads, and how infections might be prevented.

What are the symptoms of the Novel Coronavirus?

The novel coronavirus is a new strain of coronavirus that has not been previously identified in humans but it shares symptoms with known strains.

The most common symptoms shared across the pathogen family include fever, coughing, shortness of breath and breathing problems.

In more severe cases, the symptoms can develop into kidney failure, pneumonia, severe acute respiratory syndrome and even death.

The WHO said: “There is no specific treatment for disease caused by a novel coronavirus.

“However, many of the symptoms can be treated and therefore treatment based on the patient’s clinical condition.”

"COVID-19 can lead to a broad range of neurologic complications including stroke, seizures, movement disorders, inflammatory diseases and more, even in moderate cases, according to a new study published in the December 9, 2020, online issue of Neurology Clinical Practice, an official journal of the American Academy of Neurology.

"We looked at people with neurologic symptoms and COVID at a racially and socioeconomically diverse hospital and found a wide range of neurologic complications—spanning inflammatory complications, stroke and other vascular conditions, metabolic problems, exacerbation of underlying neurologic conditions and more," said study author Pria Anand, M.D. of Boston University School of Medicine in Massachusetts and a member of the American Academy of Neurology. "Yet the majority of these people did not require critical care, suggesting that neurologic complications may be common in people with moderate COVID-19 as well as those with severe disease."

Now, researchers from Cleveland Clinic's Department of Biomedical Engineering note in a recent review that infection with the coronavirus may also affect the central nervous system and cause corresponding neurological disorders, including ischemic stroke, encephalitis, encephalopathy and epileptic seizures."

How to protect yourself

Here are the CDC's and other healthcare experts' suggestions for how to protect yourself from the virus while travelling:

• Try to avoid contact with people who display symptoms similar to those of pneumonia or the common cold, like coughing or a runny nose.
• Don't touch your eyes, nose, or mouth with unwashed hands.
• Wash your hands frequently with soap and water, and scrub for at least 20 seconds.
• Use alcohol-based hand sanitizer when possible.
• Avoid animals and animal markets.

The World Health Organisation is set to hold an emergency meeting on Wednesday on whether to declare the outbreak a global health emergency.

 Business Insider.

கொரோனா தீநுண்மி அல்லது கொரோனாவைரசு (Coronaviruse) பாலூட்டிகளிலும் பறவைகளிலும் நோய்களை ஏற்படுத்தும் ஒரு தீநுண்மி ஆகும், இவை பசுக்கள், பன்றிகளில் வயிற்றுப்போக்கையும், கோழிகளில் மேல் சுவாச நோயையும் உண்டாக்கும். இத்தீநுண்மிகள் மனிதர்களில் சுவாச நோய்த்தொற்றுகளை ஏற்படுத்துகின்றன. இத்தொற்றுகள் பெரும்பாலும் மிதமானவையாக இருந்தாலும் அரிதான சந்தர்ப்பங்களில் ஆபத்தானவையாக உள்ளன. இந்நோய்க்கான தடுப்பு அல்லது சிகிச்சைக்காக அங்கீகரிக்கப்பட்ட தடுப்பூசிகள் அல்லது தீநுண்மி தடுப்பு மருந்துகள் எதுவும் இல்லை.

கொரோனாவைரசுகள் நிடோவைரலசு வரிசையில், கொரோனவிரிடே குடும்பத்தில் ஆர்த்தோகொரோனவிரினே என்ற துணைக் குடும்பத்தைச் சேர்ந்தவையாகும். இவை ஒரு நேர்மறை உணர்வு கொண்ட ஒற்றைத்-தனிமைப்படுத்தப்பட்ட ஆர்.என்.ஏ மரபணு மற்றும் திருகுசுருள் சமச்சீர்மை அதிநுண்ணுயிர் அமைப்பு (நியூக்ளியோகாப்சிட்) கொண்ட உறைசூழ் தீநுண்மிகள் ஆகும். இவற்றின் மரபணு அளவு சுமார் 26 முதல் 32 கிலோபேசுகள் வரை இருக்கும், இது ஆர்.என்.ஏ தீநுண்மி ஒன்றிற்கு மிகப்பெரியதாகும்.

"கொரோனாவைரசு" என்ற பெயர் இலத்தீன் corona, கிரேக்க κορώνη (கொரீனா, "மாலை, மாலை") என்பதிலிருந்து உருவானது, அதாவது கிரீடம் அல்லது ஒளிவட்டம் எனப் பொருள். இது இலத்திரன் நுண்ணோக்கி மூலம் முதிர்ந்த நச்சுயிரிகளின் (தீநுண்மிகளின் தொற்று வடிவம்) சிறப்பியல்புத் தோற்றத்தைக் குறிக்கிறது, இது பெரிய, குழிவான மேற்பரப்பு கணிப்புகளின் விளிம்பைக் கொண்டுள்ளது, இது ஒரு அரச கிரீடம் அல்லது சூரிய கொரோனாவை நினைவூட்டுகிறது.

அனைத்து கொரோனாவைரசுகளின் ஒட்டுமொத்த கட்டமைப்பிற்கு பங்களிக்கும் புரதங்கள்
ஸ்பைக் (S), 
உறை (E), 
சவ்வு (M) மற்றும் 
நியூக்ளியோகாப்சிட் (N) ஆகும்.

கொரோனா வைரசு 1960களில் முதன்முதலாகக் கண்டுபிடிக்கப்பட்டது. கோழிகளில் தொற்று மூச்சுக்குழாய் அழற்சித் தீநுண்மி மற்றும் மனித நோயாளிகளின் நாசிக் குழிகளில் இருந்து பொதுவான சளியைக் கொண்ட இரண்டு தீநுண்மிகள் முதன்முதலாகக் கன்டுபிடிக்கப்பட்டவை ஆகும். இவை பின்னர் மனித கொரோனாவைரசு 229E (human coronavirus 229E), மனித கொரோனாவைரசு OC43 என பெயரிடப்பட்டன. இந்த நச்சுயிரிக் குடும்பத்தின் பிற தீநுண்மிகள் 2003 இல் SARS-CoV, 2004 இல் HCoV NL63, 2005 இல் HKU1, 2012 இல் MERS-CoV, 2019 இல் 2019-nCoV உள்ளிட்டவை அடையாளம் காணப்பட்டன. இவைகளில் பெரும்பாலானவை கடுமையான சுவாசக்குழாய் தொற்றுநோய்களில் ஈடுபட்டவை ஆகும்.

31 டிசம்பர் 2019 அன்று, உலக சுகாதார அமைப்பால் அதிகாரப்பூர்வமாக அறிவிக்கப்பட்ட 2019-nCoV என்ற கொரோனாவைரசின் ஒரு புதிய திரிபு சீனாவின் வுகான் மாகாணத்தில் கண்டுபிடிக்கப்பட்டது. 2020 சனவரி 24 இற்குள் 25 இறப்புகள் பதிவாகின, 547 பேர் பாதிக்கப்பட்டதாக உறுதிப்படுத்தப்பட்டது. வுகான் தீநுண்மம் 2பி குழுவின் SARS-CoV தீநுண்மியுடன் கிட்டத்தட்ட 70% மரபணு ஒற்றுமையுடன் பீட்டாகொரோனா தீநுண்மியின் புதிய திரிபு என அடையாளம் காணப்பட்டுள்ளது. இந்த தீநுண்மிகள் பாம்புகளில் இருந்து தோன்றியதாக சந்தேகிக்கப்பட்டது,ஆனால் பல முன்னணி ஆய்வாளர்கள் இந்த முடிவுக்கு உடன்படவில்லை.

Mosquito-borne diseases could be prevented by skin cream

A skin cream used to treat warts and skin cancer could help protect people against viral diseases such as Zika and dengue, according to new research.

Their findings have identified a new way we might prevent infection from a wide variety of dangerous viruses.

Scientists studied four types of a virus transmitted by mosquitos and found that applying a cream within an hour of a mosquito bite dramatically reduced infection rates in their models.

They used two different models to understand the effect of the skin cream -- human skin samples and mice. In both cases, applying the skin cream acted like a warning signal which caused rapid activation of the skin's immune response that fights any potential viral threats. This prevented the virus from spreading around the body and causing disease.

The cream, called imiquimod or Aldara, is commonly used to treat genital warts and some forms of skin cancer. The researchers caution that further testing is needed before recommendations can be made for people to start using this cream on mosquito bites.

Their research is published today in Science Translational Medicine.

Lead author Dr Clive McKimmie, from the University of Leeds' School of Medicine, said: "This study shows that a clinically approved, widely used skin cream has the potential to be repurposed as a valuable protector against insect-borne diseases.

"What is especially encouraging about our results is that the cream was effective against a number of distinct viruses, without needing to be targeted to one particular virus.

"If this strategy can be developed into a treatment option then we might be able to use it to tackle a wide range of new emerging diseases that we have not yet encountered.

"Mosquitos are expanding their range across the world as the planet gets hotter due to the climate emergency, so the health impact of mosquito-borne diseases is likely to increase in future."

There are hundreds of viruses spread by biting mosquitoes which can infect humans.

These include the dengue virus, West Nile virus, Zika virus and chikungunya virus, which have all had large outbreaks in recent years.

How does it work?

When a mosquito bites the skin, the body reacts in a very specific way to try and mitigate the physical trauma of the skin being punctured.

The bite causes a wound-healing repair mechanism to begin, however, the skin does not prepare itself to respond to viral attack.

This means mosquito-borne viruses that enter the skin through a bite are able to replicate quickly with little anti-viral response in the skin and then spread throughout the body.

By applying skin cream after a bite, researchers found that they could pre-emptively activate the immune system's inflammatory response before the virus becomes a problem. The cream encouraged a type of immune cell in the skin, called a macrophage, to suddenly spring into action to fight off the virus before it could spread around the body.

https://www.sciencedaily.com/,Science Mission

How acute stress turns hair white

"We were conducting a study on pain using black C57 mice, a dark-furred laboratory strain," the author said. "In this model, we administered a substance called resiniferatoxin to activate a receptor expressed by sensory nerve fibres and induce intense pain. Some four weeks after systemic injection of the toxin, a PhD student observed that the animals' fur had turned completely white."

The experiment was repeated several times until the researchers concluded that the phenomenon was indeed due to the application of resiniferatoxin, a naturally occurring chemical found in resin spurge (Euphorbia resinifera), a cactus-like plant native to Morocco.

Science Mission