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what is hepatitis?
inflammation of the liver
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which hepatitis virus is the most commonly occuring viral hepatitis?
Hepatitis A
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what are the modes of transmission for HAV?
- fecal/oral
- waterborne/foodborne
- blood-rare
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what is the incubation period for HAV?
15-45 days
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when is HAV the most communicable?
2-3 weeks before the onset of jaundice (preicteric)
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how are the signs and symptoms defined?
- defined by jaundice
- preicteric
- icteric
- anicteric
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what is the icteric phase of HAV and who does it appear in?
- jaundice is present
- mostly adults rare in children
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what is the preicteric phase and what are its symptoms?
- prejaundice
- abrupt onset of flu-like symptoms (long and severe)
- liver is enlarged and tender to palpation
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what is the anicteric phase?
- absence of jaundice
- 2-3 times more prevalent than icteric
- often misdiagnosed because it resembles the flu
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how can you get HAV immunity?
- AntiHAV in serum 2-3 weeks after onset
- vaccine available
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how can you prevent the transmission of HAV?
- personal hygiene-handwashing
- cooking food- 185 degree will inactivate virus
- sanitation- public health
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how do you prevent HAV in the dental setting?
- standard precautions
- sterilization
- disposable materials
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who are the risk groups for HAV that should be vaccinated?
- Travelers to places with high HAV
- Homosexual men
- drug users
- clotting disorders
- chronic liver disease
- children living in places with high rate of HAV
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what hepatitis virus has had an increased incidence in the past 20 years?
HBV
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what fluids carry infectious HBV?
- blood
- saliva
- semen
- vaginal fluids
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what are the modes of transmission for HBV?
- percutaneous-intravenous, subcutaneous
- blood transfusion
- needle stick
- sexual exposure
- perinatal-in utero
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what is a risk population?
those that have an increased prevalence of infection, increase chances or likelihood of infection and increased prevalence of disease carriers
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who are the individuals at high risk for HBV?
- infants-born to HIV infected mothers
- IV drug users
- Mental institutions-pt and staff
- hemodialysis-pt and staff
- recipients of blood products
- liver disease
- male prisoners
- health care presonnel-low risk if following ppe
- contact with HBV carriers
- military populations in countries with high endemic
- returning travelers who stayed more than 3 months or were treated
- morticians and embalmers
- immigrants and refugees
- sexual contact- multiple partners
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what is the incubation period for HBV?
- 2-6 months
- average of 60-90 days
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what indicates the communicability of HBV and when is it no longer detectible in blood?
- presence of HBsAG indicates communicability, found in blood as early as 30 days postexposure
- after jaundice no longer detectible in blood.
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what is the transient subclinical infection of HBV?
- no icteric stage
- undiagnosed
- transient infection-rapid strong immune response
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what is the disease process of acute type B HBV?
- onset is slower than other hep viruses
- cannot be distinguished on basis of clinical signs and symptoms
- period of illness is longer than hep A
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what are the symptoms of acute type b HBV?
rash itching and joint pains
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what percentages of children and infants become carriers of HBV?
- 5-10% infected after age five
- 30% infected between ages 1-5
- 90% infected at birth
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How is immunity of HBV obtained other than vaccine?
- presence of anti-HB's in serum-had an exposure
- unknown presence-subclinical HBV
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what are three ways to prevent HBV?
- transmission in infancy and childhood-immunoprophylaxis
- enforce blood bank control measures
- enforce sterilization/disposable syringes and needles
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what are the two types of active HBV immunizations?
- plasma derived
- recombinant DNA
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how is plasma derived vaccines for active immunization of HBV prepared?
prepared by using purified and formalin-treated HBsAg from plasm of chronic HBsAg carrier, it inactivates viruses
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how is recombinant DNA vaccine for active immunization of HBV prepared?
synthesis HBsAg in culture of yeast, it is purified and sterilized
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what is the effectiveness for HBV vaccines?
- 20-39 years 95% effective
- children 99% effective
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what is the most common chronic blood-borne infection in the US?
Hepatitis C
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what was hepatitis C originally called?
hep non A, non B
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how is HCV transmitted?
- percutaneous-blood, needles, syringes, transfusions
- saliva
- nonpercutaneous-sexual transmission, perinatl exposure
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what is the disease process for HCV?
- onset-no clinical symptoms or abdominal pain, nausea, vomiting and jaundice
- acute infection-chronic infection
- chronic liver disease
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what are the risk factors of having HCV?
severe liver disease
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what are the principle risk factors of transmitting HCV?
- blood transfusion before 1991
- IV drug us
- intranasal cocaine user
- tattooing, ear/body piercing
- perinatal
- sexual
- hemodialysis
- organ transplantation
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what are the prevention and control methods for HCV?
- no vaccine
- strict standard procedures
- behavior modification
- same measures for hep B
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what is Hep D coinfection with?
HBV-cannot cause infection except in the presence of HBV
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how is hep D transmitted?
- multiple exposures to HBV
- blood and body fluids
- contaminated needles
- sexual
- perinatal
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what are the characteristics of hep D
- more severe than hep B alone
- higher mortality rate
- abrupt onset, signs and symptoms resemble HBV
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what are the three parts of the disease process?
- coinfection
- superinfection
- suerimposition
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what is coinfection?
acute HDV occurring with acute HBV may lead to resolution of both types. If HBV is cleared HDV is cleared
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what is superinfection?
acute HDV is superimposed on an existing carrier of HBV. HBV unchanged but delta state develops
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what is superimposition?
chronic delta hepatitis superimposes on the chronic HBsAg carrier
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what is the prevention of Hep D?
- same as hep B
- immunization for hep B protects against hep D
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what is hep E similar to?
hep A
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how is hep E transmitted?
- contaminated water
- person-person thru oral-fecal route
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who is affected more with hep E?
adults affected more than children
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what affect does hep E have on pregnant women?
high mortality rate
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how can we prevent and control hep E?
- sanitary disposal of waste
- handwashing
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