Q: Why do some people can't fight infections?

Krishna: Immuno-compromised people cannot fight infections properly like healthy people do. What causes this condition? 

Primary immunodeficiencies  arise when someone is born with a condition that directly affects their immune system. These illnesses are rare and usually diagnosed early in life. They include common variable immunodeficiency, severe combined immunodeficiency and X-linked agammaglobulinaemia.

Secondary immunodeficiencies are more common and arise as a consequence of outside factors. Exposure to environmental toxins including some pesticides, heavy metals, petrochemicals and air pollutants such as cigarette smoke can reduce the effectiveness of the immune system, particularly at the surface of the lung. Poor nutrition and drug and alcohol abuse can also impair immunity, as can medications, age and even pregnancy.

Some illnesses and injuries can cause someone to be immunodeficient. These are also classified as secondary immunodeficiencies. This includes acquired immunodeficiency syndrome (AIDS) as a consequence of HIV infection, severe burns, and not having a functional spleen. This organ is crucial for blood filtration and coordinating the immune response.

Cancers of the bone marrow and white blood cells, such as leukemia and lymphoma can also cause immunodeficiency. Bone marrow and white blood cells usually fight infections. The treatment for these cancers is commonly to wipe out all white blood cells using chemotherapy. This incapacitates the immune system even more.

Medications can bring about an immunocompromised state. These drugs are called immunosuppressants.

People who receive organ transplants are one group who need to take immunosuppressants. This dampens their immune system so it cannot react against and reject the donor’s transplant.

People with autoimmune diseases, which cause the immune system to attack the body’s own cells and tissues, also use these medications. Between 2% and 7% of the population have an autoimmune disease, such as multiple sclerosis, type I diabetes, rheumatoid arthritis and Sjogren's  syndrome etc.

Age is a key element to consider when thinking about our immune system and its ability to work optimally.A newborn will have no mature immune system to protect his or her body against invaders. In this context, breastmilk will be a precious source of antibodies to help fight viruses. On the other side, older people are also considered immunocompromised, as they have an ageing, weakened immune system, not fit enough to start and win a fight.

Pregnancy weakens women’s immune systems.

Through our evolution, we have developed a necessary state of immunosuppression during pregnancy. This is because within the pregnant mother’s body is an organism with parts that look foreign to the mother, encoded by the DNA from the other biological parent. Natural suppression of the immune system during pregnancy stops the mother’s immune system from mounting a response against the baby.

Q: Does corona virus spread through faecal matter? 

Q: Have scientists found corona virus in the digestive tract?

Krishna: We don't yet know whether this virus can spread through faecal matter although it was found in GI tract and the excreta originated there. 

Some COVID 19 patents also have gastrointestinal symptoms including diarrhoea, vomiting and abdominal pain . This is likely because SARS-CoV-2, the virus that causes COVID-19, is found in the gut as well as the respiratory tract. Importantly, the gut’s involvement in coronavirus illness points to the possibility COVID-19 could spread through faeces.

At this stage we don’t know for certain whether or not that occurs – but we will have to take precautions to prevent that route if there is a chance.

We say there is a chance because we know how this virus enters human cells.

SARS-CoV-2 gains entry into human cells by latching onto protein receptors called ACE2, which are found on certain cells’ surfaces.

Around 2% of the cells lining the respiratory tract have ACE2 receptors, while they’re also found in the cells lining the blood vessels.

But the greatest numbers of ACE2 receptors are actually found in the cells lining the gut. Around 30% of cells lining the last part of the small intestine (called the ileum) contain ACE2 receptors.

Clinicians have detected coronavirus in tissue taken from the lining of the gut (oesophagus, stomach, small bowel and rectum) through routine procedures such as endoscopy and colonoscopy, where we use cameras to look inside the body. They found abundant ACE2 receptors in those tissue samples.

While some researchers have proposed alternative explanations, it’s likely people with COVID-19 experience gastrointestinal symptoms because the virus directly attacks the gut tissue through ACE2 receptors.

Q: What distance is really safe to avoid corona viruses?

Krishna: The research is still going on and we can't say with certainty what distance is really safe. 

Recent studies show that people infected with the new coronavirus could be spreading "aerosolized" viral particles as they cough, breathe or talk in a 13-foot radius, and viral particles can also move around on people's shoes.

Standard protective gear appears to effectively shield health care workers from these aerosolized droplets and infection, and even cloth face masks could curb the spread of exhaled droplets. Experts say,  maintaining some distance from others is better than none. Six feet is better than 5 feet. In the age of coronavirus, the more the better. It really comes down to the likelihood of viral transmission.

Doctors in Wuhan, China, in a study noted that when people exhale, heavier droplets (potentially containing virus) tend to drop to the ground because of gravity, whereas lighter droplets can remain suspended in breathable air. Their tests found that 70% of swab samples from the hospital floor came up positive for coronavirus, "perhaps because of gravity and air flow causing most virus droplets to float to the ground," the study authors said.

In addition, as medical staff walk around the ward, the virus can be tracked all over the floor, as indicated by the 100% rate of positivity from the floor in the [hospital] pharmacy, where there were no patients," the researchers said. "Therefore, the soles of medical staff shoes might function as carriers."

Also swabs taken of often-touched surfaces—doorknobs, bed rails, trash cans and computer mice—typically came up positive for coronavirus. And what about the air people breathe? The closer to an infected patient, the more likely an air sample was to come up positive, Guo's group said. "Virus-laden aerosols were mainly concentrated near and downstream from the patients," the team reported.

But tiny airborne aerosols could travel farther than the 6 feet now recommended in most social distancing advisories. In fact, "the maximum transmission distance of [coronavirus] aerosol might be 4 meters (13 feet) this group reported. They published their findings online April 10 in the journal Emerging Infectious Diseases (2).

In another study, researchers found that droplets were dispersed into the air, but wearing a "slightly damp washcloth over the speaker's mouth" effectively stopped most of the dispersion.

Experts are now warning that while 6 feet is certainly ideal based on recommendations by the U.S. Centers for Disease Control and Prevention, we are now learning that aerosolized droplets from coughing or sneezing, which may then be carried by currents indoors and outside, may make this distance less than ideal. 

Moreover, other factors—including how deeply into the lungs viral particles penetrate, and the strength of a person's immune system—are also involved in the infection process.

The potential for this virus to spread via aerosols is particularly scary, because it's essentially a hybrid between an airborne and a droplet virus, and that the droplets are able to hang out in the air for an extensive period of time and potentially infect other people.

Q: Does hot water kill viruses?

Krishna: Viruses are non-living particles outside a living body. Therefore, strictly speaking, you should not use the word "kill" while dealing with viruses. 

However, you can inactivate viruses using heat.  

In fact temperature has been the most studied factor in research, and is indeed often recognized as the most influential one to inactivate viruses (1). It has been universally demonstrated that higher temperatures mean faster viral inactivation. At low temperatures above freezing, viruses may survive for extended periods of time, often longer than the duration of the studies, and sometimes for several years. At higher temperatures, the viral population will be reduced by several orders of magnitude in a few days.Heating will inactivate viruses within minutes . Freezing temperatures allow viruses to remain stable for several months at least, although an initial decrease may be observed in the first days.

Studies of the impact of temperature often focus on 2 or 3 levels, generally including a low temperature (4 or 10°C), ambient temperature (20-25°C), and body temperature (37°C). It is then possible to infer the influence of temperature on viral stability. For example, it has been shown that poliovirus, echovirus, and coxsackievirus populations in seawater were reduced by 5 log units* in less than a week at 37°C, while it took 1 year at 4°C in laboratory conditions. In free-flowing ocean water, a 5-log reduction of poliovirus and echovirus occurred in 1 month in summer (water temperature 21-26°C), and in a little more than 2 months in winter (4-16°C) . In mineral water, poliovirus lost 1 log unit in 330 days at 4°C, while it took 60 days at 23°C; hepatitis A virus proved more resistant than poliovirus in similar conditions . Astrovirus in tap water was reduced by 2 log units in 60 days at 4°C and 30 days at 20°C . Adenovirus in groundwater lost 1 log unit in 132 days at 4°C, and in 36 days at 20°C . A similar 4-log reduction of H5N1 in river, lake, or seawater was observed in 5 weeks at 6°C, and in 3 weeks at 22 or 35°C . The viral decrease is not always log-linear, however, as an initial stability may be observed in less aggressive conditions . Likewise, small variations of temperature may produce no significant differences in inactivation kinetics .

Solar light is another important factor producing viral inactivation, through the action of UV radiation. Viruses survive better in the dark than when exposed to sunlight. 

* A logarithmic unit or log unit is a unit that can be used to express a quantity (physical or mathematical) on a logarithmic scale, that is, as being proportional to the value of a logarithm function applied to the ratio of the quantity and a reference quantity of the same type.

Q: Isn't it better to believe in God in these difficult times than science?

Krishna: Just read these reports ...

Pastor Who Defied Social Distancing Dies After Contracting Covid-19, Church Says.

He said "God is greater than this dreaded virus". 

https://www.nytimes.com/2020/04/14/us/bishop-gerald-glenn-coronavir...

A person who made TikTok videos to ridicule the use of masks, saying ‘trust in god not in a piece of cloth’, has had a sobering lesson after testing positive for Covid-19

https://timesofindia.indiatimes.com/city/bhopal/he-made-anti-mask-v...

If you can really think you will understand whom to trust.   

Q:Can air conditioners transmit Corona virus?

Krishna: As the work is still going on, we can't confirm much. However, 

I came across this research letter. It says ...  strong airflow from the air conditioner could have propagated droplets from table C to table A, then to table B, and then back to table C in the restaurant. ... We conclude that in this outbreak, droplet transmission was prompted by air-conditioned ventilation. The key factor for infection was the direction of the airflow.

COVID-19 Outbreak Associated with Air Conditioning in Restaurant, Guangzhou, China, 2020

Citations: 

1. https://www.karger.com/Article/Fulltext/484899

2. https://medicalxpress.com/news/2020-04-exhaled-aerosols-coronavirus...