New diseases and increased risk of diseases in companion animals and horses due to transport.

Dogs and horses are transported within the European Union for a number of reasons. The transport per se may cause physical problems, exemplified by hyperthermia in dogs and pleuropneumonia in horses, and the stress may reactivate latent infections such as canine herpesvirus-1 and equine herpesvirus-1. Preventive treatments are vital to protect dogs from ticks and mosquitoes transmitting their potentially lethal infectious agents, such as Leishmania donovani infantum, Babesia canis, Ehrlichia canis, and Dirofilaria immitis. However, records show that the travelling dogs are not fully protected since cases occur in non-endemic regions. The brown dog tick also poses a risk for humans by transmitting Rickettsia conorii causing Mediterranean spotted fever. Further, the trade in stray dogs from southern Europe has placed a particular focus on the occurrence of vector-borne diseases in the Mediterranean basin. The unknown origin of strays also poses a risk for rabies. With respect to horses, those transported to southern Europe may be exposed to Theileria equi and Babesia caballi, both of which are transmitted by ticks. Horses with antibodies against these parasites are not permitted to enter the USA. Additionally, viral diseases such as African horse sickness, transmitted by midges, and Borna disease, of the mode of transmission is yet unclear, may also pose a risk for horses travelling to potentially endemic regions.