New diseases are created everyday: Ebola and HIV are just two names unheard of in the1970s. For most of these new diseases, we know little how and where they might strike but for a lot of other diseases, the writing is on the wall. Few however take clue from these indications. I will try to summarize effect of global changes in our environment and how it has and will continue to affect our health and thus the need for appropriate medicines to treat them.
Our environment is actually a continuous part of ourselves. We breathe, we feel the warmth and cold and we expose ourselves to all elements that constitute environment, from the ultraviolet rays from sun to the toxic fumes from the cars. The two most widely studied subjects are ozone depletion and climate changes, which have substantial hidden impact on our health, poorly understood and appreciated so far.
The depletion of ozone in the upper atmosphere invariably increases ultraviolet radiation; the amount of melanin (and thus the color of our skin) determines the level of damage caused by UV radiation. Exposed extensively, the skin first becomes wrinkled and loses its elasticity, eventually becoming coarsely furrowed and lumpy as seen in the craggy faces of elderly peasants in hot countries. Finally, skin cancer ensues and about 2.3 million people every year come down with it, mainly due to exposure to UV radiation. Three types of cancers occur on the skin. The basal cell carcinoma gradually nibbles away at tissues but does not spread to other tissues and is readily cured by surgery; the squamous cell carcinoma may spread to local lymph nodes and requires radiotherapy; the malignant melanoma is most dangerous that appears in the cells that produce melanin (the color pigment) causing at first patching, changes in moles, and finally spreading throughout body.
The above connection of radiation and disease is well known but how UV radiation affects our immunity to disease is a new finding. With skin function compromised, many infecting organisms find their way readily into our body when damaged by UV radiation. Our eyes are also continuously absorbing UV radiation and this can bring malfunction to ocular pigment cells, which are required for sharpening our sight; melanoma of eye, blindness and death can ensue. The lens of the eye undergoes rapid fogging when exposed to UV radiation leading to early cataract. There are 3 million cases of cataract a year and a 10% increase in UV radiation will increase it by 1.7 million cases per year; the cost of treating cataract is huge, as it requires surgical intervention.
Besides humans, UV radiation also affects animals and plants. Phytoplanktons the lowest member of the food chain in marine life float on the surface and is significantly affected by UV radiation; how a change in the population of phytoplanktons can affect the entire marine life is a dread topic to discuss. Crops and livestock are also affected by UV radiation. The yields of Soya beans, peas and beans are decreased 25% when exposed to intensive UV radiation; this can upset global distribution of calories leading to world-wide malnutrition, which in turn would make this population more susceptible to the effects of UV radiation. A perfect Catch-22.
The global warming as a result of ozone depletion and green house effect is expected to raise the world temperature by 3.5 C by year 2100. We are likely to see more heat-waves, as much as 50-times more, causing widespread deaths. For example, if the carbon dioxide levels rise by 100% in Shanghai, the death toll from hot summers will increase from 420 to 3,600 per year. Other extremes of weathers such as storms, hurricanes and floods, could increase in both number and force. In Bangladesh, for example, hundreds of thousands lives were lost in cyclone in 1970 and over 21 million people were left homeless in the flooding that followed; the El Niño and El Niña effects are still fresh in our minds. A big tsunami is not too far, if things continued, at any shore, from Manhattan to Oman.
The financial losses of storms are well calculated but how they make significant changes in infectious disease profile of the world is not yet fully understood. Global warming leads to rising sea level. A rise of about half a meter would double the number of people flooded, to 92 million per year. Displacing people creates a dilemma, where would all these people go? Such migrations would lead to public hygiene problems as it is known how warm weather favors the vectors, or animal carriers, of several infectious diseases. Malaria and dengue fever are just two dread diseases on the rise. Tuberculosis is again a world epidemic. Schistosomiasis spread by small worms has already infected over 200 million people.
Lowered agricultural productivity from global warming would bring economic disasters in the agrarian communities; the projections are a fall in 10% of the productivity in areas of the world where biggest increases in the population are projected. Hunger and famine would not be too far. Water supply can be reduced and fresh water contaminated with seawater. Cholera bug often resides in phytoplanktons, whose population can increase in warm waters; spread of cholera from mixing of seawater is imminent.
As we enter the next millenium we are looking for a remarkable change in the health statistics of the world; unfortunately, it does not look very healthy. More significant is our lack of appreciation of the indirect effects of global warming, ozone depletion, and changes in weather patterns. No longer can we write off the traditional pharmaceutical products for gastrointestinal infection to protection of skin in favor of the new generation of genetically-derived, high tech pharmaceuticals. As old as the climate is, it is going to remain with us for a while and therefore the calamities it brings. It behooves us to reading of human history, how it enters disasters, calamities and mass migrations, before deciding on which line of pharmaceutical products to manufacture.