Network analysis of pig movements in Ecuador: strengthening surveillance
of classical swine fever
Abstract
The analysis of domestic pig movements have became useful in the
understanding of disease spread patterns and epidemiology, which
facilitates the development of more effective animal diseases control
strategies. The aim of this work was to analyse the static and spatial
characteristics of the pig network, to identify its trading communities
and to analyse the contribution of the network to the transmission of
classical swine fever. Pig movement data were extracted from the
national veterinary service database (2017-2019), using social network
analysis and spatial analysis we constructed a network with registered
premises as nodes and their movements as edges, and also a network of
parishes as its nodes aggregating their premises movements as edges. The
annual network metrics showed in average a diameter of 20.33, a number
of neighbours of 2.61, a shortest path length of 4.39 and a clustering
coefficient of 0.38 (small-world structure). The most frequent movements
were to or from markets (57%). Backyard producers made up 89% of the
network premises, and the top 2% of parishes (highest degree)
contributed to 50% of the movements. The highest frequencies of
movements between parishes were in the centre of the country, while the
highest frequency of movements to abattoirs was in the south-west.
Finally, the pattern of CSF disease outbreaks within the Ecuador network
was likely the result of network transmission processes. In conclusion,
our results represent the first exploratory analysis of domestic pig
movements at premise and parish levels. These results could be taken
into account by the surveillance system to improve its procedures and
update the disease control and management policy, allowing the
implementation of targeted or risk-based surveillance.