3.1.1

Epidermologist: Study and investigate health related matters

Resolving outbreak:

1. Receive call from healthcare facility

2. Gather initial info

3. Facility extends full invitation for an on site team

4. DDT arrives and gathers info/conducts testing

5. Team analyzes info and conducts risk factors

6. Reccomend new/revised steps for prevention

7. Facility implements reccomendations

8. Make adjustments as needed

Spread of disease:

Sporadic disease: disease that occurs irregularlly

Nosocomial disease: infection acquired in hospital, ex: pnemonia, UTI, bloodstream infection

Outbreak: sudden increase of a disease in a localized area

Endemic: disease present in a community/population

Pandemic: endemic that’s spreads past multiple boarders

3.1.2

Terms:

Infection: disease causing organism invades and grows in another host

Host: organism where another organism lives

Pathogen: disease - causing organism (ex: bacteria)

Disease: infection impairs bodily function

Virulence:

How easy a disease is to catch

• High: easy to catch

• Low: harder to catch

Microbes:

Microbiome: microorganisms in a particular environment

Normal flora/microbiota: bacteria that lives in and on us

Microbes: tiny agents

• Microscopic: not visible to naked eye (microbes)

Macroscopic: visible to naked eye

Infectious agents:

Prions: non living, submicroscopic, bad protien

• exposure through infected meat and medical equipment

• Proteins in brain fold abnormally

• Diagnosed with MRI, EEG, cerebrospinal fluid analysis, and blood test

• ex: Mad cow disease (dementia, psychosis, coma)

Virus: non living, submicroscopic, outer protien shell (trying to spread bad DNA/RNA)

• Exposure through touch, saliva, blood, sexual contact

• Diagnosed with physical exam and lab tests

• Some treated with antivirals

• Infect and take over host cells protien synthesis, destroying cells and tissues

• ex: Flu (fever, chills, body aches, cough, runny nose)

Bacteria: living, microscopic, unicellular prokaryotic organism)

• Invade cells causing tissue damage, producing toxins

• Exposure through office (nose and mouth), wound, normal flora imbalance

• Diagnosed with physical exam and labs

• Treated with antibiotics

• ex: Tuberculosis (cough, chest pain, coughing blood, fever)

Protists: living, microscopic, single celled eukaryotic animal - like organism

• Deprive organs of essential nutrients and cause organ/tissue damage

• Exposure through contaminated food/water with feces from infected organisms

• Diagnosed with fecal exam

• Treated with antiprotozoal

• ex: Giardia Lambils →giardiasis ( parasites in shells outside intestines)

Fungi: living, multicellular, eukaryotic like yeast

• Cause tissue damage

• Exposure through inhalation or touch

• Diagnosed through tissue exam from infected area or blood

• Treated with antifungals

• ex: Athletes foot (dryness, itching, burning, peeling skin)

Helminths: living, multicellular, eukaryotic worms, micro or macroscopic

• Deprive host of nutrients in food, cause tissue and organ damage

• Exposure through contaminated food and water

• Diagnosed with microscopic exam of fecal material or blood

• Treated with deworming medications

• ex: Tape worms (nausea, weight loss, abdomonal pain)

3.1.3

Chain of Infection

Susceptible Host: Person vulnerable to infection

• For a host to encounter an agent, the agent must leave its reservoir (previous location), be transmitted, then enter new host

1. Agent of disease (prions, bacteria)

2. Reservoir (People)

3. Portal of Exit (GI tract, respiratory tract)

4. Mode of transmission (direct/indirect)

5. Portal of Entry (skin, GI tract)

6. Susceptible Host (kids, elderly)

• Direct contact- host touches infected person, exposed to bodily fluids

• Indirect contact- host inhales infected particles, touches infected object, or is bitten by infect insect

Infectious dose:

# of organism it takes to cause illness following exposure

• Lower infectious dose=less needed=stronger the virus

COVID 19:

Structure: M,S, and E protien

Symptoms: cough, fever, fatigue, coughing up phlegm

• Acute Respritory Distress Syndrome (ARDS): lining of air sacs and blood vessels around them become damaged (oxygen is blocked by fluid)

Immunity:

Innate Immunity: nonspecific defense your born with

• ex: tears, stomach acid, fever, inflammation

Acquired Immunity: specific defense acquired over time, reacts to certain antigens

• Active immunity: aquired from getting the disease or vaccine

• Passive immunity: aquired from mother (placenta and breastfeeding)

Natural Immunity: built from getting the disease

Artificial Immunity: built from getting the vaccine

Herd Immunity: most people in community get vaccinated, so others are automatically protected too

When an antigen(foreign invader) is in the body, the body sends a T-cell (type of WBC) to the infection site to kill it. The body also makes B-cells to build antibodies.

R- naught (Ro):

Term to measure how infectious an agent is

Ro >1: 1 sick person on average infects <1 person

Ro=1: 1 sick person on average infects 1 person

Ro>1: 1 sick person on average infects indicated amount

• ex: Ro= 2, infects 2 people

Infectious dose:

Agent of disease determines infectious dose

Stronger agent →lower infectious dose →better at infecting/takes less for infection

Careers:

Virologist: studies viruses