What of the following remains a significant cause of morbidity and mortality worldwide?
Ans: Infectious disease
Exp: Despite the wide scale implementation of progressive public health and immunization policies infectious disease remains a significant cause of morbidity and mortality.
What is the first stage in the infectious process?
Ans: Colonization
Exp: From the perspective of the microorganisms that cause disease, the infectious process undergoes four separate stages of progress: colonization, invasion, multiplication, and spread.
For which microorganism is the skin the site of reproduction?
Ans: Bacteria and fungi
Once they have penetrated the first line of defense, which microorganisms do neutrophils actively attack, engulf and destroy by phagocytosis?
Ans: Bacteria
Exp: Invasion results in direct confrontation with an individual's primary defense mechanisms against bacteria, which include the complement system, antibodies, and phagocytes, such as neutrophils and macrophages.
Cytokines are though to raise the thermoregulatory set point to cause fever by stimulating the synthesis of which chemical mediator?
Ans: Prostaglandin
Exp: These cytokines seem to raise the thermoregulatory set point through stimulation of prostaglandin synthesis and turnover in thermoregulatory (brain) and nonthermoreglatory (peripheral) tissue.
One systemic manifestation of an acute inflammatory response is fever that is produced by:
Ans: Endogenous pyrogens acting directly on the hypothalamus
Exp: There is little evidence that exogenous pyrogens cause fever directly. Such pyrogens indirectly affect the hypothalamus through endogenous pyrogens released by cells of the host.
Which statement about vaccines is true?
Ans: Vaccines require booster injections to maintain lifelong protection.
Exp: In general, vaccine-induced protection does not persist as long as infection-induced immunity, thus booster injections may be necessary to maintain protection throughout life.
Which of the following is a characteristic of HIV?
Ans: The virus is a retrovirus
Exp: One particular family of viruses, retroviruses (e.g. HIV) carries an enzyme reverse transcriptase that creates a double-stranded DNA version of the virus.
What is the role of reverse transcriptase in HIV infection?
Ans: It converts RNA into double-stranded DNA
Exp: One particular family of viruses, retroviruses (e.g. HIV) carries an enzyme reverse transcriptase that creates a double-stranded DNA version of the virus.
Infectivity
The ability of the pathogen to invade and multiply in the host.
Virulence
The capacity of a pathogen to cause severe disease. The potency of a pathogen is measured in terms of the number of microorganisms or micrograms of toxin required to kill the host.
Toxigenicity
An important factor in determining a pathogen's ability to produce disease by production of a soluble toxin.
Pathogenicity
The ability of an agent to produce disease/