Sero-epidemiology of foot-and-mouth disease in Darfur area, Western Sudan.

Nussieba A. Osman,Alsadig E. Hamid,Nussiba H. Ahmed,Wefag Alfouz,Yazeed A. Raouf

doi:10.1007/s11259-021-09815-1

Nussieba A. Osman, Alsadig E. Hamid + Show 3 more

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https://doi.org/10.1007/s11259-021-09815-1

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Abstract

A total of 367 bovine sera positive to antibodies against non-structural proteins (NSPs) of foot-and-mouth disease (FMD) virus were screened for serotype O, A and SAT2 antibodies using the virus neutralization test (VNT). Sera had been collected in 2016 from North (228) and South (139) Darfur States in Western Sudan, where high and low circulation of FMD virus, respectively, prevailed. Tested sera represented the positive-NSPs portion in a random sample of 669 sera collected from both States. According to standard statistical methods, calculations for serial testing (NSPs ELISA and VNT) were applied to estimate prevalence rates of serotype-specific antibodies in the two States. In each State, approximately 20% of NSPs positive sera failed typing. Prevalence's detected were 49% ± 5% (O), 27% ± 5% (A) and 14% ± 4% (SAT2) in North Darfur State and 27% ± 5% (O), 17% ± 4% (A) and 8.0% ± 3% (SAT2) in South Darfur State. In both States, prevalence rates were significantly higher for serotype O, followed by A then SAT2; the same order that was known in most parts of Sudan. Consistently, estimated prevalence's were statistically significantly higher (P < 0.05) in North Darfur than in South Darfur State. Apart from serotype SAT2, detected prevalence rates were lower or similar to those inside the country in previous occasions. Frequency and pattern of distribution of serotype O prevalence were consistent with its suggested pattern of circulation from the Nile valley to other parts in Sudan and significant within the country's circulation. Alternatively, serotype SAT2 prevalence and distribution in Darfur area were suggestive of sporadic occurrence. However, slightly higher prevalence rates of SAT2 antibodies in Darfur than in neighbouring Kordofan areas in 2013 reflected the wide dissemination of SAT2 ( http://www.wrlfmd.org ) in Sudan in early 2014. Risk of FMD in Darfur seemed to be associated with the movement of animals to the North in the wet season as part of the pastoral system, and with movement related to trade into urban centers more than with pastoralism across the Western borders. Generally, the result presented little evidence to suggest presence of FMD primary endemic foci in Darfur area.

Highlights

Foot and mouth disease (FMD) is, perhaps, an important transboundary animal disease
In North Darfur State, index of prevalence of FMD infection decreased from 74.0% by non-structural proteins (NSPs) serology to 61.0% by the serial testing approach (Table 2)
Sero-prevalence of Foot-and-mouth disease virus (FMDV) serotype-specific antibodies in North and South Darfur States

Summary

Introduction

Foot and mouth disease (FMD) is, perhaps, an important transboundary animal disease It is caused by an Aphthovirus of the family Picornaviridae of seven immunologically distinct serotypes; O, A, C, Asia, SAT1, SAT2 and SAT3 that, apart from serotype C, show sustained activity (OIE Manual 2018; Paton et al 2021). It affects a wide range of cloven-footed animals including domestic and wild ruminants and pigs (Thomson et al 2003; Alexandersen and Mowat 2005). It is agreed upon that national and regional control measures would unlikely be successful unless clear insight in its epidemiology is acquired

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