Enhancing lumpy skin disease control: Effective competitive and indirect ELISAs for serological surveillance.

Lumpy skin disease (LSD), caused by the LSD virus (LSDV) from the Capripoxvirus genus, affects cattle, water buffalo, and wild bovines, leading to significant economic losses. Characterised by fever, skin nodules, and mucosal lesions, LSD raises global concerns due to vector-borne transmission. The World Organisation for Animal Health (WOAH) classifies LSD as a notifiable disease, emphasising the need for rapid diagnostic methods for timely disease confirmation and control. This study evaluates the performance of two previously developed ELISA tests - competitive and indirect. The validation involved 450 field sera from infected and vaccinated herds in Albania (collected in 2016, during the LSD outbreak), 332 sera from vaccinated cattle in Serbia (collected in 2017 from farms with no prior history of LSD detection), 90 sera from experimental infections at Friedrich-Loeffler-Institut, and 412 field negative sera from a Capripox-free country. The comparison with the virus neutralisation test - the gold standard - demonstrated high specificity (≥0.95) and significant sensitivity (0.87-0.94), with 8-9 % of sera showing discordant results. The results diverged more in sera from animals with a single vaccination or sampled five months post-vaccination, indicating reduced antibody detectability over time. The study confirms the ELISAs' efficacy for large-scale LSDV serological surveillance, highlighting their potential to provide a cost-effective and rapid solution for monitoring and controlling LSD in endemic regions.