ANALYSIS OF THE FUSION PROTEIN SIGNAL PEPTIDE OF CANINE DISTEMPER VIRUS ISOLATES: SEEKING FOR NEW GENOMIC REGIONS FOR MOLECULAR CHARACTERIZATION

NICOLAS SARUTE; YANINA PANZERA; GALLO CALDERON, MARINA; LA TORRE, JOSE; JESSIKA LLANES; NOELIA GARRACINI ; MARTIN HERNANDEZ; LOURDES FRANCIA; RUBEN PEREZ

Workshop; Molecular Biology of Viral Diseases; 2011

Canine Distemper virus (CDV) (Morbillivirus, Paramyxoviridae) has a single-stranded, negative RNA genome of 15.7 kb. CDV is the etiological agent of Canine Distemper (CD), one of the most severe infectious diseases in wild and domestic terrestrial carnivores. Although is controlled by attenuated vaccines, recently many outbreaks have been registered worldwide, even in populations properly vaccinated. Our region seems not to be absent to this issue. These cases render necessary the fast detection of the virus and the characterization of the circulating strains. On this way, we developed a Real-Time PCR based method for the detection of CDV genome, and we also performed the molecular characterization of Argentinean and Uruguayan field isolates through the analysis of the Fusion protein signal peptide (Fsp). Urine, blood and ocular discharges samples from dogs with clinical symptoms of CD and a sample of a commercial vaccine (Onderstepoort strain), were subjected to RNA extraction, specific-primer retrotranscription and were analyzed by TaqMan Real-Time PCR using a probe that binds in a conserved region of nucleocapsid gene. Viral RNA of a commercial vaccine of Infectious Bronchitis Virus was used as inner control. We detected the viral genome in 77% of samples analyzed. From these samples, we obtained the Fsp region sequences of 7 Uruguayan and 4 Argentinean field isolates. Recently, it has identified that Fsp shows high values of genetic variability, even more than Hemagglutinin which is usually employed in characterization studies. At this work, we present the first report in South America of molecular characterization of CDV isolates based on the Fsp region analysis. Amplification of the Fsp region was carried out by RT-PCR using specific-primers. Amplicons (405 pb) were sequenced in both directions twice. The analysis of the Fsp aminoacidic sequences revealed high values of identity among Uruguayan isolates and an Argentinean one (93.3 – 100%), whereas the remaining Argentinean isolates also showed high aminoacidic identity (97.8 – 100%). However, sequences of both groups differed clearly (78.8 – 81.7%). The comparison with isolates around the world, indicated that Uruguayan and one Argentinean isolates are linked with European strains, nevertheless the rest of Argentinean isolates form a group without apparent connection with strains abroad.