What is Hepatitis?
General: inflammation of liver parenchyma cellsWorst case: life threatening liver cirrhosis, liver failure and/or liver cancer
Causes of hepatitis?
Primary: drug induced hepatitis, viral hepatitisSecondary: syphilis, T.B
Viral hepatitis
Hepatitis A virus (picornovirus)
Hepatitis B virus (hepadnavirus)
Hepatitis C virus (flavivirus)
Hepatitis D, E, F, G viruses and non A-G
Epstien-Barr virus
Cytomegalovirus
Yellow fever virus
Infectious mononucleosis
Hepatitis A Virus -HAV-
The Facts
Picornaviridae, SSRNA, non enveloped
Destroyed by autoclaving, boiling, dry heat
Oral-fecal transmission
Occurs as epidemic
i.p 2-7 wks, mild jaundice, hepatospleenomegaly
No carrier state
Recovery within 2 months with solid immunity
Diagnosis and treatment
ELISA for HAV antibodiesTreat complicated case with Ig.
Prevention: decontaminate utensiles, cloths, water
Vaccination to prevent spread of disease
HEPATITIS B
DNA and RNA (Hepadnaviruses)3 forms of HBV in blood
small 22 nm (spherical
200 nm (filamentous)
Dane particle 42 nm
(spherical) infectious
Viral antigens
HBs Ag
Abs are protective blood
HBe Ag
Abs are not protective blood
HBc Ag
Abs not protective hepatocytes
Infection varies
Sub-clinicalFulminant (hepatic necrosis)
Chronic carrier (hepatocellular carcinoma)
Transmission
Direct inoculation of blood or plasma (needle, transfusion)
Indirect precutaneous (infected serum) skin cut, abrassion
Adsorption of infected serum (mucosal surface)
Adsorption of potentially infectious secretion (saliva, vaginal, semen) to mucosal surface
oral-fecal NO
Role of saliva Negative except human bite
Incidence
HBs is predominant in adults
21% oral surgeons
22% general surgeons
13-30 % dentists
significant of HBs is carrier up to 10% in HBs infections
Interpretation of serological markers
+HBs Ag: carrier and infectious
persist for 6 months acute
persist for year carrier
Anti HBs : recovery and immunity
vaccination
HBe Ag: Acute disease of high infectivity
if persist chronic liver damage
Anti HBe: partial recovery from infection
HBc Ag: present in liver
Anti HBc: Active (recent infection)
Great risk to Dentist
Known and unknown carriersHigh risk patients include:
Jaundice (6 months), Blood therapy (hemophilia and thalassemia), chronic renal failure, multiple blood transfusion, addicts and homosexual
Prevention: Engerix B vaccine (subunit)
0, 1, 6, booster after one year
HEPATITIS C
RNA Chiron 1988Transmition: post-transfusion, associated with hepatocellular carcinoma
Diagnosis: ELISA for detection of Anti HCV
Dental implication: lichen planus, oral malignancy, saliva contains HCV, Needle stick is common way of transmission
HEPATITIS D
Defective RNA requires HBs for function
Occurs as coinfection with HBV
Transmitted parenterally
Diagnosis by ELISA
bad prognosis - higher incidence of liver necrosis, mortality
HEPATITIS E
RNA (Calicivirus)
Transmission: fecal/oral
Disease: 3-6 week incubation, abrupt onset, mild except if pregnant, 20% fatality rate
Jaundice: unknown
Chronic: no
HEPATITIS F: post transfusion
HEPATITIS G:1996, transmitted through blood
cause mild disease, present in saliva
Transfusion transmitted virus(TTV)
Post transfusional hepatitis, non envelop, ss RNA (parvo virus)
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