Haemonchus contortus in Swedish sheep : compilation of two decades of diagnostics

Sammanfattning

The aim of this quantitative study was to compile and map the Swedish Haemonchus contortus data from sheep to compare with temperature, precipitation and hours of sunshine as well as with a compilation of the earlier decade (2005-2014). The key findings of this study are that the prevalence of H. contortus has decreased between the last two decades although there are significant differences between some years. There was also a decrease in the number of sheep, an increase in the number of tests being sent in for diagnosis and overall no difference in the number of sheep holdings. The results further show no correlation between prevalence and temperature, precipitation and hours of sunshine, much like the findings of the earlier decade. The results also show a geographical spread of H. contortus in Sweden with time. These findings show a need to analyse this kind of data in greater detail, as annual means might not give accurate or true results. In other words, the number of parasites cannot be determined using only annual weather means. On the other hand, visualising the geographical spread using coordinates proved to be an effective method to show possible H. contortus spread. Further research into how detailed weather data needs to be established for making accurate correlations could be crucial to determine the impact on future prevalence.