Use of the Reverse Transcription-Polymerase Chain Reaction for differential detection of two lineages of the canine distemper virus in Chile

Abstract

Worldwide, Canine Distemper Virus (CDV) infection is a highly prevalent disease with high morbidity and mortality. CDV causes a multisystemic disease in a wide range of hosts including 9 families of mammals among them some primates, cetaceans and numerous carnivores. It presents a high tropism for lymphoid, neurological and epithelial tissue, leading to an infection of almost all systems, so the clinical signs observed are very varied. The diagnosis is made based on the clinical presentation of the disease, which considers a variety of signs and must be confirmed by a laboratory diagnostic method. The molecular technique called Reverse Transcription Polymerase Chain Reaction (RT-PCR) has been used to characterize viral strains based on the basis of genetic differences on the hemagglutinin (H) gene of CDV has allowed the identification of 14 circulating lineages in the world. Two lineages, namely the America-1 and the Europe-1/South America-1 have been described in Chile. The goal of this work was to implement a multiplex RT-PCR protocol, which was built on the in silico design of primers based on the H gene nucleotide sequences stored in the Genbank® database. This method was capable of detecting the previously described two circulating genetic lineages of CDV in a differential way providing a supporting diagnostic tool for epidemiological studies in the country. These results suggest that the primers described here are extremely selective for the above-mentioned lineages. In addition, our initial screening indicated that most analyzed clinical samples corresponded to the America-1 lineage, stressing the need for a continuous surveillance in order to properly address the prevalence of both lineages in Chile.