Diseases may be caused by many factors. Some are artificial factors while others are environmentally connected. A few of the common diseases that are strongly linked to environmental conditions and exposures includes Asthma, autism, breast cancer, lung diseases, lupus, parkson’s disease and reproductive health. Pathogens such as bacteria, viruses, and parasites, which cause diseases in humans and animals, may depend partially or entirely for their existence on other physical, chemical, or biological factors. Many are strictly vector –dependent while others are not. Environmental factors can affect directly or indirectly, survival, persistence and ability to produce disease.
There are quite a number of environmental factors that causes health threats to human being. These factors may directly connect or indirectly connected. They most occur as a result of pollution. This entails air pollution, water pollution and sound pollutions
Many diseases that are environmentally hazard will be channeled to human being through water and air.
Environmental factors to which man is exposed to, that may cause adverse health effects are chemicals or factors like dioxins, endocrine disruptors, lead, molds, pesticides, ozone and electric and magnetic fields
Dioxins are a class of chemicals contaminants that are formed during combustion processes such as waste incineration, forest burning, and backyard trash burning, as well as during some industrial processes such as paper pulp bleaching and herbicide manufacturing. Dioxins are taken in to human body by eating food contaminated by these chemicals accumulation of dioxins in the fatty tissues for months or years cause the development of chloracne. Other studies show that levels of dioxins increase the risk of cancer, reproductive and developmental problems, and an increased risk of heart disease and diabetes.
Endocrine disruptors are those chemicals that may interfere with the body’s endocrine system and produce adverse developmental, reproductive, neurological, and immune effects in the body. These include a wide range of natural and man-made substances. Endocrine disruptors are found in many everyday products which may include plastic bottles, metal food cans, detergents, flame retardants, food, toys, cosmetics, Research show that endocrine disruptors may pose the greatest danger during prenatal and post natal development when organs and neural systems are forming.
Although electric and magnetic fields have played a major role in the developing of industrial countries in terms of power supply and electronic appliances, these invisible lines of forces poses great risk when exposed to man. In 1980s, studies indicated that there is a link between magnetic field strength and the risk of child leukemia. A recent research on rat suggested that heavy use of mobile phone will put people at risk for neuronal damage. The 1979 study found that people who live near large electrical wire had excess cancer. Too weak Elf’s- EMFs are thought to initiate cancer i.e. they are cancer promoters and thus these could conceivably play a biological role in carcinogenesis.
Elemental chemical substances may also pose a health hazard in the environment. Lead is a high toxic metal found in small amounts in the earth’s crust. It is widely used as in compound form in paints, ceramics, pipes, solder, batteries and cosmetics. Lead can also be found in contaminated soil, drinking water, lead crystals and lead –glazed pottery. An extreme exposure to lead can caused neurological disorders such as lack of muscular coordination convulsion and coma. Lower concentration of lead have associated with measurable changes in children mental development and behavior such as lowered performance on intelligence tests, hand- eye coordination and reaction time among others. At the chronic level, adults develop increased blood pressure, decreased fertility, muscle and joint pain and memory problems.
One of the major environmental factors that causes diseases is exposure to pathogenic microbes like bacteria, protozoa’s, fungi and molds. Molds as microscopic organisms play an important role in the decomposition of animal and plants matter. Disturbance of molds leads to the release of tiny cells (spore).the exposure to these spores produces nasal and sinus congestion, eye irritation and blurred vision, sore throat and chronic cough Exposing child of one year to molds might increase the risk of the child to asthma.
Ozone is compound that is produced when air pollutants from automobile emission and plant manufacturing operations interact with sunlight. It is said to be highly reactive form of oxygen which forms a protective layer in the upper atmosphere. It shields us from the sun’s ultraviolet rays. At ground level, ozone is harmful air pollutant and is primarily constituent of urban smog. Long exposure to high concentration of ozone may cause a significant reduction in the lung function, inflammation of the airways and respiration distress. Researchers at the university of Southern California have shown for first time that ozone may actually cause asthma.The finding indicates that high exposure to ozone through time spent outdoor in the contaminated air and increased breathing rate from physical activity might affect the development of asthma in the previous health children.
Scientist has developed new method of controlling pest and pest diseases. one of commonly used method is by the application of pesticide which are chemical substances for controlling, killing or even repelling certain form of plant and animal life ,are harmful to man’s life. Because of the widespread use of agricultural chemicals in food production, people are exposed to low levels of pesticides residues through their diet. It has been shown that farmer who use agricultural insecticides experience an increase in headache fatigue, dizziness and hand tremor.
Other key factor is temperature. Sunlight affect the persistence and spreading of pathogen.it is mostly associated with the growth of zooplanktons.temperature changes the humidity content in the atmosphere which plays a very important role in the occurrence of many diseases. It well understood that bacteria survive longer in less humid or dry areas.
Microbe like bacteria, viruses, and the other often require a substrate to attach themselves to before they can multiply.this attachment is either host specific or site specific. the attachment and the subsequence colonization of these pathogenic organisms is influenced by the surface characteristic of the various material, as well as the chemical and organic origin.Heukelekian and Heller showed that at low nutrient concentrations substrate played a pivotal role in pathogen multiplication and especially in aquatic environment.
There are many diseases common to tropical climate that are linked to water transmission.this is because if transmission does not involve vectors, then water or at least humid conditions can be involved in the transmission.For instance, vibrio cholera will proliferate rapidly to the level of infective dose if it is found in warm and humid region. Generally it is impossible to separate environmental factors from those of biological origin because of the interrelationships in nature that play a significant role the emergence of infectious diseases. Higher animals are very sensitive to temperature and humidity changes and terrestrial vertebrates are more likely to be affected by changes in environmental temperature and humidity as compared to these animals living in an aquatic environment. Higher temperature means more evaporation in aquatic environments, causing both increased concentration of nutrient and general change in ecology.
Diseases like malaria and eastern encephalitis which are transmitted via the mosquitoes depend on temperature and precipitation. Rodent –associated diseases are similarly correlated with climate. As an example, Hantavirus disease in U.S (1993) increased dramatically due to increase in deer mice
There has been a dilemmatic argument on some disease whether they are environmentally influenced such Parkinson’s disease in men. Researchers postulate that environmental exposures are often sufficient to lead to Parkinson’s disease risk in men. Demetrius, M.D says “for women genetic predisposition may be more important because they are less exposed to environmental risk factors linked to Parkinson’s disease in previous research.: Also, estrogens may protect women’s brains from the effect of these environmental factors,” It is also seen that some diseases are influenced by the kind of work that one does and the degree of exposure to the environment. Dr. Maraganore said “the cause of Parkinson’s disease differ between men and women,” “traditionally ‘ men have been out in the work force becoming exposed to environmental risk factors such as pesticide and industrial chemicals or suffering head injuries.
References
- Dobson A, Casper R. Biodiversity. Lancet, 1993, 342:1096-9.
- Fletcher M. Effect of proteins on bacterial attachment to polystyrene. Journal of genetic microbiology, 1976, 94:400-4.
- Huq A et al. Influence of water temperature, salinity and pH on survival and growth of toxigenic Vibrio cholerae O1 associated with live copepods in laboratory microcosms. Applied environmental microbiology, 1984, 48:420-4
- Wentzel, RP. A new Hantavirus infection in North America New England Journal of Medicine 330:1004-5.