foot-and-mouth disease(redirected from aphthous fever)
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hoof-and-mouth disease,highly contagious disease almost exclusive to cattle, sheep, swine, goats, and other cloven-hoofed animals. It is caused by a virus, specifically an aphthovirus, that was identified in 1897. Among its symptoms are fever, loss of appetite and weight, and blisters on the mucous membranes, especially those of the mouth, feet, and udder. Discharge from the blisters is heavily infected with the virus, as are saliva, milk, urine, and other secretions. Thus the disease is readily spread by contact; by contaminated food, water, soil, or other materials; or through the air. Humans, who seldom contract the disease, may be carriers, as may rats, dogs, birds, wild animals, and frozen meats.
Quarantine, slaughter and complete disposal of infected animals, and disinfection of contaminated material, are prescribed to limit contagion. There is no effective treatment. With vaccines, introduced in 1938, and sanitary controls, foot-and-mouth disease has been excluded or eliminated from North and Central America, Australia and New Zealand, Japan, and Ireland; and occurrences have become infrequent in Great Britain and continental Europe. The disease persists through much of Asia, Africa, and South America. Hand, foot, and mouth diseasehand, foot, and mouth disease
(HFMD), infectious viral disease that most commonly occurs in children under five years of age. Symptoms include fever, poor appetite, and a sore throat, followed by painful sores in the mouth and a skin rash on the palms of the hand, soles of the
..... Click the link for more information. , which is primarily a disease of young children, is not related.
See publications of the U.S. Dept. of Agriculture.
an acute viral disease of cloven-footed animals and man. The causative agents are seven types of viruses of the picornavirus family, which are resistant to various environmental factors.
In animals. Foot-and-mouth disease is extremely contagious. It occurs in many countries of South America, Africa, and Asia in the form of periodic epizootics. In European countries it is enzootic. Periodic outbreaks of the disease caused by viruses O and A have been recorded in the USSR. The disease may also assume the form of a panzootic, or it may occur sporadically.
The main source of the causative agent is an infected animal, which excretes the agent into the environment with saliva, milk, urine, and feces. Infection occurs upon direct contact of a healthy animal with an infected one, chiefly through the mucous membrane of the oral cavity and through the skin, especially if the skin is not intact. The disease can also be transmitted by way of the clothing worn by persons tending the animals, transportation equipment, feed, and products of animal origin. The foot-and-mouth disease virus can be transmitted mechanically by birds and insects; it can also be carried by air for considerable distances.
Outbreaks occur mostly in the summer and autumn. The incubation period is five to seven days. A distinction is made between mild and malignant forms of the disease. The mild form is characterized by fever as high as 40.5°–11.5oC, the absence of rumination, and copious salivation. Two to three days after the onset of fever, characteristic aphthae (blisters filled initially with transparent and then with turbid fluid) appear on the oral mucosa, tongue, and wings of the nose. They may also appear on the nipples of the udder and on the skin of the coronary band above the hoof (the animals limp). When the aphthae burst, ulcers form, which heal in six to eight days. The disease is frequently complicated by secondary bacterial infection. Adult animals recover but with a loss of 20–30 percent of their economic value. Young animals frequently die.
The malignant form of foot-and-mouth disease is characterized by cardiac impairment and by lesions of the blood vessels, myocardium, and muscles. The mortality rate is about 80–90 percent. Animals that recover acquire immunity, lasting several years in adults and several months in young animals.
The diagnosis is made on the basis of epizootiological and clinical data and laboratory tests. Treatment includes serotherapy and the administration of symptomatic agents. Prevention includes the adoption of measures to safeguard against the introduction of the causative agent and to regúlate the transport of animals, the sale of products of animal origin, and the transport of feeds; other measures include vaccination and disinfection. An affected farm is quarantined, and the infected animals are isolated; no animals are permitted to be brought in or out, and nondecontaminated milk and meat from animals that had to be slaughtered may not be shipped out.
In humans. Human beings are less susceptible to foot-and-mouth disease than animals. The source of human infection is an infected animal. Infection occurs through the digestive tract (mainly after drinking raw milk) and injured skin and oral mucosa (in veterinarians, milkers, and slaughterhouse workers). The incubation period is two to ten days. The principal symptoms are fever, chills, headache, muscular pain, and the appearance of small blisters on the lips and oral mucosa within two to three days. The blisters then burst, forming aphthae. Since aphthae sometimes appear elsewhere on the body, a distinction is made between the stomatic and dermal forms of foot-and-mouth disease. The disease usually lasts about two weeks but may sometimes linger for several months. Such complications as bronchopneumonia and gastroenteritis may develop because of the supervention of another infection. Those recovering from the disease acquire stable immunity.
The diagnosis is made using serological and sometimes virological and biological methods. Patients are treated in a hospital for infectious diseases. There is no specific therapy. Antibiotics, Novarsenol, and topical applications of silver nitrate, potassium permanganate, or hydrogen peroxide are prescribed. Preventive measures include proper veterinary supervision, the sanitary control of dairy products, and the observance of the rules of personal hygiene when caring for diseased animals.
REFERENCESRukovodstvo po mikrobiologii, klinike i epidemiologii infektsionnykh boleznei, vol. 8. Moscow, 1966.
Rudnev, G. P. Antropozoonozy. Moscow, 1970.
Röhrer, H. lashchur. Moscow, 1971. (Translated from German.)
Siurin, V. N., and Iu. V. Fomin, “lashchur.” In Laboratornaia diagnostika virusnykh boleznei zhivotnykh. Moscow, 1972.
V. P. ONUFRIEV and L. M. MARCHUK