Opinion: All cases in India are linked to International air travel. All were asymptomatic before in the country of origin, during air travel and at the time of landing.

All developed fever and cough after a few days of reaching India.  One of the possibilities is that they acquired infections not in the country but the airport.

Average incubation period of corona is 3-5 days (2-14 days) from people coming from outside Wuhan.

Earlier studies have shown that corona viruses thrive better in cool, dry climates. That should make countries with hot and tropical weather, less conducive for the virus to thrive. Most of the studies indicate that the virus dont persist in hot, humid environments. Hot and humid climate means over 30 deg C, and having humidity levels of above 80 per cent.

The temperature in Iran is 14 degree (humidity 60%), Italy 14 (humidity 62%) , Dubai 23 ( humidity 90%) and Thailand 29 ( humidity 709%) degree centigrade. At this temperature the virus should not be living in Dubai and if circulating the only reason will be AC atmosphere. For visitor AC atmosphere will be the air-port where they stay for some time.

Also, air-conditioning is something that cant be helped in most countries especially during the hot months. Enclosed spaces are less humid and cooler and can spread the respiratory diseases.

Therefore, all air-ports have round the clock conditioners and may be the harbour of corona viruses.   Also, airports have travellers from all across the word.

The Diamond Ship

23% of persons got corona virus on the Diamond Princess cruise ship despite a two-week quarantine.

As per the Purdue University air quality expert have mentioned that the cruise ship air conditioning systems are not designed to filter out particles as small as the coronavirus, hence allow the disease to circulate rapidly to other cabins.

It is a standard practice for the air conditioning systems of cruise ships to mix up outside air with inside air to save energy. The problem is that these systems cannot filter out particles smaller than 5,000 nanometers. If the coronavirus is about the same size as SARS that is 120 nanometers in diameter, then the air conditioning system can carry the virus to every cabin.

Aircraft

For aircraft, the coronavirus is more likely to spread by touch than through the air, since the air conditioning systems of planes are capable of filtering out particles as small as viruses. But air carrying the virus could transfer to other people sitting in the same row as an infected passenger or a neighboring row.

Toilets would be the biggest hot spot for the virus on a plane. Stool also contains viruses. Close the toilet lid before flushing to limit on how much of it goes into the air. Planes should also provide wet wipes with alcohol to prevent the further spread of the virus through touch.

General advisory: All international travellers should closely watch for fever and cough and report if they develop it.

Dr KK Aggarwal

President CMAAO, HCFI and Past National President IMA