Hepatitis, Viral Pathogenesis, Prions

Question 1

Hepatitis (Background Info)

Answer 1

Hepatitis viruses are not closely evolutionarily related to each other, but symptoms are similar because they all infect hepatocytes (liver), can cause acute hepatitis, treated with supportive care, diagnosis by serology, liver transplant alleviates liver failure but can become infected if virus is not cleared from secondary infection sites

Question 2

Hepatitis A

Answer 2

fecal oral transmission, vaccines available, IgM=acute, IgG=recovered/vaccinated,

Question 3

Hepatitis B

Answer 3

sex/birth/blood transmission, vaccines available, viral surface antigen=acute, IgG against viral surface antigen=recovered/vaccinated, can cause chronic hepatitis leading to cirrhosis and/or cancer

Question 4

Hepatitis C

Answer 4

sex/birth/blood transmission, EIA=real or false positive, RIBA=confirmation, can cause chronic hepatitis leading to cirrhosis and/or cancer

Question 5

Complementation

Answer 5

occurs when two viruses infect one cell. gene function of one virus replaces a mutated gene of another. produces progeny that cannot replicate.

Question 6

Phenotypic mixing

Answer 6

occurs when two viruses infect one cell. exchange of capsid proteins. could lead to virus progeny with capsids that are a mixture

Question 7

Pseudotype

Answer 7

occurs when two viruses infect one cell. genetic material of one virus in the capsid/envelope of another

Question 8

Recombination

Answer 8

occurs when two viruses infect one cell. exchange of genes by crossing over at regions of homology. results in hybrid virus that can reproduce.

Question 9

Reassortment

Answer 9

occurs when two viruses infect one cell. rearrangement of parts of a segmented genome to form a new set of segments

Question 10

Interference

Answer 10

infection by one virus tends to prevent infection by another

Question 11

Diseases that might be treated with gene therapy

Answer 11

Cystic fibrosis, Combined immune deficiency, Hemophilia, Various enzyme-deficiency disorders

Question 12

Problems associated with gene therapy

Answer 12

Short duration of expression, low efficiency of gene transfer, inflammation in response to the virus, potential for chromosomal disturbances by virus

Question 13

Sporadic CJD (sCJD)

Answer 13

rapid onset of brain shrinkage and deterioration, cannot be transmitted from human contact or meat contaminated with BSE (mad cow disease), definitive diagnostic test is brain biopsy, disease duration is 5-6 months, occurs more often in eldery

Question 14

Variant CJD (vCJD)

Answer 14

slower onset of brain function loss, bovine to human transmission of BSE, definitive diagnostic test is brain biopsy, disease duration is 14 months, characterized by type 4 prion, peripheral pathogenesis, round amyloid core surrounded by ring of spongiform vacuoles, occurs most often in younger population

Question 15

Mechanisms of Viral Transmission (8 total)

Answer 15

respiratory, fecal-oral, contact, zoonoses, blood, sexual, maternal-neonatal, genetic

Question 16

direct cell injury

Answer 16

caused by virus replication

Question 17

indirect cell injury

Answer 17

caused by host response

Question 18

chronic patterns of infection

Answer 18

persistent, latent, slow

Question 19

primary viremia

Answer 19

when virus can start to be detected in blood. leads to replication in internal organs, may occur without symptoms (incubation stage)

Question 20

secondary viremia

Answer 20

a lot of viruses in blood, virus can be readily detected, results in clinical symptoms

Question 21

susceptibility and severity of viral disease depend on

Answer 21

nature of exposure, viral dose, status of the person, virus-host interaction

Question 22

sites of virus entry

Answer 22

conjunctiva, respiratory tract, alimentary tract, urinogenital tract, anus, skin, scratch/injury, capillary (mosquito)