Sunday, September 13, 2020


How Does Coronavirus Antibody Testing Work? The coronavirus antibody test is performed to determine the blood level of antibodies that are developed against the virus. This test determines if a person was infected by a coronavirus in the past.

What is Coronavirus?

Coronaviruses are a group of viruses that cause respiratory infections in humans. The infections can range from mild (common cold) to severe (Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS)).

Importantly, coronavirus disease 2019 (COVID-19) is a severe, highly infectious disease caused by very recently identified coronavirus namely severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2).

How coronavirus is detected in COVID-19 patients?

Presently, two types of viral tests are approved by the U.S Food and Drug Administration (FDA): molecular test and antigen test.

In molecular tests, the viral genetic material is detected using polymerase chain reaction (PCR). The test is done using biological fluid collected from nasal or throat swab or using saliva. Some at-home test kits, such as nasal swab kit and saliva kit, are also effective in detecting coronavirus.    

In antigen tests, biological samples collected from nasal or throat swab are used to detect certain viral proteins. Compared to molecular tests, antigen tests are less sensitive and accurate, because there is a possibility of getting false-negative results.

What is the coronavirus antibody test?

Antibodies are produced by the immune system to identify and destroy harmful foreign substances (antigens), such as bacteria and viruses.

Coronavirus antibody tests are done to detect the presence of antibodies in the blood that has been developed against coronavirus. A positive corona antibody test presumably means that a person was infected by coronavirus at some point in the past. However, a positive result does not indicate that a person is currently having coronavirus infection.

How do coronavirus antibody tests work?

In the case of a novel coronavirus, a detectable antibody level in the blood can be achieved 1 – 2 weeks post-infection.

The basic method of coronavirus antibody test involves examining the binding of targeted antibodies to specific viral proteins (antigens). The platforms that are used for performing coronavirus antibody tests include enzyme-linked immunosorbent assay (ELISA), chemiluminescent immunoassay, and lateral flow assay.

For the test, collected blood samples are incubated with the viral antigens on an assay platform. If the antibody against coronavirus is present in the blood, it will bind to the viral antigen, and a positive result will be obtained.

The viral antigens that are used to detect antibodies against coronaviruses include spike protein (a specialized surface protein that binds the host cell and facilitates viral entry), nucleocapsid (an RNA-binding protein used to form the viral capsid), and receptor-binding domain (a part of spike protein that binds the host receptor for coronavirus namely angiotensin-converting enzyme 2 (ACE 2)).

The types of antibodies being detected via antibody tests include IgM (the first antibody to be produced upon infection), IgG (most abundant antibody in the blood), and IgA (protects mucosa). Also, the total antibody level can be measured.    

How accurate is the coronavirus antibody test?  

The accuracy of coronavirus antibody tests depends on many factors, such as the duration between infection onset and test execution, antigen specificity, and types of antibody being analyzed.

Since the immune system usually starts producing antibodies within 1 – 3 weeks post-infection, a test done soon after the viral exposure may not be able to detect antibodies in the blood. In addition, there are possibilities of getting false-positive or false-negative results.

A false-positive result means a person is tested positive in the antibody test but does not have the antibodies in the blood. Likewise, a false negative result means a person is tested negative in the antibody test, despite having detectable antibody levels in the blood. The likelihood of getting false-positive results is higher in a community where the prevalence of coronavirus infection is very low.

Cross-reactivity is another concern that can significantly reduce test accuracy. Antibody assays designed specifically for the novel coronavirus can cross-react with related viruses (common coronavirus, SARS-CoV, and MERS-CoV), and thus, can give false-positive results.

What are the benefits of coronavirus antibody tests?

If a person tests positive in an antibody test but does not have disease-related symptoms, there is very little possibility of having a current infection. However, having a negative result in the antibody test does not completely rule out the possibility of a current infection.

Some people may take longer to make antibodies, and the negative result may thus be due to inaccurate test timing.

Studies conducted on people with novel coronavirus infection have suggested that the presence of antibodies in the blood may reduce the likeliness of viral reinfection; however, it is still not certain if those antibodies can provide any long-term benefits.

Nevertheless, an antibody test can particularly be important in identifying the part of a population that has been exposed previously to coronavirus and has developed herd immunity.    

In addition, an antibody test can be used to identify people who have recovered from the coronavirus infection recently and are eligible for donating blood for convalescent plasma therapy.



Thursday, August 13, 2020


Coronavirus has mutated into 31 different strains according to Scientists and some study so which are those strains?

Coronavirus has mutated into 31 different strains according to Scientists, Covid 19 Strains

How Many Coronaviruses are there?

Scientist identified 31 Strains of Coronavirus. Coronaviruses didn’t just pop up recently. They’re a large family of viruses that have been around for a long time. Many of them can make people ill with sniffles or coughing. Before the SARS-CoV-2 outbreak, coronaviruses were thought to cause only mild respiratory infections in people.

The new (or “novel”) coronavirus is one of several known to infect humans. It’s probably been around for some time in animals and birds. Sometimes, a virus in animals crosses over into people. That’s what scientists think happened here. So this virus isn’t new to the world, but it is new to humans. When scientists found out that it was making people sick in 2019, they named it as a novel coronavirus.

There are around 31 strains of coronavirus which infect animals, human and birds. Each strain has different virulence power. Some are more potent and some are less which we can see in some countries especially in case of SARS-COV-2 outbreak. High virulence strain damaged more host cell and less virulence strain could not affect more.


Why Viruses Change their structure?

Coronaviruses have all their genetic material in something called RNA (ribonucleic acid). RNA has some similarities to DNA, but they aren’t the same.

When viruses infect you, they attach to your cells, get inside them, and make copies of their RNA, which helps them spread. If there’s a copying mistake, the RNA gets changed. Scientists call those changes mutations.

These changes happen randomly and by accident. It’s a normal part of what happens to viruses as they multiply and spread.

Because the changes are random, they may make little to no difference in a person’s health. Other times, they may cause disease. For example, one reason you need a flu shot every year is because influenza viruses change from year to year. This year’s flu virus probably isn’t exactly the same one that circulated last year.

If a virus has a random change that makes it easier to infect people and it spreads, that strain will become more common.


Main Types of Coronavirus:

A.    Alphacoronavirus: 11 Strain- mainly found in Animals and Human

B.     Betacoronavirus: 16 Strain- mainly found in Animals and Human

C.    Gammacoronavirus: 2 Strain- mainly found in birds

D.    Deltacoronavirus: 2 Strain- mainly found in birds


Today, we will discuss about all strains:

Coronavirus has mutated into 31 different strains according to Scientists, Covid 19 Strains



1. Canine coronavirus

Canine coronavirus (CCoV) is an envelopedpositive-sensesingle-stranded RNA virus which is a member of the species Alphacoronavirus 1. It causes a highly contagious intestinal disease worldwide in dogs. The infecting virus enters its host cell by binding to the APN receptor. It was discovered in 1971 in Germany during an outbreak in sentry dogs. The virus is a member of the genus Alphacoronavirus and subgenus Tegacovirus.


2. Feline coronavirus

Feline coronavirus (FCoV) is a positive-stranded RNA virus that infects cats worldwide. It is a coronavirus of the species Alphacoronavirus 1 which includes canine coronavirus (CCoV) and porcine transmissible gastroenteritis coronavirus (TGEV). It has two different forms: feline enteric coronavirus (FECV) that infects the intestines and feline infectious peritonitis virus (FIPV) that causes the disease feline infectious peritonitis (FIP).

Feline coronavirus is typically shed in feces by healthy cats and transmitted by the fecal-oral route to other cats. In environments with multiple cats, the transmission rate is much higher compared to single-cat environments. The virus is insignificant until mutations cause the virus to be transformed from FECV to FIPV. FIPV causes feline infectious peritonitis, for which treatment is generally symptomatic and palliative only. The drug GS-441524 shows promise as an antiviral treatment for FIP, but at the moment it's only available on the black market and still requires further research.


3. Transmissible gastroenteritis coronavirus

Transmissible gastroenteritis virus or Transmissible gastroenteritis coronavirus (TGEV) is a coronavirus which infects pigs. It is an envelopedpositive-sensesingle-stranded RNA virus which enters its host cell by binding to the APN receptor. The virus is a member of the genus Alphacoronavirus, subgenus Tegacovirus, species Alphacoronavirus 1.


Proteins that contribute to the overall structure of TGEV include the spike (S), envelope (E), membrane (M) and nucleocapsid (N). The genomic size of coronaviruses ranges from approximately 28.6 kilobases. Other coronaviruses that belong to the species Alphacoronavirus 1 are Feline coronavirusCanine coronavirus and Feline infectious peritonitis virus.


4. Human coronavirus 229E

Human coronavirus 229E (HCoV-229E) is a species of coronavirus which infects humans and bats. It is an envelopedpositive-sensesingle-stranded RNA virus which enters its host cell by binding to the APN receptor.  Along with Human coronavirus OC43 (a member of the Betacoronavirus genus), it is one of the viruses responsible for the common cold. HCoV-229E is a member of the genus Alphacoronavirus and subgenus Duvinacovirus.


5. Human coronavirus NL63

Human coronavirus NL63 (HCoV-NL63) is a species of coronavirus, specifically a Setracovirus from among the Alphacoronavirus genus. It was identified in late 2004 in a seven-month-old child with bronchiolitis in the Netherlands. The virus is an envelopedpositive-sensesingle-stranded RNA virus which enters its host cell by binding to ACE2. Infection with the virus has been confirmed worldwide, and has an association with many common symptoms and diseases. Associated diseases include mild to moderate upper respiratory tract infections, severe lower respiratory tract infectioncroup and bronchiolitis.


The virus is found primarily in young children, the elderly, and immuno compromised patients with acute respiratory illness. It also has a seasonal association in temperate climates. A study performed in Amsterdam estimated the presence of HCoV-NL63 in approximately 4.7% of common respiratory illnesses. The virus originated from infected palm civets and bats. Estimates of its divergence from another coronavirus (HCoV-229E) are around 1000 years ago: it has likely circulated in humans for centuries.


The evolution of HCoV-NL63 appears to have involved recombination between an ancestral NL63-like virus circulating in African Triaenops afer bats and a CoV 229E-like virus circulating in Hipposideros bats. Recombinant viruses can arise when two viral genomes are present in the same host cell.


6. Miniopterus bat coronavirus 1

Miniopterus bat coronavirus 1 (Bat-CoV MOP1) is a novel envelopedsingle-stranded positive-sense RNA virus species in the Alphacoronavirus, or Group 1, genus with a corona-like morphology. It causes severe acute respiratory syndrome in bats. Isolates have not been found in humans.


7. Miniopterus bat coronavirus HKU8

Miniopterus bat coronavirus HKU8 (Bat-CoV HKU8) is an envelopedsingle-stranded positive-sense RNA virus species in the genus Alphacoronavirus with a corona-like morphology. It causes severe acute respiratory syndrome in bats. Isolates have not been found in humans.


8. Porcine epidemic diarrhea virus

Porcine epidemic diarrhea virus (PED virus or PEDV) is a coronavirus that infects the cells lining the small intestine of a pig, causing porcine epidemic diarrhoea, a condition of severe diarrhea and dehydration. Older hogs mostly get sick and lose weight after being infected, whereas newborn piglets usually die within five days of contracting the virus. PEDV cannot be transmitted to humans, nor contaminate the human food supply.


It was first discovered in Europe, but has become increasingly problematic in Asian countries, such as KoreaChinaJapan, the Philippines, and Thailand. It has also spread to North America: it was discovered in the United States on May 5, 2013 in Indiana, and in Canada in the winter of 2014. In January 2014, a new variant strain of PEDV with three deletions, one insertion, and several mutations in S (spike) 1 region was identified in Ohio by the Animal Disease Diagnostic Lab of Ohio Department of Agriculture.


PEDV has a substantial economic burden given that it is highly infectious, resulting in significant morbidity and mortality in piglets. Morbidity and mortality rates were lower for vaccinated herds than for nonvaccinated herds, which suggests the emergence of a new PEDV field strain(s) for which the current vaccine, based on the CV777 strain, was partially protective. Consumers are likely to feel the effects of the viral disease in the form of higher prices for pork products.


9. Rhinolophus bat coronavirus HKU2

Rhinolophus bat coronavirus HKU2 (Chinese horseshoe bat virus; Bat-CoV HKU2) is a novel envelopedsingle-stranded positive-sense RNA virus species in the Alphacoronavirus, or Group 1, genus with a corona-like morphology.


10. Scotophilus bat coronavirus 512

Scotophilus bat coronavirus 512 (Bat-CoV 512) is an envelopedsingle-stranded positive-sense RNA virus species in the Alphacoronavirus, or Group 1, genus with a corona-like morphology. It was isolated from a lesser Asiatic yellow house bat discovered in southern China.


11. Ferret coronavirus

The ferret coronavirus is a coronavirus which infects ferrets and is a strain of the species Mink coronavirus 1. The first cases in ferrets were detected in march of 1993 in the east coast of the United states. It used to be called green slime disease. This illness is highly contagious among ferrets and has a mortality rate of about 5 percent. It also has a short incubation period. Symptoms include diarrhoea and intestinal damage. Less pronounced symptoms are bloody stools, dehydration, lethargy, weight loss, and weakness.



12. Bovine Coronavirus

Bovine coronavirus is a coronavirus which is a member of the species Betacoronavirus 1. The infecting virus is an envelopedpositive-sensesingle-stranded RNA virus which enters its host cell by binding to the N-acetyl-9-O-acetylneuraminic acid recepter. Infection causes calf enteritis and contributes to the enzootic pneumonia complex in calves. It can also cause winter dysentery in adult cattle. It can infect both domestic and wild ruminants and has a worldwide distribution. Transmission is horizontal, via oro-fecal or respiratory routes. It has, like other coronaviruses from genus Betacoronavirus, subgenus Embecovirus, an additional shorter spike-like surface protein called hemagglutinin esterase (HE).


13. Human coronavirus OC43

Human coronavirus OC43 (HCoV-OC43) is a member of the species Betacoronavirus 1, which infects humans and cattle. The infecting coronavirus is an envelopedpositive-sensesingle-stranded RNA virus which enters its host cell by binding to the N-acetyl-9-O-acetylneuraminic acid receptor.


OC43 is one of seven known coronaviruses to infect humans. It is one of the viruses responsible for the common cold. It has, like other coronaviruses from genus Betacoronavirus, subgenus Embecovirus, an additional shorter spike protein called hemagglutinin esterase.


14. China Rattus coronavirus HKU24

It is mostly found in Camel as of now.


15. Myodes coronavirus 2JL14 (Embecovirus)

Embecovirus is a subgenus of coronaviruses in the genus Betacoronavirus. The viruses in this subgenus, unlike other coronaviruses, have a hemagglutinin esterase (HE) gene. The viruses in the subgenus were previously known as group 2a coronaviruses.


16. Bat Hp-betacoronavirus Zhejiang2013

It is mostly found in Bat.


17. Eidolon bat coronavirus C704

It is mostly found in Bat and Rodents.


18. Rousettus bat coronavirus GCCDC1

It is mostly found in Bat and Rodents.


19. Hedgehog coronavirus 1

Hedgehog coronavirus 1 is a mammalian Group C Betacoronavirus, a positive-sense RNA virus, discovered in European hedgehogs (Erinaceus europaeus) from Germany and first described in 2014.


Most Betacoronavirus clade c viruses are known from bats. The hedgehog is in the animal order Eulipotyphla, which is phylogenetically related to the bats, Chiroptera, so the researchers investigated faecal samples to look for coronaviruses.


The virus was found in the highest concentrations in the lower gastrointestinal tract.


20. MERS-Coronavirus (MERS-COV)

MERS-COV causes Middle East Respiratory Syndrome (MERS). According to WHOTrusted Source, it emerged in September 2012 in Saudi Arabia, although initial cases were later traced back to Jordan.

Humans contract MERS-CoV through contact with camels that have contracted the infection. The virus is also transmitted by coming into very close contact with a person who has the infection.

Since 2012, 27 countries have reported more than 2,400 MERS cases. To date, the majority of cases have occurred in Saudi Arabia.

In 2015, an outbreak in South Korea led to 186 casesTrusted Source and 36 deaths. According to the CDCTrusted Source, this outbreak originated with a traveler returning from the Middle East.

According to the European Center for Disease Prevention and Control (ECDPC), there were more than 200 cases of MERS-CoV reported in 2019.

Health authorities around the world continue to monitor MERS cases.


21. Murine coronavirus

Murine coronavirus (M-CoV) is a species of coronavirus which infects mice. It is an envelopedpositive-sensesingle-stranded RNA virus which enters its host cell by binding to the CEACAM1 receptor.  It has, like other coronaviruses from genus Betacoronavirus, subgenus Embecovirus, an additional hemagglutinin esterase (HE) gene.


The Murine coronavirus is a coronavirus that causes an epidemic murine illness with high mortality, especially among colonies of laboratory mice. Prior to the discovery of SARS-CoV, M-CoV (MHV, specifically) had been the best-studied coronavirus both in vivo and in vitro as well as at the molecular level. Some strains of M-CoV cause a progressive demyelinating encephalitis in mice which has been used as a murine model for multiple sclerosis. Significant research efforts have been focused on elucidating the viral pathogenesis of these animal coronaviruses, especially by virologists interested in veterinary and zoonotic diseases.


A feature of the MHV is that many strains have the hemagglutinin-esterase gene turned into a pseudogene. This does not, however, apply to M-CoVs in general, as other members like PV (Puffinosis coronavirus) retain a functional version of this gene.


22. Pipistrellus bat coronavirus HKU5

Pipistrellus bat coronavirus HKU5 (Bat-CoV HKU5) is an enveloped, positive-sense single-stranded RNA mammalian Group 2 Betacoronavirus discovered in Japanese Pipistrellus in Hong Kong. This strain of coronavirus is closely related to the newly identified novel MERS-CoV that is responsible for the 2012 Middle East respiratory syndrome-related coronavirus outbreaks in Saudi ArabiaJordanUnited Arab Emirates, the United KingdomFrance, and Italy.


23. Rousettus bat coronavirus HKU9

Rousettus bat coronavirus HKU9 (HKU9-1) is an enveloped, positive-sensesingle-stranded RNA mammalian Group 2 Betacoronavirus discovered in Rousettus bats in China in 2011. This strain of coronavirus is closely related to the EMC/2012 strain found in London which is related to the Middle East respiratory syndrome-related coronavirus (MERS-CoV). The MERS-CoV species is responsible for the 2012 Middle East respiratory syndrome coronavirus outbreak in Saudi ArabiaJordanUnited Arab Emirates, the United KingdomFrance, and Italy.


24. Severe acute respiratory syndrome-related coronavirus (SARS-CoV)

SARS-CoV causes Severe Acute Respiratory Syndrome (SARS). According to the World Health Organization (WHO)Trusted Source, the first human cases appeared in southern China in November 2002.

SARS-CoV may have originated in bats and were transmitted to other animals before infecting humans.

During the 2002-2003 epidemic, more than 8,000 people in 26 countries. Trusted Source around the world contracted SARS. There were 774Trusted Source reported deaths.

The outbreak was contained in mid-2003 with the implementation of infection control practices such as isolation and quarantine. Since then, a handful of cases have occurred due to laboratory accidents.

There are currently no reported cases of SARS transmission in the world. However, if the virus re-emerges, it could pose a significant threat to the public.


25. Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2)

SARS-CoV-2 causes COVID-19. This new coronavirus appeared in Wuhan, China, in late December 2019 after health officials noticed an increase in pneumonia cases with no known cause.

These cases have since been linked to a market selling seafood and poultry. Though the virus likely evolved from an animal source, its exact source is unknown.

Within a few months, SARS-CoV-2 has spread to hundreds of countries around the world after being transmitted through person-to-person contact.


26. Bat SARS-like coronavirus WIV1

Bat SARS-like coronavirus WIV1 (Bat SL-CoV-WIV1), also sometimes called SARS-like coronavirus WIV1, is a strain of Severe acute respiratory syndrome-related coronavirus (SARSr-CoV) isolated from Chinese rufous horseshoe bats (Rhinolophus sinicus). Like all coronaviruses, virions consist of single-stranded positive-sense RNA enclosed within an envelope.


27. Tylonycteris bat coronavirus HKU4

Tylonycteris bat coronavirus HKU4 (Bat-CoV HKU4) is an enveloped, positive-sense single-stranded RNA virus mammalian Group 2 Betacoronavirus that has been found to be genetically related to the Middle East respiratory syndrome-related coronavirus (MERS-CoV) that is responsible for the 2012 Middle East respiratory syndrome coronavirus outbreak in Saudi ArabiaJordanUnited Arab Emirates, the United KingdomFrance, and Italy.




28. Avian coronavirus

Avian coronavirus (IBV) is a coronavirus that infects birds, causing the associated disease avian infectious bronchitis (IB). It is a highly infectious avian pathogen that affects the respiratory tractgutkidney and reproductive systems of chickens.


IBV affects the performance of both meat-producing and egg-producing chickens and is responsible for substantial economic loss within the poultry industry.


29. Beluga whale coronavirus SW1

Beluga whale coronavirus SW1 (Whale-CoV SW1) is a mammalian Gammacoronavirus, an RNA virus, discovered through genome sequencing in the liver of a single deceased beluga whale and first described in 2008. This was the first description of the complete genome of a coronavirus found in a marine mammal.


The captive-born whale was male and died at age 13 after a short illness. This illness was characterised by generalised pulmonary disease and terminal acute liver failure. The liver demonstrated pathological signs, including areas of necrosisElectron microscopy showed many round viral particles measuring around 60–80nm in the liver cytoplasm, but it could not be confirmed whether these corresponded with the RNA identified. It is not known whether the beluga is the natural host of this virus or whether the virus is pathogenic in whales. Other coronaviruses can cause liver pathologies, but it could not be confirmed whether that was the case here.


A genetic analysis showed the virus to be highly divergent, but closest to the Gammacoronavirus group.  A closely related virus was subsequently reported in bottlenose dolphins, with the authors proposing that both should be included in the same species, Cetacean coronavirus.



30. Bulbul coronavirus HKU11

Bulbul coronavirus HKU11 (Bulbul-CoV HKU11) is a positive-sense single-stranded RNA Deltacoronavirus of avian origin found in Chinese bulbuls.


31. Porcine coronavirus HKU15

Coronavirus HKU15, sometimes called Porcine coronavirus HKU15 (PorCoV HKU15) is a virus first discovered in a surveillance study in Hong KongChina and first reported to be associated with porcine diarrhea in February 2014. In February 2014, PorCoV HKU15 was identified in pigs with clinical diarrhea disease in the U.S. state of Ohio. The complete genome of one US strain has been published. Since then, it has been identified in pig farms in Canada. The virus has been referred to as Porcine coronavirus HKU15, Swine deltacoronavirus and Porcine deltacoronavirus.


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