Why Are Epidemiologists Sometimes Interested in Epizootics?

Epizootics

Why are epidemiologists sometimes interested in epizootics?

"Epidemics in animals are called epizootics" (Epizootics, 2012, University of Liverpool). The evolution of epidemics in animal populations can mirror the spread of disease in humans, or the diseases in animals can present features of interest to epidemiologists because of their potential to pass diseases to humans through contact or consumption. Examples of diseases that can be transmitted from animals to humans include foot and mouth disease, rabies, and 'mad cow' disease. For example, in foot and mouth disease, animals can spread the disease to other organisms through salvia, milk and dung manure and blood. In the case of foot and mouth, "Animals start to excrete the virus even before the symptoms appear and so may pass it on to many others before anyone realises that they are infected" (Epizootics, 2012, University of Liverpool). This can cause the disease to spread extremely rapidly. And although, as the name suggests, the disease primarily affects cloven-footed animals, it can also be spread to humans

Epizootics can be extremely costly for livestock owners as well as dangerous for humans. During the 2001-foot and mouth epidemic in Great Britain, "6 million animals had to be culled and because of this, £3.1 billion of compensation was given to those working in agriculture and food supply industries who lost income as a result of the epidemic" (Epizootics, 2012, University of Liverpool). Understanding epizootics is important for farmers and consumers as well as epidemiologists for financial and safety reasons. "In many cases animal epidemics are the result of either home grown diseases or factors we can control through proper animal husbandry" (Epidemics, 2002: 1). During the last mad cow epidemic in Great Britain "feeding of the remains of dead sheep and cows to livestock, and possibly through the injection of hormones taken from the pituitary glands of slaughtered cows to improve breeding" was found to be the source of the epidemic Epidemics, 2002: 1).

Epidemiologists need to track how certain diseases begin and spread -- for example, an epidemic may start in a wild population, but then is passed to domestic animals and then to humans -- for academic purposes. But there is also often public health concerns involved in studying epidemics. In the case of rabies, for example, although most domestic pets are inoculated against the illness, the methods of transmission may vary from place to place, and humans can still be infected by wild animals. While "bats are carriers of rabies but largely immune to its ravages" and do not usually attack humans in the United States but "Mexico and South America vampire bats, which live on blood, do act as vectors for both rabies and other diseases" in the areas in which they live (Epidemics, 2002: 2). Raccoons and skunks have also been known to be carriers of rabies. Lyme disease can be transmitted from either pets or wildlife in the U.S., if an infected tick falls from an animal and attaches itself to a human.