INVESTIGADORES
DIAZ Luis Adrian
congresos y reuniones científicas
Título:
MOLECULAR CHARACTERIZATION OF EPIDEMIC AND NON- EPIDEMIC ST. LOUIS ENCEPHALITIS VIRUS (SLEV) STRAINS ISOLATED IN ARGENTINA
Autor/es:
LUIS ADRIÁN DIAZ; SANDRA GOÑI; JAVIER ISERTE; CRISTOPHER LOGUE; AMBER SINGH; ANN POWERS; MARTA S. CONTIGIANI
Lugar:
Atlanta
Reunión:
Congreso; American Society of Tropical Medicine 59th Annual Meeting; 2010
Institución organizadora:
American Society of Tropical Medicin
Resumen:
SLEV (Flavivirus) is an emerging/reemerging arbovirus in South Americacausing isolated encephalitis human cases or outbreaks in Argentinaand Brazil. In the city of Córdoba (Argentina), during a human SLEoutbreak, two genotype III SLEV strains were isolated, belonging to thesame genotype isolated 27 years ago in Province of Santa Fe (Argentina).Preliminary results show some biological differences among epidemic (Ep) and non-epidemic (NEp) strains. The factors which lead this emergence are not known. The aim of this project was to characterize and compare molecularly both Ep (CbaAr-4005) and NEp (79V-2533) SLEV strains.A complete genome strategy was designed for both Ep and NEp SLEVstrains. A bioinformatic analyze was carried out in order to detectcleavage protease site, genetic distance (GD), nucleotide and aminoacidicsubstitutions and relative homologies index (RHI). Finally a phylogeneticanalyze was realized including 26 SLEV strains nearly complete genomesequence available at GenBank. SLEV complete genome consists of 10963 ntds (ORF=3429 aas). Proteins C, PrM, NS2A, NS2B and NS4B have wide regions with RHI greater than >0.80. The most variables proteins (GD) were NS4B (2.7), NS1 (1.7) and M (1.3). A total of 49 conservative and 20 non-conservative aminoacidic substitutions and one deletion were detected in reference with Kern217 SLEV strain (NC_007580.2) sequence.Among Ep and NEp viral strains we detected 17 aminoacidic changes,which 8 of them were non-conservative and located in proteins E, NS1,NS3 and NS5. It is unknown if detected aminoacidic differences would berelated to the biological differences previously observed. The development of reverse genetic system will allow us to understand the meaning of such substitutions. The phylogenetic analysis shows two big clades: North and Central America (NCA) and South America (SA). The analyzed strains isolated in Argentina constitute a subgroup inside the NCA group. Likely, ancestors of genotype III could be introduce and originated the SLEV strains circulating in North and Central America.