1. Pathogens that cause disease
1.1. Bacteria
1.1.1. single-celled organisms without a nucleus
1.2. Viruses
1.2.1. thread-like particles that reproduce by taking over living cells
1.3. Fungi
1.3.1. simple organisms, including mushrooms and yeast, that grow as single cells or thread like filaments
1.4. Protozoa
1.4.1. single-celled organisms with a nucleus
2. chain of infection
2.1. infectious agent
2.2. reservoirs
2.3. portal of exit
2.4. means of transmission
2.5. portal of entry
2.6. susceptible host
3. timeline for infection
3.1. dynamics of infectiousness
3.1.1. latent period
3.1.2. infectious period
3.1.3. non-infectious
3.2. dynamics of disease
3.2.1. incubation period
3.2.2. symptomatic period
3.2.3. non-diseased
4. tuberculosis
4.1. active tb
4.1.1. usually has a skin test or blood test result indicating TB infection
4.1.2. may have an abnormal chest x-ray or psoitive sputum smear or culture
4.1.3. has active TB bacteria in his/her body
4.1.4. usually feels sick and may have symptoms such as coughing, fever and weight loss
4.1.5. may spread TB bacteria to others
4.1.6. needs treatment to treat active TB disease
4.1.6.1. Standard drug regimen: RIPE
4.1.6.1.1. Rifampin
4.1.6.1.2. isoniazid
4.1.6.1.3. pyrazinamide
4.1.6.1.4. ethambutol
4.2. latent tb
4.2.1. usually has a skin test or blood test result indicating TB infection
4.2.1.1. TST test
4.2.1.1.1. read 48-72 hours after administration. measurement in millimeters of the induration (hardness and swelling). Persons risk of being infected with TB
4.2.2. has a normal chest x-ray and a negative sputum test
4.2.3. has TB bacteria in his/her body that are alive but inactive
4.2.4. does not feel sick
4.2.5. cannot spread TB bacteria to others
4.2.6. needs treatment for latent TB infection to prevent TB disease; however, if exposed and infected by a person with MDR TB or XDR TB, preventative treatment might not be an option
4.2.7. BCG test
4.2.7.1. BCG is a vaccine given to infants and children in endemic countries if they have access to medical or public health care
4.2.7.2. proven to decrease TB menigitis and disseminated TB in children in endemic countries
4.3. people with HIV are vulnerable to TB disease
4.4. MAKE SURE TO ISOLATE IF ACTIVE TB
4.5. very small, wax coat, scourge for thousands of years, chronic dz ultimately fatal for some
4.6. evade immune system- after phagocytosis, tb prevents lysosomes from fusing, but gets "walled off" in tubercles due to fibrosis and calcification... can lead to lung destruction and cavitation
4.7. carefully monitored diseases are called "reportable" or "notifiable"
4.8. TB precautions in hospital
4.8.1. negative pressure ventilation
4.8.2. tb precautions
4.8.3. std precautions
4.8.4. airborne
5. natural history of disease timeline
5.1. stage of suscpetibility
5.1.1. exposure
5.2. stage of subclinical disease
5.2.1. pathologic changes
5.2.2. onset of symptoms
5.3. stage of clinical disease
5.3.1. usual time of diagnosis
5.4. stage of recovery, disability or death
6. what are infectious diseases?
6.1. caused by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi; that can be spread, directly or indirectly, from one person to another… or following exposure to an animal that harbors a pathogenic organism that is capable of infecting humans.
7. Emerging vs Re-emerging
7.1. Emerging- infections that have recently appeared within a population or those whose incidence or geographic range is rapidly increasing
7.1.1. Emerging infections can be caused by:
7.1.2. Previously undetected or unknown infectious agents
7.1.3. Known agents that have spread to new geographic locations or new populations
7.1.4. Previously known agents whose role in specific diseases has previously gone unrecognized.
7.2. Re-emerging- incidence of a disease that had significantly declined in the past, but whose incidence of disease has reappeared
8. measles
8.1. etiology
8.1.1. virus. Humans are the only natural host of measles virus. Very contagious and live in the nose and throat mucus of an infected person
8.2. transmission
8.2.1. The measles virus is shed from the nasopharynx [beginning with the onset of prodrome symptoms until 3–4 days after rash appears].Transmitted from person-to-person by direct contact or by contaminated secretions of the nose and the mouth. Infectious droplets (airborne) spread when an infected person breathes, coughs, or sneezes. Measles virus can remain infectious in the air for up to two hours after an infected person leaves an area.
8.3. pathogenesis
8.3.1. measles is an acute viral respiratory illness
8.3.1.1. incubation period: measles virus migrates to regional lymph noes, primary viremiadisseminates the virus to the reticuloendothelial system, secondary viremia spreads virus to body surfaces
8.3.1.2. prodromal illness: begins after the secondary viremia, associated with epithelial necrosis, giant cell formation and virus shedding
8.3.1.3. with onset of the rash, antibody production begins and viral replication and symptoms begin to subside
8.3.2. characterized by a prodrome of fever (as high as 105°F) and malaise, loss of appetite, diarrhea, cough, runny nose, red & watery eyes, a pathognomonic enanthema (Koplik spots) followed by a maculopapular rash. On average, the rash appears about 14 days after a person is exposed (range, 7–21 days), or 2–3 days after the fever begins. The rash spreads from the head to the trunk to the lower extremities.
8.4. clinical manifestations
8.5. incubation period
8.6. infectious period
8.6.1. from exposure to the first symptom (usually a fever, prodrome symptoms) avg. 10-12 days
8.6.2. patients are considered to be contagious from 4 days after the rash appears. Sometimes immunocompromised patients will not develop a rash
8.7. treatment
8.7.1. supportive care
8.8. clinical course
8.8.1. usually self-limited, usually lasts 7 to 10 days, but some patients may have complications: otitis media, bronchopneumonia, laryngotracheobronchitis, brain damage, blindness, deafness, and death.
9. how to prevent infectious diseases
9.1. hand hygiene in healthcare settings
9.1.1. alcohol-based handrub
9.1.2. washing hands with soap and water
9.1.2.1. wet, lather, scrub (20 seconds), rinse, dry