Exploiting serological data to understand the epidemiology of bluetongue virus serotypes circulating in Libya

The epidemiological patterns of Bluetongue (BT) in North Africa and Mediterranean Basin (MB) dramatically changed by emergence of subsequent episodes of novel bluetongue virus (BTV) serotypes with highly pathogenic indexes and socio-economic impacts. The objective of the study was to investigate the sero-prevalence and serotype distribution of BTV in Libya. During 2015-2016, a total of 826 serum samples were collected from domestic ruminants in Libya. All sera were assayed by competitive enzyme-linked immunosorbent assays (c-ELISA). C-Elisa-positive samples (43.3%; 173/400) were further analyzed by virus neutralization assay to identify BTV serotypes and determine the antibody titre of positive samples. An overall BTV sero-prevalence was 48.4% (95% CI: 45.0%-51.8%). Neutralizing antibodies were detected against the following BTV serotypes namely: BTV-1, BTV-2, BTV-3, BTV-4, BTV-9 and BTV-26. While BTV-1, BTV-2, BTV-4 and BTV-9 circulation was unsurprising as they have been responsible of the last year outbreaks in Northern African Countries, the detection of BTV-3 and BTV-26 was definitely new and concerning for the animal health of the countries facing the Mediterranean Basin. It is crucial that European and Northern African authorities collaborate in organizing common surveillance programmes to early detect novel strains or emerging serotypes in order to set up proper preventive measures, and, in case, develop specific vaccines and plan coordinated vaccination campaigns

Seroprevalence and molecular detection of Newcastle disease virus in backyard chickens in Tripoli, Libya

Background: Newcastle disease (VD) is a viral disease that affecting many avian species all over the world. Aim: ND has been successfully controlled by vaccination of commercial poultry in Libya. However, there was a lack of information about the situation of ND in backyard chickens. Therefore this study determined the prevalence of ND in backyard chickens in different locations of Tripoli. Methods: A total number of 280 cloacal swabs (190 in summer and 90 in winter) and 412 sera were collected from non-vaccinated backyard chicken flocks in different geographical locations within the area of Tripoli namely Qasr Ben Ghashier, Al-Sawani, Souq Al-Gomaa, Tajourah, Ein Zara, and Janzour. Cloacal swabs and sera were tested by real time PCR and ELISA, respectively. Results: The prevalence of NDV infection in backyard chickens in different locations of Tripoli during summer and winter was 45% using rRT-PCR. Except in Qasr Ben Ghashier, the prevalence in summer season was significantly higher than in winter (X2=46.13, P0.00001). ELISA test revealed 218 positive out of 412 tested samples with total prevalence of 53% across the city of Tripoli in all regions. Obviously, Qasr Ben Ghashier had significantly (X2=74.09, P0.00001) the highest prevalence (82%) of NDV specific antibodies followed by Tajourah (68%). Conclusion: This study demonstrated the situation of ND in backyard chicken highlighting the necessity of a comprehensive vaccination plan for backyard chickens

Reconstructing the evolutionary history of pandemic foot-and- mouth disease viruses: the impact of recombination within the emerging O/ME-SA/Ind-2001 lineage

Foot-and-mouth disease (FMD) is a highly contagious disease of livestock affecting animal production and trade throughout Asia and Africa. Understanding FMD virus (FMDV) global movements and evolution can help to reconstruct the disease spread between endemic regions and predict the risks of incursion into FMD-free countries. Global expansion of a single FMDV lineage is rare but can result in severe economic consequences. Using extensive sequence data we have reconstructed the global space-time transmission history of the O/ME-SA/Ind-2001 lineage (which normally circulates in the Indian sub-continent) providing evidence of at least 15 independent escapes during 2013-2017 that have led to outbreaks in North Africa, the Middle East, Southeast Asia, the Far East and the FMD-free islands of Mauritius. We demonstrated that sequence heterogeneity of this emerging FMDV lineage is accommodated within two co-evolving divergent sublineages and that recombination by exchange of capsid-coding sequences can impact upon the reconstructed evolutionary histories. Thus, we recommend that only sequences encoding the outer capsid proteins should be used for broad-scale phylogeographical reconstruction. These data emphasise the importance of the Indian subcontinent as a source of FMDV that can spread across large distances and illustrates the impact of FMDV genome recombination on FMDV molecular epidemiology