title: Detection of hepatitis A virus genotype IB variants in clams from Maputo Bay, Mozambique.
abstract: Clams provide an important source of food and income for the population of Maputo, Mozambique, where conditions of poor water supply and inadequate sanitation favor endemic infection with hepatitis A virus (HAV). To determine the role of bivalves in an endemic area, clams gathered from Maputo Bay were bought from market and examined for HAV. Four batches, total 150 clams, were sampled over the year. RNA extracted from individual digestive glands was assayed by nested RT-PCR and sequencing of HAV 5' noncoding region (5' NCR). Specific HAV signals were detected in one batch, 23 of 34 clams (67%) testing positive. Phylogenetic analyses of VP3/VP1, VP1/P2A, and 5' NCR determined clustering of clam strains as genotype I, subtype B. In addition to identifying HAV IB strains with predicted conserved amino acid sequence, IB variants exhibiting novel amino acid substitutions at the VP1/P2A junction were detected. HAV strains from clams showed 93%-99% homology with wild-type IB strains from South African outbreaks and from a panel of HAV IgM positive Swedish patients. DNA from enteric human adenovirus 40/41 was found in a limited number of clams from two batches, 6/34 (17%) and 4/35 (11%). Detection of HAV subgenotype IB in bivalves provided indirect evidence of the strains circulating in a densely populated coastal region where HAV is presumed to be hyperendemic. The results suggest that clams may be an important source of HAV in Maputo region, and indicate the need for further molecular study of strains circulating in the indigenous population.
authors.affiliation: Department of Clinical Virology, Göteborg University, Guldhedsgatan, Göteborg, Sweden. nancy.nenonen@microbio.gu.se
authors.forename: Nancy P
authors.initials: NP
authors.lastname: Nenonen
authors.forename: Bodil
authors.initials: B
authors.lastname: Hernroth
authors.forename: Arlindo A
authors.initials: AA
authors.lastname: Chauque
authors.forename: Charles
authors.initials: C
authors.lastname: Hannoun
authors.forename: Tomas
authors.initials: T
authors.lastname: Bergström
mesh_terms: D020121:5' Untranslated Regions; D000260:Adenoviruses, Human / Q000235:genetics / Q000302:isolation & purification; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D049872:Bivalvia / Q000821:virology*; D005516:Food Microbiology; D014644:Genetic Variation; D005838:Genotype; D030041:Hepatitis A virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D008969:Molecular Sequence Data; D009073:Mozambique; D049880:Mytilus edulis / Q000821:virology; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D017386:Sequence Homology, Amino Acid; D015678:Viral Structural Proteins / Q000235:genetics
chemical_list: D020121:5' Untranslated Regions; D012367:RNA, Viral; C096539:VP1 protein, hepatitis A virus; D015678:Viral Structural Proteins