Analysis of Risk Factors for African Swine Fever in Lombardy to Identify Pig Holdings and Areas Most at Risk of Introduction in Order to Plan Preventive Measures
Abstract
:1. Introduction
2. Results
2.1. Introduction of Pigs from Other Italian Regions and within Lombardy
2.2. Social Network Analysis
2.3. Identification of the Municipalities More Exposed to the Risk of Introducing ASF
- Fifty-eight farms of wild boar or mixed domestic pigs—wild boar, 10 of these were located in medium or high-risk municipalities, 48 in low-risk municipalities;
- Eighty-eight holdings more exposed on the basis of the introduction of pigs from other regions, 22 were located in municipalities classified as medium or high risk;
- One hundred and twenty-eight holdings more exposed based on pig movements within the region, 35 of these were located in municipalities classified as medium or high risk;
- Dealer’s premises were zero in Lombardy but 8 holdings were identified for target surveillance because they purchased pigs from dealer’s premises located in the neighboring regions;
- Fifteen holdings were identified to target surveillance because in National Database (BDN) were registered as non-commercial farms but the analysis of the movements showed that they sold pigs to other non-commercial farms.
3. Discussion
4. Materials and Methods
4.1. Description of the Area: Lombardy Region
4.2. Data
4.2.1. Source of Data
4.2.2. Data Collection
4.3. Statistical Analysis
4.3.1. Introduction of Pigs from Other Italian Regions and within Lombardy
4.3.2. Social Network Analysis
4.3.3. Identification of the Municipalities More Exposed to the Risk of ASF Introduction
4.3.4. Software
5. Conclusions
Author Contributions
Funding
Conflicts of Interest
References
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SNA Parameters | Within Region | From Other Regions |
---|---|---|
Density (n) | 0.001 | 0.001 |
Geodesic distance (mean) | 15.803 | 8.886 |
Diameter (n) | 40 | 22 |
Degree centrality (*) | 0.073 (0–4.412) | 0.209 (0–4.656) |
In-degree centrality (*) | 1.286 (0–154) | 1.079 (0–47) |
Out-degree centrality (*) | 1.286 (0–10) | 1.079 (0–8) |
Closeness centrality (*) | 0.340 (0.337–0.342) | 0.339 (0.336–0.340) |
In-closeness centrality (*) | 0.042 (0.028–0.333) | 0.106 (0.097–0.277) |
Out-closeness centrality (*) | 0.030 (0.028–0.031) | 0.101 (0.097–0.107) |
Betweenness centrality (*) | 0.115 (0–14.115) | 0.222 (0–10.647) |
Risk Factors | N. Municipalities with Low Risk | With Wild Boar Presence | N. Municipalities Medium Risk | With Wild Boar Presence | N. Municipalities With High Risk | With Wild Boar Presence |
---|---|---|---|---|---|---|
Density of pig movements | 886 | 382 | 51 | 14 | 53 | 11 |
Density of non-commercial farms | 1021 | 488 | 48 | 15 | 49 | 11 |
Density of out-doors farms | 36 | 19 | 1 | 0 | 1 | 0 |
Density of commercial farms | 682 | 269 | 37 | 8 | 45 | 8 |
Overall risk | 1398 | 585 | 54 | 15 | 55 | 11 |
SNA Parameters | Definition |
---|---|
Density | Proportion of links among all possible network links. Range from 0 (all nodes are isolated) to 1 (all nodes are connected). |
Pathway | Single path between two nodes. |
Geodesic distance | The number of relations in the shortest possible path from one node to another. |
Diameter | The largest geodesic distance in the network. |
Degree centrality | The number of links of each node. |
In-degree centrality | The number of farms from which each farm receives animals. |
Out-degree centrality | The number of farms to which each farm sends animals. |
Closeness centrality | How many paths are required for a particular node to access every other node in the network |
In-closeness centrality | The number of paths from which each farm receives animals. |
Out-closeness centrality | The number of paths to which each farm sends animals. |
Betweenness centrality | The number of shortest paths between all other nodes that go through a particular node. It measures the importance of a particular node as an intermediary in the network. |
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Bellini, S.; Scaburri, A.; Tironi, M.; Calò, S. Analysis of Risk Factors for African Swine Fever in Lombardy to Identify Pig Holdings and Areas Most at Risk of Introduction in Order to Plan Preventive Measures. Pathogens 2020, 9, 1077. https://doi.org/10.3390/pathogens9121077
Bellini S, Scaburri A, Tironi M, Calò S. Analysis of Risk Factors for African Swine Fever in Lombardy to Identify Pig Holdings and Areas Most at Risk of Introduction in Order to Plan Preventive Measures. Pathogens. 2020; 9(12):1077. https://doi.org/10.3390/pathogens9121077
Chicago/Turabian StyleBellini, Silvia, Alessandra Scaburri, Marco Tironi, and Stefania Calò. 2020. "Analysis of Risk Factors for African Swine Fever in Lombardy to Identify Pig Holdings and Areas Most at Risk of Introduction in Order to Plan Preventive Measures" Pathogens 9, no. 12: 1077. https://doi.org/10.3390/pathogens9121077