Plague of Animals

PLAGUE OF ANIMALS. Besides the epizootic plague of rats, susliks, tarbagans and other rodents, completely identical with the bubonic plague (see) of humans, the name "plague" is applied to certain etiologically different acute febrile infectious diseases of domestic and wild animals, characterized by inflammatory-necrotic changes in the mucous membranes, severe course with high mortality in affected animals, and caused by filterable viruses. - Plague of cattle (pestis bovina) causes enormous losses and almost total mortality of cattle in places where the disease is observed for the first time, while in areas with constant existence of it, only small losses are usually observed. The disease is widely distributed in Asia and Africa, much less so in Europe. In pre-revolutionary Russia, plague in some years caused the death of up to 3-5% of all cattle, whereas at present the USSR is free of this disease. The causative agent is a filterable virus, present in the blood, secretions and excretions throughout the course of the disease; it easily perishes in the air and under the influence of ordinary disinfectants; in the meat of sick animals it remains for up to 4 days, but perishes immediately when heated to 60°. The disease spreads among animals through sick animals, as well as through raw animal products (meat, skin, etc.) and manure. Infection occurs through the digestive tract. Besides cattle, other animals are susceptible: sheep, goats, buffaloes, camels, wild ruminants; humans are completely immune. The incubation period is 3-9 days. Symptoms: fever, weakness, sharp inflammatory-necrotic changes in the mucous membranes (especially the tongue and gums), digestive disorders, cough. Duration 4-7 days; death most often on the 2nd-3rd day. Treatment only in the form of serotherapy. Preventive vaccinations with specific serum, widely used at present, give good results, but for a short time (1-2 months). Veterinary-sanitary measures: closing borders from the side of unfavorable areas regarding the disease, compulsory slaughter of all sick and suspicious animals, and thorough disinfection. Meat from sick animals is not permitted for human consumption. Plague of swine (pestis suum), a septicemic-hemorrhagic disease, characterized by inflammatory and necrotic processes in the intestinal canal and in the lungs and caused by a filterable virus with the simultaneous presence of Bac. suipestifer from the Paratyphus B group or Bac. suisepticus from the Pasteurella group. It causes large losses among swine and is widely distributed in Europe, America and South Africa. The virus is present throughout the acute period of the disease in the blood and organs; it perishes when heated to 70° for an hour, but in the air at ordinary temperature retains viability for several days. The usually accompanying bacterial infection causes subsequent diseases of the intestines and lungs. Infection occurs through the digestive tract. Young swine and especially valuable breeds are most susceptible. The disease appears in acute or chronic form, causing up to 90% mortality and manifesting as fever, hemorrhagic changes in the skin, scabs on the mucous membranes of the mouth, necrosis of the intestinal mucosa and lobar pleuropneumonia. Treatment with specific serum. Preventive vaccinations with immunizing serum and a mixture of the latter with virulent blood give good effect. Ordinary veterinary-sanitary measures are successful only when carried out sufficiently early and energetically. Meat from plague-stricken swine is classified as conditionally suitable meat products (Art. 67 of the Veterinary Statute of the USSR), subject to preliminary neutralization by boiling or sterilization with steam, with the exception of affected parts of the carcass and its organs. Plague of dogs (febris catarrhalis et nervosa canum) - a frequently observed acute infectious disease, mainly of young dogs, characterized by the presence of acute catarrh of the mucous membranes, fever, frequent complications of catarrhal pneumonia and disorders of the nervous system (strong excitability, convulsions, paralysis). The causative agent is a filterable virus, transmitted through contact with infected dogs. Incubation 2-4 days; duration of the disease on average 3-4 weeks with subsequent very slow recovery. Mortality up to 50%. Treatment is limited to the use of symptomatic agents, proper diet and appropriate care. Immunotherapy and immunoprophylaxis do not give reliable results. - Plague of cats - a disease quite similar to plague of dogs, but much less frequently observed. - Plague of birds (pestis avium), an acute infectious disease, similar to chicken cholera and caused by a filterable virus. It is observed among chickens, turkeys, pheasants, sparrows and much less frequently in geese, ducks and other waterfowl. It usually causes devastating epizootics. The virus is found in the blood, secretions and excretions, in the nervous system, as well as in the eggs of affected birds. Infection occurs mainly through the feces of sick birds. The incubation period is 3-5 days. Symptoms: severe weakness, drowsiness, high temperature (up to 44°), dark color of the comb and wattles, catarrh of the mucous membranes, difficulty breathing, paralysis. The disease lasts on average 2-4 days and usually ends in death. Treatment is futile. "Plague diseases" are also observed in horses, northern reindeer, guinea pigs (see Pathology of Laboratory Animals), crayfish.