Examples of Single Tissue Autoimmune Diseases
Autoimmune hemolytic anemia (RBC)
Thyroid - Graves' disease, Hashimoto's thyroiditis
Pancreas - type I diabetes
Relationship between organisms living together
One organism benefit, the other is not affected
Both organisms' benefit (us and normal flora)
One benefits (parasite) and the other organism is harmed (host)
One organism produces a substance that kills or inhibits another organism. (Penicillium mold produces penicillin that kills bacteria)
What is normal microbiota (flora)?
Bacteria we pick up through life based on numerous factors such as birth, diet, and environment
What is the difference between resident microbiota and transient microbiota?
Resident stays with you and transient is temporary
How do these organisms interact with the host and when is the normal microbiota developed?
The host is generally going to be benefited by microbiota
Promote bacterial growth
Provide food to microbiota
What are opportunistic organisms?
A pathogen that usually does not cause us harm but can take advantage of an opportunity if we are immunocompromised
When do opportunistic organisms cause disease?
1. Introduction of an organism into a different area of the body
2. Immune suppression
3. Changes in the microbiome (Microbial competition and antagonism)
4. Stressful conditions
How does contamination differ from infection?
Contamination: The organism is present. Infection: Organism overcomes host defense and multiplies
What are reservoirs?
Continual source of the pathogen
Animal (non-human) reservoirs
May not show symptoms but can pass on to others (Typhoid Mary)
Non living reservoirs
soil, water, food, etc. (typically fecal contamination and fecal-oral transmission
Portals of entry
the way that the microbe gets into the body
Bypasses normal barrier to enter
How many of a specific organism takes to cause infection (ID50 and LD50) 50% of those exposed
microbes that are capable of establishing disease
What are pathogens?
microbes that are capable of establishing disease
When does microbe induced disease occur?
when the microbe is in sufficient numbers and has breached host defense
***What is pathology?
The scientific study of disease
How are infectious diseases classified?
Symptoms: Subjective: changes sensed or felt by individual
Signs: Objective: changes that can be observed or measured by someone else
Syndrome: a disease process that has a specific set of symptoms and signs associated with a particular disease
What the cause of the disease is
Germ Theory of Disease
idea that infectious diseases are caused by microbes
Anything that allows the microbe to be better able to establish disease
The ability to cause a disease
Degree to which an organism can cause a disease
coagulase and kinase
Released by the cell
Gram - cells Lipid A portion of LPS (fever, inflammation, diarrhea, hemorrhaging, blood coagulation
make you susceptible
Development: (stages of disease)
1. Incubation: time from when organism first infects to body to when symptoms are shown
2. Prodromal period: start to feel that something is wrong
3. Illness: Most severe signs and symptoms are present
4. Decline: Either you are getting better or dying
Portals of exit
Orifices on the body
How a disease transfers from one host to another
- Direct: touching
- Indirect: Fomite (inanimate object that has pathogen on it)
- Droplet: Passed in droplets from a sneeze or cough <1m
Through airborne, waterborne, and foodborne
- Biological: A specific pathogen
- Mechanical: Random
Symptoms develop rapidly and end quickly
Milder symptoms which last longer
Ranges between acute and chronic
Disease that appears a long time after infection
Disease transmitted from one host to another
A disease easily passed from one individual to another
Disease is not passed from person to person
The study of when and where diseases occur and how they are transmitted (John Snow 1854)
Number of new cases of the disease
Total number of cases in same population
Frequency of outbreaks
Low levels in the population all the time
The disease happens occasionally
Sharp increase in number of cases in certain location
Epidemic in more than one continent at a time
If health care facility diagnosis individual, facility is required by law to report to local health officials
Go to the source and ask questions, index case
Analyzing the information that was obtained during the descriptive stage, try to determine etiology, transmission, etc.
Application of Koch's postulates if possible
Pathogen comes from the environment in the healthcare facility
Pathogen comes from the patient's normal microbiota; superinfections (Clostridium difficile)
Iatrogenic infectious (HAIs)
Factors: Presence of microorganisms in hospital environment, presence of immunocompromised patient, Transmission of pathogen between staff and patients and between patients
Control of HAI's
Aseptic practices, disinfection, antisepsis, cleaning the rooms properly, cleaning linens properly
How does epidemiology connect to Public Health?
How the data is conveyed to the public
-Educating the public
-CDC (more towards epidemiology) and the NIH (more towards research)
-World Health Organization (WHO)
-State public health agencies and local public health agencies
Host Defense (3 lines)
- 1st Line of defense (innate) Physical and chemical barriers
- 2nd Line of defense (Innate) Cells and other chemicals
- 3rd Line of defense (specific/immune response) Humoral immune response (antibody); cell mediated immunity (cellular response)
property that protects a type of organism from infection by pathogens of other, very different organisms
Skin and mucous membranes - first line of defense
These form a physical and chemical barrier to prevent the entry of pathogens
Multibranched phagocytes (found throughout the body but especially in skin and mucous membranes); antigen presenting cells (APC)
Oil and sweat gland secretions
Drop the pH on the skin from 3-5
Chains of about 20-50 amino acids that have antimicrobial properties; produced by the sweat glands (dermicidins), Produced by neutrophils in mucous; broad spectrum
Mucous membranes and Other defense mechanisms
Traps microbes, contains antimicrobial peptides and can contain antibody (part of specific defense)
Cilia pushes the mucous back out so that it does not reach the lungs
Flushing system for the eye, glands produce tears
Normal Microbiota and Microbial Antagonism
Organisms of the normal microbiota compete with potential pathogens and invaders to keep them out, release chemicals which kill invading bacteria
Found in mucous, production is triggered when the system has microbes on the surface
About 90% water, electrolytes (conduct electricity), proteins (immunoglobulin, clotting factors), Waste products, dissolved O2 & Co2, hormones.
Binds and transports iron in the body
Protein that stores iron in the liver
Proteins produced by microbes that try to bind to our iron; take iron from transferrin
Protein that takes iron back away from siderophores
Does not contain clotting factors found in plasma
2-4%: important in inflammatory infections, allergies, parasitic infections, limited phagocytic activity
0.5-1%; inflammation and possibly blood clotting
3-8%; blood precursor to the macrophage
20-25%; Smallest of leukocytes, involved in specific defense: B cells, T cells and NK cells (nonspecific)
Travel throughout the body
Resident population in a specific organ: Kuppfer cells in liver, alveolar macrophages in alveoli, microglial cells in CNS
Natural Killer cells
Non-T, non-B lymphocyte; nonspecific defense; kill altered self-cells by punching a hole in the membrane
movement of cells out of the blood into the tissue
Left Shift (Shift to the Left)
indicates an active infection process; cells are less mature
The cell eats
Stages of phagocytosis
1. Chemotaxis: Movement of a cell toward or away from a chemical stimulus
2. Adherence: Sticks to the pseudopod
3. Ingestion: Microbe is brought to the inside of the phagocyte, food vacuole forms around it
4. Phagosome Maturation and Microbial Killing: ly
How do microbes try to evade phagocytosis?
Using capsules, along with other virulence factors
Extracellular killing by leukocytes
What is meant by a disorder of the immune system?
Any situation where the immune system does not function normally is considered to be a disorder. These are divided into two different categories: hyperimmune responses (hypersensitivity and autoimmunity) where the immune system responds to non-dangerous a
This is an "over the top" response to non-dangerous, environmental antigens.
The antigen in this case is called an allergen.
Type I (anaphylactic reactions) - Immediate type hypersensitivity
Type I reactions are called immediate type because the reaction happens very quickly after the person who is sensitive is exposed to the antigen.
It involves the action of IgE and MAST cells, basophils and eosinophils. This can have a genetic component (r
This is the process that happens the first time the person's system "sees" the allergen as dangerous. It causes the production of IgE instead of IgG during the immune response. IgE is homocytotrophic - meaning that it can bind to the surface of our cells
Degranulation of Sensitized cells
This occurs when the sensitized individual encounters the allergen again. The allergen must bind to two different IgE molecules on the surface of the granulated cells. This is called cross-linking. It sends a signal into the cell to release the content of
Roles of Degranulating Cells
The cells release their chemicals. The first cells involved are the mast cells and the basophils. Their granules contain potent chemicals that cause inflammation. These chemicals include histamine (vasodilator and effects smooth muscles), kinins (inflamma
Clinical Signs of Localized Reactions
Localized reactions include itching (skin and mucous membranes), runny nose, watery eyes, sneezing, rashes (urticaria - aka hives), swelling, and constriction of smooth muscle tissue causing the symptoms of asthma.
Clinical Signs of Systemic Reactions (Acute Anaphylaxis)
While localized reactions are uncomfortable, and sometimes dangerous (asthma symptoms), systemic reactions can be quickly deadly. These reactions happen in response to certain types of antigens. These would include insect venoms, certain vaccines, certain
Diagnosis of Type I
The two major categories of testing for type I reactions are skin tests and blood tests. The skin test is typically the most common form used, even though your book mentions it as secondary. In skin testing, a small amount of the purified antigen is injec
Prevention of Type I
AVOIDANCE! That is the primary prevention. Your book lists examples of methods used to help allergy sufferers avoid antigens (p. 529). Immunotherapy (allergy shots) are very beneficial to some. The concept is to give very small doses of the allergen, buil
Treatment of Type I
This is typically treated using antihistamines and/or antileukotrienes that help neutralize the effects of those chemicals, corticosteroids that suppress the immune response, bronchodilators that help open up airways, and epinephrine that neutralizes the
Type II (cytotoxic reactions)
These are called cytotoxic reactions because they result in the destruction of cells in the sensitive person. Antibody against the cell binds to the cell forming an antigen-antibody complex. These complexes activate complement through the classical pathwa
Type III (immune complex reactions)
Type III reactions happen when antibody binds to a soluble antigen, forming an immune complex (still an antigen-antibody complex) which can stick in our tissues. These activate complement (if they are not cleared out by the macrophages) resulting in destr
Typically caused when allergens are inhaled deeply into the lungs - the disease is often named for the occupation of the individual, since certain occupations expose people to certain types of inhalable antigens.
In the kidneys - causes damage to the glomeruli in the nephrons, and ultimately can cause kidney failure.
Rheumatoid Arthritis (autoimmune)
In the joints - complexes are deposited in the tissues of the joint, damaging it, causing pain and deformity of the joint
Systemic Lupus Erythematosus (autoimmune)
Antibody is produced against self molecules (including nucleic acid), the complexes form and lodge, and damage the tissues. Lupus is considered a systemic autoimmune disease since multiple areas of the body are affected. It can damage the heart, lungs, jo
A small amount of purified protein from Mycobacterium tuberculosis is injected into the skin and then checked for a Type IV reaction. This is an indicator of someone being exposed to the disease or actually having had it.
Allergic Contact Dermatitis
Classic example is the reaction to poison oak and poison ivy, metals, etc.
This is a failure of self-recognition. Something triggers the immune system to inappropriately respond to its own tissues.
Single-Tissue Autoimmune Diseases
These are autoimmune diseases that affect a specific type of tissue or specific organ.
Systemic Autoimmune Diseases
These are disease that affect multiple systems and tissue types such as lupus.
These are the opposite of the hyperimmune response diseases. They involve the inability of the immune system to respond against infectious agents the way that it should. These fall into two groups
Primary (Congenital) Immunodeficiency Diseases
These are typically genetic disorders that affect one or more areas of the immune system. They include SCIDs (severe combined immunodeficiency) that wipes out the entire response system that involves lymphocytes, DiGeorge syndrome where there is no T cell
Secondary (Acquired) Immunodeficiency Diseases
Secondary imunodeficiencies are acquired after the person is born. These can be due to infectious agents (such as HIV/AIDS) or exposure to chemicals or other components that cause suppression of the immune response.