Sheikh Mizanur Rahman
The current outbreak of COVID-19 was identified in Wuhan, China, in December 2019, and recognized as a pandemic by the WHO.
Until 06 May’20 it infected 3.72 million individuals in 212 countries around the Globe resulting 258,344 deaths. Countries located in Sub-tropical and Temperate zone (Northern hemisphere) are highly vulnerable.
Tropical zone (Northern Hemisphere) exhibits low vulnerability. Being a tropical country, Bangladesh falls under low vulnerability zone with very low infection cases and deaths until now and it is likely to improve further in the coming days.
This study exposes COVID-19 thrives at temperatures between 5-11°C and loses its stability above 36°C; high temperature and high humidity significantly reduces the transmissibility, and sunlight reduces its infectivity.
It survives well on surfaces of typical indoor environments with AC and in aerosol condition, where temperature ranges from 22-25°C with relative humidity from 40–50%; in healthcare/hospital condition it can survive for days.
In the study of latitudinal effect on spread of COVID-19 in the world, 63 countries covering 6 continents were taken as sample, and their community outbreaks have been evaluated (Figure-1).
Figure-1: Map showing coronavirus pandemic and vulnerability in relation to climatic zones of the world.
As depicted in the map Sub-tropical and Temperate (Northern hemisphere) zone extends from 23.5°N to 66.5°Nof the north latitude; with an average temperature in winter months between 2 °C to 13 °C, in some countries it may go to freezing or below.
Data of 30 countries in this zone exhibit highest infection cases and death toll from 13 to 17,359individuals/million and 2 to 1208 persons/million respectively.
Tropical zone (Northern hemisphere) extends up to 23.5°N latitude; data of 20 countries with temperature from 13°C to 30°C exhibit infection cases from 1 to 869 individuals/million and death toll from0.1to7 persons/million, which is quite low.
In Sub-tropical and Temperate zone (southern hemisphere) extends from23.5°S to 66.5°S latitude with temperature from 14°C to 25°C, data of 6 countries exhibit infection of 111 to 1152 individuals/million and death toll from 2 to 14 persons/million, which is quite low.
In 7countries of Tropical (southern hemisphere) extends up to 23.5°S latitude with temperature from 18°C to 29°C exhibit infection of 2 to 1807 individuals/million, and death toll from 0.3 to 89persons/ million, which is quite low.
Analyzing world vulnerability scenario to COVID-19, sub-tropical and Temperate zone (Northern hemisphere) registered 91%, Tropical zone (Northern hemisphere) registered 3%, Sub-tropical and Temperate zone (Southern hemisphere) registered 2% and Tropical zone (Southern hemisphere) registered 4% infection cases.
Against total infection cases7% people died of Covid-19 in the world; among them Sub-tropical and Temperate zone (Northern Hemisphere) registered 96%, Tropical zone (Northern Hemisphere) registered 0.7 %, Sub-tropical and temperate zone (Southern Hemisphere) registered 0.6% and Tropical zone (Southern Hemisphere) registered 2.7% death toll (Figure-A).
In estimation of vulnerability index (VI) total infection cases and death tolls have been extrapolated and weighted, which represent degrees of vulnerability of climatic zones; and accordingly three classes have been developed.
• Sub-tropical and Temperate zone (Northern Hemisphere) with 0.94 (considering total as 1) VI value fall undervery high vulnerability zone.
• Tropical zone (Northern hemisphere) with 0.02 VI value, and Tropical zone (Southern hemisphere) with 0.03 VI value fall underlow vulnerability zone.
• Sub-tropical and Temperate zone (Southern Hemisphere)with0.01 VI value fall under very low vulnerability zone.
So, it is evident from the fact COVID-19 virus’s fatality is highest in Sub-tropical and Temperate zone (Northern Hemisphere); and all the countries of this zone fall under very high vulnerable zone in comparison to other 3 climatic zones. All the countries of Tropical zone (Northern Hemisphere) including Bangladesh fall under low vulnerability zone.
Future Predictions: In Sub-tropical and Temperate zone (Northern Hemisphere)countries of Europe and North America with the increase of summer temperature situation will improve, but if they fail to bring it under control incoming fall and winter the situation would be devastating and deadly.
In Tropical countries (northern hemisphere) including Bangladesh, in summer month’s infections and death tolls will decrease further; but in next winter it may revive again.
Among traditional medicines (TM) combination of garlic (with antiviral alkaloid), turmeric, zinger, cinnamon and clove (with antiviral and anti-inflammatory properties) based hot drinks 3 times daily; consumption of black cumin (Nigella sativa) seeds daily (contain alkaloid like thymoquinone and dihydrothymoquinone) could be effective; and all these TM have immune-regulatory effects, and through reducing toxicity will boost up immunity system.
We do not have any defined drugs and vaccines yet for COVID-19 treatment, but some important candidates are favipiravir, remdesivir and lopinavir; chloroquine and hydroxychloroquine in combination with Azithromycin exhibit good result in the countries of China, S Korea, India, France and US; and it could be effective for treatment of COVID-19 patients.
In case of secondary infections of pneumonia or any other respiratory disease (Bacterial), treatment with Amoxicillin, Azithromycin and Fluoroquinolones might be effective. In this situation, medical experts and doctors through analyzing the conditions of the patients can advise the potential drugs; we are running out of time.
Considering present situation it is worthwhile to mention that Prime Minister Sheikh Hasina has been credited for handling the situation sensibly with firm steps. While, the situation has not touched the peak or started going down yet, to keep the economy running relaxing or easing lockdown might be necessary.
Hope, lessons learned from COVID-19 pandemic, will make the world more resilient with greater cooperation and solidarity.
Shaikh Mizanur Rahman is a consultant, biodiversity conservation program at Padma Multipurpose Bridge Project (PMBP)