Global warming and emerging infectious diseases of animals and humans: current scenario, challenges, solutions and future perspectives – A Review

Since the origin of earth temperature has played a significant role in the beginning of life on this planet. Continuous increase in the temperature of the earth is referred to as global warming that may have long term effect. Increased use of fossil fuels; use of natural gas and coal; population explosion; industrial wastes and agricultural fertilizers along with anthropogenic activities contribute to global warming. Increased level of Carbon dioxide (CO2) also has a negative impact on the marine ecosystem. The outcomes of global warming include rise in sea levels and expansion of tropical and sub-tropical deserts. Importantly, the risk of contracting diseases both in human and animals increases. Increase in global temperature primarily by human activities, especially the burning of fossil fuels, has lead to the emergence of threat of diseases in human and animals particularly those of vector borne diseases like Blue tongue, West Nile, Japanese encephalitis, Dengue, Hanta virus etc. Species extinctions due to change in habitats and transport of livestock facilitates movements of viruses and arthropods (especially ticks) from one place to another. Variation of temperature and humidity have lead to increased growth of bushy plants, thereby increasing rodent population thus causing an increased risk of contracting various rodent borne infections (viz. Leptospirosis; Plague etc.). El Niño Southern Oscillation (ENSO) signal on vector-borne diseases due to changes in temperature have direct effects (in form of flood, famine, drought and extreme weather conditions of heat and cold) and indirect effects (in terms of changes in transmission and outbreaks of infectious diseases, especially of the diseases transmitted by vectors and vehicles) on human health. To mitigate the effect of global climatic change on infectious disease incidences and geographic spread, combined efforts consisting of mitigation to reduce further emissions of greenhouse gas; adaptation of intervention measures to reduce the damage caused by warming and geo-engineering (recycling) to reverse global warming must be properly implemented. In addition, vector control, improved reporting of animal diseases affected by climate change, strengthening of surveillance and disease investigation capacities in human and animal population, association and coordination of Medical and Veterinary institutions with various non-governmental organizations (NGOs) as well as international professional bodies and animal welfare organizations are all crucial to prevent and control emerging infectious diseases linked to global warming. Researchers, scientists, professional, environmentalist, administration, government and persons must work together to overcome this threat. The present paper describes the problem of global warming in general, its causes and multi-dimensional impacts, effect on animal productivity, interaction between climate change, pathogen and vectors, and presents a special focus on important emerging pathogens / infectious diseases of animals and humans being flaring up due to fluctuating environmental conditions, appropriate prevention and control measures to be followed to combat global warming in the current scenario and future perspectives.