Every once in a while, you may hear of an unfamiliar disease affecting people on epidemic proportions around the world. The main diseases affecting people have changed over the years for many reasons. Many previously incurable diseases can now be treated, while vaccinations, immunizations, and lifestyle changes prevent the contraction and development of many others. New diseases do spring up, however, and there are several ways this might happen.
Types of Diseases
There are four main causes and types of diseases. Infectious diseases are those caused by pathogens such as bacteria, viruses, and other parasites. Deficiency diseases are causes when the body lacks vital nutrients or element, and an example is iodine deficiency, which causes goiter. The third type of disease is a hereditary disease. These can be genetic as well as non-genetic hereditary diseases. The fourth type of disease is a physiological disease, which happens when an organ in the body malfunctions, as is the case in asthma and diabetes.
New variants of diseases or disorders can form in these different classes of disease through many different methods. Pathogens, genetics, lifestyle choices, other internal and external agents, harmful chemicals, and other unknown methods can bring about some of these diseases.
New Disease Formation
As far as infectious diseases are concerned, their roots can be traced to the pathogens that cause them. Very often, unfamiliar diseases that emerge and cause outbreaks, epidemics, and pandemics are not entirely new. The disease organisms such as bacteria and viruses might have gone underground only to re-emerge many, many years later. For diseases that have been completely eradicated such as polio, such success hangs on there being no more strains of the polio virus anywhere. Even within an individual, a disease can be dormant for years, only for it to reemerge after some time.
Another source of diseases is through animal to human contact. Animals experience some unique strains and variations of infectious diseases, and these can end of infecting human beings. Although these diseases are not new in the truest sense, they are new to humans, and this is a cause for concern. Examples of diseases that can be spread from animals to people include intestinal illnesses, cat scratch disease, and valley fever.
DNA structure and genetics also play a significant role in the causes of disease. This can be through human genetics or the genetics of the pathogen itself. On the human end, DNA changes can happen. These are called mutations and cause many different diseases and conditions, including cancer. Mutations in human DNA can be caused by exposure to radioactive substances, environmental factors such as sunlight, and random errors as DNA replicates itself within the cells. Mutation is random, hard to control, and impossible to predict, and as a result, it is the cause of many, many unique conditions and diseases.
As far as the mutation of pathogens such as bacteria and viruses, this also happens due to environmental factors. Natural selection also plays a part. Bacteria replicate themselves at an alarming rate. Random mutations and changes in the DNA structure can easily be continued, resulting in new strains. This is one of the causes of drug resistance.
Some viruses are well-known for mutating at an incredible rate. This is the case for the HIV virus, and this makes it difficult to create a cure because the structure of the virus changes and transforms regularly.
These are just some of the way that new or partially new diseases can form or emerge. Other factors, such as toxic chemicals and unbalanced diets can cause organ malfunctions and new deficiencies, respectively. Thanks to modern medicine and research, the understanding of disease causes is better understood.