Outbreak investigation and molecular diagnosis of Lumpy skin disease among livestock in Saudi Arabia 2016.

Lumpy skin disease (LSD) is a highly infectious disease of cattle caused by a virus of the Capripoxvirus genus in the family Poxviridae. The disease is a major concern for the dairy industry in Saudi Arabia. In this study, an outbreak of LSD in cattle herds was detected in Saudi Arabia in 2016. LSD outbreak was investigated in five regions of Saudi Arabia: Al-Hassa, Al-Sharqia, Al-Qassim, Riyadh and Al-Taif during the period from April to July 2016. Tissues from skin nodules were collected to characterize the virus by a real-time polymerase chain reaction (rt-PCR). During this period, 64,109 cattle were examined and morbidity, mortality and case fatality rates were 6%, 0.99% and 16.6%, respectively. The analysis showed 3,852 infected cases and 641 deaths. highest number of infected animals was reported in Al-Hassa (2,825), followed by Al-Qassim (547), Riyadh (471), Al-Sharqia (6) and Al-Taif (3). The highest morbidity rates were observed in Al-Qassim (6.8%), Al-Hassa (6.2%), Riyadh (5.5%) and Al-Taif (0.96%), while the lowest morbidity rates were recorded in Al-Sharqia (0.27%). The highest mortality rates were also observed in Al-Qassim (2.3%), followed by Al-Hassa (0.97%), Riyadh (0.19%) and lowest in Al-Sharqia and Taif (0%). LSD virus was detected in all samples (n = 191) by real-time PCR analysis. The disease has been observed in the cattle regardless of previous vaccination using the locally Romanian-pox vaccine; therefore, vaccination programme and vaccine efficacy should be assessed under field conditions.