Did humans approached diseases or the opposite happened?

Ghadi news

Thursday, April 2, 2020

Did humans approached diseases or the opposite happened?

"Ghadi News"

**Bachir Abi Salloum

In the past two decades, the incidence of pandemic viral outbreaks became much more frequent such as Severe Acute Respiratory Syndrome (SARS; SARS-CoV) that broke out during 2002 in South China. It was suspected that this virus has been transmitted from bats to humans through at transient host called civet cats. In 2012, there was a pandemic outbreak of Middle Eastern Respiratory Syndrome (MERS; MERS-CoV), it was thought that the transmission was from bats through camels to humans. The first infection with MERS was in Saudia Arabia. Today, the world is witnessing the pandemic outbreak of coronavirus Covid-19 that started in Wuhan China at the fish market and it is suspected its transmission from bat to humans through pangolin after undergoing mutations. All these aforementioned viruses belong to the family of Coronaviridae that contains a ribonucleic acid type of viruses (RNA-viruses) known for their high mutation rates. Thus they can be easily transformed within a species from non-infectious to infectious and contagious virus.

With these pandemic outbreaks that have caused colossal economic losses leading to economic recession with its all repercussions, some questions will be risen. First, why is this high incidence of pandemic outbreaks taking place? Secondly, have humans encroached the vital space of wildlife? This latter question can be addressed regarding if bats trespassed the human habitat or the opposite has occurred?

These two questions are interrelated. One inherent component to these RNA-viruses is their ability to mutate rapidly. However, like any other viruses these non-living particles require a host to multiply and propagate and thus can be an environment or medium that may trigger the changes in the viral genome leading to transition from non-infectious state to an infectious state in humans. For example, temperature, pH, the characteristics of enzymes within the cells of the transient host and other factors may will prompt some alterations in gene and protein expressions of the RNA-viruses, especially changes related to spike proteins these latter proteins are found on the outermost of the virus and will bind to receptors of human lungs cells. This will enable the infiltration of these viruses into the lung cells of leading to the alteration of this vital organs. This malfunctioning of the lungs with increases in inflammation and perfusion of fluids into the lungs, and the decrease in oxygen supply will launch a domino effect inflicting serious physiological disruptions in other vital organs such as the liver and the kidney. Consequently and in aggravated situations, dead can step into the life of patients putting an end to it.  

Furthermore, an encounter between infectious viruses and humans will increase the risk of man to contract a viral infectious disease. This is more induced by the behavioral pattern of mankind. Man is deteriorating natural habitats to many wild species including bats at a very high pace. Scientist are estimating that natural resources are used at a rate of 175% from their potential.  The habitat of animals will shrink and may force the closer distances to human residential and urban areas. For example, research findings suggest that human exposure to bats is increasing, these animals had underwent coevolution with viruses over millions of years so that they developed adequate immune responses to these viruses while the transmission of viruses to humans or other naïve species to these viruses may trigger serious diseases.

Many scientists enumerate also many factors that may play a role. One of these factors is climate change that has increased the incidence of flooding, cyclones which may increase the outbreaks of some bacterial disease such leptospirosis or viral such as West Nile virus. Second factor involved in the increase of infectious disease outbreaks is the change in temperature pattern especially the increase in temperature that may be favorable for the development of certain diseases.

In addition, the tremendous expansion of urban sprawl which led to fragmentation of natural habitats and increased level of pollution which have contribute to compromising immune system of wild animals living in urban and suburban area such as bats. This compromise in immune system in urban wildlife makes wild animals to spread more viruses in these densely human populated areas. 

Furthermore, there is a huge lack of knowledge related to wildlife viruses. Nowadays, scientists know about only one percent approximately of them. Therefore, it is essential that more efforts should be invested to understand better these microscopic enemies that can cost the human economies trillion of dollars like what influenza had done several years ago. On the other hand, it will be not costly for human kind to leave the wildlife without disturbance. It is about time to learn to use wisely the ecosystem services in a sustainable fashion and not to overuse it. Economic speculations anticipate an 8 trillion dollar costs due to Covid-19 pandemic outbreak and expansion and thousands of human lives are already claimed.

Our mother nature is generous in providing us with many free of costs vital services, if we continue misusing it, it will hit back in many forms such as cyclones, pandemic infectious disease or the like. The human kind must be cautious and vigilant otherwise its smooth sustainable existence is at the stake.      

**PhD in Agricultural Sciences

Adjunct Faculty of Viral Infectious Diseases, Epidemiology, Endocrinology

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