Are Exotic Pets a Disease Risk to European Horses?

Among imported live animals, imported exotic pets (mostly rodents, reptiles, and caged birds) are of particular concern to potentially introduce vector-borne disease agents that could be deadly to horses.

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Exotic pets might carry foreign vector-borne disease agents that can be deadly to horses, particularly in several recently identified “hot spots” of entry into the European Union (EU), French researchers say.

Among imported live animals, imported exotic pets (mostly rodents, reptiles, and caged birds) are of particular concern, said Benoit Durand, PhD, of the Animal Health Laboratory at the Veterinary School of Maisons-Alfort, France. He recently conducted a study analyzing the risk these animals pose of introducing into the EU four arboviruses (viruses transmitted via insect vectors): Eastern and Western equine encephalomyelitis (EEE and WEE), Venezuelan equine encephalitis (VEE), and Japanese encephalitis (JE).

Durand and his colleagues investigated EU importation data from 2005-2009 and information on the presence of vectors as well as human and horse density data to develop specific risk indicators for virus introduction. That risk fraction jumps to 100% for JE; 81% for EEE; 35% for WEE; and 1% for VEE. These diseases are all considered emerging in European horses, Durand said.

Officials have identified parts of Belgium, the Netherlands, and northern Italy as the “hot spots” of entry for the viruses causing these diseases, Durand said. These locations have high human populations and significant live animal imports. Belgium and the Netherlands also have dense horse populations.

“It is worth noting that, besides the four considered viruses, these hot spots are consistent with recent emergences of arboviruses in the EU: bluetongue serotype 8 in Belgium and in the Netherlands, Schmallenberg virus in Germany and in the Netherlands, Usutu and West Nile viruses in northern Italy,” he stated in his study report.

Poultry and livestock also carry potential infection risks, said Durand. Horses, however, present a low risk of transporting these diseases—except for VEE. Horses are considered “dead-end carriers” for EEE, JE, and WEE, meaning they don’t generally spread the disease via vectors to other animals. However, horses can act as VEE carriers, he said: Imported horses are believed to be responsible for 98% of the risk of VEE introduction and case occurrence in horses.

These results suggest that tighter disease surveillance of imported animals—and in particular exotic pets—is necessary, especially in the hot spot zones, Durand said.

Due to the nature of the imported animals, current control measures are insufficient, Durand said: “If regulations of international farm animal trade have been designed to protect the disease-free status of importing countries, it is not the case for the regulations of the international trade of wild animals, which have rather been designed to protect endangered species.”

The matter is further complicated by the fact that there are hundreds of exotic pet species that control officers do not easily recognize, he said. Meanwhile, exotic pet imports are on the rise: During the five-year study period, the EU imported 43,000 primates, 1.5 million caged birds and birds of prey, 8.8 million reptiles, and 613,000 rodents—a trend supported by the Internet, Durand said.

It is important to note, however, that thus far none of these diseases has actually developed in European horses, he added. The risks described, he said, are of the probability of them occurring and are not based on actual case occurrences themselves.

The study, "Identification of hotspots in the European union for the introduction of four zoonotic arboviroses by live animal trade," was published in PLoS One

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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