A simple method to estimate the number of doses to be included in a vaccine bank: Example of lumpy skin disease in France?

© 2018 L'Association pour l'Etude de l'Epidemiologie des Maladies Animales. All Rights Reserved. The lumpy skin disease (LSD) virus is a DNA virus belonging to the family Poxviridae and the genus Capripoxvirus. LSD is a highly contagious transboundary disease in cattle that causes significant economic losses. The disease was reported for the first time during the year 2014 in the European Union, (Cyprus, and next year in Greece. In 2016, it spread to different Balkan countries. A simple stochastic method for estimating the size of a vaccine bank is presented. It was applied to the hypothetical introduction of an epizootic of the LSD in France. The size of the vaccine bank was calculated taking into account three parameters which are the spatial spread of the disease, the time needed to obtain a good vaccination coverage of the population of interest and the density of the livestock in the region where the epizootic starts. The results were compared to a more refined and validated model, used as a reference method. The differences between the simplified model and the refined model in different scenarios considered vary from 7.0% to 10.5% more vaccines in the simple method compared to the refined method to cover 90% of the simulations and 9.0% to 13.8% for 75% of the simulations. Assuming a necessary 7 week period to vaccinate all animals, and a disease spread of 7.3 km/week, the number of cattle would be 740,716 heads or less for 90% of the simulations (608,196 for 75% simulations). The simplified model is easy to use and adapt to different diseases and countries and does not require many data to work.