Alfredo Acosta

and 9 more

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.

Jean Carlos Silva

and 17 more

Leptospirosis has been widely reported in insular environments worldwide, characterizing a major public health threat. Although low genetic biodiversity is expected in these regions, the introduction of domestic and synanthropic mammals may contribute to the wider diversity leptospiral strains in insular settings. This study proposes a large-scale investigation of Leptospira infection in animals from Fernando de Noronha archipelago, Brazil. A total of 1,265 blood samples from domestic (n=682), synanthropic (n=133) and wild (n=450) animals were collected between 2007 and 2014, totaling 12 species. The presence of anti-Leptospira spp. antibodies was investigated by the Microscopic Agglutination Test (MAT) and kidney samples from synanthropic rodents were collected for the isolation of Leptospira spp. The leptospires recovered were further characterized by MAT with polyclonal antibodies, whole genome sequencing and Multilocus Sequence Typing (MLST). The MAT results revealed the presence of agglutinins in 90 samples (7.1%), and the most frequently found serogroup was Icterohaemorrhagiae (n=57) in practically all species included. Viable leptospires were recovered from one brown rat, and characterization revealed that the isolate belongs to L. interrogans serogroup Pyrogenes. This study stands as the most comprehensive investigation of Leptospira spp. infection in Fernando de Noronha archipelago, also providing the characterization of the first leptospiral strain ever isolated from an insular setting in Brazil. The results suggest that synanthropic rodents play a major role in the transmission of leptospirosis among wildlife and domestic species in the archipelago.