SARS-CoV-2 in a Mink Farm in Italy: Case Description, Molecular and Serological Diagnosis by Comparing Different Tests.

This study described a SARS-CoV-2 infection in minks on an Italian farm. Surveillance was performed based on clinical examination and a collection of 1879 swabs and 74 sera from dead and live animals. The farm was placed under surveillance for 4.5 months, from the end of July 2020, when a man working on the farm tested positive by RT-PCR, till mid-December 2020 when all the animals were sacrificed. Clinical examination revealed no clinical signs or increased mortality rates attributable to SARS-CoV-2, while diagnostic tests detected only four weak PCR-positive samples, but 100% of sera were positive for SARS-CoV-2 anti-S antibodies. The phylogenetic analysis of two SARS-CoV-2 sequences from two minks and the sequence of the worker showed that they belonged to different clades. It could be therefore assumed that two distinct introductions of the virus occurred on the farm, and that the first introduction probably occurred before the start of the surveillance period. From the data collected, and especially from the detection of specific antibodies through the combination of different tests, it can be postulated that syndromic surveillance combined with genome detection by PCR may not be sufficient to achieve a diagnosis in asymptomatic animals. In particular, the serological approach, especially when using tests directed towards the S protein, may be useful for improving the traceability of virus circulation in similar environments.

Analysis of surveillance and prevention plan for African Swine Fever in Italy in 2020.

BACKGROUND: African Swine Fever (ASF) is a challenge for pig health worldwide. The disease has spread to multiple countries on five continents. ASF-free countries need to apply effective strategies to prevent the introduction of infection. METHODS: Italy implemented a surveillance and prevention plan for ASF in 2020, supported by a dedicated information system. Several pillars for action have been identified: passive surveillance in both domestic pigs and wild boar populations, verification of the implementation of biosecurity measures on farms and an awareness campaign for all involved stakeholders. RESULTS: There were some regional differences in the management of passive surveillance. In order to identify all critical points and apply corrective measures, regional authorities were called to carry out a gap analysis exercise in July 2020. There were an adequate number of samples collected from wild boar but the number of samples collected from domestic pigs was below the target in most regions. Furthermore, sample distribution within the country was not homogeneous. CONCLUSIONS: During the forthcoming year, some issues must be addressed in order to establish an effective early detection system in Italian ASF-free regions.

Simulated African Swine Fever (ASF) virus detection in Italy: average numbers of farms and pigs under restriction.

African swine fever is a devastating contagious viral disease of kept and wild porcine animals that will challenge the Veterinary Services involved in its eradication. Nowadays, ASF represents one of the biggest challenges for the pig sector at a global level. Following a number of simulated virus random introductions, the paper estimates the average number of farms (including their type) and animals that will be under restriction, and finally the average distance of infected farms from the nearest rendering plant. The study includes data referring to 101,032 farms with 9,322,819 pigs which are available in the Italian National Database (BDN). The simulations consider 5 different biogeographic regions with their own domestic pig distribution, breeding systems, and wild boar presence. Following an index case in a farm, and in the worst­case scenario, in the 10 km radius of the restriction area, there will be: 2,636 farms in South Italy; 470,216 animals in Po Valley; 147 km in Central Italy is the longest mean distance from the infected farm to the nearest rendering plant.