Three Hepatitis A virus (HAV) genotypes, I, II and III, divided into A and B subtypes, infect humans. Genotype I is the most frequently reported while genotype II is hardly ever isolated and its genetic diversity is unknown. From 2002 to 2007, a French epidemiological survey of HAV identified 6 IIA isolates mostly in patients who did not travel abroad. The possible African origin of IIA strains was investigated by screening the 2008 mandatory notification records of HAV infection: 171 HAV were identified in travellers to West Africa and Morocco. Genotyping was performed by VP1/2A junction sequencing in 68 available sera. Entire P1 and 5" untranslated regions of IIA strains were compared to reference sequences of other genotypes. The screening retrieved 5 IIA imported isolates. An additional autochthonous case and 2 more African cases were identified in 2008 and 2009 respectively. A total of 14 IIA isolates (8 African and 6 autochthonous) were analysed. IIA sequences presented lower nucleotide and amino-acid variability than other genotypes. The highest variability was observed in the N-terminus region of VP1 while for other genotypes it was observed in the VP1/2A junction. Phylogenetic analysis identified 2 clusters, one gathering all African and two autochthonous cases and a second including only autochthonous isolates. In conclusion, most IIA strains isolated in France are imported by travellers returning from West Africa. However, the unexplained contamination mode of autochthonous cases suggests another still to be discovered geographical origin or a French reservoir to explore. (R.A.)
Auteur : Desbois D, Couturier E, Mackiewicz V, Graube A, Letort MJ, Dussaix E, Roque Afonso AM
Journal of Clinical Microbiology, 2010, vol. 48, n°. 9, p. 3306-15
