An infectious disease is a term that refers to certain diseases caused by micro-organisms. Virus, bacteria, and parasites can, for example, cause infectious diseases. Diseases and conditions continue changing, as humans change. The diseases spread from one country to the next as people move to new countries and new areas. The bird flu is a good example of how a disease spreads. The outbreaks experienced in the United States and other countries might never have happened, had it not been for a few travelers coming home with the virus from Asian countries. It was the same case scenario in the 1980s for the spread of the AIDS virus in the gay community: travel and high number of sex partners allowed the epidemic to reach the United States and Europe.
Climate changes play a key role in how diseases spread, as well as the type of diseases common in a specific area. When an area experiences a high level of rainfall, the rain leads to pools or standing water. That water attracts certain types of insects, including mosquitoes. Those insects carry multiple infectious diseases, such as the west Nile virus. All it takes is one bite from a mosquito to infect a person and that person can transfer that virus to dozens of other people. High rainfall can also lead to other diseases, including Hantavirus pulmonary syndrome and rift valley fever.
Every single thing that happens to the environment causes changes to the common diseases in the surrounding area. Reforestation occurs when areas begin planting new trees and replacing open areas with wooded spaces. The abundance of trees and vegetation causes outbreaks of Lyme disease because the ticks living in the vegetation carry the disease. As the climate of an area changes, the climate causes changes to the environment. Even something as simple as climate changes caused by the urbanization of an area can cause an outbreak of infectious diseases.
Urban areas are only capable of handling a set number of people. The utility lines in that city carry water and electric to residents. When too many people live in that city, the city does not have enough water or electric for those residents. The utility lines quickly become overloaded, which leads to standing water and keeps the hospitals from getting the right amount of electric. Cholera and dengue are two infectious diseases caused by urbanization. As climate changes continue occurring, it is evident that diseases will change as well. Humans might suffer from conditions as simple as asthma or allergies, but the spread of serious conditions will also increase.
