Science, Art, Litt, Science based Art & Science Communication

Q: What is the difference between cleaning and disinfecting?

Krishna: Just Cleaning is not equal to disinfecting. 

Cleaning is the process of removing visible debris, dirt, and dust and organizing a space. Cleaning a surface uses soap or detergent and, usually, water to remove soil and germs through chemical (cleaner), mechanical (scrubbing), and thermal (water temperature) action. Cleaning may or may not kill bacteria and germs, but it will dilute their numbers and aid in lowering the risk of spreading infectious microbes.

When a product claims to sanitize a surface, it is promising to make the surface free of germs that could be harmful to your health according to public health standards or requirements. Sanitizing reduces, not kills, the number and growth of bacteria, viruses, and fungi. Sanitizing is particularly important in food preparation areas where germs and fungi can cause foodborne illnesses. Chemicals may not be needed because extreme heat—at least 170 degrees F—in a dishwasher or by using a steam cleaner can kill bacteria.

The act of disinfecting kills microscopic organisms (germs, viruses, fungi) on surfaces. Disinfection is usually achieved by using chemicals that kill the organisms and prevent them from spreading. Items can also be disinfected using UV-C germicidal short wavelength, ultraviolet light that breaks apart the DNA of bacteria and germs leaving them unable to harm or reproduce. This is the same UV-C light technology used in hospital surgical suites to aid in killing superbugs. Disinfecting does not necessarily remove visible dirt and debris from a surface and is much more effective if basic cleaning is done first.

Q: What are the steps to follow?

Krishna: I am glad you asked me this Q. A lot of people spray a surface and then wipe it around right away. But you're not letting the disinfectant do its job. 

That's because dirty surfaces are coated in clusters of germs called biofilm that resist disinfectants. These germs have to be removed before a chemical can effectively kill off any lingering viruses or bacteria.

the first step in the cleaning process should be putting soap on a rag or paper towel and then folding the towel into quarters. The towel will lift the biofilm off the surface so only residual germs are left behind. After you've wiped down a small surface – a couple of square feet – flip the towel over and use the other side, then turn it inside out and use the remaining quarters.

People sometimes will walk around the house with the same rag, cleaning all the surfaces. That doesn't do anything because now they're just spreading the germs around. Once that towel or rag that you're using is full of germs, it's not going to absorb anymore.

After the surface is clean, you can apply a disinfectant spray or wipe.

The back of every disinfectant bottle was marked with a "dwell time" – how long the disinfectant needs to sit on a surface before it kills germs. Some disinfectants take 10 minutes, while others only about 30 seconds.

So strictly follow the instructions on the labels for maximum efficiency.

Q: How can we disinfect the surfaces easily?

Krishna: You can use these easily available things, according to experts (1) to disinfect the surfaces...

Soap and water

Soap and water are your first line of defence to remove the virus from surfaces. Soap interferes with the fats in the virus shell and lift the virus from surfaces and this is then rinsed off by water. Of course, you also need to wash your hands when you come in from the shops and wash your food as normal.


The active ingredient in bleach – sodium hypochlorite – is very effective at killing the virus. Make sure you leave the bleach to work for 10-15 minutes then give the surface a wipe with a clean cloth. The bleach works by destroying the protein and what’s known as the ribonucleic acid (RNA) of the virus – this is the substance that gives the blueprint for making more virus particles when you become infected. Be sure to use the bleach as directed on the bottle.

Surgical spirit

Surgical spirit is mostly made up of the alcohol ethanol. Ethanol has been shown to kill coronaviruses in as little as 30 seconds. Like bleach, the alcohol destroys the protein and RNA that the virus is made up of. Moisten a cloth with some neat surgical spirit and rub it over a surface. This will evaporate and you will not need to wipe it off.

Surface wipes

The active ingredient in surface wipes in an antiseptic –- usually benzalkonium chloride. The wipes work by physically removing germs through the pressure you apply when you use them, and the germs then attach to the wipe.

They also leave a layer of the antiseptic on the surface that works to kill germs. The antiseptic works well on bacteria as well as on coronaviruses that infect mice and dogs – but it seems to make no difference to the spread of human coronavirus. Antiseptics work by disrupting the fats in pathogen cells, but SARS-CoV-2 does not contain many fats. So far, there is no evidence that antiseptics can kill human coronaviruses.

Hand sanitisers

A word of warning though about hand sanitisors. The main ingredient in hand sanitisers that will kill SARS-CoV-2 is ethanol, the alcohol in surgical spirit. But its concentration in the sanitiser is very important –- it has to be over 70 % or it will not kill the virus effectively.

One thing you can also do is make sure you air out the spaces you are spending time in regularly. An infected person will produce thousands of tiny droplets which contain the virus every time they cough. SARS-CoV-2 can survive in the air for up to three hours. So by opening the window, you can remove and disperse the droplets and reduce the amount of virus in the air – which will reduce the risk of infection for others.

Q: How can we handle the surfaces we come across?

Krishna: Researchers found SARS-CoV-2 remains infectious in airborne droplets for at least three hours. This doesn’t mean infected humans produce enough virus in a cough to infect another person, but they might.

Hard, shiny surfaces such as plastic, stainless steel, benchtops, and likely glass can support infectious virus, expelled in droplets, for up to 72 hours. But the virus rapidly degrades during this time. On fibrous and absorbent surfaces such as cardboard, paper, fabric and hessian, it becomes inactive more quickly.

Frequently touched surfaces are all around us. Benches, handrails, door handles – they are in our homes, on our way to work, school, play, shop, and every other destination. There’s a risk of contaminating these surfaces if we touch them with virus-laden fingers, and a risk we’ll contract the virus from such surfaces.

Think of your hands as the enemy. Wash them well and more often than usual. Between hand-washing, avoid constantly touching the mucous membranes that lead to your airways. Basically, try not to rub your eyes, pick your nose, or touch your lips and mouth.

To slow the spread of SARS-CoV-2, assume everything outside your home is potentially contaminated, and act accordingly. So don’t touch your face, sanitise frequently while you are out, and wash your hands and clean your phone once home.

While it’s best to stay home, keep these tips in mind if you must leave the house (4).

• Going shopping

Grocery shopping requires touching surfaces and items, including trolleys and baskets. Sometimes sanitiser or antibacterial wipes are available for hands and handles at the store entrance - but they’re often not, so bring your own (if you can get some). It probably doesn’t matter what type of bag you use, but have a plan for how to avoid bringing the virus into your home.

• Making payments

Cards and cash could transfer the virus to your hands. That said, card payment is probably lower risk because you retain the card and don’t have to touch other people. But wherever possible, contact-free bank transfers would pose the least risk.

• Handling and eating fresh and canned food

SARS-CoV-2 is inactivated at temperatures well below those required in the process of canning food, so canned food is free of it. For freshly packaged food, risk depends on whether the person doing the packing was sick or not. If you are concerned, stick with food that can be cooked, peeled or washed in mild soapy water, and thoroughly rinsed.

While evidence is weak, we know soap and water should inactivate SARS-CoV-2 on food - but this will work better on foods with a shinier, harder outer surface, compared to foods that have been cut or have softer surfaces, such as strawberries and raspberries. If you decide to wash any food with soap, make sure all the soap is removed.

• At the park

Avoid equipment that is likely used a lot, including play equipment and water fountains. It would be safer to kick a ball around or play on the grass, rather than use swings. Sandpits hold horrors other than SARS-CoV-2.

• Takeaway and deliveries

When getting takeaway food, or for businesses offering it, avoid plastic containers and use more fibrous materials such as cardboard, paper and fabric for packaging. Researchers found no infectious SARS-CoV-2 on cardboard after 24 hours.

Also, avoid proximity to servers and delivery people, and opt for contactless delivery whenever you can.

• Public transport, escalators, elevators and bathrooms

Frequently touched hard, shiny surfaces such as lift buttons and handle bars in trams are a big risk, more so than fabric seats, or taking the stairs. Even the most high-tech overseas surface cleaning efforts are intermittent, so you’ll need to take responsibility for yourself. Also, after using public bathrooms, wash your hands well.

For items that are hard to clean, sunshine may be valuable. Leave your shoes outside, soles up, in the sun. Coronaviruses begin degrading quickly in temperatures higher than 56 degrees Cels....

Ultimately, the best ways to avoid SARS-CoV-2 infection are primitive ones - sanitise your hands and stay away from others. Physical distancing remains the most effective measure to slow the progression of this pandemic

Q: Coughs and sneezes spread the corona virus, so how is it possible for asymptomatic people to spread the infection?

Krishna: People with mild or no symptoms can have a very high viral load in their upper respiratory tracts, meaning they can shed the virus through spitting, touching their mouths or noses and then a surface, or possibly talking. Even people who don’t feel ill occasionally cough or sneeze.

Once symptoms develop, a person’s viral load declines steadily, and they become increasingly less infectious. However, people appear to keep shedding the virus for around two weeks after they recover from covid-19, both in their saliva and stools (medRxiv, This means that even once a person’s symptoms have cleared, it may still be possible to infect other people.

Airborne droplets are likely to be the main infection route, but contaminated surfaces could play a role too. A study published last week suggests that this is a serious underestimate, with viable virus surviving on cardboard for 14 hours and plastic and stainless steel for up to three days (New England Journal of It can also hang around in the air for at least 3 hours.

Survival of coronaviruses for days on touch surfaces is a hygiene risk. It is difficult to avoid touching [contaminated objects or surfaces] such as door handles and push plates, bed and stair rails, public touch screens etc.

So advising only people with a cough or fever and their families to self-isolate won’t prevent the coronavirus from spreading, thanks to its fiendish ability to cause very mild symptoms in people, and to peak in infectiousness before people even realise they are sick.

There are silent carriers. That is why WHO says test, test, test, test to control corona virus. And countries that tested as many people as possible 're able to control the virus efficiently.

Q: Why don't we kill all the bats that are responsible for deadly diseases?

Krishna: No, you can't do that - because bats are very helpful to humans. 

70 percent of the bat species in the world feed off insects, many of which are harmful to agriculture and our health, like mosquitos that spread dengue and other diseases. With lots of bats eating lots of insects, there will be fewer insects to bug you. Farmers like bats because they can use fewer pesticides on their crops, which save the farmers lots of money.

In the tropics, fruit and nectar eating bats are important for dispersing seeds and pollinating flowers. In fact, more than 300 tropical plants depend on bats for seed dispersal and pollination. These plants include bananas, mangoes, avocados, date, and figs. By dispersing seeds, bats are helping rebuild rainforests that humans have cut down.

This might surprise you, but vampire bats are important to humans too. Vampire bats have a special chemical in their saliva that keeps blood from clotting. This allows them to easily drink blood from cows and pigs. Scientists studied this chemical and used it to develop medicine that helps humans that suffer from blood clots and strokes.

If you kill all the bats that would disturb ecological balance severely.

(another detailed answer is added below)

Q: How many corona viruses are dangerous?

Krishna: The family Coronaviridae contains about 39 different species of corona viruses. Of these, only seven coronaviruses have been reported to infect and cause disease in people. Four coronaviruses cause mild symptoms similar to the common cold, but three coronaviruses cause severe and possibly deadly infection: the severe acute respiratory syndrome corona virus (SARS-CoV), the Middle East respiratory syndrome coronavirus (MERS-CoV), and now, SARS-CoV2, which is responsible for the current coronavirus disease COVID-19.

Q: Do bats get sick too with viruses?

Krishna: Bats are pretty incredible animals. They are the only mammals that fly. Scientists have linked the genetic modifications associated with flight with beneficial modifications to the bat's immune system. For example, the bat's immune system fights viral infections but does not overreact to them, preventing bats from falling ill from the many viruses they have.

Q: How do viruses jump from other animals to human beings? 

Krishna: Every animal species hosts unique viruses that have specifically adapted to infect it. Over time, some of these have jumped to humans – these are known as ‘zoonotic’ viruses.

The majority of new diseases affecting humans are zoonotic, meaning that they originate in wild animals (mostly mammals) and then cross over to people. Among mammals, bats have a higher number of zoonotic viruses. These viruses might cause mild to no symptoms in bats. People and animals interacting with bats (or their urine, feces or saliva) might catch these zoonotic viruses and then spread them to other animals or people.

The trapping of wild animals for pets, food or medicinal purposes puts wild animals like bats in close contacts with other animals and people. That is what happened in the previous two coronavirus outbreaks. In the 2003 outbreak, the SARS coronavirus jumped from bats to civets being sold as food in a market, and then from civets to people. In the MERS outbreak, the MERS coronavirus jumped from bats to camels and from camels to people. 

As our populations grow, we move into wilder areas, which brings us into more frequent contact with animals we don’t normally have contact with. Viruses can jump from animals to humans in the same way that they can pass between humans, through close contact with body fluids like mucus, blood, faeces or urine. 

We are destroying the natural habitats of the animals, making them extinct. The viruses that infect them have to find new hosts. Very often, we are becoming easy targets to them. 

Because every virus has evolved to target a particular species, it’s rare for a virus to be able to jump to another species. When this does happen, it’s by chance, and it usually requires a large amount of contact with the virus.

Initially, the virus is usually not well-suited to the new host and doesn’t spread easily. Over time, however, it can evolve in the new host to produce variants that are better adapted.

When viruses jump to a new host, a process called zoonosis, they often cause more severe disease. This is because viruses and their initial hosts have evolved together, and so the species has had time to build up resistance. A new host species, on the other hand, might not have evolved the ability to tackle the virus.

The outcome of a virus infecting an animal depends on two general factors: The first is how strong, or virulent, is the strain of the virus. The second is the effectiveness of the infected animal's immune defenses. Initially, a virus might be highly lethal to animals. Rapidly killing its host is not beneficial to the virus because it limits the virus's capacity to spread to other animals. Therefore, the virus become less virulent with time. On the other hand, animals sensitive to the virus die quickly, while animals with inherited resistance to the virus survive, passing that resistance to their offspring. This combination of events, over a large period of time, results in an equilibrium where the animal's immune system is able to control a virus infection without completely eradicating it. In people, this type of equilibrium could be observed with herpes infections.

Q: Why are scientists taking so much time to find a vaccine for corona virus?

Krishna: Developing a vaccine is not  an easy process. 

For researchers working on possible corona virus treatments, time is short.

More than 100 clinical trials of dozens of potential coronavirus treatments are already underway around the world, a mobilization of global medical resources rarely seen before in human history. But science can be slow and indirect. And despite the sheer number of scientists involved in these efforts, the scientific method requires a rigour that can only be sped up so much.

It could take at least 12 to 18 months before a vaccine is commercially available to administer widely — a timeline already seen as aggressive. And with international attention focused on coronavirus efforts, some researchers are warning about the potential pitfalls of accelerating scientific research and the risks of overpromising what science can deliver in a short time.

Experts are voicing concerns about the unusual nature of relying on science to find a swift solution to a problem with still many unknowns that is unfolding in real time (2). The scientific method inherently takes time, and involves basic research to first identify the problem and subsequently applying that research to test and build on scientists’ understanding. Now, scientists are trying to do both at the same time. This is not just fixing a plane while it’s flying — it’s fixing a plane that’s flying while its blueprints are still being drawn. 

As new coronavirus cases multiply in many countries and fatalities rise, the scientific community is under enormous scrutiny and pressure to identify potential treatments.

The proposed timeline of 12-18 months for a vaccine is already exceptionally fast given the normal pace of vaccine development and trials.

It often takes 10 years for a new vaccine to make it through all the steps and all the tests necessary. The public health urgency of this is definitely moving things faster than would generally be done.”

Part of the challenge of working at such an accelerated pace is ensuring that safety is not compromised.

Typically, clinical trials are made up of three main stages. Most of the trials currently underway are in the first phase, which is designed to test whether the experimental drug of a vaccine candidate is safe to give to humans.

Phase one is about basic safety — does it make people get violently ill, or are there other extreme consequences? This step is not necessarily to see if the drug even does what you want it to do.

Once safety is established, the drug moves into phase two, which is designed to test its effectiveness and the specificity of the treatment.

If you give somebody a drug and it does a good job of killing the invading cells, but it also kills three of your main organs, it may be effective but it doesn’t work specifically on what you want it to work on.

The last step, and sometimes the most involved, requires demonstrating that the drug is effective in different populations, and thus would be safe and ready to administer widely.

But over the course of a clinical trial, there are few, if any, opportunities to speed up the process, particularly because scientists need to monitor the long-term effects of these new drugs. All these things take time, and if we cut corners, bad things can happen.

In 1982, for instance, research emerged that benzyl alcohol — which is used as an anti-bacterial agent in some medical solutions and was approved for use in adults but had not been studied in children and infants — was associated with 16 neonatal deaths at two medical centers in the U.S. And in the 1970s, pressure to rapidly develop and issue a new flu vaccine was later associated with hundreds of cases of a type of paralysis known as Guillain-Barré syndrome. Avoiding these types of dangers is even more important during a pandemic, because researchers will likely have to weigh potential risks and benefits that are magnified by the urgency of the situation.

Ideally you want a vaccine that is more than 90 percent effective. But we would have to look at: Even with a less-than-ideal effectiveness, are there greater benefits if we can reduce the pressure on the health system? So it may be that under certain circumstances, a 50 percent effective vaccine is better than nothing.

Regulators will most likely also have to weigh these same risks in deciding whether a potential vaccine is safe for the general public. In some cases, this may involve accepting the results of smaller trials that may carry more uncertainty than normal.

Putting pressure on the meticulous and sometimes deliberately lengthy scientific process could have negative impacts for both members of the public looking for hope and answers, and the scientists who are trying to deliver them.

Experts worry (2) that engendering false hope will cause complacency that will deprive us of the time needed to find a lasting solution. And they also worry about lasting damage if science over promises but cannot deliver on them. So they think, “Let’s underpromise. Let’s overdeliver” is the better way to do a balancing act.  

Science will definitely deliver but it takes a long time to do that. Please wait and have patience.

Update (3): The first COVID vaccine was developed just four weeks after the first genetic sequence was available from China. The reason that was possible was in part because of investment by the Coalition for Epidemic Preparedness and Innovation. CEPI is a global partnership set up three years ago, specifically with a mission "to stimulate and accelerate the development of vaccines against emerging infectious diseases and enable access to these vaccines for people during outbreaks." One of the things they have focused on is preparing for "Disease X," meaning some disease that would exist in the future which we didn't yet know about and for which we didn't yet have a vaccine. CEPI was founded to support the development of technology platforms that—no matter what the pathogen—could be used for rapid vaccine development. These technologies allow you to go from genetic sequence to vaccine without having to isolate the germ. COVID-19 is Disease X.

Researchers have fast-tracked vaccine development—getting from pathogen sequence to vaccine products available for clinical trials in a matter of weeks is a truly remarkable accomplishment. However, there are aspects of the trials that just can't be rushed. It takes time to develop an immune response to the vaccine, and it also takes time to evaluate the safety of these vaccines.

With that said, in an emergency situation, some stages of vaccine testing can be streamlined. How quickly you progress through the stages of vaccine evaluation will be influenced by the urgency of the problem. In the context of a pandemic, scientists will move forward as safely and quickly as possible.

Q: How do you test whether you have the corona virus in your body or not?


There are two types of tests:

Antigen (nucleic acid test) This tests for presence of the genetic signature (RNA) of SARS-CoV-2, the virus which causes COVID-19. A swab is used to collect a sample from inside the nose or back of the throat of an individual.

Antibody (serological test) This tests if an individual has been exposed to COVID-19 infection and has developed antibodies. It can also be performed in specific laboratories but also can be adapted into a testing format for community use.

Much of the testing  involves doctors sticking something akin to a long cotton swab deep into a patient's nose or throat to retrieve cells that contain live virus. Lab scientists pull genetic material from the virus and make billions of copies to get enough for computers to detect the bug. Results sometimes take several days.

Rapid antigen tests have shorter swabs that patients can use themselves to gather specimens. They are akin to rapid flu tests, which can produce results in less than 15 minutes. They focus on antigens—parts of the surface of viruses that trigger an infected person's body to start producing antibodies.

However,  experts think that the rapid tests may be significantly less reliable than the more time-consuming method.  Spanish scientists, who conducted these tests say the rapid tests for coronavirus they reviewed were less than 30% accurate. The more established lab tests were about 84% accurate.

So are 'finger-prick tests' that can provide important information in minutes. Highly unreliable.

Antibody tests are most valuable as a way of seeing who has been infected in the recent past, who became immune to the disease and—if done on a wide scale—how widely an infection has spread in a community.

The antibody tests also will allow scientists to get a better understanding of how deadly coronavirus is to all people, because they will provide a better understanding of how many people were ever infected, ranging from those who never showed symptoms to those who became fatally ill. The results will also guide vaccine development.

The  virus produces two types of antibodies: first, IgM antibodies, which are shortlived and may indicate that the virus is still present. These  usually appears within five to six days after exposure to the virus, and which fades after 20 days. As a person heals, that antibody, which indirectly shows contagion, is slowly replaced by another antibody, which indirectly shows that a person has had the virus. When only the second antibody is detected, it means the person is probably no longer infected.

 The second ones are more durable type, IgG antibodies. No one knows yet how long these will last and provide resistance to reinfection — anything from a few months to a few years seems possible.

But so much is still unknown, including how long antibodies—and immunity—lasts.







Q: Why aren't bats executed if they carry so many viruses?

Krishna: No, you can’t do that! Because bats are very helpful to humans.

70 percent of the bat species in the world feed off insects, many of which are harmful to agriculture and our health, like mosquitos that spread dengue and other diseases. With lots of bats eating lots of insects, there will be fewer insects to bug you. Farmers like bats because they can use fewer pesticides on their crops, which save the farmers lots of money.

In the tropics, fruit and nectar eating bats are important for dispersing seeds and pollinating flowers. In fact, more than 300 tropical plants depend on bats for seed dispersal and pollination. These plants include bananas, mangoes, avocados, date, and figs. By dispersing seeds, bats are helping rebuild rainforests that humans have cut down.

This might surprise you, but vampire bats are important to humans too. Vampire bats have a special chemical in their saliva that keeps blood from clotting. This allows them to easily drink blood from cows and pigs. Scientists studied this chemical and used it to develop medicine that helps humans that suffer from blood clots and strokes.

If you kill all the bats that would disturb ecological balance severely.

Qs people asked me on science and my replies to them - Part 175

Moreover, according to experts, we ourselves, are creating the conditions for the spread of diseases by reducing the natural barriers between virus host animals — in which the virus is naturally circulating — and themselves. Major landscape changes are causing animals to lose habitats, which means species become crowded together and also come into greater contact with humans. Species that survive change are now moving and mixing with different animals and with humans. The health risks in a natural environment can be made much worse when we interfere with it.

“We cut the trees; we kill the animals or cage them and send them to markets. We disrupt ecosystems, and we shake viruses loose from their natural hosts. When that happens, they need a new host. Often, we are it.”

It is important to reiterate that bats do not choose to interact with humans. We put ourselves at risk when we take animals from the wild and bring them into contact with humans.

Then why blame innocent animals for our own mistakes?

Why we ourselves are responsible for the deadly disease outbreakes

You want to kill your friend (helpful bats) for the mistakes you made? That is not fair!

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