Micro: Viruses Flashcards
Naked dsRNA virus.
Rotavirus
Transmission of rotavirus.
Fecal-oral
Naked RNA virus, cruise ships.
Norwalk virus
Naked DNA virus, swimming pools, conjunctivitis, diarrhea.
Adenovirus
IC pts., organ transplants, ulcers, bloody diarrhea.
CMV
What about rotavirus allows one child to be infected more than once?
Segmented RNA allows it to do Antigenic shift
Main virulence factor of Rotavirus and what it does.
Viral Protein 7 (VP7)
-induces formation of neutralizing Abs
How does Rotavirus cause diarrhea?
NSP4 protein acts like a toxin to cause calcium influx into cells. Results in chloride, sodium, and water efflux resulting in diarrhea
Type of vaccine for Rotavirus
Oral live
Yellow Fever vector
Aedes mosquito
Viral characteristics of yellow fever
RNA, enveloped
Symptoms of Yellow Fever infection.
Jaundice, dark urine, pale stools, black vomit
Pathogenesis of Yellow fever.
- Virus invades hepatocytes
- Hepatocytes produce MHC I
- CD8 T cells recognize MHC I and kill hepatocytes
- results in jaundice
- jaundice causes all the other symptoms
Type of vaccine for yellow fever.
Live Attenuated
Pathogenesis of Hep A virus.
Cell Mediated Immunity (CMI) causes the hepatitis.
-children are at risk of chronic infection because they have an immature immune system which allows the virus to survive
Type of vaccine for Hep A
Killed vaccine
What are Dane particles?
Infectious form of Hep B virus containing surface Ag proteins surrounding viral DNA and RT enzyme
Name the 3 antigens present in a Hep B infection and what they can tell us thru serology.
Surface antigen - patient currently infected
Core antigen - patient currently infected
Envelope antigen - patient infected and has active viral replication occuring
What do the Surface antigen antibodies and core antibodies tell us about a patient with Hep B?
Anti-sAg: patient received vaccine or cleared a previous infection
Anti-cAg: patient cleared a precious infection
What dictates if a Hep B infection will be acute or chronic?
Patients CMI. A strong immune response will show an acute attack with symptoms after just a couple weeks after infection. Then the body usually clears the virus.
A weak immune response leaves the liver intact initially but does not kill the virus, so the virus remains for longer than 6 months
Type of vaccine for Hep B
Genetically engineered to only have the Surface Ag.
2 treatments for Hep B.
- RT inhibitor
2. INF-alpha (inhibits Elongation Factor 2 preventing protein synthesis)
What are the 3 C’s of Hep C?
Chronic, cirrhosis, cancer
How does Hep C get into hepatocytes?
Coats itself with LDL and VLDL which recognizes surface receptors on the hepatocytes
Treatment for Hep C infection.
Recombinant INF-alpha
and ribavarin
Why does Hep D need Hep B do infect the liver?
Hep D will use the surface antigens made by Hep B and sent out into the blood.
What is the difference between a Hep B and Hep D coinfection vs. superinfection?
Co infection occurs when the two viruses infect the body at the same time. The Hep B surface antigen takes longer to be made and provide Hep D with a way to enter hepatocytes.
Superinfection occurs when Hep B infection is followed by Hep D and the surface antigens of B are already disseminated. The result is the same but occurs much faster in superinfection.
Who is at the greatest risk for a Hep E infection in the U.S.?
Pregnant patients
