Zlin prevented the spread of the ASF infection by confining the contaminated zone via odor fences. Odor fences with a total length of 44.5 km were effective in keeping wild boar inside the health zone. In 2018, Romania experienced a nationwide African swine fever pandemic, which prompted the slaughter of most farm pigs. In August 2018, authorities announced the first outbreak of African swine fever in Bulgaria. By July 2019 five Bulgarian pig farms had had outbreaks of African swine fever. In July 2019, authorities announced the first outbreak of African swine fever in Slovakia. In February 2020, authorities announced the first outbreak of African swine fever in a restricted area of Northern Greece. In January 2021, Romania suffered again from a new breakout of the African swine fever virus that started in the Brăila County. In January 2022, ASF cases were reported in Northern Italy, Latvia and Hungary. 2018-2020 African swine fever panzootic China and East Asia In August 2018, China reported the first African swine fever outbreak in Liaoning province, which was also the first reported case in East Asia. By September 1, 2018, the country had culled more than 38,000 hogs. Since the week of September 10, 2018, China has blocked transports of live pigs and pig products in a large part of the country to avoid spread beyond the 6 provinces where the virus was then confirmed. By the end of 2018, the outbreaks had been reported in 23 provinces and municipalities across China. On April 25, 2019, the virus was reported to have spread to every region of China, as well as parts of Southeast Asia, including Cambodia, Laos, Thailand and Vietnam. The Chinese pig population was reported to have declined by almost 100 million compared with the previous year, driving European pork prices to reach a six-year high. Ze Chen, Shan Gao, and co-workers from Nankai University detected ASFV in Dermacentor (hard ticks) from sheep and bovines using small RNA sequencing. This 235-bp segment had an identity of 99% to a 235-bp DNA segment of ASFV and contained three single nucleotide mutations (C38T, C76T and A108C). C38T, resulting in a single amino-acid mutation G66D, suggests the existence of a new ASFV strain, which is different from all reported ASFV strains in the NCBI GenBank database and the ASFV strain (GenBank: MH713612.1) reported in China in 2018. In December 2019, China banned imports of pigs