Transcript Infectious Diseases - bloodhounds Incorporated

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Infectious Diseases
Sexually Transmitted Infection
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What is a Disease?
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Disease = Any interference with the normal functioning of
the body organs or systems
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Human Disease may be caused by
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Environmental factors
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Defects of body structures or functions
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Activities of infectious microorganisms
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Signs, Symptoms and Syndromes
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Signs
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A more or less observable and obvious feature of a disease
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Includes things like diarrhia, a rash, peeling of the skin
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Painless lesion of syphilis called a chancre
Symptom
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Any change in a body structure of function that can be observed
or felt by the individual
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Asymptomatic
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Signs, Symptoms and Syndromes
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Syndrome
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Etiology
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A combination of signs and symptoms occurring in a typical
pattern
The cause, set of causes, or manner of causation of a disease or
condition
Sequelae
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Some diseases leave aftereffects
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Viral infections of the liver can result in the loss of functioning
liver cells and interference with bloodflow through the organ
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Signs, Symptoms and Syndromes
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The outcome of a disease depends on
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Genetics
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Age
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Nutritional status
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Prior exposure to the infectious agent
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Resulting levels of body protection or immunity
Prognosis
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Predict the course and outcome of a disease
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Types of Diseases
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Diseases can be placed in descriptive groups:
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Hereditary and congenital
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Degenerative
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Neoplastic
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Metabolic
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Immunological
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infectious
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Hereditary and Congenital
Diseases
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Hereditary Diseases
 Caused by errors in the
information present in an
abnormal gene or genes
 May be abnormalities in
 The number and
distribution of
chromosomes
 Interaction of genetic and
environmental factors
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Down’s Syndrome
 Abnormal distribution of
chromosomes
 Trisomy 21
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Hereditary and Congenital
Diseases
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Abnormalities that develop between the time of fertilization
(conception) and birth are divided into two categories
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Embryonic Period
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First eight weeks of pregnancy
Fetal Period
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From the ninth week of pregnancy to birth
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Embryonic Period
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Changes occurring produce visible deformities of organs or
other body structures
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Embryonic or congenital defects
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Are present at birth
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Drugs, excessive X-ray exposure, or certain infections may
disrupt the developing embryo or fetus
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The embryo is most vulnerable to injury during the 3rd to 8th
week of pregnancy
Infections acquired by the mother may injure the developing
fetus and cause congenital defects
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Mental retardation, blindness, brain injury, even death
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German measles (rubella), Syphilis, Genital Herpes
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Degenerative Diseases
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The breakdown of various body parts
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Aging
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Chronic (long lasting) illnesses that can lead to death
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Heart attack
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Stroke (bleeding and/or blockages in blood vessels of the
brain)
Could occur even without aging
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Hardening of the arteries
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Certain forms of arthritis
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Degenerating joints
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Diverticulitis
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Neoplastic Diseases
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Diseases associated with abnormal cell growth that leads to
the formation of various types of tumors
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Benign (harmless)
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Malignant (cancerous)
One in five persons die in the United States of some form of
cancer
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Human papilloma viruses cause genital warts
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Has been associated with cervical cancer
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Metabolic Diseases
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These diseases include a variety of disorders in which the
body’s production of chemical products essential to its
functioning either are nonexistent or defective
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Hormones
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A chemical product body a body organ or gland, which is
carried by the blood to another body site where it stimulates a
particular function
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Endocrine
Enzymes
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A complex proteins produced by cells, that causes changes in
other substances without being changed in the process
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Immunologic Diseases
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Diseases that result from the improper or impaired
functioning of the body’s immune system
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The immune system provides protection against various disease
agents and other factors in an individual’s environment
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The immune system can destroy or neutralize disease agents
and factors considered to be foreign by the immune system
Inflammation
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A response to tissue injury
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Swelling, redness, local heat, pain, and abnormal functionin of
the part involved
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Immunologic Diseases
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Immunologic diseases are grouped into two categories:
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Primary Immunodeficiencies
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Arise from an inherited lack of development of one or more
parts of the immune system
Secondary Immunodeficiencies
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Occur more frequently than primary
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Results from many factors that suppress an individual’s immune
responses to events such as infection
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AIDS
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Infectious Diseases
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Microbiota
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Microscopic forms that live on the skin, in the mouth and the large
intestine
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Most are harmless
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Some, if given the opportunity can cause a disease
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These are known as opportunists
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Can lead to opportunistic infections
Pathogens
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Microorganisms that cause severe problems upon gaining
entrance to the host tissues
Pathogenesis
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Eventual development of a diseases
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Infectious Diseases
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Pathogenicity
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Virulence
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The disease producing capability of a pathogen
The degree or intensity of pathogenicity
Infectious Diseases are caused by infectious agents
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Bacteria
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Fungi
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Protozoa
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Viruses
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Helminths (worms)
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Infectious Diseases
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Communicable or Contagious
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Certain infectious diseases can spread from person to person
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Flu or measles
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Gonorrhea or syphilis
Noncommunicable or not contagious
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Caused by an infectious agent but does not spread from person to
person
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Tetanus
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The Course of an Infectious
Disease
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Incubation Period
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The time between the multiplication of the pathogen and the
appearance of signs and symptoms
Prodromal Phase
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The early stage of some diseases in which nonspecific symptoms
such as headache and general weakness appear
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The Course of an Infectious
Disease
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Invasive Phase
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The period during which pathogens invade and cause tissue
damage
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Convalescence Phase
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Signs and symptoms of the disease appear at the same time
The time period during which recovery occurs and includes
healing and regaining strength
Even if signs and symptoms disappear individuals may still
be able to spread an infectious diseases
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The Course of an Infectious
Disease
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Acute
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Disease occurs rapidly and sometimes with intense symptoms
Chronic
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Disease develops more slowly and lasts for a longer, indefinite,
period of time
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The Concept of Infectious Disease
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Girolamo Fracastorius, a Franciscan monk in 1546
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Anton Van Leeuwenhoek, late 1600s
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Distinguished several ways an infectious disease was able to
spread
 Contact with the skin
 Contact with objects close to a sick person
 The air in a sickroom
Created the first real microscope
Discovered microorganisms with his microscope
Rober Koch1876
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Koch’s Postulate - “Germ theory of disease”
 Demonstrated a specific bacterium
caused anthrax
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Factors Contributing to the Success of
an Infectious Disease
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Pathogens act in certain ways to cause diseases
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Gaining access to the host
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Attaching to and reproducing on the cell surface
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Invading body tissues
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Producing poisonous substances known as toxins to breakdown
the body’s defenses
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Toxins may also cause allergic responses in some people
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The Microbial World
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Bacteria
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Single-celled microorganisms
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May be beneficial or harmful to the host
Bacteria are differentiated from one another by several factors:
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Shape
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Color reactions
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Chemical composition
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Growth
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Responses to chemicals such as
antibiotics
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Shape of Bacteria
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Coccus
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Bacillus
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Spherical form
Rod
Spirillum
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Twisted or bent
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Tight corkscrew known as a
spirochete
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Coccus
Bacillus
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Isolating and Growing (Culturing)
Bacteria
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Medium –
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Nutrient used to grow
bacteria
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Made from broth or liquid,
and solid or agar
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Contains nutrients
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Sugar
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Protein
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Vitamins
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Minerals
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Fungi
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Fungi
Single- and multi-cellular forms of life
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Yeast
Molds
Mushrooms
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The majority of fungi are involved natural decomposition of
rotting and decaying plant and related material
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Commercial production of some bakery goods, cheeses,
antibiotics, alcoholic beverages and other chemicals
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Some fungi can attack the
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Skin, nails and hair
Causes different forms of ringworm
 Athlete’s foot
Some can form STD’s like a yeast infection
Fungi are opportunistic
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Fungi
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Protozoa
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Single-celled animal-like
microorganisms
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Most are harmless and found
in the soil and water
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Some causes diseases such as
malaria, African sleeping
sickness and Amebic
dysentery
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Protozoa are opportunistic and
cause STD’s
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Viruses
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Cannot be seen by an ordinary light microscope
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Must use an electron microscope
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Viruses are therefore called submicroscopic
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Chicken pox
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HIV
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Viruses are not cells
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Viruses vary in shape
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Viruses
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Virions
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Individual virus particles
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Contain a single type of nucleic acid
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Capsid
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Either DNA or RNA but never both
Protein coat encloses the nucleic acid component
Culvitation
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Viruses can only replicate in living cells
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Helminths or Worms
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Helminths that cause most of
human disease are
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Flatworms
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Roundworms