[Research Note]: Phylogenetic Analysis of Tilapia Lake Virus (TiLV) Isolates from the Philippines Based on Partial Genome Segment 3 Sequences

  • The Philippine Agricultural Scientist
  • Dan Joseph Logronio
  • Joselito Somga
  • Maria Rowena Romana-Eguia
  • Sonia Somga
  • Demy Catedral
  • Gonzalo Jr Coloma
Keywords: phylogenetics, Tilapia Lake Virus, segment 3, Philippines

Abstract

This study aimed to expand current knowledge on TiLV genetic diversity by sequence analysis of a portion of genome segment 3 of TiLV detected from the Philippines. This includes a recently deposited sequence in GenBank (Accession No. LC504279) and six new sequences from cases of infection reported from 2017 to 2020. Phylogenetic analysis of 179 bp fragment of segment 3 showed that the seven TiLV isolates from the Philippines can be divided into three phylogenetic groups. When comparing all sequences, unique nucleotide substitutions and amino acids were noted among these groups. Variation in mortality rates in naturally infected samples was also observed; however, poor environmental conditions during the disease outbreak may also contribute to the mortalities. These suggest the presence of at least three phylogenetic groups of TiLV in the Philippines which has significant implications for the future development of a vaccine, diagnostic kits, and genetic selection programs.

Cover image from the article of Dan Joseph C. Logronio, Joselito R. Somga, Maria Rowena R. Romana-Eguia, Sonia Somga, Demy Catedral, and Gonzalo Coloma Jr. (2022), p. 100. Healthy Nile tilapia and red tilapia. Tilapia is a cheap source of protein. However, diseases caused by viruses such as the Tilapia Lake Virus (TiLV) can affect the culture of this fish. Logronio et al. (2022) studied the genetic diversity of TiLV detected in the country based on sequencing data. Identification of the three phylogenetic groups of the virus has significant implications for tilapia disease diagnostics, vaccine development, and selective breeding of disease resistant tilapia stocks. {Photograph courtesy of Dr. Ma. Rowena Eguia, Binangonan Freshwater Station, Southeast Asian Fisheries Development Center/ Aquaculture Department (SEAFDEC/AQD)}
Published
2022-04-18
Issue
Vol 105 No 1 (2022): Vol. 105 No. 1 (Mar 2022)
Section
Articles