Epidemic characteristics and prevention and control measures of swine epidemic diarrhea
Porcine epidemic diarrhea is caused by the coronavirus infection and is an acute contact enteric infectious disease. The main characteristics of sick pigs are severe diarrhea, vomiting, severe dehydration and weight loss. The disease is easy to be in the cold winter, It occurs in the spring season, and only pigs will develop the disease, and pigs of any age can develop the disease. The younger the onset age, the more severe the symptoms and the higher the mortality rate. Seriously endanger the development of the pig industry, so the daily prevention and control of the disease must be strengthened. Let's take a look at the epidemic characteristics and prevention and control measures of swine epidemic diarrhea.
1. Popular features
Porcine epidemic diarrhea virus is the pathogenic microorganism that causes porcine epidemic diarrhea. The disease is a coronavirus, which is very prone to mutation, which greatly increases the difficulty of preventing and treating the disease. The virus is very easy to survive in low temperature conditions, but is not resistant to high temperatures. In addition, the virus is more sensitive to light and a variety of disinfectants, such as the use of quaternary ammonium salts, sodium hydroxide, formalin and other disinfectants can make it inactivated.
The disease is prone to occur mainly in late winter and early spring. In recent years, due to the continuous adoption of large-scale breeding of pigs, the disease can also occur in summer. The disease can occur in pigs at any stage, but the transmission speed and prevalence are relatively milder than swine epidemic gastroenteritis, and as pigs age, the incidence and mortality of the disease continue to decrease. The main source of infection of the disease is sick pigs, which are often spread through the digestive tract. Piglets aged 1 to 5 days are most susceptible to this disease, which causes greater harm, and all deaths occur after basic infection. After weaned piglets, fattening pigs and breeding pigs are infected with the disease, they have milder symptoms and lower mortality, but within a few days it will cause disease in the entire farm.
2. Clinical symptoms
The main features of the disease are watery diarrhea, vomiting and dehydration in sick pigs, and newborn piglets have a high mortality rate. The disease usually has an incubation period of 5-8 days, but it only has an incubation period of 8-24 h by artificial infection. Sick pigs have watery diarrhea, discharge gray-yellow or yellow feces, and emit a foul smell. The body temperature usually remains normal, and individual body temperatures will rise by 1 to 2°C. Sick pigs have different ages of onset, and they will show symptoms of different severity. Usually, the younger they are, the more severe the symptoms are. Piglets show depression, vomiting, and severe dehydration after illness.
Piglets younger than 1 week of age mainly show severe diarrhea after illness, which usually lasts for 2 to 4 days, causing obvious dehydration and causing metabolic acidosis, which eventually occurs Death, and lower body temperature before death, the fatality rate is usually around 50%. Growing pigs have mild symptoms after being infected with the disease, mainly including mild loss of appetite, lack of energy, and watery diarrhea. Most of them gradually recover after 7 to 10 days of diarrhea. The fatality rate is only about 1% to 3%.
3. Pathological changes
The autopsy revealed that the small intestine of the sick and dead pigs was mainly caused by lesions in the small intestine, the intestinal tube was swollen and filled with yellow liquid, the intestinal wall was loose and thin, the small intestinal mucosa was congested, the mesentery had cord congestion, and the mesenteric lymph nodes were congested and edema. There are a large number of yellow-white curds in the stomach of some sick pigs, and the gastric mucosa has different degrees of congestion and bleeding. The main feature of histological changes is the shedding of small intestinal villi epithelial cells and obvious villi atrophy, especially the intestinal villi in the middle and back of the jejunum will have obvious lesions, the epithelial cells will form vacuoles, and the epidermis will fall off.
4. Prevention and control measures
Strengthen feeding management. In pig production, an all-in, all-out system must be adopted. During the sow farrowing process, it is necessary to strengthen the control of the farrowing room temperature, especially in the cold winter and spring season, the sows and piglets must be protected from cold and warm, and at the same time, proper ventilation should be paid to the house. Feed high-quality feed to ensure that there is no deterioration. Disinfect regularly, and often choose to use disinfectants such as 2% sodium hydroxide, 4% anhydrous sodium carbonate, sodium hypochlorite, etc.
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