v to dx

Question 1

HAV

Answer 1

Serology to dx
• HAV is antigenic and the host will produce IgM and IgG (later) abs against it.
• Abs will remain forever and only show that the person was affected at some point.

Question 2

west nile virus from flavivirus

Answer 2

• Culture or RNA amplification from PCR.
• IgG and IgM against WNV in the serum..
• CSF IgM against WNV.
• 4X increase serum ab titers.

Question 3

HCV

Answer 3

• Looking for the HCV abs after 6-8 weeks after exposure.

* Can measure using recombinant immunoblot assay (RIBA) or by measuring the HCV viral RNA.

Question 4

early detection HIV

Answer 4

p24 capsid protein

Question 5

AIDs

Answer 5

CD4 count of less than 200, a serologic test confirming HIV, and/or having an AIDS opportunistic infection like candida esophagitis, pneumocytosis carinii pneumonia, kaposi’s sarcoma, or many others.

Question 6

dx HIV AIDS

Answer 6

o HIV viral ags are in the bloodstream within weeks.
• Can be tested with PCR for the viral ags.
o 3-6 weeks after infection there will be abs.
• ELIZA can be used to test for this, but these rapid tests need to be confirmed with western blot as they can give false positives
o Now have rapid tsest of blood, plasma, saliva
o AIDS when CD4 less than 200 and/or opportunixtic infections

Question 7

influenza from orthemyxoviridans

Answer 7

o Virus isolation: culture of the virus to perform genetic and ag analysis.
o Detection of viral protiens: new one hour tests can be done to help choose antiviral agent.
o Detection of RNA using reverse transcriptase and PCR (RT-PCR), most sensitive.
o Serological diagnosis: 4X increase in specific ab levels over 2 weeks.

Question 8

Bird flu pandemic H5N1

Answer 8

• Viral culture or RT-PCR from nasal-pharyngeal washings or feces.
• Serology tests for H5 ag or 4X increase in H5 abs.

Question 9

metapneumovirus

Answer 9

RT-PCR from respiratory secretions and nasopharyngeal swabs

Question 10

ebola virus form filoviridae

Answer 10

PCR for viral RNA, usually able to be found by the 3rd day of symptoms

Question 11

CMV

Answer 11

• There is higher yield of CMV if the buffy coat layer, which contains that WBCs, is cultured since CMV infects WBCs.
• CMV ag: the ag can be found in the blood using an ab only when the v is actively replicating.
• PCR: CMV DNA can be found only when the virus is actively replicating.

Question 12

HBV

Answer 12

serology test:
• HBsAg: presence of this means that there is a live virus and infection
• HBcAg abs (IgM: new infection, IgG: old infection_
• HBeAg: means that there is high infectivity, while anti-HBeAg to this means that there is low infectivity