Parenteral Hepatitis B, C and D
By: Dr Ashraf Hussain
MBChB, PhD. Comm. Med.
1. Hepatitis B Virus
VIRAL HEPATITIS B: ICD-10 B16
Infectious agent
Also callled (Type B hepatitis, Serum hepatitis, or HB).
Agent—Hepatitis B virus (HBV), a hepadnavirus, is a double-stranded
DNA virus
4 major subtypes: adw, ayw, adr and ayr.
Because of the common “a” determinant, protection against one subtype appears to
confer protection against the other subtypes, but no differences in clinical features
have been related to subtype.
Case presentation
A small proportion of acute hepatitis B virus (HBV) infections may be clinically
recognized.
Less than 10% of children and 30%–50% of adults with acute hepa s B virus (HBV)
infection show icteric disease.
In those with clinical illness, the onset is usually insidious, with anorexia, vague
abdominal discomfort, nausea and vomiting, sometimes arthralgias and rash, often
progressing to jaundice.
Severity ranges from inapparent cases detectable only by liver function tests to
fulminating, fatal cases of acute hepatic necrosis.
The case-fatality rate is about 1%; higher in those over 40.
Fulminant HBV infection also occurs in pregnancy and among newborns of infected
mothers.
After acute HBV infection, the risk of developing chronic infection varies inversely
with age.
PDF created with pdfFactory Pro trial version
Ø
Chronic HBV infec on occurs among about 90% of infants infected at birth,
20%–50% of children infected from 1 to 5 years, and 1%–10% of persons
infected as older children and adults.
Ø
Chronic HBV infection is common in persons with immunodeficiency
Worldwide chronic HBV infec on is found in 0.1%–20% .
An es mated 15%–25% of persons with chronic HBV infec on will die prematurely of
either cirrhosis or hepatocellular carcinoma.
HBV may be the cause of up to 80% of all cases of hepatocellular carcinoma
worldwide.
Serological characteristics
Three clinically useful antigen-antibody systems are identified for hepatitis B:
1. Hepatitis B surface antigen (HBsAg) and anti-HBs Ab
2. Hepatitis B core antigen (HBcAg) and anti-HBc.
3. Hepatitis B e antigen (HBeAg) and anti-HBeAb
HBsAg occur in acute infection and persists in chronic infections.
Anti-HBc appears at the onset of illness and persists indefinitely (always indicate
occurrence of HBV infection, current or past).
The presence of HBsAg indicates that the person is potentially infectious.
The presence of HBeAg is associated with relatively high infectivity.
Occurrence—Worldwide
In countries where HBV is highly endemic (HBsAg prevalence 8% or higher), most
infections occur during infancy and early childhood.
Where HBV endemicity is intermediate (HBsAg prevalence from 2%–7%), infec ons
occur commonly in all age groups although the high rate of chronic infection is
primarily maintained by transmission during infancy and early childhood.
Where endemicity is low (HBsAg prevalence under 2%), most infec ons occur in
young adults, especially those belonging to known risk groups.
Even in countries with low HBV endemicity, a high proportion of chronic infections
may be acquired during childhood because the development of chronic infection is
age-dependent.
PDF created with pdfFactory Pro trial version
High-risk groups
Injecting drug users, tattoos and acupuncturists
Household contacts and sex partners of HBV-infected persons.
Health care and public safety workers who have exposure to blood in the workplace
Heterosexuals with multiple partners.
Men who have sex with men.
Clients and staff in institutions for the developmentally disabled.
Hemodialysis patients and patients with bleeding disorders who receive blood
products due to failure to adhere to recommended infection control practices
against transmission of HBV and other bloodborne pathogens in these settings
Prisoners.
Reservoir: Humans (an animal reservoir in nature has not been recognized).
Mode of transmission
Body substances capable of transmitting HBV include:
blood and blood products.
Saliva
Body fluids include: Cerebrospinal fluid; peritoneal, pleural, pericardial and synovial
fluids.
Amniotic fluid;
semen and vaginal secretions and any other body fluid containing blood;
unfixed tissues and organs.
Transmission occurs by percutaneous (IV, IM, SC, intradermal) and permucosal
exposure to infective body fluids.
Fecal-oral or vector-borne transmission has not been demonstrated.
Major modes of HBV transmission include sexual or close household contact with an
infected person, perinatal mother-to-infant transmission, injecting drug use and
nosocomial exposure.
Communally used razors and toothbrushes have been implicated as occasional
vehicles of HBV transmission in this setting.
PDF created with pdfFactory Pro trial version
Incubation period—Usually 45–180 days, average 60–90 days.
Period of Communicability:
All persons who are HBsAg-positive are potentially infectious.
The infectivity of chronically infected individuals varies from high (HBeAg-positive) to
modest (anti-HBe-positive + ????).
Susceptibility:
Susceptibility is general.
Disease is often milder and anicteric in children;
In infants it is usually asymptomatic.
Protective immunity follows infection if antibodies to HBsAg (anti-HBs) develop and
HBsAg is negative.
Persons with Down syndrome, lymphoproliferative disease, HIV infection and those
on hemodialysis appear more likely to develop chronic infection.
Methods of control
A. Preventive measures:
1. Rou ne vaccina on Program:
Two types of hepatitis B vaccines.
The first, prepared from plasma from HBsAg-positive persons, is still widely used.
The second, from recombinant DNA (rDNA), is produced by using HBsAg synthesized
by yeast or cell-lines into which a plasmid containing the gene for HBsAg has been
inserted.
The current WHO hepatitis B prevention strategy is based on routine universal
newborn or infant immunization
Such immunization has the highest effects in countries with high endemicity as most
cases occur in the young aged children in contrary to low or medium endemic
countries where most infection occur among adolescents and young adults.
Immunity against HBV is believed to persist for at least 15 years after successful
immunization so vaccine strategies for older children, adolescents and adults may be
desirable.
Testing to exclude people with pre-existing anti-HBs or anti-HBc is not required
PDF created with pdfFactory Pro trial version
for infants doses should be at birth, 1–2 and 6 months of age.
For infants born to HBsAg posi ve women addi onal 0.5 ml of HBIG should be
received.
Pregnancy is not a contraindication for receiving hepatitis B vaccine.
2. Adequately sterilize or use diposable syringes, needles and lancets.
3. Screening of donated blood in blood banks.
4. Maintain surveillance
Control of patient, contacts and the immediate environment
1. Report to local health authority: Official report obligatory
2. Isolation: Universal precautions to prevent exposures to blood and body
fluids.
3. Concurrent disinfection: Of equipment contaminated with blood or infectious
body fluids.
4. Quarantine: Not applicable.
5. Immunization of contacts: Products available for postexposure prophylaxis
include HBIG and hepatitis B vaccine.
A)
Infants born to HBsAg positive mothers should receive a single dose of vaccine
within 12 hours of birth and, where available, HBIG (0.5 ml IM), the first dose of
vaccine to be given concurrently with HBIG but at a separate site; second and third
doses of vaccine (without HBIG) 1–2 and 6 months later.
It is recommended to test the infant for HBsAg and anti-HBs at 9–15 months of age
to monitor the success or failure of prophylaxis.
Infants who are anti-HBs positive and HBsAg negative are protected and do not need
further vaccine doses. Infants found to be anti-HBs negative and HBsAg negative
should be reimmunized.
B)
After percutaneous (e.g. needlestick) or mucous membrane exposures to blood that
might contain HBsAg, a decision to provide post exposure prophylaxis must include
consideration of:
PDF created with pdfFactory Pro trial version
i) whether the source of the blood is available
ii) the HBsAg status of the source;
iii) the hepatitis B immunization status of the exposed person.
For previously unimmunized persons exposed to blood from an HBsAg positive
source, a single dose of HBIG should be given as soon as possible, but at least within
24 hours of high-risk needlestick exposure, and the hepatitis B vaccine series should
be started.
B) cont.
HBIG is not usually given for needlestick exposure to blood that is not known or
highly suspected to be positive for HBsAg, since the risk of infection in these
instances is small; however, initiation of hepatitis B immunization is recommended if
the person has not previously been immunized.
For previously immunized persons exposed to an HBsAg positive source,
postexposure prophylaxis is not needed.
For persons whose response to immunization is unknown, hepatitis B vaccine and/or
HBIG should be administered.
C):
After sexual exposure to a person with acute HBV infection, a single dose of HBIG
(0.06 ml/kg) is recommended if it can be given within 14 days of the last sexual
contact.
For all exposed sexual contacts of persons with acute and chronic HBV infection,
vaccine should be administered.
6. Investigation of contacts and source of infection.
7. Specific treatment: No specific treatment available for acute hepatitis B.
2. VIRAL HEPATITIS C ( ICD-10: B17.1)
(Parenterally transmitted non-A non-B hepatitis , Non-
B transfusion associated hepatitis or HCV infection
Identification— Onset is usually insidious, with anorexia, vague abdominal
discomfort, nausea and vomiting;
Progression to jaundice less frequent than with hepatitis B.
PDF created with pdfFactory Pro trial version
Although ini al infec on may be asymptoma c (in more than 90% of cases) or mild,
a high percentage (50%–80%) develop a chronic infec on.
Of chronically infected persons, about half will eventually develop cirrhosis or cancer
of the liver.
Diagnosis depends on detecting antibody to the hepatitis C virus (anti-HCV).
Occurrence—Worldwide distribution
Reservoir—Humans
Mode of transmission—HCV is primarily transmitted parenterally.
Sexual and mother-to-child have been documented but appears far less efficient or
frequent than the parenteral route.
Incubation period—Ranges from 2 weeks to 6 months; commonly 6–9 weeks.
Period of communicability—From one or more weeks before onset of the first
symptoms; may persist in most persons indefinitely.
Susceptibility is general.
Methods of control —
A. Preventive measures: Prophylactic IG is not effective.
In blood bank operations, all donors should be routinely screened for anti-HCV and
all donor units with elevated liver enzyme levels should be discarded.
Nosocomial control activities must be maintained.
Control of patient, contacts and the immediate environment:
General control measures against HBV apply.
Available data indicate that postexposure prophylaxis with IG is not effective in
preventing infection.
Curable treatment is now available for treatment of chronic hepatitis C infection.
3. DELTA HEPATITIS
ICD-10 B17.0
Viral hepatitis D, Hepatitis delta virus
Infectious agent
PDF created with pdfFactory Pro trial version
HDV is a virus-like particle stranded RNA that can have a linear or circular
conformation.
HDV is unable to infect a cell by itself and requires co-infection with the HBV to
undergo a complete replication cycle.
Hepatitis D is the only agent in this family that infects animal species.
Case presentation
Onset is usually abrupt, with signs and symptoms resembling those of hepatitis B.
Delta hepatitis infection may
occur as acute co-infection with hepatitis B virus, or as super-infection in persons
with chronic HBV infection.
Super infection will lead to fulminant hepa s in 25%–50% of cases.
Occurrence—Worldwide
Reservoir—Humans.
Mode of transmission—Thought to be similar to that of HBV:
exposure to infected blood and serous body fluids, contaminated needles, syringes
and plasma derivatives such as antihemophilic factor, and
Sexual transmission.
Incubation period—Approximately 2–8 weeks
Period of communicability—Blood is potentially infectious during
all phases of active delta hepatitis infection
Susceptibility—All people susceptible to HBV infection or who
have chronic HBV can be infected with HDV.
Preventive measures Prevention of HBV infection with hepatitis B vaccine prevents
infection with HDV.
Among persons
with chronic HBV, the only effective measure is avoidance of
exposure to any potential source of HDV.
PDF created with pdfFactory Pro trial version