Transcript Infectious Diseases

Infectious Diseases
© Lisa Michalek
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
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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
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Candidiasis (vaginal)
Athlete’s foot
Ringworm
Jock itch
Other Pathogens
• Protozoa
– Microscopic, singlecelled 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 of
triggering an
immune response
is an antigen
• When invaded
by an antigen,
the body forms
antibodies to destroy or weaken the antigen
Vaccines
• A vaccination consists of an injection of a dead
or weakened form of a disease-causing
microorganism.
• This organism can no longer cause the disease,
but can still stimulate
antibody production
by white blood cells.
• This type of immunity
lasts a long time.