Chapter 9 Microbiology

A collection of flashcards covering key vocabulary and concepts from Chapter 9 in microbiology.

Epidemiology

Monitoring and controlling disease occurrence to promote public health.

Etiology

Study of the cause of disease.

Incidence rate

Number of new cases in a population during a specific time.

Source of infection

Object or organism that transfers the pathogen from reservoir to host.

Epidemic

Widespread outbreak in a specific region and time.

Sporadic disease

Isolated infections in a population.

Reservoir of infection

Natural habitat of a pathogen (animate or inanimate).

Pandemic

Epidemic that spreads across multiple countries.

Infectious disease

Illness caused by pathogens.

Endemic infection

Disease routinely detected in a population or region.

Carrier

Asymptomatic person harboring an infectious agent.

Zoonotic disease

Disease transmitted from animals to humans.

Who is the Father of Epidemiology?

John Snow.

Communicable disease

Can be passed from person to person.

Noncommunicable disease

Cannot be passed person-to-person; spread via animals, vectors, or objects.

Signs

Objective indicators of disease.

Example of a sign

Fever, heart rate, blood pressure.

Symptoms

Subjective feelings reported by the patient.

Example of a symptom

Pain, nausea, fatigue.

Endogenous source

Pathogen originates inside the host.

Exogenous source

Pathogen comes from outside the host.

Direct contact transmission

Physical contact with pathogen (e.g., fluids, bites, breastfeeding).

Indirect contact transmission

Transmission via droplets, vectors, needles, droppings without physical contact.

Biological vector

Pathogen undergoes life stage inside vector (e.g., mosquito with Plasmodium).

Mechanical vector

Pathogen is carried without life stage inside vector (e.g., cockroach with fungi).

Incubation period

Time between infection and symptoms.

Prodromal phase

Early, mild symptoms.

Acute phase

Peak of illness and symptoms.

Decline period

Symptoms begin to subside.

Convalescence

Recovery and return to health.

Three factors in the epidemiological triangle

Host factors, Environmental factors, Etiological agent.

Three strategies to break the triangle

Education, Quarantine, Vector control.

Prevalence

Existence of disease in a population at a given time.

Two factors that impact prevalence

Incidence rate, Duration of infection.

Common HAIs

Staphylococcus aureus, Escherichia coli, Clostridium difficile, Pseudomonas aeruginosa.

Practices to reduce HAIs

Hand washing, PPE use, Environmental sanitization, Equipment sterilization.

Additional HAI prevention practice

Limiting patient transport and isolation.

Emerging infection

New or newly identified disease (e.g., SARS, COVID-19).

Reemerging infection

Previously controlled disease now increasing (e.g., measles).

Impact of Tuskegee Syphilis Experiment

Highlighted need for informed consent and patient protection.

Herd immunity

When ~85% of population is immune, protecting those who can't be vaccinated.

How does herd immunity help?

Reduces disease presence and protects vulnerable individuals.

Incubation Period

Prodromal Phase

Acute Phase

Decline Period

convalescence phase