Environmental Health: Infectious Diseases and Pollution
Infectious Diseases
Infectious diseases are those caused by pathogenic microorganisms, such as bacteria, viruses, protozoa, and fungi. Most organisms in nature are harmless to us, but those that can cause disease are called pathogens.
Air Pollution
Human activities, such as industry, heating, and traffic, can modify the composition of the air, adding compounds (gases and particles) that affect health.
Common Air Pollutants:
- Carbon Monoxide: Toxic to humans, affecting oxygen transport in the blood.
- Sulfur Dioxide: Causes difficulty breathing, throat irritation, and coughing. High levels can be deadly.
- Oxides of Nitrogen: Affect the lungs and are toxic.
- Particulate Matter: Solid (smoke) or liquid (aerosols) particles that cause respiratory diseases.
Water Pollution
Water pollutants can be organic, inorganic, or biological, all of which are harmful to health.
Types of Water Pollutants:
- Organic: Sewage, livestock waste, pesticides, grease, and plastics. Promote microorganism proliferation and are toxic.
- Inorganic: Nitrates and phosphate fertilizers, acids, salts, and toxic metals. Favor algae and microorganism growth and are toxic.
- Biological: Microorganisms that cause diseases.
Food Contamination
Food can become contaminated with substances that can have negative health effects, even in small quantities.
Common Food Contaminants:
- Pesticide residues
- Heavy metals
- Antibiotics and hormones in meat
- Food additives in excess or not allowed
Transmission of Infectious Diseases
For an infectious disease to occur, the pathogen must enter the body.
Transmission Routes:
- Direct Contact: Skin-to-skin contact, sneezing, sexual contact
- Water: Contaminated water sources
- Food: Contaminated fruits, vegetables, meat, or eggs
- Animals: Vectors such as mosquitoes
Normal Flora
Our bodies contain large numbers of bacteria, known as normal flora, which reside on the skin and lining the digestive, respiratory, and vaginal tracts.
These bacteria are not pathogenic and provide benefits, such as producing vitamins. They also prevent the establishment of pathogenic microorganisms. However, under certain conditions, normal flora organisms can proliferate and cause disease, becoming opportunistic pathogens.