Standardized Methodology for Target Surveillance against African Swine Fever

Abstract

African swine fever (ASF) remains the most serious pig infectious disease, and its persistence in domestic pigs and wild boar (WB) is a threat for the global industry. The surveillance of WB plays a central role in controlling the disease and rapidly detecting new cases. As we are close to eradicating ASF, the need to find any possible pockets of infection is even more important. In this context, passive surveillance is the method of choice for effective surveillance in WB. Considering the time and economic resources related to passive surveillance, to prioritize these activities, we developed a standardized methodology able to identify areas where WB surveillance should be focused on. Using GIS-technology, we divided a specific Sardinian infected area into 1 km2 grids (a total of 3953 grids). Variables related to WB density, ASF cases during the last three years, sex and age of animals, and the type of land were associated with each grid. Epidemiological models were used to identify the areas with both a lack of information and an high risk of hidden ASFV persistence. The results led to the creation of a graphic tool providing specific indications about areas where surveillance should be a priority.

ASF Exit Strategy: Providing cumulative evidence of the absence of African swine fever virus circulation in wild boar populations using standard surveillance measures

“…In Sardinia, less than 10% of the total tested samples is provided by passive surveillance and most of these samples are from wild boar killed in road traffic accidents. Most of the wild boar samples, however, are taken during active surveillance and the sampling period is limited to the hunting season, which lasts from November to January (Cappai et al., 2020). Because the data in Sardinia are submitted mostly during the hunting season that lasts from November until the end of January, during the rest of the year very few wild boars have been sampled and tested for ASF and the data were not considered sufficient to perform GEE analysis to study the trend of seroprevalence in young and adult animals separately.…”

African Swine Fever in Smallholder Sardinian Farms: Last 10 Years of Network Transmission Reconstruction and Analysis

“…During these actions, several ASFV-positive animals were detected (6,39). In Sardinia, swine husbandry has been a secondary activity compared to sheep livestock production (40)(41)(42)(43). Thus, domestic pig farms have a familiar or working relationship with other farms or are mainly for self-consumption, and only 5% are commercial farms (44).…”

“…The surveillance program implemented by the ASF-EP15/18 includes different measures to control the disease, such as outbreaks identification by screening checks or for suspicion of disease (42,43). With each subsequent ASF outbreak diagnosed, during the stamping out, the veterinary authority (VA) conducts an inspection aimed at identifying the origin of ASFV introduction (Legislative Decree n. 54, 20 February 2004).…”

Superficial Inguinal Lymph Nodes for Screening Dead Pigs for African Swine Fever

“…One of the greatest challenges faced by ASF-free countries is detecting an ASFV incursion as quickly as possible to minimize the economic and social impact due to associated high mortality, stamping out, trade sanctions and regaining the disease-free status. For early detection of ASF, many countries have implemented surveillance programs for both domestic and wild pigs [6,7].…”

“…Viruses 2022, 14, 83 2 of 10 Passive surveillance based on testing dead pigs is one of the most effective ways to detect an ASF incursion [7][8][9]. Screening of dead pigs in large commercial farms, backyard farms, markets, or packing plants and those that are dead on arrival at the slaughterhouses as part of ongoing surveillance increases the probability of detecting an ASF incursion into disease-free areas.…”