Understanding the Causes of Communicable Diseases Communicable diseases are caused bykinds of microorganisms. If you have ever “” an illness from someone before, you contracted a communicable disease.
Understanding the Causes of Communicable Diseases Communicable diseases, also known as contagious and infectious diseases, occur when pathogens enter your body. Communicable disease
Understanding the Causes of Communicable Diseases If your body does not fight off the invaders quickly and successfully, you develop an infection. Infection
Viruses Two of the most common communicable diseases—the cold and the flu—are caused by viruses. Virus
Viruses A virus invades living cells. The virus begins to multiply. The virus starts taking over other cells. Disease sets in. The body’s immune system jumps into action. Usually, the virus is killed by the immune system.
Bacteria Bacterialive almost everywhere on earth. Bacteria
Bacteria • Most bacteria are. Some are even helpful, like the ones that help youfood. • Unfortunately, some bacteria dodiseases.
Bacteria Disease-causing bacteria can produce toxins. Toxins
Bacteria • Antibioticswork against viruses. • A bacterial disease can often bewith antibiotics. However, some bacteriabecome resistant to antibiotics as they have evolved.
Other Pathogens Plantlike organisms that can cause diseases of the lungs, the mucous membranes, and the skin Fungi Single-celled microorganisms that are larger and more complex than bacteria Protozoa Microorganisms that enter the body through insect bites Rickettsias
How Diseases Spread Diseases can bein a variety of ways. Knowing how diseases are transmitted is your first line of defense against them.
How Diseases Spread • Direct Contact • Direct contact with an infected person • Biting • Puncture wound • Childbirth • Contact with infected animal
How Diseases Spread • Indirect Contact • Doorknob, phone, money, handrail • Organisms that carry & transmit pathogens (flies, mosquitoes, ticks) • Improper handled food or stored incorrectly • Water supply contaminated or not properly filtered
How Diseases Spread • Tiny droplets that can travel as far as 10 feet
Taking Precautions You can take steps toinfection. A few simple practices can dramatically reduce your risk of contracting communicable diseases.
Wash Your Hands When to Wash Your Hands Before and after inserting contact lenses or applying makeup After touching an object handled by an infected person
Protect Yourself from Vectors Protect Yourself from Vectors Limit the time you spend outdoors at dawn and dusk, when mosquitoes are most active. Wear pants and long-sleeved shirts to avoid insect bites. Use insect repellent, and avoid contact with dead birds.
Other Prevention Strategies Avoid sharing personal items, such as eating utensils. Avoid tobacco, alcohol, and other drugs. Cover your mouth when you cough or sneeze, and wash your hands after using a tissue.
Respiratory Infections Many diseases begin as respiratory infections. The respiratory tract connects the outside world to the inside of your body.
Respiratory Infections Many communicable diseases occur in the respiratory tract, the passageway that includes the nose, throat, and lungs. Respiratory tract
Common Cold • The common cold is a viral infection that causes inflammation of the mucous membrane. Mucous membrane
Influenza • Influenza, or the flu, is ainfection of the respiratory tract. • Symptoms include, fatigue,, muscle aches, and coughing.
Pneumonia • In severe cases, the flu can lead to pneumonia. Its symptoms are similar to those of the flu. Pneumonia
Pneumonia • Viral pneumonia istreated with antiviral drugs. • Bacterial pneumonia, if diagnosed early enough, can bewith antibiotics. • Can be when strikes older adults & people with lung or heart problems
Strep Throat • Strep throat is ainfection spread bycontact with an infected person or throughtransmission. • Symptoms include sore throat,, and enlarged lymph nodes in the neck.
Tuberculosis • Tuberculosis, or TB, is adisease that usually attacks the lungs • Spreads through the & typically affects people with weak immune systems • Symptoms include fatigue, coughing, fever, weight loss, and night sweats. • Is with antibiotics
Respiratory Infections Avoid close contact with sick people. If you’re ill, stay home. Avoiding Respiratory Infections Abstain from smoking. Wash your hands often. Avoid touching your mouth, eyes, and nose. Eat right and get physical activity.
Hepatitis There arecommon types of hepatitis. Hepatitis is ainfection that causes inflammation of the liver.
Hepatitis • Hepatitis Ausuallythe digestive system throughwith the feces of an infected person. • Common symptoms include, vomiting,, abdominal pain, and jaundice.
Hepatitis • Hepatitis Bcan bethrough sexualor contact with an infected person’s. • It has symptoms similar to those of hepatitis A, but it can cause failure and cirrhosis.
Hepatitis • Hepatitis Ccan is most often spread bycontact with needles that are contaminated withblood.
Hepatitis • Symptoms of Hepatitis C include • jaundice • dark urine • abdominal pain • It can lead to chronic liver disease, liver cancer, and liver failure.
Other Communicable Diseases Stay informed about communicable diseases. The more you know about these diseases and how they are transmitted, the better your chances of not getting them.
Other Communicable Diseases Disease Type Transmission Mononucleosis Measles Virus Direct or Indirect Contact Encephalitis Virus Meningitis Virus or Bacteria Direct or Indirect Contact Chicken Pox Direct or Indirect Contact
Physical and Chemical Barriers Physical and chemical barriers make up your body’s first line ofagainst pathogens. Your body has its own built-in barriers to handle invasion from microscopic pathogens.
Physical and Chemical Barriers • block pathogens from invading your body. • Skin, mucous membranes, & cilia • destroy those invaders • Tears, saliva, & gastric juice
Physical and Chemical Barriers and saliva contain enzymes that disable and evenpathogens.
Physical and Chemical Barriers Mucous membranes form a protective lining for your mouth, nose, and many other parts of your body. These membranespathogens and carry them to other parts of the body for disposal.
Physical and Chemical Barriers Skin is like a personal coat of armor,most pathogens in their tracks as they try to enter the body.
Physical and Chemical Barriers Cilia are small hairs that line parts of your respiratory system. Ciliamucus and pathogens to the throat, where they can be swallowed or coughed out.
Physical and Chemical Barriers Gastric juice in the stomachmany pathogens that enter your body through the nose or mouth.
The Immune System Your body’s immune system is your best ally in the fight against communicable diseases. Some pathogens can get past your body’s physical and chemical barriers.
The Immune System The immune system fights pathogens using two major strategies: the inflammatory response and specific defenses. Immune system
The Inflammatory Response When a splinter or a cut becomes becomes red and swollen, these are symptoms of the inflammatory response. Inflammatory response
The Inflammatory Response Blood vessels near the injury expand to allow more blood to flow to the area. 1 Fluid and cells from the bloodstream cause swelling and pain because of pressure on the nerve endings. 2 Phagocytes surround the pathogens and destroy them with special chemicals. 3 With the pathogens killed and tissue damage under control, the body begins to repair the tissue. 4
The Inflammatory Response Pus, a mass of dead phagocytes and damaged tissue, may build up at the site of inflammation as a response to bacteria. Phagocytes
Specific Defenses When the immune system recognizes a particular pathogen, itspecific defenses in an attempt to prevent this type of infection from occurring again.