Transcript hepatitis a virus - Kardz Medicine | Better Information | Healthy living

Hepatitis A is a highly contagious liver infection
caused by the hepatitis A virus.
•
Hepatitis A is one of several types of hepatitis
viruses that cause inflammation that affects the
functions of the live.
•
•Every
year, approximately 10 million people
worldwide are infected with the virus.




Picornavirus (non-enveloped, positive
standard RNA viruses)
Humans are only natural host
Stable at low pH
Inactivated by high temperature (185°F or
higher), formalin, chlorine
HEPATITIS A VIRUS
The hepatitis virus is usually spread when a person
ingests tiny amounts of contaminated fecal matter.
The hepatitis A virus infects the liver cells and causes
inflammation. The inflammation can impair liver
function and cause other signs and symptoms of
hepatitis A.




Following ingestion, HAV enters the bloodstream
through the epithelium of the oropharynx or
intestine. The blood carries the virus to its target, the
liver, and multiplies within hepatocytes and Kupffer
cells (i.e., liver macrophages).
There is no apparent virus-mediated cytotoxicity,
and liver pathology is likely immune-mediated.
Virions are secreted into the bile and released in
stool.
HAV is excreted in large quantities approximately 11
days prior to appearance of symptoms or antiHAV IgM antibodies in the blood.
Hepatitis A signs and symptoms typically don't appear until you've
had the virus for a month. Signs and symptoms of hepatitis A include:
• Fatigue
• Nausea and vomiting
Abdominal pain or discomfort, especially in the area of your liver on
your right side beneath your lower ribs
•Loss of appetite
•Low-grade fever
•Dark urine
•Muscle pain
•Itching
•Yellowing of the skin and eyes (jaundice)
Signs and symptoms of hepatitis A usually last less than two months,
but may last as long as six months. Not everyone with hepatitis A
develops signs or symptoms.


30 days on average (range 15-50 days)
infectious latter half of incubation period while
asymptomatic through 1 week after having
jaundice.
TRANSMISSION
•Close personal contact
(e.g., household contact, sex contact, child
day-care centers)
•Contaminated food, water
(e.g., infected food handlers)
•Blood exposure (rare)
(e.g., injection drug use, rarely by
transfusion)
Geographic Distribution of HAV
Infection
Anti-HAV Prevalence
High
Intermediate
Low
Very Low
You're at increased risk of hepatitis A if you:
Travel or work in regions with high rates of hepatitis A
•
Are a man who has sexual contact with other men
Use injected or noninjected illicit drugs
•
•
Live with another person who has hepatitis A
Receive clotting-factor concentrates for hemophilia or
another medical condition
•
CONCENTRATION OF HEPATITIS A VIRUS
IN VARIOUS BODY FLUIDS
Body Fluids
Feces
Serum
Saliva
Urine
100
102
104
106
Infectious Doses per mL
Source:
Viral Hepatitis and Liver Disease 1984;9-22
J Infect Dis 1989;160:887-890
108
1010
Hepatitis A - United States, 1966-2007
70000
Vaccine
Licensed
60000
Cases
50000
40000
30000
20000
10000
0
1966
1970
1975
1980
1985
Year
1990
1995
2000
2005
•Blood
tests are used to detect the presence of hepatitis A
in the body. A sample of blood is taken, usually from a
vein in the arm, and sent to a laboratory for testing.
•signs and symptoms

Acute infection is diagnosed by the detection of
HAV-IgM in serum by EIA.

Past Infection i.e. immunity is determined by the
detection of HAV-IgG by EIA.
No specific treatment exists for hepatitis A. Your body
will clear the hepatitis A virus on its own. In most cases
of hepatitis A, the liver heals completely in a month or
two with no lasting damage.
Hepatitis A treatment usually focuses on coping with
signs and symptoms of hepatitis A infection. For
instance:
Expect to have less energy. Many people with hepatitis
A infection feel tired and have less energy for their daily
tasks. Rest when you need to. You may need several
days off work or school in order to recover.



Find ways to cope with nausea. Nausea can make it
difficult to eat. Find ways to make food more
appealing. Eat small snacks throughout the day,
rather than three large meals. Try soft, easily
digested foods, such as soup or broth, yogurt and
toast, as these may be the most appealing.
Give your liver a rest. Your liver may have difficulty
processing medications and alcohol if you have
hepatitis A. Review your medications, including
over-the-counter drugs, with your doctor. Your
doctor may recommend stopping or changing some
of your medications. Stop drinking alcohol while you
have signs or symptoms of hepatitis A infection.
Shot of immune globulin up to 2 weeks after
exposure
 Good hand washing
 Cook food well
 Good diaper hygiene
 Only drink clean water
 VACCINE!!!


Who needs immune globulin?
Living with someone with Hep A
 Eaten food handled by someone with Hep A
 Sexual contact with person with Hep A
 Traveling to an area where Hep A is common
 Child or employee at a child care program where
someone else has Hep A

• Highly immunogenic
• 97%-100% of children, adolescents, and adults have
protective levels of antibody within 1 month of receiving
first dose; essentially 100% have protective levels after
second dose
• Highly efficacious
• In published studies, 94%-100% of children protected
against clinical hepatitis A after equivalent of one dose

Adult



1 dose
booster dose 6-18 months after first dose
Children and Adolescents


1 dose
booster dose 6-18 months after first dose


Recently identified cause of enterically
transmitted non-A, non-B (NANB) hepatitis
Calicivirus
spherical, non enveloped, 27-34 nm particles
containing a ssRNA genome.
Hepatitis E Virus
Incubation period 30-40 days
Acute, self limiting hepatitis, no chronic carrier
state
Age: predominantly young adults, 15-40 years
Hepatitis E - Clinical
Features

Incubation period:

Case-fatality rate:


Illness severity:
with age
Chronic sequelae:
Average 40 days
Range 15-60 days
Overall, 1%-3%
Pregnant women,
15%-25%
Increased
None identified
Hepatitis E Epidemiologic Features




Most outbreaks associated with faecally contaminated
drinking water.
Several other large epidemics have occurred since in the
Indian subcontinent , China, Africa and Mexico.
In the United States and other nonendemic areas, where
outbreaks of hepatitis E have not been documented to
occur, a low prevalence of anti-HEV (<2%) has been found
in healthy populations. The source of infection for these
persons is unknown.
Minimal person-to-person transmission.
Spherica
Spherical
27
Stability
• HEV is extremely sensitive to high salt
concentrations
• HEV should be stored as cold as
possible,
• It is rapidly degraded when freezethawed.
• The virus is sensitive to degradation by
proteolytic enzymes
28
Similar to hepatitis A; virus replicates in the
gut initially, before invading the liver, and
virus is shed in the stool prior to the onset of
symptoms.
Viraemia is transient. A large inoculum of virus
is needed to establish infection.


Prodromal-phase symptoms include the following:
 Fever with mild temperature elevations (25-97%)
 Anorexia (66-100%)
 Nausea/vomiting (30-100%)
 Weight loss (typically 2-4 kg)
 Dehydration
 Right upper quadrant pain that increases with physical activity
Icteric-phase symptoms include the following:
 Jaundice - May be difficult to see with some patients' natural skin color; serum
bilirubin level is greater than 3 mg/dL; scleral icterus is present
 Dark urine
 Light-colored stools (20-40%)
 Pruritus (50%)


Other features include the following:
 Diarrhea
 Rapidly increasing serum amino transferase (alanine aminotransferase
[ALT], aspartate aminotransferase [AST]) levels that peak within 4-6
weeks of onset and gradually decrease to normal within 1-2 months
 Viral excretion in stool persisting 14 days from onset
Symptoms of HEV are similar to other hepatitides and include the
following:
 Abdominal pain (35-80% of patients)
 Jaundice
 Anorexia
 Hepatomegaly (10-85%)
 Malaise (95-100%)
 Vomiting
Predisposing factors
• International travelers to regions of the
world where HEV is endemic
• Refugees residing in overcrowded
temporary camps following catastrophies,
especially in Sudan, Somalia, Kenya and
Ethiopia
• Persons who have chronic liver disease
• Possibly persons working with non-human
primates, pigs, cows, sheep and goats
32
Transmission
HEV is spread by the oral-faecal route
Consumption of faecally contaminated drinking water
has given rise to epidemic cases,
Ingestion of raw or uncooked shellfish has been the
source of sporadic cases in endemic areas
Most outbreaks associated with faecally contaminated
drinking water
33
Susceptibility and Resistance
• People who never have contracted
HEV are at risk of infection
• Poor sanitation
34
Host immune response
• Virus excretion in stools continues for up
to 14 days after onset of illness,
• Antibodies to HEV (IgM and IgG)
develop at the time symptoms occur,
35


No routine laboratory tests are available as yet.
Virus cannot be cultured in vitro.
1) Calicivirus-like particles in the stool, by
electron microscopy
2) Specific IgM in serum
3) PCR HEV-specific sequences in stool
• The most characterisitc markers of infection
are the serum aminotransferases
– ALT and AST
• Increase proportionally during the
prodromal phase and can reach 20 x
normal.
• Peak when the patients are jaundiced.
• Bilirubin can reach 20 mg/dL
37

There are no specific medicines that can cure hepatitis E. Therefore,
treatment of hepatitis E is focused on dealing with any symptoms
or complications that may occur. This is known as supportive care.
Even without specialized treatment for acute hepatitis E, most
people recover completely within a few weeks.




However, there are some things you can do that might help you feel
better. There are also certain things that you should avoid.
Specific Hepatitis E Treatment Suggestions
Get enough calories. Many people with hepatitis E get nauseated,
especially late in the day. In order to get enough calories, try eating
the majority of your calories early in the day. Eating several small
meals throughout the day (instead of three large meals) may also be
helpful. If you feel sick in the morning, try eating some crackers or
dry toast before getting out of bed. It may also help to drink lemon
water or have a lemon drop.




Get as much rest as you can while your body fights off the virus.
Drink plenty of fluids. You should try to drink at least 10 to 16 glasses a day of
water, clear juices, or other drinks that do not have caffeine in them.
Avoid alcohol. Alcohol poisons your liver and can cause even more damage to the
cells that are already fighting the hepatitis E virus. The exact amount of alcohol
that will harm the liver isn't known. Therefore, it's generally recommended that
people with hepatitis E avoid alcohol completely.
Exercise regularly. Do light-to-moderate exercise, such as walking, for 30 minutes
a day.
Once a person has recovered from a hepatitis E infection, the virus is no longer
present in the body.
Vaccines
•Subunit HEV vaccines
The direct intramuscular injection of purified
plasmid DNA containing the full-length
ORF2 of HEV has induced a prolonged
humoral immune response
(>12 months)
To the expressed structural protein ORF2 in
80% and 100% of two separate groups of
challenged mice, respectively
40

THANK YOU