Epizootic

Epizootic, the simultaneous disease of a large or significant number of animals with any infectious disease. When E. covers large territorial spaces (an entire country), it is called a panzootic. When in a certain limited area an infectious disease has a constant character or recurs without being introduced from outside, it is called an enzootic. The etiology of E. is just as diverse as the etiology of infectious diseases in general. According to the type of pathogen, several groups are distinguished (see Zoonoses).-Methods of infection are also very diverse. Along with infections of purely contact nature (such as glanders, white diarrhea, plague of cattle, peripneumonia, contagious equine metritis), there are those transmitted by contaminated soil (anthrax), drinking water (glanders), feed, foreign objects, as well as those carried by insects (hemoglobinuria, plague of rodents); finally, rabies spreads exclusively through bites by sick animals.-This diversity determines the different routes of spread of individual E. In most cases, E. are introduced from outside, and only partly they arise repeatedly in the same place after an apparent cessation, due to the preservation of the infectious agent in a latent form in animals (carrier state) or in the soil (for example, in anthrax). As factors facilitating or hindering the occurrence of E., as well as the degree of their development and extent, they depend mainly on the veterinary-sanitary organization of the given country, but along with this, the most important significance is the culture of animal husbandry, the development of zoohygiene and veterinary-sanitary education of the population themselves.-A particular epidemiological interest is represented by a number of E., caused by so-called zoonoses (see), i.e., infectious diseases common to humans and animals. The fight against them in most cases comes down to carrying out appropriate veterinary-sanitary measures (anthrax, glanders, brucellosis, foot-and-mouth disease, rabies). The economic damage caused by E. to the national economy is not limited only to the reduction of livestock due to mortality or forced slaughter of sick animals, but also due to the temporary decrease in offspring (birth rate). It is also necessary to take into account those losses that are caused by the temporary decrease in productivity of recovered animals in terms of milk and meat production and the working capacity of working animals. The fight against E. is regulated in each state by its own special legislation. All legislations provide for general measures against infectious and invasive diseases of animals in general and special measures against the most important E. In the USSR, according to the 'Veterinary Charter', the following are included: plague of cattle, peripneumonia, foot-and-mouth disease, anthrax, symptomatic carbuncle, tuberculosis, rabies, hemorrhagic septicemias (see Pasteurellosis), epizootic abortion of cattle and horses, scabies, sheep pox, glanders, epizootic lymphangitis of horses, glanders, influenza and contagious pleuropneumonia of horses, strangles of horses, swine erysipelas and swine plague, poultry cholera, plague of chickens, diphtheria (pox) of birds; in addition, there are international treaties and veterinary-sanitary conventions aimed at mutual notification of the occurrence and course of E. and protection of borders from their introduction. There is also a special International Veterinary Bureau, which deals with the development of relevant international conventions; the USSR is also a member. In the fight against E., the primary role belongs to prevention. The principles on which it is built partly coincide with the principles of anti-epidemic prevention, such as: mandatory reporting, registration of diseases, ensuring early diagnosis, isolation of the sick, quarantine measures, current and final disinfection, declaration of areas as unfavorable or threatened, mass preventive vaccinations, etc. On the other hand, anti-epizootic prevention in many respects has its own specific character. These include: mass diagnostic vaccinations, mass specific treatment, slaughter of sick and suspicious animals, neutralization of infectious carcasses and manure, regulation of the use of pastures and watering places in affected areas, veterinary supervision of places of animal concentration, strictly regulated veterinary supervision on cart, railway and waterways of communication. Particular epidemiological importance is attached to veterinary supervision over the safety of animal raw materials and the industry processing it. - The problems of in-depth study of E., improvement of methods of combating them and the search for new anti-epizootic measures are part of the tasks of scientific research veterinary institutes and departments of epizootiology at veterinary higher educational institutions and are discussed at periodically convened special conferences both at the regional and all-Union level.

A. Vladimirov.