Lect 27 viral hep and HIV Flashcards
List the 4 of 6 types of hepatitis viruses and what they cause
- type A: infectious hepatitis
- type B: serum hepatitis
- type C: transfusion associated hepatitis
- type D: delta agent, only in patients with active HBV infection
subclinical and aniceteric course of viral hepatitis is recognized by
seroconversion
prodrome (pre-icterus) stage of typical acute icteric hepatitis has what symptoms
- fatigue
- malaise
- anorexia
icterus stage of typical acute icteric hepatitis has what symptoms
- dark urine, jaundice
- hepatomegaly
- elevation ALT and AST
3 phases of typical acute icteric hepatitis
- prodrome
- icteric phase
- convalescent phase
unique about Fulminant hepatitis
high fatality rate
what type of hepatitis viruses are able to become chronic
- B
- C
- D
transmission of Hepatitis A virus
- food and water borne transmission
- primarily seen in closed populations with poor hygiene at risk
how is Hepatitis A virus diagnosed
- IgM antibody by ELISA
- many asymptomatic infections occur, antibody is common
Hepatitis A virus prevention
- handwashing
- avoidance of caontaminated food (uncooked shellfish)
- water chlorination
- post exposure prophylaxis with immunoglobulin
- killed virus vaccine is available
What is the most common and widespread cause of chronic hepatitis and also the infectious cause of primary hepatocellular carcinoma
Hepatitis B virus
Key Hepatitis B virus antigens
- HBsAg: HBV surface antigen
- HBcAg- HBV core antigen
- HBeAg: surface antigen
presence of which HBV antigen indicates patient is infectious
HBeAg: surface antigen
HBV virus is present in what parts of body? how is transmissited?
- serum
- blood
- semen
- transmission
- needle sharing
- acupuncture
- ear piercing
- tattooing
reservoir of HBV
chronic hepatitis patients
when is HBV shed
during asymptomatic periods
HBV can cause perinatal-congenital infection. what is the greatest risk factor
- chronic infection in mother
- HBeAg positive mother
- 90% of infected infants will become chronically infected
what populations are at risk for HBV infections
- healthcare workers
- IV drug users
- homosexuals
- promiscuous heterosexuals
- prison
- family contacts of infected individuals
HBV replicates almost exclusively in what organ
liver
prodrome of HBV infection has what symptoms
- fever
- urticarial rash
- symmetrial arthraligias
10% of patients with chronic HBV will develop
cirrhosis and liver failure
80% of what cancer is linked to chronic HBV
primary hepatocellular carcinoma
Which HBV antigens are secreted into blood stream during infection
- HBsAg
- HBeAg
What is the hallmark of initial ongoing HBV infection if present with HBsAg
IgM anti-HBc
which indicates past infection, and if present with HBsAg indicates chronic infection
IgG anti-HBc
What is the best indications of the presence of infectious HBV
HBeAg
rapid hepatitis virus tests detects
HBV surface antigen
HBV prevention
- subunit vaccine available
-
immunoglobulin available for prophylaxis
- within 1 week of exposure
- given to newborn infants of HBsAg + mothers (plus vaccination)
Hepatitis D virus has the delta agent which is
a viral parasite of another virus
- replication requires the presence of HBV for helper functions
Hepatitis D infection is possible under what 2 conditions
- co-infection with HBV
- superinfection in patients with chronic HBV hepatitis
Hepatitis D infection does what to severity of HBV infection
- increases the severity of HBV infections
- fulminant hepatitis is more likely
reservoir for HDV
- individuals persistently infected with HBV and HDV are reervoir
how is HDV detected
- ELISA for delta antigen or antibodies
HDV prevention
- HBV vaccine prevents both HBV and HDV infection
this agent is becoming an important form of postransfusion viral hepatitis in the US
HCV
what percentage of patients with HCV develop chronic infections
-
70-85%
- often progress to cirrhosis and liver failure
list the factors that promote HCV infection progression
- alcohol use
- infection at age > 40 yo
- male
- HBV co-infection
- HIV co-infection
risk factors of HCV
- IVDU
- hemodialysis
- tattoos
- blood transfusions
- organ transplants
- **transmission not well understood
how is HCV diagnosed
- Enzyme immunoassay detection of antibody against HCV
- seroconversion at 24 weeks after infection
- chronic state and acute phase viremic patients often escape detection
- direct assays for virus
why is HCV uncommonly discovered in acute stage
infections are asymptomatic
initial HIV infection may be asymptomatic or associated with
a mononucleosis-like condition
when are patients with HIV contagious
continuously
when is AIDS diagnosed
- severe damage to immune system is evident
- CD4 T cell counts < 200 uL
list the HIV indicator diseases
- Kaposis sarcoma
- pneumocystitis pneumonia
- MAC infection
- severe CMV disease
describe HIV agent
- human retrovirus
-
RNA genome
- 2 copies of RNA in virion
- enveloped
-
reverse transcriptase
- RNA dependent DNA polymerase
origins of HIV
- zoonosis!
- contact with primates may be entry means
- bushmeat
- contact with primates may be entry means
HIV infects and replicates in what cells
- infects cells with CD4 and chemokine co-receptor molecule displayed as surface
- T helper cells, monocytyes, macrophages
how does HIV replicate
- reverse transcription of viral genome
- integration into host chromosome (using viral integrase)
- latency established
how does HIV cause immunosuppression
- T helper cell loss
- apoptosis of immune cells
HIV is able to form mutant forms called which complicates treatment
swarms
how is HIV transmitted
- sexual contact
- parenteral (IVDU, needle sticks)
- perinatal: high risk with infected mother
How is HIV diagnosed
- detection of HIV antibody in patient ( 2 steps)
- EIA screen
- western blot for confirmation
- NAT test detects and quantifies virus
screening for HIV
- rapid HIV test
- 20 min test
points of interference for treatment of HIV infections
- reverse transcriptase
- integrase
- TAT antagonists
- protease
