Coronaviruses (Chapter 32) Flashcards

Question

lytic virus Polio Virus

Answer 1

``` destruction of host cells virus is shed into stool up to 10,000 virus per infected cell) even weeks to months after symptoms gone ```

Answer 2

transmission: fecal-oral

Answer 3

RNA alone can cause infection

Answer 4

Internal Ribosome Entry Site IRES serves as the “cap” of the viral RNA, promoting translation of viral RNA into viral proteins

Answer 5

``` Because of IRES, translation starts far from the 5􀀁 end of poliovirus RNA (normal mRNA translation starts near 5’ end) ```

Answer 6

IRES serves as the “cap” of the viral RNA, promoting translation of viral RNA into viral proteins

Answer 7

central nervous system disease flaccid paralysis results from destruction of anterior horn cells in spinal cord bulbar poliomyelitis most severe form respiratory muscle paralysis (medulla oblongata) ~25% mortality factors increasing severity of poliovirus infections physical exertion and trauma tonsillectomy

Answer 8

Multiplication in various organs | Major Viremia>>>>>>>>>>>peripheral nerve ganglia/CNS=paralytic disease=1% infections

Answer 9

Live oral vaccine (Sabin) mimics the normal infection process of poliovirus Killed parenteral vaccine (Salk) only generates serum antibodies

Answer 10

``` aseptic meningitis herpangina sudden onset of fever vesicles/ulcers on tonsils and palate coxsackievirus type A16 hand, foot, and mouth disease blisters on hand, feet, and palate ```

Answer 11

heart (myocarditis) respiratory tract (pleurodynia) mucous membranes of eye (hemorrhagic conjunctivitis

Answer 12

~100 serotypes account for ~1/2 the cases of the common cold bind to respiratory epithelial cells ICAM-1 (most) or VLDL receptor (some) replication details very similar to poliovirus Acid sensitive and 33oC optimum for replication no tissue destruction

Answer 13

Icam mostly

Answer 14

sometimes infection has complications sinusitis, otitis media worsening of asthma (assoc. with 50% of attacks) vaccine prospects poor (too many variants)

Answer 15

(arthropod-borne viruses) (Chapter 33) viruses transmitted by arthropods multiply in tissues of vector, often without producing disease

Answer 16

For many arboviruses humans are 􀀁dead-end􀀂 hosts: viremia of short duration virus levels in blood are low

Answer 17

plus stranded RNA (single linear molecule) | enveloped

Answer 18

2 phases of translation -first produce early proteins and then late proteins -like coronavirus

Answer 19

Ribosomes bind to the positive-sense RNA genome early polyproteins are made

Answer 20

The polyproteins are cleaved to produce nonstructural proteins 1 to 4 (NSP1 to NSP4), which include a polymerase to transcribe the genome into a negative-sense RNA template.

Answer 21

5, The template is used to | produce a full-length 42S positive-sense mRNA genome and a late 26S mRNA for the structural proteins.

Answer 22

9, Budding from the plasma membrane releases | the virus.

Answer 23

``` Rubella virus Member of Togavirus family Rubivirus genus but not arthropod-borne Rubella = German measles one of the 5 childhood exanthems (along with measles, roseola, chickenpox, and fifth disease) ```

Answer 24

Flaviviruses plus stranded RNA (single linear molecule) Enveloped Brah!

Answer 25

Encephalatis yellow fever (heptitis) Hemorric fever DHF/DSS

Answer 26

mostly mild illness (Zika fever) except for congenital infection of fetus, which leads to microcephaly and other birth defects transmitted by mosquitos from person to person (most common) Aedes aegypti mosquito (worldwide distribution of A. aegypti below)

Answer 27

also transmitted sexually | Person to person

Answer 28

most prevalent disease caused by arboviruses does not cause significant mortality enerally not a zoonosis: transmitted by mosquitos from person to person when partial immunity exists due to prior infection dengue hemorrhagic shock (DHS) dengue shock syndrome (DSS) due to immune enhancement virus forms immune complex/readily enter macrophages increases viral load Activates memory T cells, which release cytokines and initiate hypersensitivity reactions. These reactions cause weakening and rupture of vasculature, internal bleeding, loss of plasma.

Answer 29

when partial immunity exists due to prior infection dengue hemorrhagic shock (DHS) dengue shock syndrome (DSS) due to immune enhancement virus forms immune complex/readily enter macrophages increases viral load

Answer 30

Activates memory T cells, which release cytokines and initiate hypersensitivity reactions. These reactions cause weakening and rupture of vasculature, internal bleeding, loss of plasma

Answer 31

``` Yellow Fever (caused by a Flavivirus) • historical importance – first human disease found to be caused by a virus – first viral disease confirmed to be spread by insect vector – Mosquito: Aedes aegypti • spread by two methods (via mosquito) – human to human – monkey to human ```

Answer 32

Jaundice lesions and hemorrhaging of infected organs attenuated live vaccine and insect control measures