Geographic and Phylogenetic Distribution of PRRSV in México

  • 10 minutes
  • Expertise article
  • A. Uribe; A. Mendoza; C. Martín del Campo; F. Pinal; J. Ochoa; N. Centeno; A. Esquer; E. Mondaca; J. Chévez
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A. Uribe*1; A. Mendoza1; C. Martín del Campo1; F. Pinal1; J. Ochoa1; N. Centeno1; A. Esquer1; E. Mondaca2; J. Chévez1

1Boehringer Ingelheim Animal Health Mexico; 2Epi-Vet Consulting, jose.uribe@boehringer-ingelheim.com

 

Introduction

The Porcine Reproductive and Respiratory Virus (PRRSV) genome is a single-strand positive sense RNA of 15 kb in length, containing several structural and non-structural proteins. Among those proteins, GP5 is a structural glycosylated protein and the most variable of PRRSV1. ORF5 sequences from PRRSV type 2 have been grouped per lineages and sublineages2 that can be used as a reference to determine diversity of PRRSV isolates by regions or countries. The objective of this study was to sequence and analyze the ORF5 segment in PRRSV isolates obtained in different regions of Mexico during 2015–2019, thus documenting the genetic variation in the circulating variants of PRRSV according to their different linages and assisting in the understanding of the patterns of geographical distribution of this virus in Mexico.

Materials and Methods

Three hundred and ninety seven samples (sera, oral fluid, processing fluids and tissue swabs) from 13 Mexican states (Aguascalientes, Estado de México, Guanajuato, Hidalgo, Jalisco, Michoacan, Nayarit, Nuevo Leon, Puebla, Queretaro, Sonora, Tamaulipas y Veracruz) were analyzed to identify ORF5 PRRSV during June 2015-March 2019. RNA extraction was made with QiAmp Viral RNA mini Kit catalogue number 52906. ORF5 sequencing was carried out using the Miseq System equipment, while the nucleotid sequence analysis was performed with MEGA 7.0 software3. The phylogenetic tree was built applying the Neighbor Joining building model and a 1000 repetitions Bootstrap analysis. A map showing the geographical distribution of the different PRRSV lineages by state in Mexico was generated using ArcMap 10.7.1 (ESRI, Redlands, CA).

Results

Published references at GenBank from the nine PRRSV type 2 ORF5 lineages were compared to the 397 sequences on file and a phylogenetic tree (figure 1) was generated applying MEGA 7.0 software. The tree in figure 1 shows that 161 sequences or 41% of the total belong to the lineage 1 (L1), 40 sequences (10%) to lineage 2 (L2), 125 sequences (31%) to lineage 5 (L5), 2 sequences (1%) to lineage 7 (L7) and 69 sequences (17%) to lineage 8 (L8).

The map in figure 2 shows the distribution of L1, L2, L5, L7 and L8 by state in Mexico. Six of the the 13 states in the database represent 70% of the volumen of pork production in Mexico4.

Conclusions and Discussion

This study analyzed the genetic variability of different PRRSV isolates in several states from Mexico, based on the system of lineages published by Shi et al2. The resultant phylogenetic tree shows that the main lineages on this Mexican database are L1 and L5 (MLV vaccine-related), consisting of 72% of the 397 PRRSV isolates in study, while L2 and L8 account for 27% of the isolates and only 2 sequences (1%) belong to L7. The findings from this study show a nationwide distribution of lineages L1, L5 and L8, stressing the need for a better understanding of pig movements between regions in Mexico.

Figure 1: Phylogenetic tree of 397 PRRSV Type 2 ORF5 sequences from Mexico containing isolates from 5 differentes lineages (L1, L2, L5, L7 and L8).

Figure 1 Image

Figure 2: Map showing the geographical distribution by state of the PRSV type 2 ORF5 lineages detected in Mexico.

Figure 2 Image

References

  1. Han, M. et al. 2014. Veterinary Microbiology. 2010 Dec 5;174 (3-4):279-295.
  2. Shi M. et al. 2010. Journal of Virology 84(17): 8700–11
  3. Kumar S. et al. 2016. Molecular Biology and Evolution. 2016;33:1870–1874
  4. SIAP. 2019. Acces: el 22/11/2019 http://infosiap.siap.gob.mx/repoAvance_siap_gb/pecAvanceProd.jsp