Evolutionary phylodynamics of foot-and-mouth disease virus serotypes O and A circulating in Vietnam.

Daesub Song,Van Thai Than,Thi Thu Hang Vu,Van Phan Le,Hong-Quan Duong

doi:10.1186/s12917-016-0896-0

Abstract

BackgroundFoot-and-mouth disease virus (FMDV) is one of the highest risk factors that affects the animal industry of the country. The virus causes production loss and high ratio mortality in young cloven-hoofed animals in Vietnam. The VP1 coding gene of 80 FMDV samples (66 samples of the serotype O and 14 samples of the serotype A) collected from endemic outbreaks during 2006–2014 were analyzed to investigate their phylogeny and genetic relationship with other available FMDVs globally.ResultsPhylogenetic analysis indicated that the serotype O strains were clustered into two distinct viral topotypes (the SEA and ME-SA), while the serotype A strains were all clustered into the genotype IX. Among the study strains, the amino acid sequence identities were shared at a level of 90.1–100, 92.9–100, and 92.8–100% for the topotypes SEA, ME-SA, and genotype IX, respectively. Substitutions leading to changes in the amino acid sequence, which are critical for the VP1 antigenic sites were also identified. Our results showed that the studied strains are most closely related to the recent FMDV isolates from Southeast Asian countries (Myanmar, Thailand, Cambodia, Malaysia, and Laos), but are distinct from the earlier FMDV isolates within the genotypes.ConclusionsThis study provides important evidence of recent movement of FMDVs serotype O and A into Vietnam within the last decade and their genetic accumulation to be closely related to strains causing FMD in surrounding countries.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-016-0896-0) contains supplementary material, which is available to authorized users.

Highlights

Foot-and-mouth disease virus (FMDV) is one of the highest risk factors that affects the animal industry of the country
Detection of FMDV genome and genome sequencing The viral RNA was sufficiently extracted from 80 FMDV samples (66 samples of the serotype O and 14 samples of the serotype A) (Table 1)
Phylogenetic analysis demonstrated that the VP1 coding gene of the FMDV serotype O was clustered into two distinct viral topotypes, the Southeast Asia (SEA) and Middle East-South Asia (ME-SA) (Fig. 2)

Summary

Introduction

Foot-and-mouth disease virus (FMDV) is one of the highest risk factors that affects the animal industry of the country. The virus causes production loss and high ratio mortality in young cloven-hoofed animals in Vietnam. Foot-and-mouth disease virus (FMDV), causing footand-mouth disease (FMD), is a contagious virus affecting cloven-hoofed domestic (pig, cattle, goat, and sheep) and wild animals. FMDV has been detected in >100 countries worldwide, mostly in Asia, Africa, and the Middle East [1]. The FMD causes economic losses to the livestock population and reduces food security and economic development. For this reason, FAO and OIE have launched a necessary strategy for global FMD control. The virus particle is about 25–30 nm in diameter and roughly spherical in shape [2]. Similar to that of other picornaviruses, the FMDV genome organization consists of a large single open reading frame that encodes for the structure proteins, VP4, VP2, VP3, and VP1 ( known as 1A, 1B, 1C, and 1D, respectively), in which VP1, VP2, and VP3 are surface proteins; while VP4 is located internally

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