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Genotyping of hepatitis A virus (HAV) - a useful tool for outbreak investigations Kathrine Stene-Johansen NIPH.

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Presentation on theme: "Genotyping of hepatitis A virus (HAV) - a useful tool for outbreak investigations Kathrine Stene-Johansen NIPH."— Presentation transcript:

1 Genotyping of hepatitis A virus (HAV) - a useful tool for outbreak investigations Kathrine Stene-Johansen NIPH

2 0.1 Hedmark (2) Hedmark Oslo Østfold, Nølkeby skole (4) Oslo Hedmark Marokko Kristiansand Sudan Israel Chile 1 Brasil Levanger Chile 2 IVDU-epidemi IVDU-Finland MSM-utbrudd 1997/98 Bergen Hellas Meråker England MSM-utbrudd Tyrkia USA Lørenskog HAV Picornavirus family ss RNA viral genome of 7.5 kB The capsid is composed of 3 structural proteins; VP1, VP2 and VP3 A single serotype

3 Genome organisation of HAV Costa-Mattioli M et al. J Gen Virol 84 (2003),

4 HAV genotype classification A genotype is defined as a group of viruses with > 85% nucleotide identity A sub-genotype is defined as a group of viruses with sequence variability of less than 7.5% 3 human genotypes –genotype I >90% –genotype III < 10% –genotype II2 isolates 3 simian genotypes

5 0.1 PA21 GA76 P27 NOR21 CY-145 AGM27 SLF88 CF53 MBB L-A-1 HAF-203 HM-175 AH1 FH2 LU38 FH3 LY6 AH2 AH3 FH1 GBM F.G. NCACG Genotype IIA Genotype V simian strain Genotype IIIA Genotype IA HAV genotypes Genotype IB Genotype IV simian strain Genotype IIB

6 HAV strains High endemic regions – Endemic HAV populations with closely related strains and geographic relatedness Low endemic regions – Imported strains from high endemic regions with diverse origin and relatedness

7 Genotyping HAV RNA isolation from serum Reverse transcriptase (rt) PCR Sequencing

8 Molecular epidemiology of HAV By sequencing bp in the VP1-2PA region we can distinguish between outbreak strain Within outbreaks HAV sequences are identical or very closely related so that epidemiological defined cases are confirmed or precluded

9 Notified cases of HAV infected in Norway

10 Genotyping used for outbreak investigation in Norway ( ) Epidemic among drug users Outbreak among homosexual men and 2004 Imported cases Small local outbreaks Outbreak among hemophiliacs

11 Notified cases from January July cases 723 cases associated with the epidemic among drug users 581 drug users 142 secondary cases 519 cases not associated with the epidemic among drug users Genotyping 54 genotype IA (IVDU-strain I) genotype IIIA (IVDU-strain II) 19 drug users (IVDU- strain I) 30 other variants IVDU= Intravenous drug abusers

12 Nosocomial outbreak faecal-oral transmission A hospitalised alcoholic transmitted the virus to 14 secondary cases –8 nurses –4 other patients –2 relatives Outbreak strain of genotype IA identical to outbreak strain circulating among drug users at this time ( IVDU- strain I)

13 Outbreak among hemophiliacs Parenteral transmission In hemophiliacs were transmitted with HAV, where coagulation factor VIII was the possible source of transmission 2 batches of coagulation factor VIII and serum from 2 hemophiliacs were analysed Identical virus were detected among the hemophiliacs and in the batches with coagulation factor This outbreak strain was identical to the IVDU-strain II (genotype IIIA)

14 Outbreak among homosexual men notified cases of HAV infection among homosexual men from October 97- March 98 18/23 PCR-positive Genotyping revealed 2 strains –12 MSM-strain I (genotype IA) – 5 MSM-strain II (genotype IA) Outbreak strains distinct from the IVDU-strains MSM-strain II was also detected in a local family outbreak MSM= men with sexual contact with men

15 MotherFather Sister GrandfatherGrandmother +3d/PCR- 0d/PCR+ +11d IgM- +32d/PCR- Family Outbreak Outbreak among homosexual men - 67d UncleAunt IgM-IgM-/PCR- IgM+ 18/23 PCR+

16 Outbreak among homosexual men (2004) 79 notified cases of HAV associated with homosexual men in the period May - November 2004 HAV RNA detected in 67/79 Identical sequences of genotype IA were detected The same outbreak strain caused concurrent outbreaks among homosexual men in Denmark, Sweden and the Netherlands

17 0.1 Chile Marocco Kristiansand Sudan Israel Indonesia Brazil Turkey USA Bergen Greece England MSM outbreak Chile MSM outbreak IVDU outbreak Finland IVDU epidemic IVDU epidemic Genotype IA Genotype IBGenotype IIIA Genotype III B

18 Conclusion By molecular epidemiology we have been able to characterise and distinguish outbreaks of HAV, as well as studied the dissemination of outbreak strains in the population. These studies have shown that sequencing of outbreak strains is essential in outbreak investigation, and that molecular epidemiology is an excellent tool for the surveillance of HAV.

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