Question

Q. Describe how we can detect the infection of COVID-19 in humans.

Answer 1

Q. Describe how we can detect the infection of COVID-19 in humans.

Ans.

There are tests for the virus itself, but also blood tests showing immunity or antibodies.

A new rapid test offers results in minutes rather than hours or days, but deployment is yet to be defined.

Different countries are pursuing very different strategies when it comes to testing for COVID-19. The WHO supports a policy of widespread testing. But policies around the world vary and there seem to be arguments in support of the different approaches – largely due to supplies, shortages and priorities.

latest guidelines from Chinese health authorities stated an average incubation duration of 7 days, ranging from 2 to 14 days

The first test detects an active infection by searching for SARS-CoV-2 genetic material in a patient’s airway, where the virus is most commonly found. This assessment serves two purposes: diagnosing the sick so treatments can be administered and alerting those at risk of spreading COVID-19 to others, Marcelin says.

To conduct the test, researchers first send a long, thin swab deep into the nose to collect fluid and cells from the nasopharynx, a cavity that sits just above the throat. They then extract viral genetic information from the end of the swab and prepare it for reverse transcription polymerase chain reaction (RT-PCR), a technique used in laboratories to amplify very small quantities of DNA.

SARS-CoV-2 stores its genetic information in RNA, so its genome must first be transcribed into DNA. The test then hunts for snippets of the SARS-CoV-2 genome by using tiny probes that will only bind to the DNA version of the virus’ genetic material. If the probes find their target, the DNA will get copied many times over; if no viral genome is present, the molecular Xeroxing won’t occur.

Built into the copying procedure is a fluorescent dye that lights up when it binds to DNA. When more copies of DNA are produced, the sample will glow more intensely and quickly. If the chemical reaction lights up after a few dozen cycles, the test is considered positive, suggesting the patient is infected with SARS-CoV-2.

Some governments have suggested that the detection of antibodies to the SARS-CoV-2, the virus that causes COVID-19, could serve as the basis for an “immunity passport” or “risk-free certificate” that would enable individuals to travel or to return to work assuming that they are protected against re-infection. There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection.

Laboratory tests that detect antibodies to SARS-CoV-2 in people, including rapid immunodiagnostic tests, need further validation to determine their accuracy and reliability. Inaccurate immunodiagnostic tests may falsely categorize people in two ways. The first is that they may falsely label people who have been infected as negative, and the second is that people who have not been infected are falsely labelled as positive. Both errors have serious consequences and will affect control efforts. These tests also need to accurately distinguish between past infections from SARS-CoV-2 and those caused by the known set of six human coronaviruses. Four of these viruses cause the common cold and circulate widely. The remaining two are the viruses that cause Middle East Respiratory Syndrome and Severe Acute Respiratory Syndrome. People infected by any one of these viruses may produce antibodies that cross-react with antibodies produced in response to infection with SARS-CoV-2.

Many countries are now testing for SARS-CoV-2 antibodies at the population level or in specific groups, such as health workers, close contacts of known cases, or within households.21 WHO supports these studies, as they are critical for understanding the extent of – and risk factors associated with – infection. These studies will provide data on the percentage of people with detectable COVID-19 antibodies, but most are not designed to determine whether those people are immune to secondary infections.

If you like the answer give good reting