Читать книгу Principles of Virology, Volume 2 - Jane Flint, S. Jane Flint - Страница 29

Epidemics affect animals other than humans as well, especially those in dense farming populations. The outbreak of foot-and-mouth disease in the United Kingdom in 2001 caused an agricultural crisis of historical proportions; over 10 million sheep and cattle were killed, an average of 10,000 to 13,000 a day, in an attempt to stop the infection from spreading. As there was no easy way to distinguish infected from uninfected, all of the farm animals in affected areas were destroyed, independent of signs of disease in the livestock. In the 2001 outbreak, the infection could be traced to one pig (the “index case”) on a specific farm in Northumberland. Unfortunately, the farmer did not inform the authorities of the appearance of foot-and-mouth disease, which is relatively easy to identify by characteristic lesions on the snout, mouth, and feet. The epidemic spread rapidly, accelerated by the use of the same trucks to transport animals from both contaminated and uncontaminated farms to slaughter houses. While this outbreak did not affect humans directly, the indirect financial impact on farming and tourism was enormous; it is estimated that this crisis cost the United Kingdom over $16 billion, and created great stress within the government. A vaccine for foot-and-mouth disease virus exists, and was available at the time. However, vaccine use had been rejected because farmers feared that they would then not be able to ship their meat to other countries, as vaccinated animals cannot be distinguished serologically from infected ones. A positive outcome of this epidemic is that all farm animals in the United Kingdom are now vaccinated for foot-and-mouth disease virus. Nevertheless, agricultural threats remain: while one virus of livestock has been eradicated (rinderpest virus, a relative of measles virus), and some are controlled by vaccines, others, including bluetongue virus, continue to pose a significant threat to cattle, sheep, antelopes, and deer.