Flashcards in Medical Microbiology Deck (51):
Returning to normal after period of sickness
In the first reported epidemiological study in 1854, John Snow attempted to discover the source of a London cholera epidemic by going house-to-house and recording deaths. When he mapped the results, he was able to identify the Broad Street water pump as the likely source of contaminated water. The data collected in this study was__________.
The incidence of disease in a population is termed the __________.
The typical progression of symptoms for an acute infection would be __________.
A incubation-acute period-infection-decline period-convalescence
B infection-acute period-incubation-decline period-convalescence
C incubation-infection-acute period-decline period-convalescence
D infection-incubation-acute period-decline period-convalescence
Which of the following shows the correct relationship among the epidemiology terms listed?
A incidence > prevalence > mortality
B prevalence > incidence > mortality
C mortality > morbidity > prevalence
D mortality > incidence > prevalence
The RATE of occurrence of new cases
The percentage of the population that has the disease
A large number of cases of a particular disease observed in a relatively short period of time in an area that previously experienced only sporadic cases of the disease is known as a(n)
Which stage of an acute infectious disease occurs between the time the organism begins to grow in the host and the appearance of disease symptoms?
A decline period
B incubation period
D acute period
Which body site is preferentially infected by foodborne pathogens?
A cerebrospinal fluid
C gastrointestinal tract
D respiratory tract
Cholera is an example of a pandemic disease that
A is spread through direct contact and has only a human reservoir.
B has multiple wild animal reservoirs and is thus difficult to eradicate.
C spreads from a common source and could be controlled with adequate clean water and waste sanitation measures.
D has recently emerged due to overcrowding in urban centers.
Middle eastern respiratory syndrome (MERS) is caused by
A a rhinovirus.
B the influenza virus.
C Streptococcus pneumoniae.
D a coronavirus.
What is a/are potential reservoir(s) for viruses?
Which disease listed does NOT require quarantine?
The number of ill individuals within a population is referred to as
Disease ________ is measured by the total number of new reported disease cases within a population over a period of time.
A nonliving source of an infectious agent that infects a large number of people is called a
For many years the CDC focused its seasonal influenza vaccination efforts on those groups in the population who suffered the highest influenza mortality rates, including the elderly aged 65 years and older. However, starting in 2008 the CDC shifted their focus to school-aged children and began recommending the vaccine for everyone aged at least 6 months. Research had shown no evidence for any protective effect of the vaccine in the elderly. By changing the recommendations for who should be vaccinated, the CDC planned to better protect the elderly by means of__________.
B acquired immunity.
C herd immunity.
D direct contact.
Free flu shots were given at school, but 3 of the 30 students were absent that day. The next week Bob starting showing signs of the flu and was coughing and sneezing in class. None of the other students contracted the virus, even those that missed the shot. This can be explained by __________.
A herd immunity
Pathogens and hosts provide selection pressure to each other, resulting in varying degrees of co-evolution. Which of the following types of diseases would most likely be affected by co-evolution resulting in a lessening of virulence over time?
D Common source
Most cases of mosquito-transmitted diseases occur in
A tropical and sub-tropical regions.
B the summer and fall seasons.
C rural areas.
D tropical and sub-tropical regions or during the summer and fall seasons.
Over time, the relationship between a pathogen and a naïve susceptible population tends towards
A the extinction of the pathogen.
B a balance between host and pathogen such that both are maintained.
C the extinction of either the host or the pathogen.
D the extinction of the host.
In 2011, the CDC reported a 28-state outbreak of Listeria monocytogenes that killed 33 people in the U.S. The victims were found to have eaten portions of whole cantaloupe melons originating from a single farm in Colorado. The FDA traced the source of bacterial contamination to a piece of recently-purchased used equipment that was used to wash the melons, as well as nearby puddles of water and a truck that hauled spoiled melons to a field to be fed to cattle. This would be an example of__________.
A zoonotic reservoir.
B common-source transmission.
C water-borne transmission.
D person-to-person transmission.
All students that ate in the school dining hall on Monday developed stomach cramps and diarrhea. The student clinic was overwhelmed with patients. However, by Thursday the number of patients seen in the clinic was back to normal. This could have been caused by a __________.
A vector-borne disease
B infectious disease
C common-source epidemic
D host-to-host epidemic
After tuberculosis, malaria causes more annual deaths worldwide than any other single disease. Recent research has attempted to control the spread of malaria by genetically-modifying a bacterium (Pantoea agglomerans) commonly found in the guts of mosquitos to produce a toxin that kills the malaria parasite Plasmodium falciparum. If this project is effective it could significantly decrease the incidence of malaria because__________.
A malaria is a vectorborne disease.
B the mosquitoes will die.
C Pantoea agglomerans would be killed.
D malaria is a person-to-person disease.
Which of the following is/are considered (a) direct contact infection(s)?
A skin infections
D syphilis, gonorrhea, and skin infections
The onset of a given epidemic is indicated by a sharp rise in the number of cases reported daily over a brief interval. This indicates that the mode of transmission is
A insect vector.
B host to host.
C a common source.
D mechanical vector.
Which of the following diseases is NOT normally spread by a common source?
A waterborne diseases
D foodborne diseases
Treponema pallidum is extremely sensitive to temperature changes and low moisture, thus it is transmitted
A by intimate person-to-person contact.
B through common sources such as food and water.
C by vectors.
D by fomites.
Which of the following are NOT vectors important in disease transmission?
With regards to mode of disease transmission, respiratory pathogens are generally ________, and intestinal pathogens are generally spread by contaminated ________.
A more transmissible / needles
B airborne / food or water
C spread by indirect contact / carriers
D spread by direct contact / vectors
The basic reproduction number of a pathogen
A can be determined experimentally in the lab.
B is usually high for pathogens that are transmitted through direct contact.
C can be determined experimentally and is usually high for pathogens that are transmitted through direct contact.
D can vary during an epidemic based on infection control measures.
A marked seasonality to a disease is often indicative of
A a bacterial disease.
B the presence of carriers.
C certain modes of transmission.
D a zoonotic infection.
People who have a subclinical case of a disease are frequently ________ of a particular disease.
Disease cases that exhibit new syndromes or characteristics or are linked to new pathogens are surveyed through regional laboratories and considered ________ cases.
"Typhoid Mary" is an example of a ________, because she was infected by the causative agent for typhoid fever yet was asymptomatic.
Diseases can be controlled through immunization even if the percentage of the population that is immunized is less than 100% because
A vehicles can be sterilized.
B most diseases lack reservoirs.
C of herd immunity.
D vectors can be controlled through other means.
A person who tests positive for the human immunodeficiency virus but shows no symptoms of AIDS would be termed a __________.
When the human papillomavirus (HPV) vaccine was first introduced to help prevent cervical cancer and anal warts and cancers, it was only recommended for 11- or 12-year old girls. However, the CDC later expanded their HPV vaccination recommendations to include 11- and 12-year old boys. By including males, the public health officials hoped to do all but one of the following:
A protect men from anal warts and cancer
B decrease the basic reproductive number (R0) of HPV
C decrease the incidence of cervical cancer
D increase herd immunity to HPV
but they did want to decrease the basic reproductive number.
Basic Reproductive Number:
The average number of incidences of a disease which occur from a single incidence of the disease.
The emergent H5N1 strain of avian influenza can occasionally be transmitted from birds to humans with a resulting 60% mortality rate (compared with a 2.5% mortality rate for the 1918 pandemic influenza). In 2012, after a single dead chicken in a wholesale market in Hong Kong tested positive for H5N1, all 17,000 chickens in the market and surrounding area were culled. This was an attempt to__________.
A quarantine .
B eliminate a reservoir.
C prevent migration.
D eliminate a vector.
During the 2002-2004 emergence and epidemic of Severe Acute Respiratory Syndrome corona virus (SARS-coV) the virus was found to be highly contagious, with an observed reproductive number (R) of 3.6. For this reason many rigorous means of infection control were instituted by the countries experiencing SARS outbreaks, including__________.
A culling of chickens.
B quarantine and isolation.
D application of DDT to kill mosquitoes.
Appropriate action to control infectious disease where humans are the reservoir would include __________.
A control of the vehicle
C control of the vector
D eliminate breeding grounds
Which of the following is NOT a public health measure used to control the transmission of disease?
A genetic engineering
C sanitary water and waste disposal methods
D forced quarantine
Which of the following is an example of herd immunity?
A Brucellosis is no longer found in farm animals in the United States.
B Federal law requires that all cattle not immune to anthrax be destroyed.
C If 70% of the population is immunized against polio, the disease will be essentially absent from the population.
D All farm animals used for food must be immunized against all the common agents of disease that infect humans.
Which group of organisms is difficult to control through immunization because of their rapid and unpredictable genetic mutations?
A DNA viruses
B vector-borne organisms
C RNA viruses
Which public health measure(s) is/are MOST effective against pathogens transmitted through common vehicles?
A mosquito control
B water purification
C water purification and food safety regulations
D food safety regulations
Which of the following diseases would be the easiest to control in a human population?
A an infectious disease with wild animals as a reservoir
B an infectious disease with humans as the only reservoir
C an infectious disease with several possible reservoirs
D an infectious disease with domestic cows as the only reservoir
Diseases that are good candidates for eradication have
A an environmental reservoir.
B no asymptomatic phase.
C only a human reservoir and no asymptomatic phase.
D only a human reservoir.
Pasteurization of milk is an example of a disease control measure aimed at
A preventing host-to-host transmission.
B controlling the disease vector.
C eliminating the disease reservoir.
D preventing common source diseases.