Question 1

Which of the following situations might cause normal microbiota to become opportunistic pathogens?

Accepted Answer

Treatment of a cancer patient with radiation can damage the mucosal linings of the digestive and respiratory tracts, which can alter the normal microbiota and create opportunities for normally harmless microorganisms to become opportunistic pathogens.

Question 2

Which of the following is transmitted by the parenteral route?

Accepted Answer

Yellow fever is transmitted by the parenteral route, which means it enters the body through methods other than ingestion or inhalation, such as injection or contact with contaminated blood or body fluids. Ringworm, warts, gonorrhea, and pertussis are all transmitted by other routes, such as contact, droplets, or sexual contact.

Question 3

Mutualism is a relationship

Accepted Answer

Mutualism is a relationship where both members derive benefits such that one or both parties cannot live without the other. The term "mutual" implies that both parties give and take, and both derive benefits from the relationship.

Question 4

Which of the following is a sign of disease?

Accepted Answer

Fever is a sign of disease as it indicates an increase in body temperature due to an illness or infection. The other symptoms listed (headache, dizziness, nausea, cramps) can also be signs of disease, but they can also be caused by other factors such as dehydration, stress or anxiety, food intolerance, or menstrual cycle.

Question 5

A healthcare-associated (nosocomial)disease is a disease acquired

Accepted Answer

A healthcare-associated (nosocomial) disease is one that is acquired within a healthcare setting, such as a hospital or clinic. This can include infections such as MRSA, Clostridium difficile, or pneumonia that are acquired as a result of receiving care within these facilities. Options A, B, and E do not relate specifically to healthcare settings, while option C may be associated with healthcare settings but is not as broad as the definition of a nosocomial disease.

Question 6

Chagas' disease is transmitted by a bug with mouthparts that penetrate blood vessels.Which type of exposure does this represent?

Accepted Answer

The parenteral route involves the introduction of a pathogen directly into the bloodstream, which is exactly what happens when the Chagas' disease bug penetrates blood vessels with its mouthparts.

Question 7

Figure represents a Petri dish with a fungus (F),shown in darker gray,growing in the midst of bacterial lawn (B),shown in light gray.The relationship between the fungus and the bacteria would best be described

Accepted Answer

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Figure represents a Petri dish with a...

Question 8

Which of the following stages of an infectious disease is the most severe?

Accepted Answer

The illness period is the most severe stage of an infectious disease, as this is when the individual experiences the full range of symptoms and the highest levels of pathogen replication within the body. The incubation period and prodromal period are typically characterized by milder symptoms or no symptoms at all. The decline period and convalescence period are marked by a decrease in symptoms and recovery from the infection.

Question 9

Diseases that are induced by modern medical procedures are referred to as ________ infections.

Accepted Answer

Iatrogenic infections are those that are caused by medical procedures, treatments or healthcare interventions, such as surgeries, catheterizations or the use of medical devices. Exogenous infections are caused by external factors, such as environmental agents, while opportunistic and endogenous infections are typically associated with compromised immune systems. Subacute refers to a disease that has a slower onset and milder symptoms than an acute infection.

Question 10

Symptoms are

Accepted Answer

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Question 11

The fungus Pneumocystis jiroveci is found in the lungs of most people in low numbers,but in immunocompromised people it overgrows,resulting in severe respiratory problems.The fungus is best described as

Accepted Answer

The fungus Pneumocystis jiroveci is normally found in low numbers as resident microbiota in the lungs of most people. However, in immunocompromised individuals, it can opportunistically become an overgrowth and cause severe respiratory problems as an opportunistic pathogen. Therefore, the best description of this fungus is as both resident microbiota and an opportunistic pathogen.

Question 12

In which of the following do the mucous membranes serve as a portal of entry for disease?

Accepted Answer

The mucous membranes in the eye and nasal cavity can serve as portals of entry for pathogens. If a person rubs their eye with contaminated fingers, the pathogen can enter the nasal cavity through tears.

Question 13

Which of the following is an example of an exotoxin?

Accepted Answer

Neurotoxin is an example of an exotoxin, as it is a poison secreted by certain bacteria that affects the nervous system. Coagulase, streptokinase, and collagenase are enzymes secreted by bacteria, whereas lipid A is a component of the outer membrane of Gram-negative bacteria and is responsible for the toxic effects of endotoxins.

Question 14

Among the virulence factors produced by Staphylococcus aureus are hemolysin,coagulase,hyaluronidase,and enterotoxin.Which of these factors contribute to the ability of S.aureus to invade the body?

Accepted Answer

The answer of Among the virulence factors produced by Staphylococcus...

Question 15

Which of the following situations is NOT a way in which a baby acquires normal microbiota?

Accepted Answer

Microbes do not cross the placenta during pregnancy and therefore do not contribute to the acquisition of normal microbiota in the baby. Normal microbiota is typically acquired through exposure to the environment and from the mother during delivery and breastfeeding.

Question 16

Which of the following is considered part of the indigenous microbiota of the female reproductive system?

Accepted Answer

The indigenous microbiota of the female reproductive system includes both Candida and Lactobacillus. Lactobacillus helps maintain a low pH environment that is protective, while Candida species can be found in small numbers without causing infection.

Question 17

Which of the following statements regarding the demonstration of the etiology of disease is FALSE?

Accepted Answer

The statement "The suspect agent must be the only potential pathogen present in disease cases" is false. Many diseases can be caused by multiple pathogens or can have co-infections with other pathogens.

Question 18

The close contact between newborns and family members allow them to become ________ with microbes that become established as their microbiota.(Choose the most accurate term.)

Accepted Answer

"Colonized" is the most accurate term as it refers to the establishment of microbial communities as part of the newborn's microbiota. It does not necessarily imply infection or parasitism, and the term "contaminated" or "infiltrated" carries negative connotations that are not relevant in this context.

Question 19

Which of the following is NOT an example of symbiosis?

Accepted Answer

Symbiosis refers to a close and long-term biological interaction between two different biological organisms. Microbes passing across the placenta to the fetus is not a symbiotic relationship; it is typically a harmful or pathogenic interaction.

Question 20

Which of the following is considered a mechanical vector transmission?

Accepted Answer

Mechanical vector transmission refers to the passive transport of pathogens by an insect or other animal. The pathogen does not undergo any development or multiplication within the vector. In the case of a cockroach transmitting Shigella, the cockroach can carry the pathogen on its body from feces or other contaminated sources to food or surfaces that humans then touch or consume, thus acting as a mechanical vector.

Quiz 14: Infection, Infectious Diseases, and Epidemiology