HOST MICROBE INTERACTION (by sir mod)

In a diseased individual, the number of microbes would be highest at

• prodromal

• incubation

• period of illness

• period of convalescence

Causative agent is inactive for some time but then becomes active

• Latent

• Subacute

• Chronic

• Acute

Answer explanation

Latent means hidden, dormant, inactive. A latent infection is an infection that is hidden, inactive, or dormant, as opposed to active infections, where a virus or bacterium is actively replicating and potentially causing symptoms.

Which of the following statements about exotoxins is generally FALSE?

• They are resistant to heat.

• They are produced by gram-positive bacteria.

• They are composed of proteins.

• They are more potent than endotoxins.

Answer explanation

Exotoxins can be damaged by heat. Endotoxins on the other hand resist autoclave conditions

A healthy person can be a reservoir of infection.

• TRUE

• FALSE

Answer explanation

Many people harbor pathogens and transmit them directly or indirectly to others. People with signs and symptoms of a disease may transmit the disease; in addition, some people can harbor pathogens and transmit them to others without exhibiting any signs of illness (carriers).

All of the following are normal flora in the human body except for

• Staphylococcus

• Micrococcus

• E. coli

• Streptococcus

Answer explanation

Micrococcus is found in the environment, the rest are found in the human body

A nosocomial infection is

• always caused by pathogenic bacteria.

• acquired during the course of hospitalization.

• always caused by medical personnel.

• only a result of surgery.

Answer explanation

A nosocomial infection is an infection that is acquired in a hospital or other health care facility. To emphasize both hospital and nonhospital settings, it is sometimes instead called a health care-associated infection (HAI)

The most frequently used portal of entry for pathogens is the

• parenteral route.

• mucous membranes of the gastrointestinal tract.

• skin.

• mucous membranes of the respiratory tract.

Answer explanation

The respiratory tract is in contact with air so a lot of microbes can enter.

Type of relationship between organisms that benefit from each other, whether through providing shelter or food, protection, etc.

• mutualism

• tropism

• commensalism

• parasitism

Answer explanation

Mutualism provides benefits to both parties.

In commensalism, only one benefits while the other is unharmed.

In parasitism, one party is harmed while the other benefits.

Tropism is the movement of an organism towards or away from a stimulus.

Dogs do not get measles because their cells lack the correct receptor sites for that virus.

• TRUE

• FALSE

Answer explanation

Remember that viruses can be cell-specific. If they are, that means they need to bind to a particular receptor before they can enter a cell and reproduce.

So if dogs cannot get measles, that means they lack the receptors or correct sites of attachment.

Characterized by early, mild symptoms of disease, such as general aches and malaise.

• Incubation

• Prodromal

• Convalescence

• Period of illness

Answer explanation

A prodrome is an early sign or symptom (or set of signs and symptoms) that often indicates the onset of a disease before more diagnostically specific signs and symptoms develop.