quiz topic 5

What is epidemiology?

Epidemiology is the study of how diseases affect the health and illness of populations.

Define portal of exit.

A portal of exit is a route through which a pathogen leaves its host.

Define portal of entry.

A portal of entry is the pathway through which a pathogen enters a new host.

What are communicable diseases?

Communicable diseases are infections that can be transmitted from one person to another.

What are non-communicable diseases?

Non-communicable diseases are diseases that are not spread from person to person, such as diabetes and heart disease.

Differentiate between morbidity rate and mortality rate.

Morbidity rate refers to the incidence of disease in a population, while mortality rate refers to the incidence of death within a population.

Differentiate between incidence and prevalence.

Incidence is the number of new cases of a disease in a specific time period, while prevalence is the total number of cases (new and existing) in a population at a given time.

Define endemic.

Endemic refers to a disease or condition regularly found and consistently maintained at a baseline level in a geographic area.

Define epidemic.

Epidemic refers to a sudden increase in the number of cases of a disease above what is normally expected in a population.

Define outbreak.

An outbreak is a localized increase in the incidence of a disease.

Define pandemic.

Pandemic refers to an epidemic that has spread across multiple countries or continents affecting a large number of people.

What is a reservoir? Provide examples.

A reservoir is a host or environment where pathogens normally reside and can multiply; examples include humans, animals, and the environment.

Differentiate between symptomatic infection and asymptomatic carriers.

Symptomatic infections present observable symptoms, while asymptomatic carriers harbor pathogens without showing symptoms.

Define zoonoses.

Zoonoses are diseases that are transmitted from animals to humans.

Differentiate between horizontal and vertical transmission of disease.

Horizontal transmission occurs between individuals of the same generation, while vertical transmission happens from parent to offspring.

List specific mechanisms for the transmission of microbial diseases.

Mechanisms of transmission include direct contact, droplets, airborne, vector-borne, and fomite transmission.

Define fomites.

Fomites are inanimate objects that can carry infectious agents.

Define droplet nuclei.

Droplet nuclei are small droplets containing infectious particles that can remain suspended in the air.

Define vectors.

Vectors are living organisms that can transmit infectious agents to other living organisms.

Differentiate between mechanical and biological vectors.

Mechanical vectors transport pathogens without being infected themselves, while biological vectors are infected and multiply the pathogen.

List the major portals of exit and portals of entry.

Major portals of exit include respiratory tract, gastrointestinal tract, urogenital tract, blood, and skin; portals of entry include skin, mucous membranes, and respiratory tract.

List and describe major factors that influence the epidemiology of disease.

Factors include environmental conditions, socioeconomic status, population density, vaccination rates, and public health policies.

Differentiate among descriptive, analytical, and experimental epidemiological studies.

Descriptive studies summarize disease patterns, analytical studies investigate associations between risk factors and diseases, and experimental studies test interventions.

Define risk factor.

A risk factor is any attribute, characteristic, or exposure that increases the likelihood of developing a disease.

Define placebo.

A placebo is an inactive substance or treatment designed to mimic an active treatment.

Define double-blind study.

A double-blind study is a research design where neither the participants nor the researchers know who is receiving the active treatment or placebo.

Describe cross-sectional study.

A cross-sectional study observes a defined population at a single point in time to assess health outcomes and exposures.

Describe retrospective or case-control study.

A retrospective study compares individuals with a specific condition to those without, looking back to identify potential risk factors.

Describe prospective study.

A prospective study follows participants over time to assess the occurrence of new outcomes based on their exposures.

Identify the first successful antimicrobial agent and its discoverer.

The first successful antimicrobial agent was penicillin, discovered by Alexander Fleming.

Identify the first antibiotic discovered and its discoverer.

The first antibiotic discovered was also penicillin, by Alexander Fleming.

Define chemotherapeutic agent.

A chemotherapeutic agent is a drug used to treat diseases, particularly infectious diseases.

Define antimicrobial drug or agent.

An antimicrobial agent is a substance that kills or inhibits the growth of microorganisms.

Define semisynthetic.

Semisynthetic refers to compounds that are chemically modified derivatives of natural compounds.

Define bacterial selective toxicity.

Selective toxicity refers to the ability of a drug to kill or inhibit pathogens without harming the host cells.

Define bacteriostatic.

Bacteriostatic agents inhibit bacterial growth and reproduction.

Define bactericidal.

Bactericidal agents kill bacteria.

Why must one consider selective toxicity in antimicrobial selection?

Selective toxicity is crucial to minimize harm to the host and effectively target the pathogen.

Why consider spectrum of activity in antimicrobial selection?

The spectrum of activity determines whether a drug is effective against specific pathogens.

Why consider tissue distribution in antimicrobial selection?

Tissue distribution affects the drug's effectiveness and ability to reach the site of infection.

Why consider metabolism and excretion of the drug in antimicrobial selection?

Metabolism and excretion impact the duration and intensity of the drug's effects.

What are adverse effects in antimicrobial selection?

Adverse effects are unwanted or harmful responses to the administered antimicrobial agent.

What are synergistic combinations in antimicrobial selection?

Synergistic combinations enhance the effectiveness of two or more drugs used together.

What is microbial resistance and why is it a problem?

Microbial resistance occurs when microorganisms survive despite drug treatment, making infections harder to treat.

Differentiate between broad-spectrum and narrow-spectrum antimicrobials.

Broad-spectrum antimicrobials are effective against a wide range of microorganisms, while narrow-spectrum agents target specific pathogens.

Define synergistic in antimicrobial drug combinations.

Synergistic interactions enhance the effect of two drugs when used together.

Define antagonistic in antimicrobial drug combinations.

Antagonistic interactions reduce the effectiveness of one or both drugs when used together.

Define additive in antimicrobial drug combinations.

Additive interactions yield a combined effect that is equal to the sum of the effects of each drug used separately.

List and describe the three major types of adverse effects caused by antimicrobial agents.

Types of adverse effects include allergic reactions, toxic effects on organs, and disruption of normal flora.

Why is microbial resistance a major problem?

Microbial resistance complicates treatment efforts, leads to longer hospital stays, higher medical costs, and increased mortality.

List the major antibacterial drugs by modes of action.

Antibacterial drugs include: 1. Inhibition of cell wall synthesis (e.g., penicillins), 2. Inhibition of protein synthesis (e.g., tetracyclines), 3. Inhibition of nucleic acid synthesis (e.g., fluoroquinolones), 4. Inhibition of metabolic pathways (e.g., sulfonamides), 5. Interference with cell membrane function (e.g., polymyxin B), 6. Interference with Mycobacterium tuberculosis metabolism (e.g., isoniazid).

How can sensitivity of bacteria to an antibacterial agent be determined in the laboratory?

Sensitivity can be determined using various susceptibility tests such as disk diffusion, broth dilution, or E-test.

Define minimum inhibitory concentration (MIC).

MIC is the lowest concentration of an antimicrobial that inhibits visible growth of a microbe.

Define minimum bactericidal concentration (MBC).

MBC is the lowest concentration of an antimicrobial that kills a particular bacterium.

Describe diffusion bioassay.

Diffusion bioassay measures the diffusion of an antimicrobial agent through agar to determine its effectiveness.

Describe Kirby-Bauer disc diffusion.

The Kirby-Bauer method involves placing antibiotic-impregnated discs on an agar plate inoculated with bacteria to determine susceptibility.

How to read a standard curve in diffusion assay tests?

A standard curve correlates the size of the inhibition zone to the concentration of antibiotic, helping to determine effectiveness.

List the major antifungal drugs by modes of action.

Antifungal drugs include: 1. Disruption of cell membrane synthesis (e.g., azoles), 2. Inhibition of nucleic acid synthesis (e.g., flucytosine).