Movement routes key to predicting spread of infectious diseases

Knowledge of 'movement routes' is the key to predicting the pattern of spread of infectious diseases of humans, and similar data could be crucial to understand animal disease risks, says team from the University of Edinburgh.

In a review of the topical issue of disease spread in animals in the current issue of Trends in Microbiology, scientists from the University's Royal (Dick) School of Veterinary Studies say passive detection of disease at ports of entry is an increasingly dangerous strategy as the volume of movements increases. They call for better communication between scientists, livestock traders, livestock keepers and decision makers to avoid infections spreading.

Lead author Dr Eric Fhvre explains: "Domestic and wild animal population movements are important in the spread of disease. There are many recent examples of disease spread that have occurred as a result of intentional movements of livestock or wildlife, including avian 'flu across the globe, and diseases of pets through movements associated with the UK PET travel Scheme. These animal movements can also spread diseases to humans.

"The movements of domestic and wild animals are complex and profitable but are extremely risky from a disease perspective. Movements can result in the introduction of exotic animal diseases or human pathogens, which might themselves have important economic and/or public health impacts. Minimizing such risks should be a high priority and, in some cases, this might involve preventing the animal trade altogether.

"For diseases linked to livestock, markets have an important role in the dissemination of infectious organisms. They serve as contact nodes between infected herds and the ease of transportation can result in the widespread dissemination of animals that have been in contact in a market. Contact points such as quarantine facilities, markets and ports of entry can also result in the transmission of agents between individuals and species, with rapid subsequent dissemination."

Dr Fhvre and his colleagues call for a better understanding of the risks of world-wide movements and an efficient global surveillance network in which different animal species are regularly screened, particularly before moving from their source areas.