DETECTION AND CHARACTERIZATION OF EMERGING HUMAN GROUP A ROTAVIRUS STRAINS IN SEWAGE SAMPLES

MANDILE, MARCELO; LEWEZUK, LORENA; ARGÜELLES, MARCELO; PERI IBAÑEZ, ESTEFANÍA; TEMPRANA, FACUNDO; MISTCHENKO, ALICIA; GLIKMANN, GRACIELA; CASTELLO, ALEJANDRO

Florianópolis

Simposio; IV Simpósio Latino-Americano de Virologia Ambiental.; 2018

Group A Rotaviruses (RVA) are the major etiological agent of diarrheas in children and new vaccines have been introduced to mitigate the severity of the primary viral infection and thereby reduce the morbidity and mortality of the disease. Argentine sanitary authority included the RVA vaccine in the universal immunization schedule since January 2015. In previous studies, methods for quantify and genotype RVA from sewage samples were established and sequence characterization confirmed identity between these strains and those from clinical cases. Similar methods could be applied as monitoring tools of new emerging strains with potential evasion capacity to the vaccine´s immune response. In this work, quantitative and qualitative data from circulating RVA strains were collected from clinical and sewage during 2010, 2011 and 2014 when G2P[4] and G1P[8] strains were introduced from outside the country. We intended to describe the pattern of circulation in the environment of RVA strains in the months before and after the rise of cases characterizing emergence. Clinical samples were obtained from hospitalized cases from the Children´s Hospital in Buenos Aires and sewage was obtained from the treatment plant serving the area. Virus particles were concentrated by ultracentrifugation from pre-treatment sewage and viral load was analysed by qPCR and genotype was determined using a multiplex-PCR. Diarrhea hospitalizations incidence associated to RVA, genotyping, and sequencing of strains from clinical samples were compared with results of viral load, genotyping and sequencing from sewage samples from the same months. The results confirm the relevance of sewage as a useful sample to determine the level of excretion and characteristics of the emergent strain in a given population being possible to detect an increase of the viral load of the emerging RVA simultaneously in both samples. However, we were unable to detect the emerging strains in months previous to the rise in hospitalizations. Hence, even when the study of the environmental excretion of RVA by the population is useful for epidemiological studies, it appears not to provide prognostic utility detecting wild emerging strains. Importantly, during the post-vaccination period and for several years it is necessary to maintain surveillance in sewage in order to monitor evolution of human RVA strains causing unapparent infections or mild cases in the context of vaccine selective pressure.