Promising use of Polymerase Chain Reaction Associated to Reverse Transcription for the Detection of the America-1 Lineage of Canine Distemper Virus

INTRODUCTIONCanine Distemper (CD) is one of the main diseases that affects domestic canines and causes high morbidity and mortality rates in unvaccinated dogs.In recent years it has been observed in the clinic that animals vaccinated in the same way are catching the virus.Canine Distemper Virus (CDV) also affects common and endangered species of wild animals throughout the world.Domestic dogs and other related species serve as reservoirs of the virus and play an important role in the transmission of the disease (Chinnadurai et al., 2017).CDV can affect many species, the younger ones being more susceptible, because they have lost maternal antibodies and their immune system is still immature to respond to infection (Martella et al., 2008).The genome of the virus encodes six structural proteins: nucleocapsid protein encoded by the N gene, membrane protein encoded by the M gene, phosphoprotein encoded by the P gene, large polymerase encoded by the L gene, hemagglutinin encoded by the H gene and the fusion protein encoded by the F gene (Martella, et al., 2008).CDV lineages have been described based on the analysis of the Hemagglutinin (H) gene, this gene has the highest degree of variability.At present, 14 types of lineages have been determined according to this gene, identified as America-1 (vaccine strain), America-2, Asia-1, Asia-2, Asia-3 and Asia-4, Europe1/South America-1 (EU-1 / SA-1), Arctic, European Wild (EW), South America-2 (SA-2), South America-3 (SA-3), Rockborn-like (RL), Africa-1 and Africa -2 (Ke et al., 2015).In Chile, it was determined through an analysis of a region of the H gene, that at least two circulating lineages would exist in the country's canine population: America 1 and Europe 1 (Salas et al., 2018).Because DC is a highly contagious disease, lethal and affecting many species, it is very important to implement a technique that allows antemortem viral detection and thus facilitate diagnosis and early treatment.Thus, in this report specific in silico primers were designed for the América-1 lineage of Abstract: Canine Distemper (CD) is one of the pathologies that causes the highest rate of morbidity and mortality in domestic canines worldwide and also represents an important disease in several families of terrestrial mammals: Canidae, Procyonidae, Mustelidae, Mephitidae, Hyaenidae, Ursidae ,Ailuridae, Viverridae, Felidae and some marine mammals the cape seal (pusacaspica).This disease is caused by Canine Distemper virus (CDV), a single-stranded RNA virus and negative polarity, whose genome consists of six genes, codes for six structural proteins.Among them, the Hemagglutinin encoded by the H gene, has the highest amino acid variability, induces the production of neutralizing antibodies synthesized by the host immune system.Based on the variability of the H gene, it has been described that worldwide there would be at least fourteen lineages different from the CDV and in our country has been described the presence of at least two lineages circulating among our sick dogs with the pathology: America-1 and Europe.Thus, the objective of this report was to implement the detection of the America-1 lineage of the Canine Distemper Virus by means of the Polymerase Chain Reaction associated with reverse transcription (RT-PCR) by means of in silico-designed primers.For this, the access numbers of the described nucleotide sequences were used in a phylogenetic tree constructed using the CDV H gene as target (Ke et al., 2015) and stored in the Genbank® database, The designed primers were found to be effective for CDV detection and the RT-PCR was able to detect a specific fragment of the H gene from the positive samples, therefore it could be suggested that these in silicodesigned primers can effectively be used to detect the America-1 lineage.