Date Published: June 11, 2018
Publisher: Public Library of Science
Author(s): Claude Saegerman, Stéphane Bertagnoli, Gilles Meyer, Jean-Pierre Ganière, Philippe Caufour, Kris De Clercq, Philippe Jacquiet, Guillaume Fournié, Claire Hautefeuille, Florence Etore, Jordi Casal, James P. Stewart.
The lumpy skin disease virus (LSDV) is a dsDNA virus belonging to the Poxviridae family and the Capripoxvirus genus. Lumpy skin diseases (LSD) is a highly contagious transboundary disease in cattle producing major economic losses. In 2014, the disease was first reported in the European Union (in Cyprus); it was then reported in 2015 (in Greece) and has spread through different Balkan countries in 2016. Indirect vector transmission is predominant at small distances, but transmission between distant herds and between countries usually occurs through movements of infected cattle or through vectors found mainly in animal trucks.
In order to estimate the threat for France due to the introduction of vectors found in animal trucks (cattle or horses) from at-risk countries (Balkans and neighbours), a quantitative import risk analysis (QIRA) model was developed according to the international standard. Using stochastic QIRA modelling and combining experimental/field data and expert opinion, the yearly risk of LSDV being introduced by stable flies (Stomoxys calcitrans), that travel in trucks transporting animals was between 6 x 10−5 and 5.93 x 10−3 with a median value of 89.9 x 10−5; it was mainly due to the risk related to insects entering farms in France from vehicles transporting cattle from the at-risk area. The risk related to the transport of cattle going to slaughterhouses or the transport of horses was much lower (between 2 x 10−7 and 3.73 x 10−5 and between 5 x 10−10 and 3.95 x 10−8 for cattle and horses, respectively). The disinsectisation of trucks transporting live animals was important to reduce this risk.
The development of a stochastic QIRA made it possible to quantify the risk of LSD being introduced in France through the import of vectors that travel in trucks transporting animals. This tool is of prime importance because the LSD situation in the Balkans is continuously changing. Indeed, this model can be updated to process new information on vectors and the changing health situation, in addition to new data from the TRAde Control and Expert System (TRACES, EU database). This model is easy to adapt to different countries and to other vectors and diseases.
The lumpy skin disease virus (LSDV) is a dsDNA virus belonging to the Poxviridae family and the Capripoxvirus genus . Lumpy skin disease (LSD) is a highly contagious transboundary disease in cattle that produces major economic losses . All ages and breeds of cattle are affected but calves and cows in the peak of lactation more severely so . Clinical signs occur at the cutaneous (firm nodules of 0.5–5.0 cm in diameter occupying the entire thickness of the skin) and subcutaneous (oedema) levels. The nodules either regress or progress to necrosis, ulcers and finally scars. These lesions can also appear in other tissues such as the respiratory, digestive and genital tracts as well as in the lymph nodes .
The Table 1 shows the main characteristics of the probabilities introduced in the model.
Using a QIRA modelling, the probability of an LSD outbreak occurring in France following the introduction of vectors by trucks that transport cattle was estimated at between 6 x 10−5 and 5.93 x 10−3 with a median value of 89.9 x 10−5.