Jet set pets: examining the zoonosis risk in animal import and travel across the European Union

Fooks, Anthony R; Johnson, Nicholas

When humans travel, they often take their companion animals, particularly dogs, and these in turn can relocate the pathogens and vectors they harbor. Canine parvovirus emerged in 1978 as a new disease in dogs causing hemorrhagic enteritis. Retrospective serology suggested that the disease appeared in Europe in 1976 and spread throughout the world by 1978. 5 The mechanism that enabled global dissemination of the virus has been attributed to contaminated footwear. There are numerous canine-associated diseases but relatively few are significant zoonoses. However, of these, a number are fatal to humans and control is essential to protect public health. Globally, the most significant is the rabies virus. Infection leads to fatal encephalitis, for which there is no treatment. 6, 7 Pre-exposure vaccination protects against the disease in mammals, and due to the extended incubation period between contact with a rabid animal and development of disease, often measured in months, timely post-exposure vaccination is also effective in humans. 8 The dog is the most important reservoir for the virus, and contact with dogs is responsible for virtually all human cases of the disease. Where efforts have been concentrated on controlling dog rabies, the reduction in human cases of disease has been dramatic. 9 Dog rabies has been virtually eliminated from Europe, although there are examples of reintroduction 10, 11 and cross-border movement of rabid animals. 12 Alveolar echinococcosis is caused by the tapeworm Echinococcus multilocularis. It is a fatal condition that is relatively rare in Europe although there are clear areas of endemicity, resulting in human infections in an area of Europe ranging from France in the west to Austria in the east. 13 The disease manifests as a tumor-like growth of cysts containing the larval stage of the parasite in organs such as the liver. Detection of cysts often occurs many years after initial infection, and without intervention such as surgery to remove the cyst(s), the disease is fatal. Dogs act as the definitive host for the adult form of the parasite and movement of infected dogs can lead to the spread of tapeworm eggs and introduction of the disease into new areas. As the adult worm is very small (less than 5 mm) and does not cause clinical signs in the definitive host, spreading of eggs and human infection can remain undetected until clinical symptoms develop.