and F

and F.L.; writingreview and editing, S.D.G., F.L., D.S., M.F. whole genome sequencing data showed that they were closely related to Sardinian ASFV strains collected since 2010, especially 22653/Ca/2014. Our data suggested the absence of immune-escaped ASFV variants circulating among free-ranging pigs, indicating that additional elements contributed to computer virus blood circulation among these animals. Understanding factors behind disease persistence in endemic settings might contribute to developing effective countermeasures against this disease. family [4]. The ASFV genome size varies FLJ20285 between 170 and 190 kbp size; differences are mainly due to copy numbers of five varied multigene family members (MGF), which seem to play a central part in the evasion of sponsor defences [5]. Toloxatone ASFV field strains are segregated into 24 genotypes based on analysis of the variable region of the B646L gene, which encodes the major protein p72 [4,6]. ASFV was first launched in Sardinia in 1978 and, despite several eradication programs, Toloxatone outbreaks in home pigs were recognized until 2018, while the last PCR-positive sample in crazy boar dates back to early 2019 [7,8]. All Sardinian isolates collected from 1978 to 2018 belong to genotype I ([9,10], ASF Computer virus Archive, Virology, Istituto Zooprofilattico Sperimentale (IZS) of Sardinia), whereas, in other areas of Europe, Asia, and Oceania, all the circulating ASFV isolates belong to genotype II [3,4], and all p72 genotypes are circulating in Africa [4]. Before this study, Sardinian ASFV strains were isolated only from home pigs presenting per-acute or acute medical signs of the disease or from hunted/lifeless crazy boar with unknown health status (ASF Computer virus Archive, Virology, Animal Health, IZS of Sardinia, Sassari, Italy). Natural reservoirs of the computer virus, such as naturally resilient crazy Suidae (warthogs) or ticks of the genus are absent in Sardinia [11,12]. A central part played by crazy boar in disease maintenance in Sardinia was by no means shown [13,14], whereas several studies suggested a key part for free-ranging pigs in ASFV persistence in Sardinia [13,14,15], probably acting like a reservoir of the computer virus [8,16]. Therefore, in the platform of the last ASF regional eradication strategy (PE-ASF15-18; Regional Decree Quantity 5/6, 6 February 2015, and subsequent improvements), several actions were conducted to remove illegal free-ranging pigs, coordinated by a special unit issued from the Sardinian authorities (Unit di progetto, Project Unit), as previously described [16]. Large disease prevalence was recognized during the 1st six months of these culling actions (December 2017CJune 2018) [16], and veterinarians from the Animal Health Services (AHS) or specialised task pressure GIV (Gruppo di Toloxatone intervento veterinario, Veterinary unique unit) observed that these animals were apparently healthy and in good nutritional status at the time of culling. These pigs experienced probably recovered completely from illness and might possess acted as service providers of ASFV, contributing to computer virus transmission and environmental contamination. Similar scenarios have been explained in Africa [17,18,19] and eastern Europe [20,21,22], and experts suggested that low-virulence computer virus variants were circulating in those territories. In Latvia, an attenuated non-haemadsorbing (non-HAD) genotype II ASFV strain was isolated from a crazy boar in 2017 [22]. A recent study explained that an ASFV variant with reduced virulence, showing a deletion of 14,560 foundation pairs in the 5 end, was circulating among crazy boar in North Estonia [23]. With this study, we aim to provide new information within the part of illegal free-ranging pigs in ASF persistence in Sardinia, with the hope of generating info useful to develop effective disease countermeasures. In the initial part of the work, a description of the geographic distribution and the ASFV prevalence in free-ranging pigs between 2017 and 2020 was offered. In the second part of the study, ASFV strains circulating among these illegal, apparently healthy, free-ranging pigs were characterized. We observed no evidence of non-HAD ASFV isolates in Sardinia, whereas two HAD strains were collected in two unique culling actions: 103917/18 and 55234/18. These strains circulating among apparently healthy antibody-positive pigs were analysed.