Enteric virus infections: Whitt

Question 1

Rotavirus:
Age predilection?
Model of replication and the virion structure?
Symptoms?
Control measures available?

Answer 1

Young children, infants. MCC severe diarrhea in kids and infants world-wide. Primarily acquired during winter months.

Structure and replication: Non-enveloped particle, segmented, dsRNA genome
Virus endocytosed–> capsid proteins proteolytically processed to reveal infectious subviral particle. Progeny created and released via lysis of host cell.

Symptoms/Pathogenesis: n/v/d/f dehydration. NSP4 protein acts similarly to bact. enterotoxin–> Cl- release from enterocytes–> watery diarrhea

Control measures available: vaccine.

Question 2

Noravirus:
Age predilection?
Model of replication and the virion structure?
Symptoms?
Control measures available?

Answer 2

School aged children and adults (Most common cause in adults) Cruise ships water/food contamination.
Structure and replication: non-enveloped, non-segmented, (+) strand ssRNA genome.
Virus injects RNA into host cell–> host cell machinery translates RNA–> progeny virus–> cell lysis. Otherwise, not well understood.

Symptoms: n/v/d/f dehydration. Vomiting in 50%. Illness lasts 12-60 hrs. Responsible for 60% of foodborne illness in the US!
Symptoms due to loss of microvilli–> watery diarrhea

Control measures available: NO vaccine

Question 3

Astrovirus:
Age predilection?
Model of replication and the virion structure?
Symptoms?
Control measures available?

Answer 3

Gastroenteritis in children progeny made–> budding (non-lytic) release

Symptoms: self-limiting diarrhea

Control measures available: NO vaccine

Question 4

Enterovirus:
Age predilection?
Model of replication and the virion structure?
Symptoms?
Control measures available?

Answer 4

NO AGE PREDILECTION
Structure and replication: non-segmented, non-enveloped, icosahedral, (+) sense, ssRNA virus. Initially replicate in lymphoid tissue of URT and gut.
*More of a summer virus

Symptoms:
Poliovirus- flaccid paralysis
Coxackieviruses- hand, foot, and mouth dz. meningoencephalitis, diarrhea, muscle pain, inflamm. of myocardium and pericardium.
Echoviruses- gastroenteritis

Control measures available: NO vaccine, except for polio.

Question 5

Adenovirus:
Age predilection?
Model of replication and the virion structure?
Symptoms?
Control measures available?

Answer 5

Young children and infants
large, non-enveloped, linear, dsDNA virus.
Replicate in the nucleus of vertebrate cells using the host’s replication machinery

Symptoms: diarrhea

Control measures: NO vaccine

Question 6

T/F: All these viruses can cause sporadic, acute gastroenteritis in adults.

Answer 6

True

Question 7

Pt is blowing at both ends. What virus is it?

Answer 7

Norovirus

Question 8

If you have bloody diarrhea, is it likely of viral origin?

Answer 8

No. Viruses do not cause bloody diarrhea.