Monsoon will change Covid-19 scenario for better

Dr T K Narute

The factors responsible for either plant or animal epidemic or pandemic are natural assembling of susceptible host, virulent pathogen and favourable climatic change that is called disease triangle. The first side of the disease triangle is the pathogen. When pathogens are virulent, they multiply very fast, disseminate or spread easily and finally alter the host physiology which is the cheapest source of disease initiation. Covid-19 is having all these characters beyond the limits. It is most virulent than earlier reported viral diseases. The second lateral of the disease triangle is the host. When susceptible host is easily available in mass and assists pathogen for further multiplication, it will help to build up the inoculum. The Covid-19 is predicted as most virulent mutant, multiplies ten times as compared to other viruses and infects the human host who is easily available, found in crowds with more mobility. The third major and governing factor is the climate. The changes in climate alter the physiology of host and favour the pathogen to build and disseminate/spread. If these three factors are coincidentally predominant at a time, any disease can transform into a pandemic. At present, the first two factors i.e. pathogen in hidden form and hosts in crowd are easily available. It means the third factor i.e. environment is in favour of pathogen. Presently, the disease triangle is now having all three sides with sharp edges. Today, the disease management efforts are concentrated over the first two factors by defending the pathogen by medical aids and following hygienic protocol to escape from infection. However, the third factor i.e. environment, which plays a major role, is beyond the control of human beings. Therefore, unless the third side of the disease triangle i.e. present environment is naturally changed, the decline of disease is difficult. Therefore, escaping from the Covid-19 infection by means of different ways is the best solution. If anyone is still healthy or uninfected so far, it doesn’t mean he/she is excused by pathogen. The scientific reason is either he might not have come across with pathogen or else he/she might have strong immunity. If we see the last year’s experience, the disease intensity was reduced after raining and decline continued till the monsoon season weather. It is universal truth that man neither eliminates nor stops the survival of any living things from nature. Therefore, the disease again came to the fore through the hidden patients. Thus, the climatic change plays a major role to alter all these issues on the earth. At present, the existence and virulence of Covid-19 will not remain for a long time. However, it will take time to decline the virulence and that work will be done by nature.

Change in climate has a direct impact on all livings including higher plants, animals and microorganisms. Many scientists recorded such observations on climate changes and their adverse effects on living things, but the issues were tackled very casually and neglected at all levels. Similarly, changes in microbes and their effects on living things have also not been tackled seriously so far. Microbes change their behaviour and virulence to survive in the changing climate. The pandemic happens only and only when the pathogens change their virulence and become more aggressive. These changes in virulence break the resistance of host. Once the microbes succeed in breaking the host resistance, they cover a large area within short period of time and show their existence through pandemic form.

In crowded and dense cities, the air is heavily polluted with dust, ionised metal particles, aerosol, smoke, water dew and so many inert materials which assist to hold and carry microscopic disease pathogens. When atmospheric air is clean, obviously, the inoculum load of pathogens is less. During raining, due to high air humidity, the dust particles, aerosol, smoke, water dew get overloaded with water dew and settle down and assist to reduce the airborne load inoculum. Continuous and heavy rainfall helps to wash out these air pollutants. It is universally proved that most of the pandemic diseases either in plants or animals are airborne, cover large area within short time and then spread over even larger area, may be all corners of the world. Viral diseases are abiotic and made up with the nucleic acids but they are pathogenic to the living things. The virus diseases are easily transmitted as compared to fungal, bacterial and other non-biotic diseases. In pandemic, the pathogen is impartial when it comes to infecting its host and not bothered with designation, religion, cast and country of the host. Everyone is equally handled if s/he came across it. The dispersal of primary pathogen foci of Covid-19 from hot-spot coupled with free movement of the human being across the world spreads this disease very easily.

There are a number of controversial opinions all over the world on the mode of transmission of Covid-19. At the beginning, the infected aerosols are de-marked as causing means for a limited distance. However, infected cases were reported from remote locations of persons who did not have any travel history or contact with new or unknown person and the number of disease cases went increasing. Here, the atmospheric air played a major role of transmission crossing the limit of distance. Hence, many doctors, scientists and researchers claimed the airborne nature of the Covid-19 disease.

The mode of transmission plays a major role in spread of any such pandemic plant diseases. Direct contact is the main source of any disease infection. However, in pandemic cases many other sources are involved in addition to direct contact like polluted air, water and vectors. Direct contact, water and vectors have limitations to cover area within short time. However, air transmission is the fastest way and has no restrictions over distance. As mentioned earlier, most of the time, the atmospheric air is loaded with different pollutants like dust particles, aerosol, water dew and smoke which helps the pathogen to travel from one location to other, may be in meters or kilometres.

The beneficial interference of nature by means of natural air purification through rains will definitely reduce the inoculum load and virulence of pathogen in the coming days. As a result, the coming rainy climate will definitely change the Covid-19 pandemic scenario and will help to decline the severity of the disease.

Just wait… for the monsoon to slow down Covid-19.

(The writer is Head, Department of Plant Pathology and Agricultural, Microbiology, Mahatma Phule Krishi Vidyapeeth, Rahuri, Ahmednagar)