Hepatitis type D, E, F G

HEPATITIS TYPE DOR

DELTA HEPATITISPRESENTED BY:

JARLATH FERNANDEZ

HDV• Detected in some HBV infections.;The antigen is found

within certain HBsAg particles.• In blood, HDV (delta agent) contains delta-Ag (HDAg)

surrounded by an HBsAg envelope. It has a particle size of 35–37 nm and a buoyant density of 1.24–1.25 g/mL in CsCl.

• The genome of HDV consists of single-stranded, circular, negative-sense RNA, 1.7 kb in size.

• HDAg is the only protein coded for by HDV RNA and is distinct from the antigenic determinants of HBV. HDV is a defective virus that acquires an HBsAg coat for transmission.

• One cannot become infected with hepatitis D unless infected with HBV Chronic liver disease with cirrhosis

HDV STRUCTURE

LABORATORY FEATURES

DISEASE• Because HDV is dependent on a coexistent HBV

infection, acute type D infection will occur either as a simultaneous infection (coinfection) with HBV or as a superinfection of a person chronically infected with HBV. – In the coinfection pattern, antibody to HDAg develops late in

the acute phase of infection and may be of low titer. Assays for HDAg or HDV RNA in the serum or for IgM-specific anti-HDV are preferable. All markers of HDV replication disappear during convalescence; even the HDV antibodies may disappear within months to years.

– Superinfection by HDV usually results in persistent HDV infection (over 70% of cases). High levels of both IgM and IgG anti-HD persist, as do levels of HDV RNA and HDAg. HDV superinfections may be associated with fulminant hepatitis.

HDV TREATMENT• Hepatitis B vaccine, However, vaccination

does not protect hepatitis B carriers from superinfection by HDV.

HEPATITIS TYPE E

HEV • The virus resembles caliciviruses but has not

been placed in a virus family instead it has been categorized under Hepeviridaecalled Hepevirus.

• Non-enveloped, positive-sense, single-stranded ribonucleic acid (RNA) virus

• The virus has four genotypes, but only one serotype. Genotypes 1 and 2 exclusively infect humans, whereas genotypes 3 and 4 also infect pigs and several other mammalian species.

HEV STRUCTURE

HEV TRANSMISSION• Mainly through the faecal-oral route due to

faecal contamination of drinking water. Other transmission routes have been identified, which include:– foodborne transmission from ingestion of

products derived from infected animals (pig, deer);

– transfusion of infected blood products;– Prenatal

HEV REPLICATION & ITS DISEASE

• Replication of viral particles takes place in intestinal mucosa cells, but primary in the cytoplasm of hepatocytes

• HE is typically a self-limiting disease without progression to chronic illness.

• Shares many clinical characteristics and symptoms with hepatitis A

HEV DIAGNOSIS• RT-PCR (Reverse Transcriptase Polymerase Chain

Reaction)– Molecular detection of HEV; First choice for RNA

viruses detection• Enzyme immunoassay (EIA) • Immunologic Diagnosis which is practical, highly sensitive and

inexpensive detection of Anti-HEV antibody.

• Immune fluorescence microscopy (IFE)• IFE detects Ab that reacts against HEV Ag semiquantitatively.

• Virus isolation• Immune electron microscopy (IEM)• Ani-HEV Ab concentrations can be determined

semiquantitatively by rating the Ab coating

Tx and PREVENTION • No treatment involve-self limiting, no ati-viral

therapy available• Travellers must drink purified water• Avoid eating uncooked food• Good sanitation• No vaccine yet

HEPATITIS F

HAF• Hypothetical virus linked to hepatitis. • An infection found in the Far East • Consists of double-stranded DNA and

is substantially different from HAV and HEV, both of which are RNA based.

HEPATITIS G

HAG• AKA GBV-C; Different strain of the same virus• Enveloped, single-stranded (+ strand) RNA

virus of the Flaviviridae• Often found in co-infections with other

viruses, such as hepatitis C virus (HCV)-common, hepatitis B virus (HBV), and Human Immunodeficiency Virus (HIV)

HAG STRUCTURE

HAG TRANSMISSION AND PREVENTION

• BLOOD TRANSFUSSION• PATIENTS WITH HEMOPHILIA AT HIGH RISK• PRENATAL*PREVENTION IS JUST DOING THINGS THAT AVOID THE RISK

SUMMARY

REFERENCES

• Alcamo’s Microbiology book• Bailey’s Scott• Jaweitz Microbiology book• WHO• CDC• Other internet links