RESUMEN
The aim of the present study was to report the molecular characterization of human group A rotaviruses (RVAs) circulating in Tunisia. Stool specimens were collected from children under 5 years of age who had been hospitalized or were consulting for gastroenteritis in Tunisian hospitals between 2015 and 2017. All samples were screened by reverse-transcription polymerase chain reaction (RT-PCR) for the detection of the VP6 gene specific for RVA. RVA-positive samples were further analysed for G/P genotyping by semi-nested multiplex RT-PCR. Among 454 tested samples, 72 (15.8â%) were positive for RVA. G1P[8] was the most prevalent detected strain (41.7%), followed by G9P[8] (32.8%), G2P[4] (7.5%), G12P[8] (7.5%), G1P[6] (3.0%), G2P[8] (1.5%) and G3P[8] (1.5%), with mixed infections in 4.5â% of cases. In the absence of a national anti-rotavirus vaccination strategy, RVAs remain the primary aetiological agent for gastroenteritis in Tunisian children.
Asunto(s)
Gastroenteritis/virología , Infecciones por Rotavirus/virología , Rotavirus/genética , Proteínas de la Cápside/genética , Preescolar , Heces/virología , Gastroenteritis/epidemiología , Variación Genética , Genotipo , Humanos , Lactante , Recién Nacido , Epidemiología Molecular , Prevalencia , ARN Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rotavirus/aislamiento & purificación , Infecciones por Rotavirus/epidemiología , Estaciones del Año , Análisis de Secuencia de ADN , Túnez/epidemiologíaRESUMEN
PURPOSE: Group A rotavirus (RVA) is the leading cause of severe gastroenteritis in children younger than 5 years. The most common human G-types are G1-4 and G9. G12 genotype is currently emerging worldwide, becoming the sixth most prevalent RVA G-genotype. In Tunisia, an emergence of G12 RVA strains was observed. To understand the evolution and origin of these Tunisian G12 strains, phylogenetic analyses were conducted. METHODOLOGY: A total of 1127 faecal samples were collected from Tunisian children under 5 years consulting for gastroenteritis between 2009 and 2014. Samples were screened by ELISA for the presence of RVA antigen. RVA-positive samples were used for the detection of G12 RVA strains by semi-nested RT-PCR. G12-positive specimens were subjected to VP4 genotyping reaction. PCR products of the G12-positive samples were sequenced and characterized by phylogenetic analysis of partial VP7 gene sequence. RESULTS: Globally, 270 (24â%) stool specimens were RVA-positive. Fourteen presented the G12 genotype (5.2â%) and were found to be in combination with either the P[6] (50.0â%) or the P[8] (50.0â%) genotype. Phylogenetic analysis revealed that all characterized Tunisian G12 strains clustered in the modern G12 lineage III and appear to form three different subclusters. CONCLUSION: Thus, the Tunisian G12 strains may have originated from not a single, but at least three distinct ancestral G12 strains. Detailed molecular characterization of the entire genome of these strains remains essential to help determine the extent of genetic variation and the relatedness of Tunisian G12 RVA strains to G12 strains described worldwide.