Epidemiological and Molecular Studies on Lumpy Skin Disease Outbreaks in Turkey during 2014-2015

Abstract

This study was carried out to explore epidemiological and molecular features of lumpy skin disease virus (LSDV) in the Aegean, Central Anatolian and Mediterranean regions of Turkey, to evaluate the risk factors associated with LSDV infection and to investigate the financial impact of LSD and potential role of the Culicoides spp. in the transmission of LSDV. Samples were obtained from 611 cattle, each from different farms, and each clinically suspected to be infected with LSDV during the months of July 2014 and June 2015. Culicoides spp. were trapped from April to June 2015. Genetic characterization of the local LSDV field isolates was conducted by sequencing G-protein-coupled chemokine receptor gene segment. Real-time PCR high-resolution melting analysis was used for distinguishing each type of capripoxviruses. Viral DNA was detected in 448 of the 611 animals and Culicoides midges. Three hundred and ninety-three of the 448 affected farms were surveyed. The morbidity and mortality rates detected were 12.3% and 6.4%, respectively. Phylogenetic analysis showed that the field isolates in this study were clustered together with other Africa and Middle East isolates. Genotyping of isolates from infected cattle has revealed the presence of LSDV. A generalized mixed linear model showed that there were positive associations between LSDV infection, European breeds, small-sized family-type farms and nearness of farm to a lake. The financial cost of disease presence in surveyed cattle farms was estimated to be 72.75 GBP per head. The sequence analysis of the mitochondrial cytochrome oxidase subunit I gene showed that the species of Culicoides in LSDV-positive pools was Culicoides punctatus. Detection of LSDV in Culicoides punctatus suggests that it may have played a role in transmitting LSDV. Furthermore, movement of infected animals into disease-free areas increases the risk of the transmission of LSD. Control strategies for LSDV infection should include consideration of the risk factors identified in this study.