Med Micro Exam 2

What is a disease?

A condition that disrupts normal body structure or function.

What is an infection?

When a microorganism enters and multiplies in a host.

What is a syndrome?

A group of signs and symptoms that occur together.

What is a sign?

An objective finding that can be observed or measured.

What is a symptom?

A subjective experience reported by the patient.

What is etiology?

The cause of a disease.

What is pathology?

The structural and functional changes associated with disease.

What is pathogenesis?

The process by which a disease develops.

What is the incubation period?

The time between infection and the appearance of symptoms.

What is convalescence?

The recovery period after illness.

What is an acute disease?

A disease that develops quickly and usually lasts a short time.

What is a chronic disease?

A disease that persists or develops over a long period.

What is a latent infection?

An infection that remains inactive or dormant but may reactivate.

What is a local infection?

An infection limited to one area of the body.

What is a systemic infection?

An infection that affects multiple parts of the body.

What is a nosocomial infection?

An infection acquired in a healthcare setting.

What is commensalism?

One organism benefits while the other is neither helped nor harmed.

What is mutualism?

A relationship in which both organisms benefit.

What is a primary pathogen?

A microorganism capable of causing disease in a healthy host.

What is an opportunistic pathogen?

A microorganism that causes disease when host defenses are weakened.

What is a reservoir?

The natural habitat where a pathogen normally lives.

What is vertical transmission?

Transmission from parent to offspring.

What is vehicle transmission?

Transmission through contaminated food, water, blood, or another medium.

What is direct contact transmission?

Spread through direct physical contact.

What is indirect contact transmission?

Spread through contaminated objects (fomites).

What is droplet transmission?

Spread through respiratory droplets.

What is airborne transmission?

Spread through particles that remain suspended in air.

What is vector transmission?

Transmission by a living organism such as a mosquito or tick.

What is incidence?

The number of new cases occurring during a specific time period.

What is prevalence?

The total number of existing cases in a population.

What is morbidity?

Illness or disease within a population.

What is morbidity rate?

Cases of illness per population.

What is mortality?

Death within a population.

What is mortality rate?

Cases of death per population.

What is an endemic disease?

A disease constantly present in a population.

What is an epidemic?

An unusually large number of cases in a local population.

What is a pandemic?

An epidemic occurring across multiple countries or continents.

What is herd immunity?

Protection that occurs when enough people are immune that disease transmission decreases.

True or False: Herd immunity can protect unimmunized individuals.

True.

What is antigenic drift?

Small gradual changes in viral antigens due to mutation.

What is antigenic shift?

Major abrupt changes in viral antigens, usually influenza A.

What is a retrospective study?

A study that looks backward at past records or exposures.

What is a prospective study?

A study that follows subjects forward in time.

What is a cross-sectional study?

A study examining a population at one point in time.

What is an experimental study?

A study where researchers assign an intervention.

What is the difference between incidence and prevalence?

Incidence = new cases; prevalence = all existing cases.

What is the difference between a sign and symptom?

A sign is observable; a symptom is reported by the patient.

What measure is most useful for calculating risk of disease?

Incidence.

What measure includes all current cases?

Prevalence.

What organism causes tuberculosis?

Mycobacterium tuberculosis.

What stain is used to identify Mycobacterium tuberculosis?

Acid-fast stain.

Why is Mycobacterium tuberculosis acid-fast?

Because of mycolic acids in its cell wall.

What cells are primarily infected by tuberculosis?

Macrophages.

What structure forms around persistent TB infections?

Granuloma.

What type of necrosis is associated with tuberculosis?

Caseous necrosis.

What are common symptoms of active tuberculosis?

Chronic cough, weight loss, fever, night sweats, hemoptysis.

What test screens for TB exposure?

Mantoux (PPD) skin test.

What vaccine is used against tuberculosis?

BCG vaccine.

What is latent tuberculosis?

TB infection without active symptoms.

What organism causes Chlamydia infections?

Chlamydia trachomatis.

What type of bacterium is Chlamydia trachomatis?

Obligate intracellular bacterium.

Which Chlamydia form is infectious?

Elementary body.

Which Chlamydia form replicates within host cells?

Reticulate body.

What is the major complication of untreated chlamydia in women?

Pelvic inflammatory disease (PID).

What is a long-term consequence of PID?

Infertility or ectopic pregnancy.

What antibiotic commonly treats chlamydia?

Azithromycin.

What is the most common bacterial sexually transmitted infection?

Chlamydia trachomatis.

What organism causes Rocky Mountain Spotted Fever?

Rickettsia rickettsii.

What type of bacterium is Rickettsia?

Obligate intracellular Gram-negative bacterium.

What vector transmits Rocky Mountain Spotted Fever?

Ticks.

What cells are primarily infected in RMSF?

Endothelial cells.

What is a hallmark symptom of RMSF?

Fever and rash that may become hemorrhagic.

Why is RMSF dangerous?

It damages blood vessels and can affect multiple organs.

What organism causes epidemic typhus?

Rickettsia prowazekii.

What transmits epidemic typhus?

Human body lice.

How does typhus infection occur?

Louse feces are scratched into the skin.

What organism causes salmonellosis?

Salmonella species.

What type of bacterium is Salmonella?

Gram-negative enteric rod.

What are common symptoms of salmonellosis?

Diarrhea, fever, abdominal cramps.

What is a common source of Salmonella infection?

Contaminated poultry and eggs.

What species causes typhoid fever?

Salmonella Typhi.

Who was Typhoid Mary?

An asymptomatic carrier of Salmonella Typhi.

What secretion system helps Salmonella invade host cells?

Type III secretion system.

What organism causes walking pneumonia?

Mycoplasma pneumoniae.

What makes Mycoplasma unique?

It lacks a cell wall.

Why don't beta-lactam antibiotics work against Mycoplasma?

There is no cell wall to target.

What type of pneumonia does Mycoplasma cause?

Atypical (walking) pneumonia.

What organism causes strep throat?

Streptococcus pyogenes.

What are common signs of strep throat?

Red throat, pus patches, enlarged tender lymph nodes.

How is strep throat treated?

Antibiotics.

Is there a routine vaccine for strep throat?

No.

What organism causes diphtheria?

Corynebacterium diphtheriae.

What is the classic sign of diphtheria?

A grayish-white membrane in the throat.

How is diphtheria prevented?

DTaP or Tdap vaccination.

How is diphtheria treated?

Antitoxin and antibiotics.

What organism causes whooping cough?

Bordetella pertussis.

What is the characteristic symptom of pertussis?

Severe coughing fits followed by a whooping sound.

What organism causes Legionnaires' disease?

Legionella pneumophila.

What is a common source of Legionnaires' disease?

Contaminated water systems.

What virus is a major cause of bronchiolitis in infants?

Respiratory Syncytial Virus (RSV).