Hepatitis Virus Flashcards
rules regarding blood borne pathogens are established by which of the following
CDC ADA OSHA PHS NASA NWA
OSHA
what is hepatitis
inflammation of the liver
acute hepatitis
associated with fatigue, abdominal pain, loss of appetite, nausea and vomiting, darkening of the urine, followed by jaundice
jaundice
yellowing in skin and eyes caused by the build up of bilirubin in the blood
bilirubin
a byproduct of hemoglobin metabolism due to liver not lover properly metabolizing and excreting it
chronic hepatitis can lead to
fibrosis
cirrhosis
HAV
HBV
HCV
HDV
infection hepatitis
serum hepatitis
formerly nonA nonB hep
delta particle
what causes >90% of viral hepatitis
A,B,C
what can also cause hepatitis
HSV
CMV
EBV
Yellow Fever Virus
what can cause or worsen hepatitis
alcohol abuse some drugs (acetaminophen) toxic chemicals (some organic solvents)
HBV family
ss/ds DNA
hepadna-
icosohedral
enveloped
HAV family
+ssRNA
pircorna
(entero, polio, ring are also in this family)
icosohedral
not enveloped
hard to decontaminate: resists heat and disinfectants
released by exocytosis
HCV familt
\+ss flavi (also west nile, dengue, yellow fever, zika) icosohedral enveloped
HAV
fecal oral transmission
localize outbreaks
contaminated food: vegetables and shellfish
short incubation:15-45 days
shedding virus in stool 2 weeks prior to symptoms
acute infection only
no fulminant hepatitis
lifelong ab protection after infection
symptoms last 8 wks -fatigue, -abdominal pain -loss of appetite -nausea, vomiting -dark urine -jaundice (70-80% of adults) 90% of childhood infections are asymptomatic <0.5% mortality
HAV pathogenesis
there is some lysis but is result of T cell immune response in the liver
testing for HAV
IgM and IgG
elevated liver enzymes (Aminotranferases) (general hepatitis)
prevention and treatment of HAV
-hygiene- hand washing by food preparers
-Vaccine- inactivated HAV
100% effected and recommended for people traveling to developing nations
life long immunity
-immune serum containing antibodies that can be given pre-exposure.if traveling too soon for a vaccine to become effective
this can also be given post exposure
Vaccine can be given up to 2 weeks post exposure
Hep B
serum hepatitis long incubation hepatitis ~90days (with 4-25 weeks variation) symptoms began ~90 days (60-150 days) after exposure 30% of people are asymptomatic Endemic in many developing countries
stats on Hep B
102 million people infected In US
240-350 million have chronic HBV
~25% of people worldwide will be infected with HBV at some point
how is HBV spread
- mother to fetus or childhood where there is endemic
- sexually of blood transmitted disease in the developed world
which virus led to the development of universal precaution recommendations of the ADA and CDC for dentists in the 70s following a series of disease clusters in dental practices
HBV
what type of virus is HBV and what is the implication of that
it is a DNA virus and therefore it can integrate into cell DNA
we know this because of genome sequencing. it was found in 11000 year old human remain, integrated into the DNA
Hep B infection
acute with resolution (90% in adults)
Chronic- can be a carrier or persistent
carrie can continue to spread infection despite the lack of symptoms
what is the risk of chronic infection for infants and children?
90% and 25-50% respectively
what are acute HBV symptoms similar to?
HAV but with joint pain
how many virions per day are produced by HBV
E10-E11 per day
mutates rapidly
like HIB
Chronic hepatitis (B)`
> 6 months of liver inflammation
detected by Alanin aminotransferase ALT in the blood
eventual death from infection in 15-20% of chronically infected people
what is ALT and what is it indicative of
a liver-specific enzymes
its presence in blood indicates liver injury
what does chronic infection due to Hep B lead to?
cirrhosis of the liver
liver cancer= heptocellular carcinoma
chronic inflammatory response which damages DNA in liver cells
what exacerbates liver damage
alcohol
Hep B
acute vs chronic
asymptomatic vs symptomatic
outcome determined by the cellular (Tcell) immune response
strong response causes liver disease in the short term but resolution of infection in the mid-term
in hep b, acute vs chronic
asymptomatic vs symptomatic
Weak cellular response leads to
chronic infection and long term risk of advanced disease: liver scarring, cirrhosis, liver cancer- primary hetpatocellular carcinoma
a person becomes a carrier
carriers do not necessarily display overt symptoms but can spread the virus
infection of infrequntly leads to them become chronically infected carriers
Hep B comes in 2 forms
- infection virion= dane particle
- Immune decoy
there is a lipid envelope
what is tested for in an active Hep B infection
HBsAg
prevention and treatment of Hep B
safe sex, no iV drug use (needle sharing)
there are no antivirals for acute infection
chronic can be treated with RT inhibitors that is also used for HIV (Lamivudine)
immune serum can be given after exposure and to newborns of HBV positive mothers
what is recombivax
a subunit vaccine
uses recombinant DNA technology to make HBsAg particles
3 injections and a time test for antibodies to surface antigen
what does HBV vaccine do?
elicits an antibody response
prevent virus from reaching liver
can the HBV vaccine be give to pregnant women
yes and also can be given as a post-exposure prophylaxis
HCC vs PHC
hepatocellular carcinoma= primary heptocellular carcinoma
HCC is
- associated with HBV infection 50-70% of the time
- HCC tumor DNA has HBV DNA sequences integrated in them
- alcoholism is risk factor
what does chronic HBV and HCV infection cause?
ongoing inflammatory responses and oxidative damage to chromosomal DNA of hepatocytes
how does the integration of HBV DNA occur
occurs in breaks in the cellular DNA of hepatocytes
HCV acute symptoms
similar to other hepatitis virus infections
chronic fatigue is common
what happened before a blood screen for HCV was developed?
HCV was a risk factor in transfusion and transplants
non-A and non-B hepatitis (NANBH)
facts about HCV
1989 - a new viral genius was found in hepatocytes but was impossible to grow in lab until recently
2.7-4 million infected inUS, 170 million in world
HCV spread
most spread through blood contact
IV drugs, tattooing, unsterilized surgical equipment
mother to child during childbirth
Hep C statistics
- acute infection
- chronic persistent infection
- rapid disease progression
- % of patients with liver cancer
- % of heptocellular carcinomas associated with HCV
~15% ~70% ~15% ~5% ~25%
Of every 100 persons infected with HCV, approximately
• 75–85 will go on to develop chronic infection
• 60–70 will go on to develop chronic liver disease
• 5–20 will go on to develop cirrhosis over a period of 20–30 years
• 1–5 will die from the consequences of chronic infection (liver cancer or cirrhosis)
Hep C structure
falvivirus
+ssRNA
enveloped
Mutates rapidly because an RNA virus
these is a great diversity in the glycoproteins which are the major antigens
how many visions produced per day
E10-E11
just live HIV and HBV
how many major serotypes/genotypes
6 and there is no cross protection
what is tissue damage from HCV caused by
cell-mediated immune response of infected cells
the virus itself is apparently non-cytopathic
HCV prevention and treatment
alcohol worsens liver damage
no vaccine- in part due to variability
Ribavirin+ pegylated interferon alpha
was the standard of care for HCV until sofosbuvir
side effects are severs
cure rate 50%
Sofosbuvir- how it works
recently approve to treat HepC
it inhibits the viral RNA polymerase- a chain terminator
can cure Hep C in many cases
could lead to complete elimination of HCV
chronic infections
HIV and HCV
enveloped icosahedral \+strand single- stranded RNA viruses 9kb genomes transmitted through bodily fluids mutate rapidly causes chronic infection
can HCV be spread during medical or dental procedures?
As long as Standard Precautions and other infection control practices are used
consistently, medical and dental procedures performed in the United States
generally do not pose a risk for the spread of HCV. However, HCV has been
spread in health care settings when injection equipment, such as syringes, was
shared between patients or when injectable medications or intravenous
solutions were mishandled and became contaminated with blood. Health care
personnel should understand and adhere to Standard Precautions, which
includes Injection Safety practices aimed at reducing bloodborne pathogen
risks for patients and health care personnel. If health care-associated HCV
infection is suspected, this should be reported to state and local public health
authorities.
