Infectious Diseases © Lisa Michalek. Pathogens Disease causing agents that have the ability to make...
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Transcript of Infectious Diseases © Lisa Michalek. Pathogens Disease causing agents that have the ability to make...
Pathogens
• Disease causing agents that have the ability to make you sick or even cause death
• They are found in the air and food and on nearly every object or person who you come in contact with
Uncontrollable Risk Factors
• Heredity– Chromosomal traits and family history
• Aging– Vulnerability increases with age
• Environmental Conditions– Unsanitary conditions, drugs, chemicals, and
pollutants
• Organism Resistance– Some pathogens are resistant to our body’s
defenses and/or medical treatments
Controllable Risk Factors
• Stress
• Nutrition
• Physical fitness level
• Sleep
• Drug use
• Hygiene
• High-risk behaviors
Routes of Pathogen Transmission• Direct Contact
– Touching, kissing, sexual relations
• Indirect Contact– Touching an object that an infected person
has had contact with
• Airborne Contact– Breathing in air that carries
a pathogen
• Food-borne infection– Eating something that is
contaminated by microorganisms
Routes of Pathogen Transmission
• Animal-borne pathogens– Animals can spread diseases through bites, feces, or
by carrying infected insects into living areas
• Water-borne diseases– Transmitted from drinking water, from foods washed or
sprayed with contaminated water, or from wading or swimming in contaminated streams, lakes or reservoirs
• Perinatally– Mothers can transmit diseases to an infant in the womb
or as the baby passes through the vagina during birth
Bacteria• Single-celled organisms • There are several thousands of species, but
only about 100 cause diseases in humans• Most of the time it is not the bacteria that is
causing the diseases, but it is the toxins that are produced by the bacteria
• They can be seen under a standard microscope
Bacterial Diseases• Staphylococcal Infections
– These bacteria are normally on our skin at all times and usually do not cause problems
– When a cut or break in the skin occurs, the bacteria may enter and cause an infection
– Acne, boils, styes (eyelid infections), wounds are common staph infections
Bacterial Diseases• Streptococcal
Infections– Causes strep throat
and scarlet fever
• Pneumonia– One form is caused by a
bacterial infection with the following symptoms: chronic cough, chest pain, chills, high fever, fluid accumulation and eventual respiratory failure
Bacterial Diseases• Legionnaire’s Disease
– A water-borne disease with symptoms similar to those of pneumonia
• Tuberculosis (TB)– An airborne disease where
bacteria infiltrate the lungs and cause a chronic inflammatory reaction
– Symptoms include coughing, weight loss, fever and spitting up blood
Viruses• Minute (very tiny) parasitic microbes that live
inside another cell• Over 150 viruses are known to cause diseases
in humans• Viral diseases
are hard to treat because many can withstand heat, chemicals and large doses of radiation with little effect on their structure
Viral Diseases• The Common Cold
– There may be over 200 different viruses responsible
– Carried into the nose and throat most of the time
– Stress, allergies, and menstrual cycles appear to increase susceptibility
Viral Diseases• Influenza (flu)
– Symptoms include aches and pains, nausea, diarrhea, fever, and cold like ailments
– In healthy people, it is usually not serious– However, when
combined with other disorders, among the elderly, those with respiratory or heart disease, children under 5 the flu can be very serious
Viral Diseases• Mononucleosis (mono or the kissing disease)
– Symptoms include sore throat, fever, headache, nausea, chills, weakness or tiredness, lymph nodes may swell, jaundice (yellow skin), spleen enlargement, aching joints, and body rashes may occur
– May be transmitted through body fluids but does not appear to be easily contracted through normal, everyday contact
Viral Diseases
• Hepatitis– Causes inflammation of the liver – Symptoms include fever, headache, nausea,
loss of appetite, skin rashes, pain in the upper right abdomen, dark yellow urine, and jaundice
Viral Diseases– Hepatitis A (HAV)
• Contracted from eating food or drinking water contaminated with human feces
– Hepatitis B (HBV)• Spread through body fluids, usually during unprotected
sex• Can lead to liver disease or liver cancer
– Hepatitis C (HBC)• Some cases can be traced from people who share
needles, blood transfusions or organ transplants• Usually causes chronic infections and if not treated
may cause cirrhosis of the liver, liver cancer, or liver failure
Viral Diseases• Measles
– Symptoms appear about 10 days after exposure and include an itchy rash and a high fever and may lead to other problems such as rheumatic heart disease, kidney damage and neurological disorders
Other Pathogens• Fungi
– Multicellular or unicellular primitive plants that inhabit our environment
– Many are useful providing food such as mushrooms and cheeses
– Some produce infections• Candidiasis (vaginal)• Athlete’s foot• Ringworm• Jock itch
Other Pathogens• Protozoa
– Microscopic, single-celled organisms that can cause disease• Trichomoniasis
– transmitted sexually
• Giardiasis– found in water
• Malaria– Via mosquitoes
Other Pathogens• Parasitic Worms
– Usually associated with eating raw fish– Cooking fish and other foods to high
temperatures will kill the worms and their eggs to prevent infestation
• Pinworms• Tapeworms
The Immune System• Protects the body from potentially harmful
substances• Any substance
that is capable oftriggering an immune responseis an antigen
• When invadedby an antigen, the body forms antibodies to destroy or weaken the antigen