Abstract
Simple SummaryContinuous mutations of the foot and mouth disease virus (FMDV) result in the emergence of new topotypes and lineages of FMDV, which contribute to an occasional vaccination failure. Thus, molecular characterization of the circulating FMDV strains associated with a recent outbreak in Egyptian water buffaloes is essential for the control strategies. The results revealed that the circulating virus was SAT-2 serotype, closely related to the lineage of lib12, topotype VII, with a similarity of 98.9%. The new incursions reported in this study explain the considerable high morbidity of FMDV outbreaks in Egypt in early 2019.Spontaneous mutations are a common characteristic of the foot and mouth disease virus (FMDV), leading to wide antigenic variations resulting in the emergence of new topotypes and lineages of FMDV, which contributes to occasional vaccination failures. The objectives of the present study were to genetically characterize FMDV isolated from water buffaloes and study the biochemical and histopathological indicators of infected animals. Fifty-four water buffaloes of both sexes and different ages suffered from acute symptoms of FMD were clinically examined and randomly selected for inclusion in this study. Oral desquamated epithelial and oropharyngeal fluid samples have been tested for FMDV by reverse transcriptase PCR (RT-PCR). Tissue and serum samples were also collected from the diseased buffaloes and subjected to histopathological and biochemical analysis. Our findings showed that all examined samples were confirmed to be positive to FMDV serotype SAT-2 and were adjusted to be responsible for the recent disease outbreak in this study. Phylogenetic analysis revealed that the circulating viruses were of the SAT-2 serotype, closely related to the lineage of lib12, topotype VII, with 98.9% identity. The new lineage of SAT-2 showed a high virulence resulting in the deaths of water buffaloes due to heart failure, confirmed by high serum levels of inflammatory and cardiac markers, including haptoglobin, ceruloplasmin, cardiac troponin I and creatine phosphokinase-MB, indicating an unfavorable FMD-infection prognosis. In conclusion, we document the presence of new incursions circulating in water buffalo populations in Egypt in early 2019, explaining the high morbidity rate of FMD outbreak in early 2019. Furthermore, the newly identified serotype SAT-2 lib12 lineage, topotype VII, showed an aggressive pattern in water buffaloes of the smallholder production system.
Highlights
Foot and mouth disease (FMD) is a devastating, highly contagious viral disease of all cloven-hoofed animals caused by the foot and mouth disease virus (FMDV) of the Picornaviridae family
50 UTR universal primers with the expected 326 bp amplicon and confirmed FMDV being responsible for the disease symptoms that clinically affected water buffaloes
VP1-coding sequencing and phylogenetic analysis revealed a substantial degree of relatedness between the representative Egyptian isolates (n = 5) with a similarity of 98.9, which clustering in topotype VII, lib12 lineage (Figure 1)
Summary
Foot and mouth disease (FMD) is a devastating, highly contagious viral disease of all cloven-hoofed animals caused by the foot and mouth disease virus (FMDV) of the Picornaviridae family. The disease poses a severe threat globally, impeding the international trade of live animals and animal by-products [1,2]. FMDV includes seven serotypes, namely, A, O, C, Southern African Territories (SAT)-1, SAT-2, SAT-3, and Asia. Each serotype has antigenically distinct subtypes due to the high mutation rate [3]. FMD is endemic in many countries in Africa, Asia, and South America [4,5]. In Egypt, FMDV serotypes O and A are endemic and cause sporadic outbreaks [6]. During 2012, widespread outbreaks due to FMDV serotype SAT-2 were reported in the Delta and Upper
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
