Serological evaluation for the current epidemic situation of foot and mouth disease among cattle and buffaloes in Egypt.

Diea G. Abo El-Hassan,Walid S. Awad,Sayed A. H. Salem,Mariam M. Abd El-Rhman

doi:10.14202/vetworld.2020.1-9

Abstract

Aim:The present study was aimed to investigate the epidemic situation of foot-and-mouth disease (FMD) in Egypt from 2016 to 2018 based on the detection of FMD virus (FMDV) in carrier or previously infected animals, by determination of antibodies against non-structural protein (NSP), implementation a pilot study on circulating FMDV serotypes and assure the efficacy of locally produced inactivated trivalent vaccine.Materials and Methods:A total of 1500 sera were collected from apparent healthy vaccinated cattle and buffaloes from three Egyptian geographical sectors, representing ten governorates. Determination of FMD antibodies against NSP was carried out using 3ABC enzyme-linked immunosorbent assay (ELISA) test. Serotyping of the circulating FMDV and assure the vaccine efficacy was performed using solid-phase competitive ELISA.Results:The 3ABC ELISA test revealed 26.4% and 23.7% positive for FMDV-NSP antibodies in cattle and buffalo sera, respectively. The highest positivity was in Delta Sector among both cattle 42.3% and buffaloes 28.8%. Serotyping of FMDV-positive NSP sera in El-Qalyubia Governorate for the circulating FMDV serotypes O, A, and Southern African Territories (SAT) 2 was 52.2%, 17.4%, and 30.4% in cattle and 31.8%, 27.3%, and 40.9% in buffaloes, respectively. The overall protection level due to the vaccination program was 62.1 and 60.9% in cattle and buffaloes, respectively, while the protective level of the FMDV serotypes O, A, and SAT2 included in the inactivated trivalent vaccine was 73.9, 84.6, and 63.8% in cattle and 72.3, 82.3, and 63.5% in buffaloes, respectively.Conclusion:The present study recommended full determination for the immunogenic relationship between the vaccine strains and the field strains to attain maximum protection against the circulating viruses.

Highlights

Foot-and-mouth disease (FMD) is one of the most important contagious viral transboundary animal diseases affecting cloven-hoofed animals, including cattle, buffaloes, pigs, sheep, and goats [1], characterized by vesicular lesions in the mouth and on the feet, teats, and nares, causing low mortality rate in adult animals, but often high mortality in young due to myocarditis [2], with important economic losses and restriction of international animal trade [3]
The overall protection level due to the vaccination program was 62.1 and 60.9% in cattle and buffaloes, respectively, while the protective level of the FMD virus (FMDV) serotypes O, A, and SAT2 included in the inactivated trivalent vaccine was 73.9, 84.6, and 63.8% in cattle and 72.3, 82.3, and 63.5% in buffaloes, respectively
The viral RNA is translated into a single polypeptide which is cleaved by viral proteases into 12 viral proteins, classified into four structural proteins (SPs) (VP1, VP2, VP3, and VP4) that form the icosahedral viral capsid, and eight non-structural proteins (NSPs) (L, 2A, 2B, 2C, 3A, 3B, 3C, and 3D) that participate in viral replication and play other functions within the host cell; and during the cleavage, the 3A, 3B, 3C, or 3A, 3B proteins are combined to form 3ABC or 3AB protein complex [9]

Summary

Introduction

Foot-and-mouth disease (FMD) is one of the most important contagious viral transboundary animal diseases affecting cloven-hoofed animals, including cattle, buffaloes, pigs, sheep, and goats [1], characterized by vesicular lesions in the mouth and on the feet, teats, and nares, causing low mortality rate in adult animals, but often high mortality in young due to myocarditis [2], with important economic losses and restriction of international animal trade [3]. There are several topotypes (genetically and geographically) which are further divided into various genotypes (lineages or strains), with up to 61 described so far, as a result of mutation from error-prone RNA replication, recombination, and host selection [7]. The viral RNA is translated into a single polypeptide which is cleaved by viral proteases into 12 viral proteins, classified into four structural proteins (SPs) (VP1, VP2, VP3, and VP4) that form the icosahedral viral capsid, and eight non-structural proteins (NSPs) (L, 2A, 2B, 2C, 3A, 3B, 3C, and 3D) that participate in viral replication and play other functions within the host cell; and during the cleavage, the 3A, 3B, 3C, or 3A, 3B proteins are combined to form 3ABC or 3AB protein complex [9].

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Results

Discussion

Conclusion