The impact of increased dispersal in response to disease control in patchy environments

Abstract

This paper uses a mathematical framework to investigate the impact of increased movement in response to disturbance caused by disease control strategies. Implementation of invasive disease control strategies such as culling may cause species to disperse beyond their natural range, thus aiding the spread of infection to otherwise infection free areas. Both linear and non-linear dispersal functions are compared with constant per capita dispersal in a coupled two patch SI model. For highly virulent or infrequently transmitted pathogens, it is found that an increase of dispersal due to control requires a higher level of disease control than in the constant dispersal model. Patches which may be sources or reservoirs of infection are investigated and it is found that if dispersal increases in response to control, then all patches, reservoir or not, must be targeted. The single host two patch model is then extended to a two host wildlife/livestock system with one species ‘wildlife’ free to move between patches and the other ‘livestock’ confined. In the two host case, control of one species alone will only achieve successful pathogen exclusion if that species is a reservoir for infection.