Determination of Serological Data to Understand the Epidemiology of Foot-and-mouth Disease Virus Serotypes Circulating in Libya

Abstract

This study was focused mainly on the third of these components to measure the level of NSP antibodies as indicator of past or current FMDV infection, irrespective of the vaccination status. Foot-and-mouth disease (FMD) outbreaks have been sporadic in Libya for nearly fifty years. A countrywide serosurvey was conducted in the spring of 2013 to assess the extent of FMD virus circulation and identify FMD virus serotypes in the country. A total of 4221 sera were collected, comprising samples from large ruminants (LR; n=1428 samples from 357 farms) and small ruminants (SR; n=2793 samples from 141 farms). FMD sero-prevalence of NSP antibodies determined by ELISA were 19.0% (271/1428) with 95% CI (16.9 - 21.0) and 13.5% (378/2793) with 95% CI (12.3 - 14.8) for LR and SR samples, respectively. The sero-prevalence of NSP antibodies in LR was 12.3% and 19.8% for age group <  year and \(\geq\) 1 year, respectively (X²=4.95,P=0.026), while in SR was 3.7%, 13.6% and 21.3% for age group <1 year, 1-2 year and >2 year, respectively (X²=118.1,P=0.000). These observed NSP serologic profiles support the hypothesis of an endemic level of FMD circulation in Libya. All positive sera were tested for SP antibodies for O, A and SAT-2 FMD virus serotypes. Serotype O was the dominant circulating serotype followed by serotype A, while evidence of SAT-2 was not found. These data provide an insight into the wider epidemiology of FMD in Libya, and contribute to field and laboratory investigations that during 2013 serotype 0 (O/ME-SA/Ind-2001 lineage) was isolated from clinical samples collected from the country. To have a better understanding of livestock production, data collecting on the management system, and risk factor analysis, more study should be done. As a result of the findings, scientists can better understand the epidemiology of FMD and design scientifically sound disease control techniques to reduce the impact of FMD on Libyan livestock.