Communicable Disease

Preventing the Spread of Disease Disease is an illness that affects the proper functioning of the mind or body. A communicable disease is one that can be passed from one person to another. A non communicable disease is one that can’t be passed.

Causes of Communicable Diseases Pathogens are tiny organisms that cause disease. An infection is a condition that occurs when pathogens enter the body, multiply, and damage cells. Bacteria are tiny one celled organisms that live nearly everywhere.

Bacterial Diseases Strep Tooth decay Boils Pneumonia Impetigo Many bacterial diseases can be treated with antibiotics. Viral infections can’t. They are now treated with prescribed medication.

Viral Disease A virus is the smallest disease-causing organism. Examples: Cold Flu Hepatitis Measles Mumps Chicken pox

Other types of Pathogens Fungi are primitive life-forms that feed of organic materials. Example- Ringworm Protozoa are single-celled organisms that are usually harmless but that can cause certain diseases. Example-Malaria Rickettsias- disease causing organisms that resemble bacteria but multiply like viruses. Example- Rocky Mountain Spotted Fever

How are Pathogens Spread? Direct contact-body fluids, kissing Indirect contact-sharing drinking glasses Contact with a Vector (an insect) Other contacts- food, water, undercooked meat.

Preventing the spread of disease Good personal hygiene If sick determine the contagious period.

The Body’s Defenses Against Infection First line of Defense-stop the entry.  Eyes, skin, stomach, mucous membranes and saliva. The immune system is a combination of body defenses made up of cells, tissues, and organs that fight off pathogens and disease. Immunity is your bodies ability to fight off disease.

The Lymphatic System A secondary circulatory system that helps the body fight pathogens and maintains a fluid balance. White blood cells are called lymphocytes. B cells produced in the bone marrow, they help develop immunity to pathogens. T cells are produced in the thymus gland, they attack invading pathogens. Immunity is present at birth. Vaccinations-figure 17.3, pg. 453

The Lymphatic System

Review 1. What are 4 risk factors associated with communicable disease? 2. How can you protect yourself from disease? 3. How does the immune system fight disease? 4. Read pages