The potential spread of severe footrot in Norway if no elimination programme had been initiated: a simulation model

Abstract

When severe footrot was detected in Norway in 2008, a surveillance programme was initiated and followed by an elimination programme. By 2013 the disease had spread to two of 19 counties and a total of 119 (1%) sheep flocks had been diagnosed with severe footrot. A simulation model was developed to estimate the potential spread of severe footrot in Norway and to estimate the relative importance of the different spreading routes. The model parameters were based on the rate of spread of the first 38 diagnosed cases and the management and climatic factors particular for Norway. The model showed that by 2013, severe footrot would have spread to six counties and infected 16% of the sheep flocks if no elimination programme had been initiated. If this is compared with the 1% of flocks that were diagnosed in Norway by 2013, there seems to be a large effect of the implemented footrot elimination programme. By 2035, it was estimated that severe footrot would have spread to 16 counties and 64% of the sheep flocks. Such an extensive spread would probably impose a large negative impact on the sheep industry and welfare of the sheep. The most effective way to curb the spread of severe footrot was by decreasing the within county infection rate. This could be achieved by decreasing the contact between flocks or by decreasing the environmental load of D. nodosus, for example by footbathing sheep, culling diseased sheep or eliminating severe footrot in the flock.

Clay content and pH: soil characteristic associations with the persistent presence of chronic wasting disease in northern Illinois

“…Lower abundances of clay also result in the reduced physical stability of soils and increased susceptibility to wind erosion and dust emissions 29 , 46 . Prions have been detected in dust 47 , and if deer can acquire CWD from dust-bound prions, it can be surmised that soil characteristics and conditions that favor dust emissions such as less physically stable soils are more likely to be aerosolized during grazing or rutting behaviors potentially leading to enhanced exposure of deer to prions in the soil through inhalation and ingestion of dust-bound prions.…”

Epidemiological and Economic Evaluation of Alternative On-Farm Management Scenarios for Ovine Footrot in Switzerland

“…The footrot transmission model has been developed based on a stochastic susceptible-infected-recovered compartmental model designed to simulate a footrot outbreak in Norway ( 29 ). The model was implemented in R 1 .…”

“… Structure of the epidemiological model simulating within and between the regional spread of footrot, modified from ( 29 ) . …”

Sheep breed and shearing influences attraction and blood-feeding behaviour of Culicoides (Diptera: Ceratopogonidae) on a UK farm

“…A wide range of examples of inter-breed differences in ectoparasite numbers and impact on ruminant livestock have been documented for arthropod groups including ticks [ 20 , 21 ], flies [ 22 – 24 ] and mites [ 25 ]. A large proportion of studies have been conducted on the horn fly, Haematobia irritans L. which is relatively straightforward to accurately record on cattle hosts by observation.…”