Hepatitis A VirusTitiek Djannatun

Bagian Mikrobiologi Fk Universitas YARSI

PendahuluanInfeksi beberapa virus dapat menyebabkan

peradangan pada hati, yang ditandai dengan gejala klinis (Mims et al., 2004):

Asimptomatis Simtomatis: badan terasa lelah, demam, nyeri

persendian, anoreksia, sakit kepala, gejala gastrointestinal seperti mual (nausea) dan muntah (vomiting), rasa tidak enak dan nyeri pada perut, diare dan bisa diikuti jaundice yaitu fase kuning (ikterik) pada kulit, sclera, membran mukosa.

Jika 6 bulan setelah infeksi tidak sembuh total penyakit hepatitis beralih menjadi fase kronis (hepatitis kronis)

AA“ Infectious”

“ Serum”

Viral hepatitis

Entericallytransmitted

ParenterallytransmittedF, G, TTV

? other

EE

NANBNANB

BB DD CC

Viral Hepatitis - Historical Perspectives

Source ofvirus

feces blood/blood-derived

body fluids

blood/blood-derived

body fluids

blood/blood-derived

body fluids

feces

Route oftransmission

fecal-oral percutaneouspermucosal

percutaneouspermucosal

percutaneouspermucosal

fecal-oral

Chronicinfection

no yes yes yes no

Prevention pre/post-exposure

immunization

pre/post-exposure

immunization

blood donorscreening;

risk behaviormodification

pre/post-exposure

immunization;risk behaviormodification

ensure safedrinking

water

Type of HepatitisA B C D E

Hepatitis A Virus

Hepatitis A Virus Naked RNA virus Related to enteroviruses, formerly known as

enterovirus 72, now put in its own family: hepatovirus

One stable serotype only Difficult to grow in cell culture: primary

marmoset cell culture and also in vivo in chimpanzees and marmosets

4 genotypes exist, but in practice most of them are group 1

Morfologi dan Komponen virus Merupakan virus RNA, single stranded, polaritas positif berat molekul 2,25-2,28x 106 dalton. Simetri ikosahedral, diameter 27-32 nm dan tidak

mempunyai selubung. Mempunyai protein terminal VPg pada ujung 5’nya dan

poli (A) pada ujung 3’. Panjang genom HAV : 7500-8000 pasang basa. Protein struktural yang dibentuk oleh virus ini adalah:

VP1 (30-33 kilodalton), VP2 (24-27 kilodalton), VP3 (21-23 kilodalton), VP4 (7-14 kilodalton).

Atas dasar sifat fisik dan kimianya, virus ini digolongkan sebagai enterovirus 72, urutan nukleotida dan asam amino HAV cukup jelas untuk memasukkan virus ini menjadi genus pikornavirus yang baru yaitu Heparnavirus.

Struktur Virus

Lemak bersifat stabil jika diberi perlakuan dengan eter, asam dan panas (60oC selama 1 jam). Infektivitasnya dapat bertahan paling sedikit 1 bulan setelah dikeringkan dan disimpan pada suhu 25oC dengan kelembaban relatif 42% atau selama bertahun-tahun pada suhu -20oC.

Virus HAV dapat diinaktivasi dengan : 1. Otoklaf (121oC selama 20 menit) 2. Sinar ultraviolet (1 menit pada 1,1 watt) 3. Formalin (1:4000 wt/vol selama 3 hari pada 37oC). 4. Klorine (10-15 ppm selama 30 menit) 5. Sodium hipoklorit 0,5% selama 15 menit 6. Pemanasan kering (180oC selama 1 jam) 7. Pendidihan dalam air selama 5 menit

Incubation period: Average 30 days

Range 15-50 days Jaundice by <6 yrs, <10%

age group: 6-14 yrs, 40%-50%>14 yrs, 70%-80%

Complications: Fulminant hepatitisCholestatic hepatitisRelapsing hepatitis

Chronic sequelae: None

Hepatitis A - Clinical Features

FecalHAV

Symptoms

0 1 2 3 4 5 6 12 24

Hepatitis A Infection

Total anti-HAV

Titre ALT

IgM anti-HAV

Months after exposure

Typical Serological Course

Close personal contact

(e.g., household contact, sex contact, child day care centers)

Contaminated food, water(e.g., infected food handlers, raw shellfish)

Blood exposure (rare)(e.g., injecting drug use, transfusion)

Hepatitis A Virus Transmission

EndemicityDisease

RatePeak Age

of Infection Transmission Patterns

High Low to High

Early childhood

Person to person;outbreaks uncommon

Moderate High Late childhood/

young adults

Person to person;food and waterborne outbreaks

Low Low Young adults Person to person;food and waterborne outbreaks

Very low Very low Adults Travelers; outbreaks uncommon

Global Patterns of Hepatitis A Virus Transmission

Laboratory Diagnosis 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. Cell culture – difficult and take up to 4 weeks, not

routinely performed

Direct Detection – EM, RT-PCR of faeces. Can detect illness earlier than serology but rarely performed.

Multiplikasi virus menginokulasikannya pada biakan sel monyet Afrika atau jenis rhesus, sel Vero, sel paru fetus manusia dan sel kanker hati manusia

Metode pilihan untuk mengukur antibodi HAV radioimunoasai, ELISA dan hemaglutinasi pelekatan imun

Dengan metode radioimunoasai, antigen HAV telah ditemukan di dalam hati, tinja, empedu dan darah orang yang terkena infeksi secara alami serta simpanse dan marmoset yang terkena infeksi dalam percobaan laboratorium

Titer HAV tertinggi ditemukan pada tinja kira-kira 1-2 minggu sebelum ditemukannya kelainan enzim hati

Many cases occur in community-wide outbreaks no risk factor identified for most cases highest attack rates in 5-14 year olds children serve as reservoir of infection

Persons at increased risk of infection travelers homosexual men injecting drug users

Hepatitis A Vaccination Strategies

Epidemiologic Considerations

Pre-exposure travelers to intermediate and high

HAV-endemic regions Post-exposure (within 14 days)

Routine household and other intimate contactsSelected situations institutions (e.g., day care centers) common source exposure (e.g., food prepared by

infected food handler)

Hepatitis A Prevention - Immune Globulin