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.
Scientists from Edinburgh 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 movement increases.
They call for better communication between scientists, livestock traders, livestock keepers and decision makers to avoid infections spreading.
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.
Minimising 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," said Eric Fèvre, lead author of the study.
"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," he added.
Fèvre and his colleagues call for a better understanding of the risks of worldwide movements and an efficient global surveillance network in which different animal species are regularly screened, particularly before moving from their source areas.
The review of this issue of disease spread in animals appears in the current issue of >Trends in Microbiology.