Relationships Between Environmental Degradation and the Rise of New Human Diseases

From Science Online

1 Rising Issue
2 Human Impact on the Environment
3 Geographical Areas
4 Emerging Threats from the Rise of Disease and Impacts on Humans
5 Solutions

Rising Issue

Environmental degradation has shown an increasing relationship with the rise and spread of human diseases. Genes evolved and became more susceptible to disease to the evironmental impacts.(Rienzo, 2005) The World Health Organization believes that almost one third of global disease can be directly related to environmental risk factors. (United Nations)Antibodies and immune stystems have developed in part as a result of environmental change. As stated in a PNAS article "Environmental change plays a large role in the emergence of infectious disease". (Eisenberg, 2006) In particular, as the human population continues to grow, the population density increases, which leads to an abundance of parasites and infection-forming conditions. (Daily, 1996) Extreme temperatures, climate-related disturbances, and air and water pollution have a direct influence on the spread of infection and disease. (United States Environmental Protection Agency)

Los Angeles is a prime example of smog, a dangerous form of air pollution that greatly effects health

(Wikipedia)Environmental exposures to chemicals and toxins are a major contributor to disease. (National Human Genome Research Insitute)

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Human Impact on the Environment

Deforestation, argicultural uses of land, climate change caused by increased carbon dioxide emmisions, and pollution have lead to create unsafe and unhygienic conditions that increase disease spread. Deforestation forces changes in watershed and local climate, which affects the transission of enteric pathogens.

An example of deforestation in southern Mexico

(Wikipedia) Improper hygiene and sanitation also increases the chance for disease carrying pathogens to be transmitted. (Eisenberg, 2006) Improper diet and exercise may also lead to the problem, as well as loss of biodiversity. By eliminating predators and habitats, disease-carrying organisms, such as rodents,cockroaches, and mosquitoes, are allowed to flourish.(Cunningham, 2001) This leads to a problem Daily and Ehrlich describe as a lack of control over disease reservoirs and vectors, such as rodents and mosquitos. As human populations move and settle, it allows the observation of the relationship between environmental change and disease to become much more apparent. A study in Ecuador showed that remoteness to the road played a large part in the prevalance of infection rates among the community. Thus, migration, creation of new communities, and increased density also affects pathogen and disease transmission. (Eisenberg, 2006)However, climate change seems to have had the biggest impact overall. It has altered the distribution of pathogens, changed predator-prey interactions, and upped the probability of disease transmission. For example, temperate zones are now showing cases of tropical diseases, such as malaria. (Daily, 1996) High levels of toxic chemicals and depletion of natural resources also contribute to the environmental problems, particularly from lead. Leaded gasoline is the major source of this problem, and causes serious and permanent disorders in children. (United Nations)

(National Human Genome Research Insitute) Nutrients and pesticides used in agriculture may run off into surrounding water and form toxic algae in lakes and oceans, leading to another source of disease transmission. (Cunningham, 2001)

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Geographical Areas

This is a worldwide problem, but is especially prevelant in areas of Africa and Asia. Cases have been reseached in the Soviet Union, Brazil, Guyana, Honduras, the Nile River, Argentina, China, Rwanda, the United States (Daily, 1996) Western and Southern Europe, (Goldstein, 2002) and many others. Cases are more obvious in areas where human activity has changed the surrounding environment, such as construction of roads, dams, and pipelines. Nevertheless, the environmental effects remain widespread and cause problems in calculating correlations between environment and disease. (Eisenberg, 2006)

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Emerging Threats from the Rise of Disease and Impacts on Humans

As we face the growing threat of climate change and increasing pollution, the chances of increasing susceptibilty to human disease greatly increase. According to a UN press release, 5,500 children die from diseases caused by polluted water and food. (United Nations) Smog, a ground-level ozone, also is linked to the abundance of respiratory disorders, by damaging lung tissue. Particulate matter, or PM, is a mixture of small particles and liquid droplets in the air, which can reach deep down into lungs and have detrimental health effects. (United States Environmental Protection Agency)Scientists are particularly growing worried over effects to the immune system. Many of the human populations affected by environmentally caused disease live in conditions of malnourishment. Therefore, the immune system already contains a weakness, and is far more susceptible. (Daily, 1996) Climate change has increased conditions in ways that allow diseases such as malaria and yellow fever to thrive in the warmer temperatures. Climate change also effects the immune system through agricultral production, and through extreme weather occurances, human health may be greatly damaged, through death, injury, disease, and stress-related disorders. Higher temperatures and prolonged rainfall increase the ideal setting for disease transmission. Also, as biodiversity is loss, the opprutunity for more pharmaceutical discovery are lost forever. (United States Environmental Protection Agency)(Daily, 1996) Further research has tied environmental stresses to the occurance of some types of cancer, as the Hsps monitered for cancer prediction and outcome are involved in radiation and toxins. (Wu, 2006) There are many Current Events in which trends may be observed. These diseases, particularly those such as cholera and maleria, cause serious illnesses, and in many cases, death. While medicines and pesticides have been developed, enivornmental change alters the patterns of the disease and disease resistance, thus allowing the pathogens to continue to flourish. (Cunningham, 2001)

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Solutions

Improvements must be made in environmental protection. Education is a key process in bettering the conditions. The National Institutes of Health have set up a Genes and Environment Initiative program to develop better methods to protect against the rising problem. (National Human Genome Research Insitute) Monitoring of climatic changes help to anticipate outbreaks, as well as changing habits, such as drainage of swamps, screening of houses, and improvements in sanitation and nutrition. Improvement of water supplies and sanitation, education of the medical community and general public, support of vaccination research, and coordinated restrictions of the use of antibiotics and pesticides. (Daily, 1996) A new study of gene-environment interactions has been developed and is called toxicogenomics. Hopefully, this will help lead to the discovery of mechanisms belonging to certain diseases, which will allow for better test stystems able to detect human risk. (Olden, 2004) Processed food, material goods, medicines, and increased access to health care and facilities will also help lessen the transmission of pathogens. (Eisenberg, 2006) Currently, the U.S. EPA and other government agencies are leading an assesment titled "The Climate Change Science Program Synthesis and Assessment Product 4.6", which is examining the effects of climate change on human health in the United States, and what information is needed to assess these risks. This program will hopefully further the education of the public to the rising environmental issue and alert them of precautions that could be made. (United States Environmental Protection Agency) The National Institues of Health are sponsoring a "Genes and Environment Initiative" to help develop improved methods for the measurement of environmental exposures and other impacts on health. (National Human Genome Research Insitute)