Re‐emergence of circulatory foot‐and‐mouth disease virus serotypes Asia1 in Bangladesh and VP1 protein heterogeneity with vaccine strain IND 63/72

Abstract

Foot-and-mouth disease virus (FMDV) serotypes O, A and Asia1 are responsible for significant number of disease outbreaks in Bangladesh; however serotype Asia1 has not been reported in circulation since 1996. The present investigation reports the detection of serotype FMDV Asia1 from local farms in 2012 and 2013 outbreaks. The farms were located in Jessore and Gazipur districts, and one of these farms was under vaccine control programme. Phylogenetic analysis of the complete VP1 gene revealed that FMDV Asia1 is under genetic lineage C having close similarity to the Asia1 sequences of Indian origin. The circulatory genotype Asia1 showed VP1 protein sequence heterogeneity of eight amino acid substitutions within the G-H loop with the vaccine strain [IND 63/72 (AY304994)] used in vaccination programme. ELISA assay revealed that, of seven, only one local field serum sample (cattle vaccinated 38 days earlier) was positive at a titre level of >2.4 (log10) but failed to protect the cattle from infection occurred by the virus. This investigation focused that the eight amino acid substitution in VP1 protein at G-H loop of the locally circulated FMDV serotype Asia1 strain may be a reason for current vaccination failure.

Emergence of novel lineage of foot‐and‐mouth disease virus serotype Asia1 BD‐18 (G‐IX) in Bangladesh

“…This may be due to a steady transmission of viruses through porous trans-border between these countries. From India, the early landmarks of incursion of G-VIII viruses into Bangladesh might happen (Ullah et al, 2015) and could be an important factor to the emergence of this new lineage, which was not possible to determine in this study due to lack of related se- Bachanek- Bankowska et al, 2018;Zhu et al, 2018). The similar scenario can happen in this case, and high sequence diversity with vaccine strain will ask the burning question in protection of cattle in this region.…”

“…This may be due to a steady transmission of viruses through porous trans‐border between these countries. From India, the early landmarks of incursion of G‐VIII viruses into Bangladesh might happen (Ullah et al, ) and could be an important factor to the emergence of this new lineage, which was not possible to determine in this study due to lack of related sequences for recent viruses circulating in the Indian subcontinent and limitation in the nature of genetic dataset. Apart from India, the uncontrolled cross‐border movement of animal and cattle handlers between Bangladesh and the neighbouring countries (Nepal, Bhutan and Myanmar) as well as possible movements of Asia1 G‐IX from central Bangladesh region towards Indian border region (Figure S1) implicate a possibility of transboundary viral transmission events.…”

“…The VP1 snapshot through reconstructing phylogenetic history and estimating sequence variation inferred the genetic diversity that can help in the understanding of comprehensive picture of Asia1 lineages. In case of the genesis of novel lineage BD‐18 (G‐IX), we can mention the emergence as another key turning point for Bangladesh after the re‐emergence of Asia1 serotype during 2012–2013 (Ullah et al, ). Expectedly, the G‐VIII isolates of Bangladesh revealed relatively closer genetic relationships with Indian isolates reported since 1987 that illustrated umbrella‐clustering pattern among sequences of near time period based on both nucleotide and amino acid identity within VP1 region (Gurumurthy et al, ).…”

“…Significantly, that lineage is circulatory in those regions showing poor or no matching with the local vaccine candidate (Asia1 Shamir) regularly (Jamal et al, ). Similarly, there could be immune pressure due to trivalent vaccination programme using genetically divergent vaccine strain (IND63/72) of serotype Asia1 compared to this novel strain, or inappropriately selected local candidate, which might ultimately favour the generation of this new strain of lineage G‐IX (Ullah et al, ). Moreover, Siddique et al () reported a novel sublineage of serotype O from Bangladesh, and then subsequent works by other contemporary groups detected the same strains across 14 countries, even outside Indian subcontinent zone, from where the strains were reported earlier stage of outbreak and spread (Alam et al, ; Bachanek‐Bankowska et al, ; Zhu et al, ).…”

“…Notably, Valarcher et al () designated previous lineage D as G‐III and Subramaniam et al () designated strains circulating after 2005 under previous lineage C as G‐VIII, while both lineages were endemic in Indian subcontinent (Sanyal et al, ). In recent years (2016–2017), Sindh‐08 (G‐VII) is the only lineage of serotype Asia1 that is in continuous circulation in its endemic region (Ali et al, ) whereas outbreaks with other lineage G‐VIII were reported sporadically (Ullah et al, ; WRLFMD, ), with the latest report from Myanmar in 2017 (Bo et al, ).…”