African swine fever
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African swine fever
African swine fever (ASF), highly contagious, deadly viral disease of swine. Its acute form, which is typically fatal, is characterized by high fever, loss of appetite, lethargy, and redness in the skin or red blotches or blackened lesions on the skin; other symptoms include vomiting, coughing and other respiratory symptoms, diarrhea, and miscarried pregnancies. Less virulent forms of the virus may cause chronic disease with loss of appetite, low fever, listlessness, coughing and other respiratory symptoms, and other symptoms, and the death rate is lower but may reach 70%. There is no vaccine. The disease is controlled by slaughtering exposed herds and disposing of the carcasses in a sanitary manner, and other sanitary measures. Although symptoms are similar to classical swine fever, the causative viruses are not related. The virus does not affect humans.
ASF is transmitted readily by direct or indirect contact. The virus may enter a herd through contaminated feed, water, equipment, clothing, or by contact with an infected animal. Feeding swine pork scraps is forbidden in some areas to prevent transmission. It also may be transmitted by some species of soft ticks, which may transmit the disease to domestic swine from wild boars and feral swine as well as from warthogs, bush pigs, and other species that can carry the disease. Outbreaks of ASF have never occurred in the United States, and it is currently eradicated in the Western Hemisphere. An outbreak that began in NE China in 2018 and continued into 2019, spreading to other E and SE Asian countries, became the most devastating animal disease outbreak known, with significant economic consequences.
African Swine Fever
(Latin, Pestis Africana suum), an acute viral infection involving the reticulo-endothelial system. This disease was first observed among the swine in South Africa by Hutchen in 1903. African swine fever occurs in Africa, Italy, Spain, and Portugal. Under natural conditions, domesticated and wild swine of all ages are subject to African swine fever. Natural infection occurs through contact between healthy swine and the sick swine and virus carriers. The infection is spread through feed, pasture grounds, and means of transport contaminated by the sick swine.
The use of unsanitized wastes from cafeterias, restaurants, and slaughterhouses in the swines’ feed also contributes to the spread of infection. Insects, birds and beasts of prey, and dogs may be carriers of the virus. The incubation period is two to five days. The disease proceeds either instantaneously or acutely and chronically. In the first case, the animals die suddenly, without showing symptoms; in the second case, their temperature increases to 42.5°C, coughing and shortness of breath develops, appetite declines, nausea and paralysis occur, blood appears in wastes, the skin on ears and snout turns blue, and the animal becomes extremely weak.
No cure has been devised. On account of the highly dangerous nature of the disease and its ability to spread very rapidly, preventive measures have been centered on strict isolation of those animals suspected of the disease. When African swine fever appears, all swine on a farm are killed. The bodies are destroyed, and the pigsties and other equipment are disinfected. The introduction of new swine on the farm is permitted only one year after the disease has been liquidated.