Pathogen characteristics of infectious serositis in ducks
Duck infectious serositis, also known as Riemerella anatipestifer, formerly known as Pasteurella anatipestifer, can be infected by ducks of all breeds, genders and dates, mainly affecting ducklings aged 2 to 3 weeks, with an incidence of more than 90% and a mortality rate of 5% to 75%. The disease is often mixed with duck colibacillosis or complicated with infection. It is characterized by fibrinous pericarditis, pericarditis, pneumocystitis, peritonitis and so on.
1. Pathogen
Riemerella anatipestifer, the pathogen of the disease, is a gram-negative microbacilli with no spores and no movement, and most of the bacteria are strongly stained at the poles. The serotype of this bacteria is complex. There are 21 serotypes reported internationally, and there is no cross-protective reaction between them, which makes it difficult to prevent and control the disease. Riemerella anatipestifer could not grow on common Agar and McConkey medium, and the colony grown on blood Agar plate medium was dewdrop-like and inhemolytic.
two。 Epidemiology
The disease has no obvious seasonality and can occur all the year round, and it occurs more frequently in spring and winter. Mainly through the respiratory tract or skin wound infection. The excessive density of ducks in the nursery, poor air circulation, wet ground, poor sanitary conditions, extensive feeding and management, low level of protein in feed, lack of vitamins and trace elements, etc., are the causes of the occurrence and epidemic of the disease. The air polluted by bacteria is an important route of transmission. The problem of transmission by breeding eggs is still uncertain.
The disease often presents an acute outbreak, sudden onset and rapid spread. at present, the disease accounts for about 35% to 45% of the three major bacterial diseases of ducklings (colibacillosis, salmonellosis, and Riemerella anatipestifer), and is prone to other diseases, leading to serious consequences.
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Research Progress on immunosuppressive principle of Porcine circovirus ⅱ infection
Circovirus infection is a newly discovered infectious disease. The infection rate of the disease to pigs is high, and it occurs widely all over the world, and it has become one of the infectious diseases seriously affecting the development of pig industry. Circovirus mainly attacks the immune system of pigs, interferes with and destroys the production and maintenance of immune antibodies to diseases, resulting in a decline in resistance, which is easy to be secondary or complicated with other diseases. In recent years, scholars at home and abroad have done a lot of research on the mechanism of porcine circovirus invading the immune system, in the mechanism of virus replication, cytokines and lymph nodes.
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South Korean scientists have bred "biochemical pigs" to produce therapeutic agents for cerebral thrombosis.
South Korean scientists have successfully developed a biochemical pig (biopig) that produces a therapeutic agent for cerebral thrombosis (cerebral hemorrhage) through urine. South Korea's Rural Revitalization Agency said a few days ago: "the gene for the treatment of cerebral thrombosis (TPA) was injected into the fertilized eggs of pigs and successfully bred four pigs whose therapeutic substances can be excreted through milk and urine." South Korea has become the second country in the world after the United States to produce animals that can be genetically modified to treat cerebral thrombosis. The United States adopted transgenic technology in 1997.
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