recently, the continuous cold wave invasion, most parts of the country there is a large range of cooling rain, rain in some areas, a large range of cooling. it is not good news for a pig farm because the weather is sudden, cold and warm. this may make it more dangerous in the autumn and winter. in the absence of specific drugs, vaccine prevention effect in general, the cold wave will make it more difficult to prevent diarrhea disease.
transmissible gastroenteritis is a highly contagious intestinal disease in pigs. characterized by vomiting, severe diarrhea, and dehydration. at all ages, within 10 days of age, the mortality rate of piglets is very high, up to 100%, the mortality rate of pigs over 5 weeks old is very low, and the adult pigs have almost no deaths. the disease was first reported in the united states in 1946. since then, it has been reported in many countries in the world, causing serious economic losses.
[pathogen]
transmissible gastroenteritis virus (tgev) belongs to the family coronaviridae (coronavirus), envelope, shape, round, oval and polygon, the diameter is 60 ~ 160nm, the surface layer of rod like spike, about 12 ~ 25nm. the tgev genome is single stranded rna.
the virus can be adapted to porcine thyroid cells, pig testis cells, fetal pig and piglet kidney cells, and salivary gland cells. ibrs2 and st cell lines are common laboratory cells. virus particles are present in cytoplasm after maturation, and virus particles are common in cytoplasm vacuoles.
[epidemiology]
the occurrence and prevalence of the disease are obviously seasonal, generally occurring in winter and spring, and the peak incidence is 1~2 months. virus transmission can be through direct contact with pigs. sow milk can be discharged and transmitted through milk to suckling piglets and also through the respiratory tract. fecal viruses are transmitted through the mouth and nose. the pigs can be poisoned for 8 weeks, which is the main source of infection in the pig farm. tgev is often mixed with escherichia coli and rotavirus, resulting in increased mortality in suckling and weaned piglets.
[symptoms]
incubation period is very short, generally 15 ~ 18h, and some can extend 2 ~ 3d. the disease spreads rapidly and spreads within a few days. piglets suddenly attack, first vomiting, followed by frequent watery diarrhea, stool yellow, green or white, often accompanied by undigested curd. it is characterized by a large amount of electrolytes, water and fat, alkaline, but contains no sugar. the sick pig was extremely thirsty, obviously dehydrated, and the weight of the pig was reduced rapidly. the younger the age, the shorter the course of disease and the higher fatality rate. within the 10 day old piglets in the death of 2 ~ 7d, such as the onset or reduce the amount of lactation sows, piglets do not have enough milk, exacerbations, nutritional imbalance, increased piglet mortality, with the age increasing mortality rate decreased gradually. the growth of piglets was bad.
the symptoms of young pigs, fat pigs and sows vary widely, and usually only 1d to days of loss of appetite or waste. individual pigs vomiting, gray brown water samples, diarrhea was jet shaped, 5 ~ 8d diarrhea stopped and recovered, rarely die. some lactating sows close contact with piglets, repeated infections, severe symptoms, elevated body temperature, cessation of lactation, vomiting and diarrhea. but some lactating sows are exposed to diseased piglets without symptoms.
[pathology]
the body was dehydrated markedly. the eye changes, the stomach is filled with curds, and the gastric mucosa is congested and bleeding. enteral filled with white to yellow green liquid, intestinal wall thinning and lack of flexibility, bowel dilatation translucent, mesenteric congestion, swollen lymph nodes, lymph no milk lian. histologically, small intestinal villi shortened and atrophied. intestinal epithelial degeneration is obvious, epithelial cells are not columnar, but flat to square immature cells. serous exudate and cell infiltration are seen in the lamina propria. the kidney is cloudy, swollen and fatty, and contains white urate salts. some piglets have complicated pneumonia. in some cases, there is no other lesion except the loss of body fluid and the presence of fluid in the intestines.
[diagnosis]
diagnosis can be made according to the epidemiology, symptoms and pathological changes. for example, the disease occurs frequently in winter and spreads rapidly. pigs of all ages can be infected with the disease. vomiting, watery diarrhea and dehydration are present in the sick pigs. 10 day old baby pig disease death rate is very high, adult pigs by rehabilitation after 5 ~ 7d, almost no death. the walls of the small intestine become thin, translucent, and the intestine enlarged and filled with a half fluid or liquid content. villous atrophy of small intestine. the ratio of the villus length to the crypt crypt depth in the jejunum and ileum was 7:1 in normal pigs and 1:1 in diseased pigs. preliminary diagnosis can be made with these characteristics, and laboratory diagnosis is necessary for further diagnosis.
[prevention and control measures]
1. do not usually pay attention from infected areas or disease of swine imported pigs, so as not to spread the disease. in case of emergency, it can be injected with long-acting antibacterial health products, such as da, which can obviously reduce the occurrence of the disease. when the herd occurrence of this disease, which should be isolated for disinfection of infected pigs, pig, environment, equipment, transportation with efficient disinfectant junduging iodine, yet the incidence of swine breeding should be immediately isolated to a safe place.
2., there is no specific treatment for this disease. symptomatic treatment can reduce dehydration, acidosis and prevent concurrent bacterial infection. and to strengthen nursing, good insulation, strengthen the effect of drinking water on the best lygo (or amoxicillin), immune interferon, oral rehydration salts, and stop breastfeeding or feeding.
3. pairs of pigs suffering from excessive dehydration, intravenous infusion of glucose, salt, vitamin c, astragalus antitoxin. |
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