Infectious Diseases: Prevention, Defense, and Treatment
Prevention of Infectious Diseases
To prevent the spread of infectious diseases, follow these guidelines:
- Do not drink water that may be contaminated.
- Store and handle food according to the instructions on their packaging.
- Heat and cook food thoroughly.
- Wash vegetables and fruits before consumption.
- Wash your hands after using the toilet and before eating or handling food.
- Use condoms during sexual intercourse.
Defense Against Infections
Defense Mechanisms
Nonspecific Mechanisms
These mechanisms protect against any infection:
- The Skin: Acts as a barrier to most microorganisms unless there is a wound.
- Mucous Membranes: These are epithelia lining body cavities in contact with the outside. They are lined with mucus and secretions that destroy microorganisms.
- Inflammation: The body’s response to microorganisms or any foreign particles that reach the interior. The affected area experiences redness, swelling, pain, and increased temperature.
Specific Mechanisms
These mechanisms target each specific microorganism:
They identify and recognize it as foreign, developing a specific defense strategy. These mechanisms constitute the immune system. The most important components of the immune system are lymphocytes. Lymphocytes can recognize microorganisms or anything foreign to our body. There are two types: B lymphocytes and T lymphocytes.
- B-lymphocytes and Antibodies: B lymphocytes produce antibodies, or immunoglobulins, that bind to antigens.
- T-lymphocytes: When a virus infects a cell, it releases proteins. T cells recognize these proteins and destroy the infected cells. Each lymphocyte recognizes a particular antigen and is activated upon recognition.
Immune System Disorders
Autoimmune Diseases
In autoimmune diseases, the immune system mistakenly recognizes the body’s own molecules as foreign. Examples include multiple sclerosis and some types of diabetes.
Allergies
Allergies occur when the immune system overreacts to antigens that it should not normally respond to, such as those found in pollen or dust mites.
Treatment of Infectious Diseases
Treatment for Bacterial Diseases
Bacterial diseases are treated with antibiotics. The first antibiotic discovered was penicillin.
Treatment for Protozoan and Fungal Diseases
Antiprotozoal and antifungal agents are used. They are not always as effective as antibiotics and can be toxic to humans.
Treatment for Viral Diseases
Viral infections are more difficult to treat because once the virus enters cells, it is difficult to target. The body must overcome the infection and eradicate the virus. Effective drugs, called antivirals, have been developed against some viruses.
Vaccines
Vaccines immunize people against various pathogenic microorganisms. They work by injecting the microorganism itself or parts of it. This stimulates the immune system to develop antibodies and memory cells, enabling a rapid response upon subsequent exposure to the same pathogen, thus preventing infection.
Vaccines are not available for all diseases due to:
- Social factors: More research is focused on diseases affecting people in developed countries.
- Scientific factors: Microorganisms have defensive strategies that make vaccine development complex.
Genetics and Vaccines
One type of vaccine being evaluated is the DNA vaccine. In this approach, DNA from the infectious agent is inserted into a plasmid, which is then injected into the individual. The plasmid carries a gene that encodes a protein, causing muscle cells to express an antigen. This triggers an immune response, leading to the production of antibodies and memory cells. The plasmid does not replicate in the vaccinated individual’s cells but only induces protein synthesis.