It was in April 2009 that swine flu first raised its ugly head in the developed countries where timely and efficient medical care facilities helped to control the diseases. As the developing world, with limited resource and poor health condition, came under the grip of H1N1influenza virus, alarm bells began to ring. In no time, the disease assumed pandemic proportions as it rapidly spread to all parts of the world, killing more than 4000 people worldwide in a span of just six month.
The reasons for the emergence of new infectious disease is not far to seek. Habitat destruction is one. It includes conversion of forest land to agriculture, urban sprawl, infrastructure development and other changes to the characteristics of the ecosystem, construction of houses in rural areas forces animals to live in crowed population, giving opportunities to microbe to mutate and emerge as new pathogens.
Population increase will be most dramatic in the poorest and least urbanized continents, Asia and Africa. Surveys indicate that all urban growth over the next 25 years will be in developing countries. One billion people, one- sixth of the worlds population, or one third of urban population, now live in slums, which are seen as breeding grounds for problems such as malnutrition, non-availability of portable water , pollution and poor sanitation-all of which contribute to high incidence and play crucial role in their spread.
Another important but neglected reason, as far as zoonosis concerned, is global warming. Climate warming allows microorganisms to move into new areas where they may harm diverse species. Pathogens that have been restricted by seasonal temperatures can invade new areas and find new victims as the climate warms and winter grow milder. Even one to two degree change in temperature can lead to disease outbreaks. Warming temperature allows insects and microbes to invade areas where they once were barred by severe seasonal chills. Many pathogens multiply more often in warmer temperatures.
The reasons for the emergence of new infectious disease is not far to seek. Habitat destruction is one. It includes conversion of forest land to agriculture, urban sprawl, infrastructure development and other changes to the characteristics of the ecosystem, construction of houses in rural areas forces animals to live in crowed population, giving opportunities to microbe to mutate and emerge as new pathogens.
Population increase will be most dramatic in the poorest and least urbanized continents, Asia and Africa. Surveys indicate that all urban growth over the next 25 years will be in developing countries. One billion people, one- sixth of the worlds population, or one third of urban population, now live in slums, which are seen as breeding grounds for problems such as malnutrition, non-availability of portable water , pollution and poor sanitation-all of which contribute to high incidence and play crucial role in their spread.
Another important but neglected reason, as far as zoonosis concerned, is global warming. Climate warming allows microorganisms to move into new areas where they may harm diverse species. Pathogens that have been restricted by seasonal temperatures can invade new areas and find new victims as the climate warms and winter grow milder. Even one to two degree change in temperature can lead to disease outbreaks. Warming temperature allows insects and microbes to invade areas where they once were barred by severe seasonal chills. Many pathogens multiply more often in warmer temperatures.
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