Principles of Disease and Epidemiology Chapter 14

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Questions and Answers

What characterizes a noncommunicable disease?

Progresses through direct infection

Can be transmitted from person to person

Results from genetic or environmental factors (correct)

Is caused by bacteria exclusively

Which of the following describes mutualism in symbiotic relationships?

One organism benefits while the other is harmed

The relationship involves competition between organisms

Both organisms benefit from the relationship (correct)

One organism is unaffected while the other benefits

What is the primary role of microbial antagonism?

To enable the host to produce more bacteria

To help pathogens establish themselves in the host

To protect the host by competing with pathogens (correct)

To enhance the growth of harmful organisms

Which of the following factors is considered a predisposing factor for disease susceptibility?

Short urethra in females Signup and view all the answers

In terms of disease classification, what distinguishes opportunistic pathogens?

They require a weakened host to cause disease Signup and view all the answers

Which of the following is NOT a component of the normal microbiota's role in protecting the host?

Directly attacking host cells Signup and view all the answers

What is the most significant lifestyle factor that can predispose an individual to disease?

Smoking and alcohol consumption Signup and view all the answers

What is the primary purpose of probiotics?

To exert beneficial effects by introducing live microbes Signup and view all the answers

What is the main focus of analytical epidemiology?

Comparison between diseased and healthy groups Signup and view all the answers

Which of the following is considered a nonliving reservoir of infection?

Tetanus Signup and view all the answers

Which metric relates to the number of individuals affected by a specific disease in a population over a certain period?

Morbidity rate Signup and view all the answers

Which method is NOT used in descriptive epidemiology?

Case control method Signup and view all the answers

What type of disease transmission involves the spread of pathogens via inanimate objects?

Indirect transmission Signup and view all the answers

Nightingale's studies during the Civil War focused on which disease?

Typhus Signup and view all the answers

Which of the following best describes 'morbidity'?

Incidence of specific notifiable disease Signup and view all the answers

What was the primary discovery attributed to Semmelweis in the context of epidemiology?

Importance of hand washing Signup and view all the answers

What does the term 'incidence' refer to in epidemiology?

Fraction of a population that contracts a disease over a specific time Signup and view all the answers

Which of the following describes a pandemic disease?

Acquired by many hosts worldwide in a short time Signup and view all the answers

What is the difference between prevalence and incidence?

Incidence measures new infections; prevalence measures all existing cases Signup and view all the answers

Which of the following terms refers to a disease consistently present in a particular area?

Endemic disease Signup and view all the answers

Which factor should always be considered when reading graphs about disease occurrences?

Other factors that may affect the data Signup and view all the answers

Who is credited with mapping the occurrence of cholera in London?

John Snow Signup and view all the answers

What does it mean if a disease is classified as sporadic?

It happens occasionally in a population without consistent patterns Signup and view all the answers

Improved sanitation practices were shown by which individual to decrease the incidence of epidemic typhus?

Florence Nightingale Signup and view all the answers

Study Notes

Chapter 14: Principles of Disease and Epidemiology

This chapter discusses principles of disease and epidemiology, covering topics like normal microbiota, symbiosis, patterns of disease, predisposing factors, and the spread of infection.

Normal Microbiota

Transient microbiota are present for days, weeks, or months.
Normal microbiota permanently colonize the host.
Symbiosis is the relationship between normal microbiota and the host.
Commensalism benefits one organism, the other is unaffected.
Mutualism benefits both organisms.
Parasitism benefits one organism at the expense of the other.
Some normal microbiota are opportunistic pathogens.
Microbial antagonism is a competition between microbes.
Normal microbiota protect the host by occupying niches that pathogens might occupy, producing acids, and producing bacteriocins.
Probiotics are live microbes applied to or ingested into the body, intended to exert a beneficial effect, perhaps by competition.

Patterns of Disease

Predisposing factors make the body more susceptible to disease: short urethra in females, inherited traits (like sickle cell gene), climate, weather, fatigue, age, lifestyle factors (potentially the biggest one), and chemotherapy.
The stages of a disease include incubation period (no signs or symptoms), prodromal period (mild signs or symptoms), period of illness (most severe signs and symptoms), period of decline (signs and symptoms), and period of convalescence.

Epidemiology

Epidemiology is the study of where and when diseases occur.
Key figures in pioneering epidemiology include John Snow (cholera in London), Ignaz Semmelweis (handwashing and puerperal fever), and Florence Nightingale (sanitation and epidemic typhus).
Descriptive epidemiology collects and analyzes data. Types include retrospective, prospective, and analytical studies (e.g., Snow's cholera study, Nightingale's study of soldiers during the Crimean War).
Analytical studies compare a diseased group to a healthy group (e.g., case-control studies, cohort studies).
Experimental epidemiology involves controlled experiments (e.g. Semmelweis' handwashing study).
Epidemiology tracks disease occurrence using case reporting systems, nationally notifiable diseases, morbidity (incidence of disease), and mortality (deaths from disease). Also includes morbidity and mortality rates.

Reservoirs of Infection

Sources of infection include humans (e.g., AIDS, gonorrhoea), or carriers with unapparent infections, and animals (e.g., rabies, Lyme disease), or some zoonotic diseases (animal diseases transmitted to humans). Nonliving reservoirs include soil (botulism, tetanus).

Transmission of Disease

Transmission can be direct (close association between infected and susceptible host), indirect (spread by fomites – objects that carry disease), droplet (airborne droplets), or via vehicles (food, water, air), or by vectors (arthropods like fleas, ticks, and mosquitoes). Mechanical and biological transmissions are different types of vector transmission.

Nosocomial Infections

Nosocomial infections are acquired in hospitals.
Factors contributing to nosocomial infections include microorganisms in the hospital environment and compromised hosts.
Common causative agents include coagulase-negative staphylococci, S. aureus, Enterococcus, gram-negative rods, and C. difficile.

Emerging Infectious Diseases

Emerging infectious diseases are new or increasing in incidence.
Contributing factors include genetic recombination, evolution of new strains, inappropriate use of antibiotics and pesticides creating resistant strains, changes in weather patterns, modern transportation, ecological disasters, and public health failures.
Examples include avian influenza, E. coli O157, V. cholerae O139, Zika, West Nile virus, Lyme disease, plague, Coccidioidomycosis, hantavirus, and diphtheria.

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Description

Explore the key concepts of disease and epidemiology in Chapter 14. This chapter covers the role of normal microbiota, different types of symbiotic relationships, and mechanisms of infection spread. Understand how these factors influence health and disease.