Ch. 37 Epidemiology and Public Health Microbiology

College dormitories are notorious for outbreaks of flu and other infectious diseases. These are particular prevalent during final exam weeks. Using your knowledge of the immune response and epidemiology, suggest practices that could be adopted to minimize the risks at such a critical time.

Conditions that contribute to disease outbreaks during finals include depressed immunity from lack of sleep, poor nutrition, and psychological stress. Spread of infections are promoted by group studying and students being together during the exams themselves.

An infectious disease may: A. be mild B. be severe C. kill the host D. all of the choices

D. all of the choices

Which of the following contributes to the emergence of new diseases? A. rapid transportation systems and the mobility of the population B. ecological disruption such as the loss of predators and the destruction of rain forests C. increased drug usage and sexual promiscuity D. all of the choices

D. all of the choices

Which of the following is considered a newly emerging disease? A. Escherichia coli O157:H7 B. Cryptosporidiosis C. Hantavirus pulmonary syndrome D. all of the choices

D. all of the choices

Which of the following is used to reduce or eliminate the source of an infection? A. treatment of sewage to reduce water contamination B. destruction of vectors by spraying insecticides C. destruction of an animal reservoir of the infectious agent D. all of the choices are used to reduce or eliminate the source of an infection

D. all of the choices are used to reduce or eliminate the source of an infection

The science of epidemiology: A. evaluates the control of disease in a defined population B. evolved in relation to the great epidemic diseases C. embraces all diseases D. all of these

D. all of these

The sudden increase in the occurrence of a disease above the expected level is called:

D. an epidemic

Which of the following is a mechanism by which new susceptible individuals enter a population?

D. birth of new individuals and migration of individuals into the population

Which of the following is the major focus of epidemiologists?

D. both the discovery of factors essential to disease occurrence and the development of methods for disease prevention

An organism that is able to be transmitted from one host to another is said to be:

D. communicable

Precautions that can be taken by individuals to prevent travel-related infectious diseases include:

D. wash hands with soap and water frequently and get or update vaccinations appropriate for specific destinations

Why is a DNA vaccine delivered intramuscularly and not by intravenous or oral routes?

DNA itself is not the antigen. To make the antigen, the DNA must enter host cells ,then be transcribed and translated. Research has shown that muscle cells do this well. Orally given DNA would likely just be degraded in the stomach and intestine. DNA injected into the bloodstream could be taken up by RBCs, but these have no nucleus and would be poor expressers of protein.

How can changes in herd immunity contribute to an outbreak of a disease on an island?

Herd immunity should inhibit the spread of an infectious agent. On an island, there may be less of a possibility of re-introduction of the agent, and herd immunity may be enough to eliminate the pathogen from the island

Which type of epidemic usually results from a single contaminated source such as food?

B. common-source

Public health surveillance is the proactive evaluation of: A. genetic background B. environmental conditions C. human behaviors and lifestyle choices D. emerging infectious agents E. all of the choices

E. all of the choices

Why does an inactivated vaccine induce only a humoral response, whereas an attenuated vaccine induces both humoral and cell-mediated responses?

Inactivated vaccines are basically just injections of antigens, as the microorganism is killed. The more immunogenic attenuated vaccine organisms are alive, and interact with the immune system more similarly to the real pathogen

Why is international cooperation a necessity in the field of epidemiology? What specific problems can you envision if there were no such cooperation?

Info about emerging infections must be widely distributed. Coordinated efforts are needed to fight worldwide scourges such as polio. Without these efforts, areas could be blindsided by emerging infections and it would be impossible to eradicate diseases, which commonly cross international borders

What common sources of infectious disease are found in your community? How can the etiologic agents of such infectious diseases spread from their source or reservoirs to members of your community?

Local sources include lakes, water parks, public gather areas. Mechanisms of spread include vectors, wild animals, etc.

T/F: Active immunization of a population will raise the general level of herd immunity

true

Living transmitters of an infectious organisms from one host to another are called ___.

vectors

___ are the leading cause of nosocomial diseases.

A. Bacteria

An infected individual who is a potential source of infection for others and plays an important role in the epidemiology of the disease is a:

A. carrier

The sudden, unexpected occurrence of a disease in a limited segment of a population is called a(n):

A. outbreak

The ___ rate refers to the total number of individuals infected at any one time regardless of when the disease began.

A. prevalence

A ___ epidemic is characterized by a relatively slow and prolonged rise then a gradual decline in the number of individuals infected.

A. propagated

Which type of epidemic usually results from the introduction of a single infected individual into a susceptible population?

A. propagated

The site or natural environmental location in which the causative organism is normally found is called the:

A. reservoir

how can you prove that an epidemic of a given infectious disease was occurring?

An epidemic is an ocurrence of cases that are above the normal, endemic level for that area. Reports from individual physicians, clinics, and hospitals generally are the first and primary source of infection data.

The Centers for Disease Control estimates that ___ of all hospital patients acquire some type of nosocomial infection

B. about 10%

The intentional or threatened use of viruses, bacteria, fungi, or toxins from living organisms to produce death or disease in humans, animals, and plants is known as:

B. bioterrorism

A ___ epidemic is characterized by a sharp rise to a peak than a rapid, but not as pronounced, decline in the number of individuals infected.

B. common source

Chlorination of water supplies represents an epidemiological technique directed at:

B. eliminating sources of infections

The first case in an epidemic is called the:

B. index case

A ___ rate measures the number of individuals who become ill as a result of a specific disease within a susceptible population during a specific time period.

B. morbidity

A(n) ___ is an increase in disease occurrence within a large population over a very wide region (usually the world).

B. pandemic

The most common nosocomial infections are:

B. urinary tract infections

Diseases of animals that can be transmitted to humans are called:

B. zoonoses

The first epidemiologist was:

C. John Snow

an epidemic is:

C. a sudden increase in the occurrence of a disease above the expected level

When a disease maintains a relatively steady, low-level frequency at a moderately regular interval, it is called:

C. endemic

___ immunity is an epidemiological concept that explains the resistance of a population to infection and the spread of an infectious organism due to the immunity of a high percentage of the population.

C. herd

The ___ rate is the relationship of the number of deaths from a given disease to the total number of cases of the disease.

C. mortality

T/F: A major, genetically determined change in the antigenic character of a pathogen is called antigenic drift.

false

T/F: Most organisms that cause nosocomial infections come from endogenous sources

false

T/F: Surveillance of health issues is typically accomplished by two methods: population surveys and antibiotic treatment

false

The location where a disease-causing organism is normally found is called the ___.

reservoir

The immediate location from which a disease-causing organism is transmitted to a host either directly or through an intermediate is called the ___.

source

it is likely that an act of ___ will be defined by a sudden spike in an unusual disease reported to the public health system.

terrorism

T/F: After an infectious disease has been identified in a population, the next step is to correlate the disease outbreak with a specific organism.

true

T/F: An infection that is incubating in a patient at the time of admission and which develops clinical symptoms during the patient's stay in a health care facility is not considered nosocomial.

true

T/F: Antigens in vaccines are mixed with an adjuvant to enhance the rate and degree of immunization

true

T/F: Nosocomial infections are ones that develop within any health care facility

true

T/F: The Public Health Security and Bioterrorism Preparedness and Response Act identifies select agents and categorizes them as either level 1, 2, or 3

true

T/F: Vaccines using inactivated pathogens do not stimulate cell-mediated immunity as effectively as vaccines using attenuated pathogens

true