Disease Pathogens

Infectious (Communicable) Disease Any disease caused by several types of small, microscopic organisms (pathogens) that enter and multiply within the human body and can be passed from person to person or animal/insect to person, or through the environment.

Bacteria A single-celled microorganism that lives almost everywhere on earth. Most are harmless and many are essential for life. Examples include: Lactobacilli Coliform Bacilli Both are found in the intestine.

Bacteria Some bacteria produce a toxin (a substance that kills cells or interferes with cell function) In healthy individuals, these bacteria are usually destroyed by the immune system. If a person’s immune system is weakened or overwhelmed, disease occurs.

Bacteria Under perfect conditions (right temperature and sufficient nourishment), bacteria can multiply by cell division. Cell division can occur every 20 minutes and after 15 ½ hours a single bacterium can have multiplied into more than 4 billion bacteria.

Bacteria Most bacterial diseases can be treated with antibiotics, but some bacteria have become resistant to the medicines that we currently have to kill them. Examples: Tuberculosis Gonorrhea MRSA

Viruses Pieces of genetic material surrounded by a protein coat. They are the smallest known type of infectious agent (one half to one hundredth the size of the smallest bacterium. They invade all known forms of life.

Viruses By themselves they are inactive (not living) and are dependent on living cells for survival and reproduction. After a virus penetrates a cell (host cell), the viruses take control of the cell to manufacture more viruses. The new viruses burst from the cell, killing it, and take over other cells.

Viruses Viruses usually run their course and are eventually killed by the immune system. Antibiotics are not effective in destroying viruses, but can sometimes treat some symptoms of a virus.

Viruses Examples include: Viral meningitis Herpes The Common Cold Influenza Viral pneumonia Viral hepatitis Polio Mononucleosis Measles HIV/AIDS Chicken Pox Viral meningitis Herpes Rabies Smallpox West Nile Virus

Rickettsias Organisms that resemble small bacteria, but like viruses are able to multiply only by invading the cells of living organisms. They are found in the intestinal tract of insects and small rodents and are passed to humans through bites or through feces deposited on the skin.

Rickettsias Examples include: Typhus Rocky Mountain Spotted Fever Hunta Virus

Protozoan's Single-celled organisms which are larger and more complex than bacteria. Most are harmless, but some can cause disease in people with a weakened immune systems.

Protozoan's Examples include: Malaria Amoebic dysentery Sleeping sickness

Fungi Simple plant-like organisms (mold & yeasts) that cannot make their own food and feed off dead animals, insects, and leaves. They prefer dark, damp environments and usually invade the deep layers of hair, nails and skin, or the mucous membranes of the lungs.

Fungi Examples include Ringworm Vaginal yeast infections Athlete’s foot “jock itch” Vaginal yeast infections

Disease Transmission Transmission can occur through direct or indirect contact and through breathing contaminated air. Some diseases can be spread in more than one way. If you know how a disease is spread, you can take precautions and avoid infection.

Disease Transmission Direct Contact Includes touching, biting (animal or human), kissing, and sexual contact. Pregnant women can transmit an infection to her unborn child through the placenta. Animal bites and scratches can also transmit disease.

Disease Transmission Indirect Contact Contaminated Objects Objects can become contaminated with infectious discharges or secretions and can be transmitted if you come into contact with the contaminated object and then touch your nose or mouth. Frequent hand washing and disinfecting objects can prevent transmission.

Disease Transmission Indirect Contact Vectors Organisms that carry and transmit pathogens to humans and other animals. Examples include dogs, cats and other animals, or insects such as the mosquito, tick or flea

Disease Transmission Indirect Contact 3. Water and Food Careless handling and storage of food are major sources of contamination and illness. Water supplies can also be contaminated with human or animal feces and cause illness.

Disease Transmission Airborne Transmission Sneezing & coughing can spray infectious droplets of saliva or mucus into a nearby person’s eyes, nose or mouth. Even when the droplets evaporate, the pathogens may float on dust particles for a long time and travel long distances. You don’t have to be close to an infected person to inhale the pathogen.

Health & Wellness IQ

All bacteria cause disease.

All bacteria cause disease All bacteria cause disease. False Most bacteria are actually helpful to the body. Few of them cause disease.

Food and water can transmit infectious disease.

Food and water can transmit infectious disease. True

Viruses are just very small bacteria.

Viruses are just very small bacteria Viruses are just very small bacteria. False Bacteria are single-celled organisms that can reproduce, metabolize, and use energy. Viruses are much smaller and simpler than bacteria. They corrupt existing cells.

Fungi normally do not cause disease.

Fungi normally do not cause disease. True

You can’t get an infectious disease just by touching someone or something.

You can’t get an infectious disease just by touching someone or something. It Depends The bacteria and viruses that cause infectious diseases can be transmitted just by touching someone or something, however, the body has lines of defense against infectious agents. If your body successfully defends against these agents, you will not contract the infectious disease.

Toxins releases by bacteria can kill cells or interfere with their function.

Toxins releases by bacteria can kill cells or interfere with their function. True

Antibiotics can cure an infectious disease caused by a virus.

Antibiotics can cure an infectious disease caused by a virus Antibiotics can cure an infectious disease caused by a virus. False Antibiotics are effective in curing bacterial infections; however, they cannot treat viral infections

Vectors are organisms that carry and transmit pathogens.

Vectors are organisms that carry and transmit pathogens. True

Most protozoans are harmless.

Most protozoans are harmless. True

Rickettsias are found in the intestinal tract of insects and small rodents.

Rickettsias are found in the intestinal tract of insects and small rodents. True