Transcript Epidemiology of Viral Hepatitis

Epidemiology of Viral
Hepatitis
Ashry Gad Mohamed
Prof. of Epidemiology
Consultant Medical Epidemiologist
Hepatitis A
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Abrupt onset.
Fever
Malaise
Anorexia
Abdominal discomfort
Jaundice
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More than 90% are asymptomatic
Seroprevalence increases with age.
At age 15, 95% are seropositive.
Case fatality rate (CFR)= 0.3%.
If age > 40 years CFR=2%.
Studies in KSA:
1997
25%
1999
25%
Taif
10-82% Jazan (1-12 years)
• Agent: RNA virus
• Reservior : Human (Clinical & subclinical
cases)
• Incubation period: 15-35 days ( median
one month).
• Period of communicability : Last two
weeks of I.P. + one week of illness.
• Modes of transmission:
Fecal-oral route.
Common source outbreaks.
Blood transfusion (rare).
Prevention and Control
• Good sanitation & personal hygiene.
“Careful hand washing”
• Day- Care centers
Hand washing after every diaper
change and before eating.
• Shellfish
heat 85-90C
4 minutes.
steam
90 seconds.
• Inactivated hepatitis A vaccine
0 -1 -6 months.
Protection after one month.
Lasting immunity at least 10 years.
• Hepatitis A patient:
Enteric precaution for the PC
Hepatitis B
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Incidous onset.
Anorexia.
Abdominal discomfort.
Nausia.
Vomiting.
Arthralgia.
Jaundice.
• Carriage rates:
Sudan 13-19%
Pakistan 10-16%
Egypt 2.7-15%
Saudi Arabia 8.5%
Jordan 7-10.
Syria 4-6%
Iraq 4-5%
Morocco 3-6%
Yemen 5-6%
More than
500,000
death/year
2 billion people infected
360
million
CHB
OVERALL PREVALENCE OF HBsAg AMONG
SAUDIS IN THE 80’S ACCORDING TO REGIONS
9.6
Positivity (%)
10
8.9
8.3
8
6
5.5
4
2
0
Central
(n=6649)
South-western
(n=7235)
Eastern
(n=8300)
Total (n=32183)
Al-Faleh. Annals of Saudi Medicine, 1988
COMPARISON OF PREVALENCE OF HBsAg AMONG SAUDI
CHILDREN IN 1989 (n=4575) AND 1997 (n=5355) – ACCORDING TO
AGE
10 9.68
7.57
7.24
6.54
6
7.2
6.71
6.51
6.35
6
5.81
5.06
4
2.31
4
5
6
0.2
0.31
0
12
3
0
11
0
10
0.3
9
0.16
8
0
7
0
2
0
0.82 0.93
Total
2
1
Percentage
8
(Age in years)
1989
1997
Al Faleh, J Infect 1999
PREVALENCE OF HBsAg POSITIVITY AMONG
BLOOD DONORS IN KKUH FROM 1987 TO 2000
Positivity (%)
5
4.7
4
3
3
1.97
2
1.4
1.7
1.2
1
0
1987
(n= 3565)
1991
(n=1991)
1996
(n=6885)
1.7
1997
(n=6285)
1998
(n=6031)
1999
(n=6841)
2000
(n=6394)
Natural History
Gow, BMJ 2001
• Agent: Double strand DNA.
Serotypes adw, ayw, adr, ayr.
• Reservior: Human (case + carrier).
• I.P. 2-3 months.
• P.C. One week of I.P. + illness period +
carriage.
• Carriage depends on age.
Concentration of Hepatitis B Virus
in Various Body Fluids
High
Moderate
blood
serum
wound exudates
semen
vaginal fluid
saliva
Low/Not
Detectable
urine
feces
sweat
tears
breastmilk
Hepatitis B Virus
Modes of Transmission
• Sexual
• Parenteral
• Perinatal
Modes of transmission:
• Percutaneous and permucosal exposure
to infective body fluids.
Blood transfusion.
Organs transplants.
Sharing needles.
Haemodialysis.
Needlestick.
Tattooing.
Razors & toothbrushes.
• Sexual transmission.
• Perinatal transmission.
Prevention and control
• Wide scale immunization of infants.
• Immunization of high risk persons.
Haemodialysis patients.
Bleeding disorders.
Susceptible households.
Health care personnels.
• Blood banks:
avoid donors from risky groups.
Education & history taking.
Testing for HBs Ag.
• Discourage:
Tattooing, Drug abuse,
Extramarital sexual relations.
• Needle stick
Single dose of HBIG (24 hours).
Vaccine series.
• Sexual exposure
Single dose of HBIG (14 days).
Vaccination.
• Infants to HBsAg +ve mothers.
0.5 ml HBIG im.
First dose of the vaccine.
2nd & 3rd doses at 1 & 6 months later.
• Health care personnel.
Universal precautions
Hepatitis C
WESTERN
FAR EAST/ASIA
EASTERN
EUROPE
60 M
MEDITERRANEAN
9M
20M
SOUTH EAST
ASIA
30 M
AFRICA
32 M
USA
4M
SOUTH
AMERICA
10 M
AUSTRALIA
0.2 M
170 Million Hepatitis C virus (HCV) carriers
WHO, 1999
3-4 MM new cases / year
AGE SPECIFIC PREVALENCE OF ANTIBODY TO
HCV/ANTI-HCV AMONG HEALTHY SAUDIS
Age Group
(years)
Community Based Study
No. tested
Anti-HCV
Pos. (%)
Location
1 – 10
1214
490
677
1096
1019
0.6
0.0
0.4
0.9
1,9
Central Province
Eastern Province
North-Western Province
South-Western Province
Southern Province
10 – 19
504
6 (1.2)
Gizan
20 – 29
361
4 (1.1)
Gizan
30 - 39
290
6 (2.1)
Gizan
40 – 49
183
6 (3.3)
Gizan
> 50
144
5 (3.5)
Gizan
Total
1482
27 (1.8)
Gizan
Al-Faleh et al, Hepatology Vol. 14(2), 1991
COMPARISON OF PREVALENCE OF ANTI-HCV IN
SAUDI CHILDREN BETWEEN THE STUDIES
CARRIED OUT IN 1989 AND 1997
0.9
0.87
0.8
0.7
Percent
0.6
0.5
0.4
0.3
0.2
0.04
0.1
0
1989 (n=4496)
1997 (n=5350)
PREVALENCE OF ANTIBODY TO HCV TO
SAUDI HIGH RISK GROUPS
High Risk Group
No.
Tested
No.
Pos.
%
Location
Hemophiliacs
28
22
78.6
KKUH, Riyadh
Thalassaemia and
sickle cell disease
78
26
33.3
KKUH, Riyadh
-thalassaemia
major
20
14
70.0
KKUH, Riyadh*
Sickle cell anaemia
55
10
18.2
KKUH, Riyadh*
Patients with
sexually transmitted
diseases
220
35
15.9
KKUH, Riyadh*
2nd-generation anti-HCV tests and confirmation were only done
in this study.
ANTI-HCV IN HAEMODYLYSIS PATIENTS IN
SAUDI POPULATION
Author
No. of Persons
Type of Test
%
895
ELISA I
53.7
20 Children
ELISA I
45.0
Ayoola et al
74
ELISA I
41.9
Huraib et al
22 HD Centre
1147 Persons
ELISA II
68.8
Fakunle et al
Al-Mugeriren et al
Hepatitis C Virus Genotypes
• 11( 6 major) with many subtypes and quasispecies
• The predominate genotype in Saudi is Genotype 4
(62.9% )
• Europe & America Genotype 1 75 (24.8) %
 severe disease
• Genotype 2 = 10.8 (7.4) %
• Genotype 3 = 5.8 (5.9) %
• Genotype 1 & 4  Poor response to therapy
Natural History of HCV Infection
Exposure
(Acute phase)
15% (15)
Resolved
85% (85)
HIV and
Alcohol
Chronic
80% (68)
Stable
20% (17)
Cirrhosis
75% (13)
Slowly
Progressive
25% (4)
HCC
Transplant
Death
MJ Semin Liver Dis 1995; 15:
Management of Hepatitis C NIH Consensus Statement 1997; March
24-26:15(3).
Important HCV Transmission
Modes
Blood
transfusio
n
1:100,000 in US
IV drug abuse
80% infected in first
year
Uncommon HCV Transmission
Modes
Household transmission
Vertical
transmission
mother - Child
?
1-5%
Needle stick injury
3%
Features of Hepatitis C Virus Infection
Incubation periodAverage 6-7 weeks
Range 2-26 weeks
Acute illness (jaundice)
Mild (<20%)
Case fatality rate
Low
Chronic infection
60%-85%
AgeChronic hepatitis related
10%-70%
Cirrhosis
<5%-20%
Mortality from CLD
1%-5%
Chronic Hepatitis C
Factors Promoting Progression or Severity
• Increased alcohol intake
• Age > 40 years at time of infection
• HIV co-infection
• Other
– Male gender
– Chronic HBV co-infection
Serologic Pattern of Acute HCV Infection with
Progression to Chronic Infection
antiHCV
Symptoms +/-
Titer
HCV RNA
ALT
Normal
0
1
2
3
4
Months
5
6
1
2
3
Years
Time after Exposure
4
Exposures Known to Be Associated With
HCV Infection in the United States
• Injecting drug use
• Transfusion, transplant from infected
donor
• Occupational exposure to blood
– Mostly needle sticks
• Iatrogenic (unsafe injections)
• Birth to HCV-infected mother
• Sex with infected partner
– Multiple sex partners
Injecting Drug Use and HCV
Transmission
• Highly efficient
– Contamination of drug paraphernalia, not just
needles and syringes
• Rapidly acquired after initiation
– 30% prevalence after 3 years
– >50% after 5 years
• Four times more common than HIV
Occupational Transmission of HCV
• Average incidence 1.8% following needle
stick from HCV-positive source
– Associated with hollow-bore needles
• Prevalence 1-2% among health care workers
– Lower than adults in the general population
– 10 times lower than for HBV infection
HCV Related to Health Care
Procedures
• Recognized primarily in context of outbreaks
–
–
–
–
Chronic hemodialysis
Hospital inpatient setting
Private practice setting
Home therapy
• Unsafe injection practices
– Reuse of syringes and needles
– Contaminated multiple dose medication vials
HCW to Patient Transmission of
HCV
• Rare
– In U.S., none related to performing invasive
procedures
• Most appear related to HCW substance
abuse
– Reuse of needles or sharing narcotics used for
self-injection
• No restrictions routinely recommended for
HCV-infected HCWs
Perinatal Transmission of HCV
• Transmission only from women HCV-RNA
positive at delivery
– Average rate of infection 6%
– Higher (17%) if woman co-infected with HIV
– Role of viral titer unclear
• No association with
– Delivery method
– Breastfeeding
• Infected infants do well
– Severe hepatitis is rare
Sexual Transmission of HCV
• Case-control, cross sectional studies
– Infected partner, multiple partners, early sex, nonuse of condoms, other STDs, sex with trauma,
Partner studies
– Low prevalence (1.5%) among long-term partners
• infections might be due to common percutaneous
exposures (e.g., drug use), BUT
– Male to female transmission more efficient
• more indicative of sexual transmission
Household Transmission of
HCV
• Rare but not absent
• Could occur through
percutaneous/mucosal exposures to
blood
– Contaminated equipment used for home
therapies
• IV therapy, injections
– Theoretically through sharing of
contaminated personal articles (razors,
toothbrushes)
Reduce or Eliminate Risks for
Acquiring HCV Infection
• Screen and test donors
• Virus inactivation of plasma-derived products
• Risk-reduction counseling and services
– Obtain history of high-risk drug and sex
behaviors
– Provide information on minimizing risky
behavior, including referral to other services
– Vaccinate against hepatitis A and/or hepatitis B
• Safe injection and infection control practices
Reduce Risks for Disease Progression
and Further Transmission
• Identify persons at risk for HCV and
test to determine infection status
– Routinely identify at risk persons
through history, record review
• Provide HCV-positive persons
– Medical evaluation and management
– Counseling
• Prevent further liver damage
• Prevent transmission to others
MMWR 1998;47 (No. RR-19)
HCV Prevalence by Selected Groups
United States
Hemophilia
Injecting drug users
Hemodialysis
STD clients
Gen population adults
Surgeons, PSWs
Pregnant women
Military personnel
0
10
20 30
40 50 60
70 80
Average Percent Anti-HCV Positive
90
HCV Testing Routinely
Recommended
Based on increased risk for infection
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Ever injected illegal drugs
Received clotting factors made before 1987
Received blood/organs before July 1992
Ever on chronic hemodialysis
Evidence of liver disease
Based on need for exposure management
• Healthcare, emergency, public safety workers
after needle stick/mucosal exposures to HCVpositive blood
• Children born to HCV-positive women
Postexposure Management
for HCV
• IG, antivirals not recommended for prophylaxis
• Follow-up after needlesticks, sharps, or mucosal
exposures to HCV-positive blood
– Test source for anti-HCV
– Test worker if source anti-HCV positive
• Anti-HCV and ALT at baseline and 4-6 months
later
• For earlier diagnosis, HCV RNA at 4-6 weeks
– Confirm all anti-HCV results with RIBA
• Refer infected worker to specialist for medical
evaluation and management
Hepatitis E - Clinical
Features
• Incubation period:
• Case-fatality rate:
Average 40 days
Range 15-60 days
Overall, 1%-3%
Pregnant women,
15%-25%
• Illness severity:
Increased with age
• Chronic sequelae:
None identified
Hepatitis E Epidemiologic Features
• Most outbreaks associated with
fecally contaminated drinking water
• Minimal person-to-person
transmission
Geographic Distribution of Hepatitis E
Outbreaks or Confirmed Infection in >25% of Sporadic Non-ABC
Hepatitis
Viral Hepatitis - Overview
Type of Hepatitis
A
Source of
virus
Route of
transmission
Chronic
infection
Prevention
B
C
D
E
feces
blood/
blood/
blood/
blood-derived blood-derived blood-derived
body fluids
body fluids
body fluids
feces
fecal-oral
percutaneous percutaneous percutaneous
permucosal permucosal
permucosal
fecal-oral
no
yes
yes
yes
no
pre/postpre/postblood donor
pre/postensure safe
exposure
exposure
screening;
exposure
drinking
immunization immunization risk behavior immunization;
water
modification risk behavior
modification