Microbiology 106: Viral Infections

Microbiology 106: Viral Infections

Microbiology 106
Viral infections: blood, lymph, GI, nervous

GI viruses
General similarities:
often hard to discern from bacterial GI infections
diarrhea, vomiting, nausea, fever, cramps, headache, aches, dehydration
dehydration is usually primary concern, esp. for elderly & infants

rotavirus '' (icosahedral, RNA, no membrane)
particularly common & nasty in children '' a leading cause of infant mortality worldwide
source: contaminated food/water, poor hygiene
vaccine '' Rotateq
no antiviral drug '' treat symptoms (*hydrate!*)

norovirus '' (Calcivirus '' icosahedral, RNA, no membrane)
source: contaminated water & food, poor hygiene
highly contagious, and many varieties of norovirus
no vaccine or antiviral treatment '' treat symptoms

enterovirus '' (Picornavirus '' icosahedral, RNA, no membrane)
2 particularly common groups:
Coxsackie virus - can move from intestines to muscles, meninges, other organs
Echovirus '' can also cause meningitis and/or skin rashes

Hepatitis viruses
A '' picornavirus (icosahedral, RNA, no membrane) '' “Case 15 on p. 461)
2-4 week incubation
begins as GI infection '' lack of appetite, nausea, fever, vomiting
virus moves to liver --> pain in upper right abdomen due to swelling
jaundice '' sometimes but not always
lasts several weeks, and relapses are common, though recover = immunity
Dx via liver function tests, anti-hepA antibodies
hygiene critical in preventing spread
three vaccines available (Havrix, Vaqta, Twinex (for A & B))
no antiviral drug '' treat by managing symptoms

B '' hepadnavirus (icosahedral, DNA, membraned)
transmitted via bodily fluid exchange '' blood, sexual fluids
* nonsterile needles for tattoos, IV drugs, body piercing, etc.
1-6 month incubation period
Symptoms: fatigue, lack of appetite, nausea/vomiting, dark urine
many patients are asymptomatic
later- liver pain, jaundice; persists...

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