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Study on the Synergistic Pathogenesis between Mildly Pathogenic Avian Influenza Virus and Avian Escherichia. coli

Author: CaoLiPing
Tutor: LiuXiuZuo；GaoZuo
School: Yangzhou University
Course: Preventive Veterinary Medicine
Keywords: Chicken E. coli Low pathogenic avian influenza virus Bacteriological examination Ultrastructural pathological changes in Collaborative pathogenic
CLC: S852.65
Type: Master's thesis
Year: 2003
Downloads: 171
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Abstract

Low pathogenic avian influenza virus (mildly pathogenic avian influenza virus, MPAIV) in our wider distribution rate of egg production flocks, broiler weight gain, especially mixed with E. coli infection can produce certain mortality in broiler attracts a higher death rate, supplies poultry industry has caused serious economic losses. So far, the relevant MPAIV E. coli (Escherichia coli, E.coli) little research collaborative pathogenic mechanism. In our MPAIV H9 subtypes widely distributed, MPAIV avian colibacillosis often complicated, secondary to the actual situation in SPF chicken in different ways the artificial infection MPAIV and E.coli O26 strain to test chicken mortality bacteria made an in-depth study of the dynamic distribution of the blood and organs, pathological changes, MPAIV detoxification law, in order to explore possible synergies between pathogenic role for to reveal both diseases concurrent secondary causes ultimately provide a theoretical basis for control of its popular. 1. Experimental chickens inoculated by different order H9 subtype of avian influenza virus, avian E. coli test the 10-day-old SPF chickens were randomized mortality after each group of 25 birds, isolation rearing intratracheal inoculation. A group of 10-day-old inoculated MPAIV; B 10-day-old inoculated with E. coli and MPAIV; C group of 10-day-old inoculated with E. coli, 48h after inoculation MPAIV of; D 10-day-old vaccination MPAIV, 48h and then inoculated with E. coli; Group E 10-day-old inoculated with E. coli; F group as a healthy control group. After the end of each group of challenged observe the circumstances of the death, the results are as follows: group A, B, C, D, mortality was 12%, 32%, 16%, 24%, E group no death for the chi-square test, A, B, C, D, and E group, B and Group A significant mortality differences. The results show that: Compared with the separate inoculation MPAIV or E.coli group, E. coli after first MPAIV vaccinated group mortality has been significantly improved, at the same time the the inoculated group's mortality significantly improved, while the first inoculated with E. coli revaccination MPAIV mortality did not change significantly, indicating that the synergistic pathogenic degree of pathogen inoculation sequence has related. 2. Dynamic distribution of bacteria in experimental chickens infected with avian E. coli alone or mixed 10-day-old SPF chickens were randomly assigned to each group of 27 birds, isolation rearing. A group of 10-day-old intratracheally inoculated with E. coli; B group of 10-day-old endotracheal simultaneously inoculated with E. coli and MPAIV; C group for the healthy control group. Each group 1-96 timing after inoculation batches culling: observe their Clinical signs and bacteriological examination. The results are as follows: bacteriological examination revealed the trachea of ??each group, the number of bacteria in the lungs, the blood, spleen, liver, and kidney and inoculation time: ① A group received 12-72h after bacteremia group B 3-96h after inoculation bacteremia. The number of bacteria in the latter constant than the former; ② The test group detecting bacteria in the lung was significantly higher than other organs. Compare B, A two groups found that B lung bacteria significantly reduced time 12h, the number of bacteria in this extension of time within the difference was very significant one with; ③ The A, B group tracheal inoculation lh proliferation of bacteria, but Group B tracheal than the proliferation of bacteria. Rapidly, the number of bacteria than Group A, l2 the number of bacteria significantly different, the difference was not significant after 3h. ④ groups spleen. Kidney and liver after inoculation occasionally isolated bacteria, and few in number. The above results show that: the the test chickens by intratracheal inoculation of pathogenic E. coli, the bacteria mainly settle in the lungs and the large population into the blood stream, causing systemic reactions; the joint infection E. coli and MPAIV after, will enable the E. coli to settle in the lungs longer . 3. The experimental chickens artificially infected Hg subtype avian influenza virus, avian E. coli respiratory ultra-dynamic pathological changes in the 10-day-old SPF chickens were randomized, the vaccinated group control group of 30 birds, 20 birds, isolation rearing. A group of 10-day-old intratracheally inoculated with E. coli; the B group IO-day-old endotracheal simultaneously inoculated with E. coli and * PA w: C group, 10-day-old intratracheal inoculation MPAIV; D group of healthy controls. Ultrafine biopsy timing batches culled after inoculation acquisition trachea, lung histology and the conventional pathological observation. The results are as follows: histopathology observed in the B group trachea and lung inflammation occurred earlier than the other groups, the recovery is also slow, lung inoculated with E. coli and MPAIV lh began to appear the inflammation continued until the end of the trial, tracheal mucociliary severe shedding. Ultrastructural observations: the B group inoculated with E. coli and MPAIV 4-48h, tracheal cilia all off, the entire mucous layer visible MPAIV particles; lung 6h, 11 type of lung epithelial cells after inoculation E. coli and MPAIV of all dissolved into vacuoles, leaving only type I epithelial cells, * epithelial cell organelle vacuolization to severe lesions sustained after inoculation 48h still visible. E COlf O26 strains can cause damage to the tracheal ciliated cells, while MPAIV not only destroy the epithelial cells of the tracheal mucosa, but also damage to the the * type epithelial cells in the lung tissue. When E COn mixed with MPAIV and infection, trachea, lung disease is more serious. 4. Experimental chicken alone or mixed Hg subtype of avian influenza virus infection, the virus in the trachea, lung and cloacal samples separated 10-day-old to knock F chicken randomized, inoculated group of 30 birds. The control group of 15 birds, isolation rearing. A group of 12-day-old inoculated intratracheally * PA w: B group of 12-day-old endotracheal inoculated E. coli MPA IV: C group IO-day-old intratracheally inoculated with E. coli dh before intratracheal inoculation MPA W: D group u inoculated with E. coli the the age intratracheal inoculation MPAIV, 48h after intratracheal; E group as a healthy control group. Days 7-17 after inoculation MPAIV timing batches culling, mining their trachea and lungs, grinding into the tissue homogenate, while mining cloaca cotton swab sample, the separation of the virus. The results show that: the two pathogenic co-infection, the virus in the trachea, no significant effect on the residence time in the lung; Group trials co-infected chicken cloaca detoxification slightly longer than MPAIV Solo inoculation group.

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CLC: > Agricultural Sciences > Livestock, animal medicine,hunting,silkworm,bee > Animal Medicine ( Veterinary Medicine) > Basic Veterinary Science > Animal Microbiology ( Veterinary Microbiology, ) > Livestock Virology
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