COVID 19 Challenges: Why at some places it is more contagious

COVID 19 Challenges: Why at some places it is more contagious

Dr KK Aggarwal

President CMAAO, HCFI and Past National President IMA

The way covid 19 has spread in local clusters in diamond princess and a church in Korea has opened questions about its contagiousness.

1.       It’s a droplet infection: Pass through droplets from coughing or sneezing. When these virus-laden droplets from an infected person reach the nose, eyes, or mouth of another, they can transmit the virus.

2.       High viremia in early illness

3.       Its infectious in both URI and LRTI stage: Respiratory illnesses generally fall into two categories: upper respiratory — infections in the nose, pharynx, or larynx, like the common cold and seasonal influenza; and lower respiratory illnesses, like pneumonia, which infect the lungs.  

The original 2003 SARS virus was a lower respiratory infection: It replicated in the cells deep within the lungs and caused the pneumonia. People also seemed to only spread the virus days into their illness, when it was already clear they were sick. This made SARS more difficult to pass on to others and the job of containing it relatively easy.

The Covid-19 disease appears to be a different. While it also can eventually lead to pneumonia, replicating in the lung cells, the virus does a great job of replicating in the upper respiratory tract, even when people don’t have any symptoms or just begin to feel sick.

In a New England Journal of Medicine paper, researchers in Germany were able to isolate the virus from patients’ upper respiratory tract even before they showed any symptoms — more evidence of the potential for asymptomatic spread of the virus from the nose and throat.

4.       The virus might spread through feces: In this new paper from the Chinese Center for Disease Control and Prevention, researchers managed to isolate live virus from stool samples of Covid-19 patients. And they’re not the first to find the virus in stool.

As with norovirus, this means the disease could be passed around when there’s less than optimal hygiene. That’s why the China CDC recommended taking measures to stop the spread of the virus this way, including: maintaining environmental health and personal hygiene; drinking boiled water, avoiding raw food consumption, and implementing separate meal systems in epidemic areas; frequently washing hands and disinfecting of surfaces of objects in households, toilets, public places, and transportation vehicles; and disinfecting the excreta and environment of patients in medical facilities to prevent water and food contamination from patients’ stool samples.

But just because the virus is found in stool doesn’t mean that’s how it’s transmitting. And, again, more research is needed to figure out how important the fecal-oral route is in the spread of this disease.

5.       Airborne transmission: One more thing to watch out for: In the first SARS outbreak, a large housing estate in Hong Kong called Amoy Gardens became ground zero of a public health nightmare when more than 300 people were infected with the disease through yet another viral transmission route: airborne transmission.

This happens when the residue from evaporated, virus-containing droplets gets suspended in the air and indirectly infects those who breathe it in. It’s different from droplet transmission, since droplets are too large to float through the air and need to get sprayed directly on someone’s eye, nose, or mouth in order to infect them.

In the case of Amoy Gardens, researchers later learned SARS was capable of going airborne, spreading through the building’s faulty plumbing and ventilation systems to the people who lived on the estate.

Vito Iacoviello, chief of the vision of infectious diseases at Mount Auburn Hospital in Cambridge, Massachusetts, and an editor at Dynamed, noted that the US Centers for Disease Control and Prevention is recommending people admitted to hospitals with Covid-19 be put in an airborne isolation room. That’s the precaution used for TB, measles, and chickenpox.

6.       The super spreader: The R0 value of the individual may be more that the R0 value of the virus or the person has more viruses than the others. It has been seen what HIV positive person sheds less virus than HIV + STI positive person. We may need to find out the additional factor which intensifies the spread.

7.        Contact period: The virus may survive on the surface longer than thought. Similar viruses have been surviving for up to a week

Corona Virus Update: All questions answered

Corona Virus Update: All questions answered

Dr KK Aggarwal

President CMAAO, HCFI and past National President IMA

It’s not new

Every decade a zoonotic coronavirus crosses species to infect human populations and in this decade, we have a virus, provisionally called 2019-nCoV, first identified in Wuhan, China, in persons exposed to a seafood or wet market.

Name

The name of coronavirus comes from its shape, which resembles a crown or solar corona when imaged using an electron microscope.

The three deadly human respiratory coronaviruses viruses so far

1.    Severe acute respiratory syndrome coronavirus [SARS-CoV]

2.    Middle East respiratory syndrome coronavirus [MERS-CoV])

3.    2019-nCoV: The virus is 75 to 80% identical to the SARS-CoV

Pathogenesis

People infected with these coronaviruses suffer a severe inflammatory response.

It has high mortality

In the current situation the mortality rate is 3%. The severity of illness is concerning: almost a third of patients developed acute respiratory distress syndrome requiring intensive care; six patients died; five had acute cardiac injury; and four required ventilation.

Its Zoonotic

It is closely related to several bat coronaviruses. Bats are the primary reservoir for the virus. SARS-CoV was transmitted to humans from exotic animals in wet markets, whereas MERS-CoV is transmitted from camels to humans. In both cases, the ancestral hosts were probably bats.

It is more infectious to humans

Notably, 2019-nCoV grows better in primary human airway epithelial cells than in standard tissue-culture cells, unlike SARS-CoV or MERS-CoV. It is likely that 2019-nCoV will behave more like SARS-CoV.

Human to Human infection is weak

Both SARS-CoV and MERS-CoV infect intrapulmonary epithelial cells more than cells of the upper airways. Consequently, transmission occurs primarily from patients with recognized illness and not from patients with mild, nonspecific signs. 

It appears that 2019-nCoV uses the same cellular receptor as SARS-CoV (human angiotensin-converting enzyme 2 [hACE2]), so transmission is expected only after signs of lower respiratory tract disease develop.

The median time from onset of symptoms to first hospital admission was 7·0 days (4·0–8·0), to shortness of breath was 8·0 days (5·0–13·0), to ARDS was 9·0 days (8·0–14·0), to mechanical ventilation was 10·5 days (7·0–14·0), and to ICU admission was 10·5 days.

Its unlikely tp spread by eating sea food in India

It has been traced to snakes in China so unlikely to spread in India by eating sea food.  Snakes often hunt for bats in wild.  Reports indicate that snakes were sold in the local seafood market in Wuhan, raising the possibility that the 2019-nCoV might have jumped from the host species -- bats -- to snakes and then to humans at the beginning of this coronavirus outbreak. However, how the virus could adapt to both the cold-blooded and warm-blooded hosts remains a mystery.

Flight Transmission

Transmission of foodborne diseases on aircraft, including cholera, shigellosis, salmonellosis, and staphylococcal food poisoning, have been well documented. Transmission of smallpox on aircraft was reported in 1965. An outbreak of influenza occurred in 1979 among passengers on a flight that had a three hours’ ground delay before takeoff. The influenza attack rate among the passengers was very high (72 %), and was attributed to the ventilation system not operating during the ground delay. Epidemiological investigations have also indicated that measles may have been transmitted aboard international flights. To date, no case of active TB has been identified as a result of exposure while on a commercial aircraft. However, there is some evidence that transmission of M. tuberculosis may occur during long (i.e. more than eight hours) flights, from an infectious source (a passenger or crew member) to other passengers or crew members.

 It’s a large droplet infection

Transmission of 2019-nCoV probably occurs by means of large droplets and contact and less so by means of aerosols and fomites, on the basis of experience with SARS-CoV and MERS-CoV.

Universal droplets precautions the answer

1.    Quarantining for two weeks of the LRTI patient

2.    Timely diagnosis

3.    Strict adherence to universal precautions

Its all over

Australia (4), Macau (1), Hong Kong ( 5), France(3), Japan (3), Malaysia (4), Nepal (1), Singapore (3), Taiwan (3), South Korea (3), Thailand (5), United states (3), Vietnam (2),

Is it a public health emergency

There is an emergency in China, but it has not yet become a global health emergency.

PMO Suggestions Sent

17^th Jan: India at threat of Corona. Advisory should be issued (18^th Indian govt issues travel advisory as China's mysterious 'Coronavirus' spread in other countries)

22^nd Jan: Still not being declared to be a notifiable disease, N 95 to be included in the list of essential drugs and prise capped, Oseltamivir, should also be prise capped, air flights should have available air masks for all passengers, not declaring flu like symptoms while boarding or landing should be a punishable offence ( 23^rd India advisory to airports)

24^th: Inter Ministerial Committee needs to be formed on Corona Virus ( PMO took a meeting on 24^th evening)

25^th Jan: Indian government should pay for Indians affected with the virus in China

26 Jan: Need of National droplet Infection Control program, Policy to ban export of face masks, policy to evacuate Indians from China affected areas, Time to collaborate on Nosode therapy

Time to Announce National Droplet Infection Control Program

Time to Announce National Droplet Infection Control Program

To Shri Narendra Modi ji

Hon’ble Prime Minister of India

Dear sir

Regarding Coronavirus

1.    It behaves like SARS

2.    Every ten year it mutates

3.    It has origin from bats

4.    It spreads like large droplets (maintaining three feet from infected person will prevent distance)

5.    Spreads only form people having lower respiratory infections and not a worry for spread from upper respiratory infections or simple fever with cough and cold

6.    We know LRTI will always have breathlessness so unlikely to spread from people travelling with no breathlessness

7.    Unlikely to spread in other countries causing serious illness

So, the answer is

National droplet infection control program

Involving respiratory hygiene and cough etiquette

Use of simple masks by patients

Will take care of pollution illnesses also

Universal precautions and not when there is panic

With kind regards

Dr KK Aggarwal

Recipient of four National Awards (Padma Shri, Vishwa Hindi Samman, Dr B C Roy National Award and National Science Communication Award)

President Confederation of Medical Associations of Asia and Oceania

President Heart Care Foundation of India

Chairman HCFI Round Table on Health & wellness, Building Consensus

Past National President and Past Honorary Secretary General, Indian Medical Association

CoV behaves like SARS, has its origin from bats, spreads like large droplets and from people having lower respiratory infections AND so preventable to an extant

It’s official: CoV behaves like SARS, has its origin from bats, spreads like large droplets and from people having lower respiratory infections AND so preventable to an extant

Dr KK Aggarwal

President CMAAO, HCFI and past National President IMA

Every decade a zoonotic coronavirus crosses species to infect human populations and in this decade we have a virus, provisionally called 2019-nCoV, first identified in Wuhan, China, in persons exposed to a seafood or wet market.

In earlier two decades we had outbreaks caused by two other pathogenic human respiratory coronaviruses (severe acute respiratory syndrome coronavirus [SARS-CoV] and Middle East respiratory syndrome coronavirus [MERS-CoV]), causing respiratory disease that is often severe. In the current situation the mortality rate is  3%.

Scientists have identified and characterized 2019-nCoV. The viral genome has been sequenced. The virus is 75 to 80% identical to the SARS-CoV and even more closely related to several bat coronaviruses.

It can be propagated in the same cells that are useful for growing SARS-CoV and MERS-CoV, but notably, 2019-nCoV grows better in primary human airway epithelial cells than in standard tissue-culture cells, unlike SARS-CoV or MERS-CoV.

Both SARS-CoV and MERS-CoV infect intrapulmonary epithelial cells more than cells of the upper airways. Consequently, transmission occurs primarily from patients with recognized illness and not from patients with mild, nonspecific signs. It appears that 2019-nCoV uses the same cellular receptor as SARS-CoV (human angiotensin-converting enzyme 2 [hACE2]), so transmission is expected only after signs of lower respiratory tract disease develop.

It is likely that 2019-nCoV will behave more like SARS-CoV.

Given its close similarity to bat coronaviruses, it is likely that bats are the primary reservoir for the virus. SARS-CoV was transmitted to humans from exotic animals in wet markets, whereas MERS-CoV is transmitted from camels to humans. In both cases, the ancestral hosts were probably bats.

Transmission of 2019-nCoV probably occurs by means of large droplets and contact and less so by means of aerosols and fomites, on the basis of our experience with SARS-CoV and MERS-CoV.

Public health measures, including quarantining in the community as well as timely diagnosis and strict adherence to universal precautions in health care settings, were critical in controlling SARS and MERS.  [ Excerpts from NEJM]