Parovirus

Question 1

structure of Parovirus

Answer 1

• it has the smallest DNA and has limited coding depending on the function of the host cell or coinfecting virus
  -Icosahedral nonenveloped ssDNA
• it contains 2 coat protiens made by overlapping DNA making VP2 identical to carboxy protiens of VP1

Question 2

families of Parovirus

Answer 2

-parovirinae infecting vertebrates
-densovirinae infecting insects

Question 3

Replication of B19 parovirus

Answer 3

only infect primary erythroid progenitors, placenta, fetal liver, heart and mature erythrocytes and infect cellular receptor P antigen the globoside
-α5β1 integrin is believed to be a coreceptor for B19 entry
-replciates in neuclus 1

Question 4

pathogensis of parovirus

Answer 4

• affects immature erythroid linage cells so adult marrow, Blood cells and fetal liver causing cell death adn interrupting RBCs production and maturation and causing erythroblast intranuclear inclusions
• in immunocompromised agent it causes chornic anemia and in fetus it causs severe anemia
• is transmitted by respraitory route, blood transfusion or blood productions

Question 5

Erythema infectiosuma (5th disease)

Answer 5

• most common
• Rash with slapped cheek appearnce , joint involvment due to immune complex deposition , arthropathy
• shortlived infection and rash ffades in 2-4 days and joint symptoms stay longer and IgG appear 15 days after infection

Question 6

Transient aplastic crisis of parovirus

Answer 6

• may complciate hemolytic anemia with patients with sickel cell disease, thalassmia and acquired hemolytic anemia in adult.
• caused after bone marrow transplant
• cessation of RBCs synthesisi in BM

Question 7

infection of B19in immunodeficient patients

Answer 7

causes pure RBCs aplasia

Question 8

infection of B19 during pregnancy

Answer 8

• cause hydrops fetalis and fetal death due anemia mostly before the 20th week

Question 9

Human bocavirus

Answer 9

prelavant among children with acute wheezing

Question 10

Lab diagnosis for B19

Answer 10

1-PCR
2-Probe hybridization of serum or issue extracts
3- situ hybdridzation on fixed tissue
- detection of B19 IgM is indicitave of recent infection
- IgG for B19 presists for years

Question 11

Epidemiology of Parovirus

Answer 11

• outbreaks in school
• children between age of 5-19
  -transmission via respiratory tract
• at onset of rash for 5th disease the patient isnt infectious