Warm weather may buy Bangladesh some time to fight coronavirus

Emran Hossain | Published: 01:10, Mar 16,2020


A group of researchers recently warned that that COVID-19 might manifest in less fierce symptoms during summer in the tropical regions before developing into serious illness in late fall while some said that high temperature and humidity were likely to reduce the probability of its spread.

Whatever the case, the warm weather might buy Bangladesh some time to prepare for the worst with confirmed presence of the novel coronavirus in the  country while it continues to wreak havoc on the health systems in countries as technologically advanced as USA, the UK and many European nations. 

Very little is known about the virus, which causes the disease called COVID-19, as scientists and physicians around the world continue to try to grasp the way the virus is supposed to act under different weather conditions.

Some researchers have seen a pattern as the new coronavirus outbreak gradually shifted its epicentre from where it was first reported in China to the current hotbed of coronavirus infection in European nations, places where temperatures ranged from 5 C to 11 C.

Other researchers, however, warned against jumping into any conclusions since the new coronavirus seems stronger than other members of the coronavirus family and is able to infect humans, some of whom thrive in as warm weather as in the middle-eastern countries.

‘The truth is that this is a new virus and we know nothing about it except that our immune system is not capable of fighting it off,’ said Bangabandhu Sheikh Mujib Medical University’s virology professor Said Ullah Munshi.

A research published last week in SSRN, formerly known as Social Science Research Network, however, says that the virus shows signs of potential seasonality after analysing latitude and temperature of places the virus has already spread to.

A group of seven researchers from different universities in the USA and Iran conducted the research and said that the virus could ‘prevail at low levels in tropical regions similar to influenza and ramp up again in late fall, in time for traditional flu season.’

They said that the places where the virus established community transmission are distributed along a narrow east west line ‘along the 30-50 N corridor at consistently similar weather patterns (5-11C and 47-79 per cent humidity).’

The study said that soon after the epidemic broke out in Wuhan, China, it was though that it would soon spread to regions in Southeast Asia, specifically Bangkok, because of geographical proximity and significant travel connections.

But the epicentre of the outbreak centred on regions more or less the same latitude — to South Korea, Japan, Iran, and Northern Italy, said the study.

‘In the months of January 2020 in Wuhan and February 2020 in the other affected, there is a striking similarity in the measures of average temperature (5-11 C) and relative humidity (47-79 per cent),’ said the study.

The declining number of new infections in Wuhan may have something to do with the rising temperature there, the study said.

A group of four German researchers reviewing 22 studies on pathogenic viruses published a study in the Journal of Hospital Infection in late February saying that a higher temperature such as 30C or 40C reduced the duration of persistence of highly pathogenic viruses including some coronaviruses.

They said that persistence of viruses such as TGEV and MHV increases significantly in low temperatures such as 4C.

Dhaka Medical College’s virology department associate professor Monira Pervin said that viruses are generally sensitive to natural ultraviolet rays of the sun and high temperature.

‘Viruses are also not much fond of high humidity,’ she said.

She said that if Bangladesh can check the spread of coronavirus through direct contact with infected individuals, the other ways of transmission of viruses would likely to remain in check because of high humidity and temperature.

‘I believe it is possible to contain the virus in the country by April,’ she said.

High temperature and humidity are typical of Bangladesh’s spring and summer weather.

On Sunday, the country’s highest maximum temperature of 36.7 C was recorded at Sitakunda with temperature in six of the eight divisions exceeding 30 C.

The Met Office recorded 83 per cent humidity at 6:00am.

The Met Office predicted further rise in temperature next week, up to 40 C.

Bangladesh so far announced five positive coronavirus cases since March 8.

Despite poor screening and an influx of expatriate workers from the infected countries the spread of coronavirus seems still under control with no unusual rise in the number of respiratory related illnesses reported by the health department.

World Health Organisation has advised countries to test as many suspected patients as possible to break the chains of the virus transmission.

Ever since the first coronavirus positive case was announced eight days ago, Bangladesh tested only 231 people whereas in South Korea the number of tested patients were around 15,000 on a daily basis.

‘The virus is fast and furious. I wonder how pneumonia caused by the virus can spread so fast,’ said BSMMU’s pathology professor Kamrul Hasan Khan.

The coronavirus pandemic has already killed more than 5,700 people as it spread to 137 countries since it emerged in December last year. It infected about 1.5 lakh people.

Besides human to human direct contact, the virus is likely to be capable of airborne and fomite transmission, said a US government study released four days ago. 

The study said that aerosol and fomite transmission of the new coronavirus is plausible, as the virus can remain viable in aerosols for multiple hours and on surfaces up to nine days.

The German review of literature on highly pathogenic viruses, including some coronaviruses, said that above 30 C temperature reduces their viability.

US-based forecaster AccuWeather quoted Dr John Nicholls, a pathology professor at the University of Hong Kong, as saying that sunlight is really good at killing the virus.

Nicholls, whom AccuWeather identified as a leading coronavirus researcher in the world, said that the survival of coronavirus directly depend on temperature and environment.

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