Summary of the invention
The object of the present invention is to provide a kind of BYD of prevention virus infection to cause inactivated vaccine of duck egg drop syndrome and preparation method thereof.
The invention provides (Family Flaviviridae, GenusFlavivirus, Ntaya virus group, Duck BYD virus) the JXSP strain of duck BYD virus, separate morbidity duck cerebral tissue from duck field, Baiyang Lake, Chinese Hebei province.The JXSP strain has been preserved in China Committee for Culture Collection of Microorganisms common micro-organisms center (CGMCC) on September 22nd, 2011; No. 3, Yard 1, BeiChen xi Road, Chaoyang District, Beijing City, address; Institute of Microorganism, Academia Sinica; The classification name: duck BYD virus, deposit number is CGMCC No.5266.
Duck BYD virus JXSP of the present invention strain belongs to flaviviridae (Flaviviridae) Flavivirus (flavivirus).Under the Electronic Speculum, virus particle is spherical in shape, and the about 45-60nm of size has the electro-dense nuclear core of the about 30nm of a diameter and the lipid cyst membrane of parcel nuclear core.Mainly in the kytoplasm of cells infected, duplicate.Viral genome is the sub-thread positive chain RNA, and size is 10990nt.Genome 5 ' and 3 ' end respectively have one section non-coding region (NCR), and the coded sequence of whole gene is 5 '-NCR-C-PrM-E-NS1-NS2A2B-NS3-NS4A4B-NS5-NCR-3 '.
The invention provides the application of duck BYD virus JXSP strain in the preparation vaccine.
The invention provides the vaccine that utilizes duck BYD virus JXSP strain preparation.
The invention provides a kind of method for preparing duck BYD virus JXSP strain virus liquid, comprise the steps:
1) cell of enlarged culturing is pressed 1% of nutrient solution and add JXSP strain virus seed, 37 ℃, adsorbed 1 hour;
2) add 1% foetal calf serum and keep liquid, cultivate down for 37 ℃, gather in the crops freeze thawing 3 times when above when cytopathy reaches 75%;
3) centrifugal or remove by filter cell debris, collect supernatant, this supernatant is duck BYD virus JXSP strain virus liquid.
Duck BYD virus JXSP strain can be in DEF (DEFs) multiplication by culture; And generation CPE (cell rounding, shrinkage, pyknosis; Being the kitchen range shape comes off), virus also can infect BHK-21, Vero cell and produce CPE, but on other cells such as PK-15, ST, MDCK, does not all produce CPE.Therefore, above-mentioned cell may be selected to be BHK-21, Vero and/or DEF.
In one embodiment of the invention; Select the BHK-21 cell to carry out the seed culture of viruses multiply test of duck BYD virus JXSP strain; Be specially: BYDV-JXSP the 2nd generation duck embryo allantoic liquid poison is seeded in the BHK-21 cell cultures, in 5%CO after with 5 times of dilutions of serum-free DMEM substratum
2In the incubator, 37 ℃ leave standstill cultivation, and when treating that pathology appears in 75% cell, harvested cell liquid is got 100 times of dilutions of supernatant postoperative infection inoculation BHK-21 cell after the freeze thawing 2 times, so reached for the 8th generation, harvested cell liquid in-70 ℃ of preservations as kind of a poison, viral level>=10
5.5TCID
50/ mL.
During with BHK-21 cell proliferation virus; Can carry out enlarged culturing before the inoculation: get the BHK-21 cell that liquid nitrogen is preserved, place 37 ℃ of water-baths thawings immediately after, the centrifugal 5min of 800r/min; Abandon supernatant; Add the DMEM cell growth medium suspension cell deposition that contains 10% foetal calf serum, change in the Tissue Culture Flask, in 5%CO
2In the incubator, 37 ℃ leave standstill cultivation, treat to carry out passage after cell monolayer forms.Discard cell culture fluid, add an amount of sterilization PBS and clean cell surface gently 2 times, abandon PBS; The trysinization liquid (0.25%) that adds 37 ℃ of preheatings leaves standstill 5~10min; The observation of cell gap obviously enlarges under the inverted microscope, cellular form becomes bowlder, and the tipping trypsin solution adds the DMEM piping and druming cell dispersion that contains 10% foetal calf serum gently; And install to new cell cultures flask culture in 1: 3 ratio branch, in 5%CO
2In the incubator, 37 ℃ leave standstill cultivation.
The present invention also provides the method for preparing duck BYD viral inactivation vaccine, is the duck BYD of above-mentioned preparation virus JXSP strain virus liquid is carried out deactivation and emulsification as seedling with viral liquid successively, obtains duck BYD viral inactivation vaccine.
Said viral liquid viral level>=10
5.5TCID
50/ mL.
Described deactivation is to be that 0.2% (V/V) ratio adds formaldehyde solution (formaldehyde content is 37%) with viral liquid in final concentration, and fully mixing is put 37 ℃ of effect 24h inactivation of viruses.
Described emulsification be with the viral liquid after the deactivation as water, after mixing according to water oil phase volume ratio 4: 6,10000~12000r/min emulsification 2min adds Thiomersalate solution before stopping stirring, and makes final concentration reach 0.01% volume ratio.
The oil phase preparation method adds Triple Pressed Stearic Acid aluminium 2g for getting 94 parts of injection white oils (mL) among the present invention, and the limit edged stirs, and is transparent until fully, adds 6 parts of (mL) Si Ben-80 again, abundant mixing, and autoclaving obtains the 100mL oil phase; The preparation method of water is that the cell culture and virus liquid 100 parts (mL) of getting deactivation adds the tween-80 that 4 parts (mL) sterilize, and fully shakes up to tween-80 and dissolves fully, obtains the 104mL water.
The duck BYD-JXSP viral inactivation vaccine outward appearance of the present invention's preparation is an oyster white emulsion.
Can be used for of vaccine of the present invention, carried out the neck subcutaneous vaccination to the healthy duck of 5~7 ages in days, every 0.5mL vaccine.
In an embodiment of the present invention; Safety examination to the BYD-JXSP viral inactivation vaccine that makes is found; The healthy susceptible duck (HI antibody titer≤1: 20) of 5~7 ages in days is through neck subcutaneous injection vaccine 1mL, the part that does not take place in the observation period to occur because of vaccinate and the untoward reaction of whole body; In the efficacy test to the BYD-JXSP viral inactivation vaccine that makes; Reach the healthy susceptible duck (HI antibody titer≤1: 20) more than 60% with 5~7 ages in days or laying rate; Every through neck subcutaneous injection vaccine 0.5mL, the strong poison of inoculation back 3 all intracranial inoculation JXSP (virus titer>=10
5.5TCID
50/ mL, 0.1mL/ are only), in the observation period, vaccine reaches more than 90% the protection ratio of immune duck.
Duck BYD virus JXSP provided by the invention strain has good immunogenicity, this strain is inoculated on the responsive host cell, and harvested cell liquid, emulsification after the deactivation obtains a kind of safe, effective, controlled duck BYD viral inactivation vaccine.Behind this vaccine inoculation duck, do not see untoward reaction, cut open the inspection inoculation position; Not symptom such as swollen, the suppuration of show, and vaccine is absorbed fully, and security is good; Good immune effect, the infection that can resist the strong poison of duck BYD helps the prevention and control of duck egg drop syndrome in the large-scale cultivation.
Embodiment
Following examples further specify content of the present invention, but should not be construed as limitation of the present invention.Under the situation that does not deviate from the present invention's spirit and essence, modification or replacement to the inventive method, step or condition are done all belong to scope of the present invention.
If do not specialize; Duck used among the embodiment is provided by Guangdong Dahuanong Animal Health Products Co., Ltd.; Used chemical reagent, raw material, equipment be for can buy the commercially available prod that obtains among the embodiment, the conventional means that used technique means is well known to those skilled in the art among the embodiment.
Embodiment 1 virus is separated with pathogenic
1, isolation identification should virus be separated the morbidity duck cerebral tissue from duck field, Baiyang Lake, Chinese Hebei province.10% homogenate is processed with aseptic PBS by sick duck brain tissue sample, the centrifugal 20min of 3000r/min, filtration sterilization is not after after allantoic cavity approach inoculation 9~12 ages in days have maternal antibody duck embryo, 37 ℃ of hatchings 5 days, the results allantoic fluid also goes down to posterity in the duck embryo.With the 2nd generation the allantoic fluid poison be seeded on the BHK-21 cell monolayer, in 5% CO2gas incubator, leave standstill cultivation, observed 7 days, results culture when waiting cytopathy to occur ,-70 ℃ of preservations.
The ultrathin section(ing) transmission electron microscope of preparation cells infected is observed down; Visible a large amount of about 50nm of diameter, sphere have the togavirus particle to gather heap or are dispersed in back cell cytoplasm or the vesicle more than 24 hours of infection, and most of virus particle is it is thus clear that there is the electro-dense nuclear core of the about 30nm of diameter.The spissated virus-culturing fluid of ultracentrifugation, through the phospho-wolframic acid negative staining, transmission electron microscope is observed the visible about 50nm of diameter down, the spherical virus particle of cyst membrane is arranged.
Whole genome sequence is measured the result and is shown that viral genome is the sub-thread positive chain RNA, and size is 10990nt.Genome 5 ' and 3 ' end respectively have one section non-coding region (NCR), and the coded sequence of whole gene is 5 '-NCR-C-PrM-E-NS1-NS2A2B-NS3-NS4A4B-NS5-NCR-3 '.The kind system that has the full genome of flavivirus of sequence data to make in utilization takes place in the evolutionary tree, and BYD virus (JXSP strain) is nearest with bagaza virus (Bagaza Virus) evolutionary relationship, and homology is about 72%.The JXSP strain is preserved in China Committee for Culture Collection of Microorganisms common micro-organisms center (CGMCC) on September 22nd, 2011, No. 3, Yard 1, BeiChen xi Road, Chaoyang District, Beijing City, address, Institute of Microorganism, Academia Sinica, classification name: duck BYD virus.Deposit number is CGMCC No.5266.
2, pathogenic virus inoculation laying ducks, clinical manifestation descends for searching for food and egg productivity sharply descends.Laying rate has dropped to below 12% from 60.9% in back 6 days of infection, until stopping production.Infect that to cut open the visible ovarian follicle of inspection in back 3 days hemorrhage, the degeneration that occurs ovary along with the development of the course of disease changes ovarian follicle sex change and atrophy.The visible sick duck ovarian hemorrhage of tissue examination, follicular development stops, locking or disintegration, and circle or the red corpusculum that dyes of particulate state that differs in size in a large number arranged, and is full of an ovarian follicle or a matter of disintegration.The visible microglia of some cases brain is soaked into kitchen range, and little perivasculitis cell forms oversleeve spline structure (vascular cuffing), is apyetous encephalitis pathology.Histopathology changes and cuts open the inspection finding substantially and the duck clinical symptom of falling ill conforms to basically, can detect and be recovered to virus with fluorescence RT-PCR and viral separation test.
Virus intracranial inoculation 1~7 duck in age in week can cause tangible nervous symptoms, shows as the decline of searching for food, weak and limp, circus movement, paralysis and death, and mortality ratio is 40%~60%.Histological examination shows as typical apyetous encephalitis pathology.
The preparation of embodiment 2 duck BYD virus JXSP strain virus liquid
1, seed culture of viruses is bred being seeded in the BHK-21 cell cultures after 5 times of dilutions of BYDV-JXSP the 2nd generation allantois duck blastochyle poison; In 5% CO2gas incubator, 37 ℃ leave standstill and cultivate when treating that pathology appears in 75% cell harvested cell liquid; Get 100 times of dilutions of supernatant postoperative infection inoculation BHK-21 cell after the freeze thawing 2 times; So reached for the 8th generation, harvested cell liquid in-70 ℃ of preservations as seed culture of viruses, viral level>=10
5.5TCID
50/ mL.
2, the BHK-21 cell that liquid nitrogen is preserved is got in cell seminal propagation, place 37 ℃ of water-baths to melt immediately after, the centrifugal 5min of 800r/min; Abandon supernatant; Add the DMEM cell growth medium suspension cell deposition that contains 10% foetal calf serum, change in the Tissue Culture Flask, in 5% CO2gas incubator; 37 ℃ leave standstill cultivation, treat to carry out passage after cell monolayer forms.Discard cell culture fluid, add an amount of sterilization PBS and clean cell surface gently 2 times, abandon PBS; The trysinization liquid (0.25%) that adds 37 ℃ of preheatings leaves standstill 5~10min, and the observation of cell gap obviously enlarges under the inverted microscope, cellular form becomes bowlder, tipping trypsin solution gently; Add the DMEM piping and druming cell dispersion that contains 10% foetal calf serum; And install to new cell cultures flask culture in 1: 3 ratio branch, in 5% CO2gas incubator, 37 ℃ leave standstill cultivation.
3, after the viral liquid of preparation treats that the BHK-21 cell monolayer forms, discard cell culture fluid, add an amount of sterilization PBS and clean cell surface gently 2 times, abandon PBS; To plant poison with 100 times of dilutions of DMEM basal liquid do, be inoculated into cell monolayer, and make liquid evenly cover cell surface by 10% (V/V) of the final volume of cell culture fluid; In 5% CO2gas incubator, 37 ℃ left standstill 1 hour, added the DMEM that contains 1% foetal calf serum then; Put in 5% CO2gas incubator, cultivated 96 hours for 37 ℃, when pathology (showing as the cell circle contracts and come off) appears in the cell more than 75%; Results; Multigelation 3 times is through centrifugal or remove by filter cell debris, collecting cell nutrient solution (virus titer>=10
5.5TCID
50/ mL), be the viral liquid that the preparation vaccine is used, preserve below-20 ℃.,
The preparation of embodiment 3 duck BYD viral inactivation vaccines
1, the deactivation of viral liquid
Is the ratio adding formaldehyde solution of 0.2% (volume ratio) with the viral liquid of preparation among the embodiment 2 in final concentration, and mixing fully shakes up the back in 37 ℃ of effects 24 hours, inactivation of viruses.
2, inactivating efficacy check
The BHK-21 cell is cultured to individual layer on 24 orifice plates; The viral liquid of the BYDV-JXSP of 10 times of dilutions of formalin-inactivated processing in the step 1 is inoculated on the BHK-21 cell monolayer by the 0.2mL/ hole; Each sample is inoculated 3 holes; Hatch after 1 hour and discard sample liquid, keep cultivation, establish the contrast of positive control and blank well simultaneously with keeping liquid washing continued; Observe positive control hole visible cell pathology after 48 hours, sample and blank hole are negative; 2 generations of blind passage, the same observation, CPE appears in positive hole if CPE does not appear in the cell in experimental port and blank hole, explains that then inactivating efficacy is good.
3, the preparation of vaccine
(1) injection white oil 94mL is got in the preparation of 100mL oil phase, adds Triple Pressed Stearic Acid aluminium 2g, and the limit edged stirs, and is transparent until fully, adds 6mL Si Ben-80 again, abundant mixing, and autoclaving is subsequent use;
(2) tween-80 of 4 parts of (mL) sterilizations of 100 parts of (mL) addings of cell culture and virus liquid of deactivation is got in the water preparation, fully shakes up to tween-80 and dissolves fully;
(3) join seedling and get 6 parts of oil phases and put into colloidal mill or emulsion cylinder, stir at a slow speed, slowly add 4 parts of waters simultaneously, add behind the water with 10000~12000r/min emulsification 2min; Before stopping stirring, add 1% Thiomersalate solution, final concentration reaches 0.01%.After the emulsification, sampling 5~10mL is with the centrifugal 15min of 3000r/min, if demixing phenomenon, emulsification are again arranged.
(4) the quantitative packing of vaccine that packing is good with emulsification seals.
The safety examination of embodiment 4 vaccines
1, vaccine and laboratory animal
Get the duck BYD viral inactivation vaccine of three crowdes of embodiment, 3 preparations, lot number is respectively 2011001,2011002,2011003.Healthy duck is provided by Guangdong Dahuanong Animal Health Products Co., Ltd..
2, vaccine uses a single dose inoculation to minimum days old animal
Every batch of vaccine is distinguished 10 of the healthy ducks of immunity 5~7 ages in days, every neck subcutaneous injection vaccine 0.5mL; The injection continued observe to be raised 14 days, observed the reaction of immunity back animal, every group the part duck was dissected, and observed the absorbing state of injection site vaccine.
3, vaccine is to target animals single dose repeated inoculation
Every batch of vaccine is distinguished 10 of the healthy ducks of immunity 5~7 ages in days, every neck subcutaneous injection vaccine 0.5mL; In 2 weeks of back of immunity for the first time, carry out two and exempt from, every neck subcutaneous injection vaccine 0.5mL once more; The injection continued observe to be raised 14 days, observed the reaction of immunity back animal, every group the part duck was dissected, and observed the absorbing state of injection site vaccine.
4, vaccine is to an overdose inoculation of target animals
Every batch of vaccine is distinguished 10 of the healthy ducks of immunity 5~7 ages in days, every neck subcutaneous injection vaccine 1mL; The injection continued observe to be raised 14 days, observed the reaction of immunity back animal, every group the part duck was dissected, and observed the absorbing state of injection site vaccine.
5, test-results
More than each group test duck part and systemic adverse reactions all do not appear, the mental status of animal and appetite are good after the vaccination, the part duck is carried out anatomic observation show; The vaccination position is symptom such as swollen, the suppuration of show not, and vaccine absorbs fully, and the result sees table 1.Therefore, three batches of vaccines of the embodiment of the invention 3 preparation under the situation of single dose, overdose, repeatedly inoculation all to duck safety.
Table 1 safety testing result
The efficacy test of embodiment 5 vaccines
1, vaccine and laboratory animal
Get three batches of duck BYD virus (JXSP strain) inactivated vaccines that embodiment 3 makes, lot number is 2011001,2011002,2011003.Healthy duck is provided by Guangdong Dahuanong Animal Health Products Co., Ltd..
2, vaccine immunization
Every batch of vaccine is distinguished 10 of the healthy ducks of immunity 5~7 ages in days, every neck subcutaneous injection vaccine 0.5mL; Establish 10 of non-immune control group ducks simultaneously.
3, Serum Antibody Detection
Immunity blood sampling in back 21 days separation of serum adopts indirect ELISA method to detect antibody horizontal.Concrete operation method is following:
1. virus antigen breeding and purifying are done BYD virus (JXSP strain) to be inoculated on the DEF that grows up to individual layer after 100 times of dilutions with the DMEM basal liquid, inhale behind 37 ℃ of absorption 1h and abandon viral liquid, and adding is kept liquid and continued to cultivate, and observe every day; Treat that pathology appears in 75%~90% cell, collect viral liquid, in 4 ℃; 10, get supernatant behind the 000r/min high speed centrifugation 45min, supernatant is in 4 ℃; 40,000r/min ultracentrifugation 2.5h abandons supernatant; The 1/100 usefulness sterilization PBS that the presses original volume deposition that suspends places on the sucrose layer of 20% (W/V) and 50% (W/V) suspension-s in 4 ℃ 40 afterwards; 000r/min ultracentrifugation 3h gets two concentrating virus bands between the sucrose layer in-80 ℃ of preservations, uses antigen as encapsulating of ELISA detection.
2. above-mentioned purifying antigen is diluted to 6 μ g/mL with carbonate buffer solution (pH9.6), joins in (100 μ L/ hole) in the 96 hole enzyme-linked reaction plates, 4 ℃ are spent the night and encapsulate enzyme-linked reaction plate;
3. get the enzyme-linked reaction plate that encapsulates, the tipping coating buffer was with PBS (pH7.4) washings (PBST) washing that contains 0.05% tween 20 3 times, each 3 minutes;
4. every hole add 150 μ L confining liquids (5% skimmed milk, PBST), 37 ℃ the effect 2 hours, 3. each hole liquid of tipping wash 3 times with reference to step;
5. every hole adds 100 μ L duck serum to be checked (1: 200) dilution, and 37 ℃ act on 1 hour.Each Sptting plate is respectively set up 2 positive and negative serum control wells simultaneously.3. each hole liquid of tipping wash 3 times with reference to step;
6. every hole adds the goat-anti duck IgG (H+L) (dilution in 1: 500, U.S. KPL company produces) of 100 μ L horseradish peroxidase-labeled, and 37 ℃ act on 1 hour.3. each hole liquid of tipping wash 3 times with reference to step;
7. every hole adds tmb substrate liquid 100 μ L, and 15min is made in 37 ℃ of lucifuge senses, adds 50 μ L 2M sulphuric acid soln termination reactions, measures OD with ELIASA
450nmValue, the record result.
4, Serum Antibody Detection result
The antibody test result all reaches more than 0.85, control group serum all negative (result sees table 2).Serum Antibody Detection result shows, can induce behind this vaccine of duck immunization to produce good immunoreation.
Adopt fixed virus-dilute serum neutralization test serum to be carried out parallel detection, duck serum ELISA antibody titer OD
450nm>=0.85 o'clock, virus neutralization tires>=and 1: 100.The protection ratio of strong poison being attacked poison can reach more than 90%.
Table 2 Serum Antibody Detection result
Test is divided into groups |
The vaccine lot number |
Detected result |
One group of immunity |
2011001 |
OD
450>1.05
|
Two groups of immunity |
2011002 |
OD
450>0.89
|
Three groups of immunity |
2011003 |
OD
450>0.95
|
Non-immune control group |
/ |
OD
450<0.2
|
5, challenge test
3 all intracranial inoculation checks are with strong poison (BYD-JXSP strain BHK-21 cell cultures the 3rd generation virus liquid that embodiment 2 makes, its virus titer>=10 after the immunity of experiment duck
5.5TCID
50/ mL, 0.1mL/ are only), continue to observe 14 days, the reaction of writing down each treated animal comprises appetite, clinical symptom, cuts open the variation of inspection general pathology.To die of illness duck with attack the test duck that slaughtered on the 14th day poison back, detect brain and the in-house BYD-JXSP of spleen is viral with the fluorescence RT-PCR method.
6, challenge test result
(1) attacks poison contrast duck and attack back 9/10 duck morbidity of poison, 5/10 duck death.
Sick duck shows as: 1. clinical observation is seen the minimizing of searching for food, the neck that contracts, is trembled, walking step state is undesired, ataxy and paralysis etc.; 2. cut open inspection natural death duck splenomegaly, extravasated blood substantially, observation was slaughtered the duck eye to 14 days and is not seen obvious pathology; 3. apyetous encephalitis such as the visible little blood vessel oversleeve of the brain appearance glial cell invasion of pathological study, glial cell invasion kitchen range change.
To die of illness duck with attack the contrast duck slaughtered in back 14 days of poison, it is all positive with fluorescence RT-PCR method detection BYD viral (JXSP strain) to get brain and spleen.See table 3 for details.
Table 3 contrast duck challenge test is table as a result
(2) vaccine immunity duck
Three batches of inactivated vaccine immune group; Clinical manifestation is normal after most of immune duck immunity; Every group has the part duck attacking that poison back can occur one crossing that property subtracts food in 4~8 days, the neck that contracts, clinical symptom such as rocking, and immune three groups of 1 ducks are in attacking poison back death in the 8th day, and it is thus clear that indivedual ducks are ataxia.Cut open the inspection no abnormality seen substantially, the accidental spongiocyte of pathological study is little focal hyperplasia.Brain and spleen detect BYD virus (JXSP strain) with the fluorescence RT-PCR method, and three groups only 4 samples are positive.
The result sees table 4.
Visible by experimental result, behind three batches of vaccine immunity ducks that the embodiment of the invention 3 makes, can make the infection of duck opposing duck BYD virus, do not cause untoward reaction, have good protection and render a service.
Table 4 vaccine immunity group is attacked poison back summary sheet as a result
The comprehensive test of embodiment 6 immune effect of vaccine
1, vaccine and laboratory animal
Get 1 batch of the duck BYD viral inactivation vaccine that embodiment 3 makes, lot number is 2011001.Healthy duck is provided by Guangdong Dahuanong Animal Health Products Co., Ltd..
2, the safety examination of vaccine
10 of the healthy ducks of 5~7 ages in days, every neck subcutaneous injection vaccine 1mL; The injection continued is observed and was raised 14 days, does not see part and systemic adverse reactions, and the inoculation duck searches for food normally.
3, efficacy test
1. vaccine immunization is with 10 of the healthy ducks of vaccine inoculation 5 ages in days, every neck subcutaneous injection vaccine 0.5mL; Establish 10 of non-immune control group ducks simultaneously.
2. 3 all intracranial inoculation checks are with strong poison (BYD-JXSP strain BHK-21 cell cultures the 3rd generation virus liquid that embodiment 2 makes, its virus titer>=10 after attacking malicious protection test immunity
5.5TCID
50/ mL, 0.1mL/ are only), continue to observe 14 days.4/10 duck occurred one crossing that property subtracts food in 3~8 days after immunity, the neck that contracts, clinical symptom such as rock, and did not have deadly in back 14 days to attacking poison, all survived.Cuing open inspection after slaughtering does not substantially see obviously unusual.It is positive that brain and spleen detect 0/10 in BYD virus (JXSP strain) and 1/10 with the fluorescence RT-PCR method.
Non-immune contrast duck is attacked back 9/10 duck morbidity of poison, 5/10 duck death.
Sick duck shows as: 1. clinical observation is seen the minimizing of searching for food, the neck that contracts, is trembled, walking step state is undesired, ataxy and paralysis etc.; 2. cut open inspection natural death duck splenomegaly, extravasated blood substantially, observation was slaughtered the duck eye to 14 days and is not seen obvious pathology; 3. apyetous encephalitis such as pathological study visible vessels oversleeve appearance glial cell invasion, glial cell invasion kitchen range change.
To the contrast duck that dies of illness duck and slaughtered in 14 days, it is positive that brain and spleen detect 8/10 in BYD virus (JXSP strain) and 9/10 with the fluorescence RT-PCR method.See table 5 for details.
Table 5 efficacy test result
4, confirm that duck morbidity standard does
Following 3 indexs meet 2, and decidable is the morbidity duck:
1. dead;
2. the minimizing of searching for food is seen in clinical observation; Occur contracting neck, tremble, nervous symptoms such as walking step state is undesired, ataxy and paralysis; The laying ducks egg number obviously descends, even is 0;
3. 8/10 above brain and spleen fluorescence RT-PCR detect the BYD virus-positive.
According to experimental result; It is thus clear that BYD-JXSP virus strain provided by the invention has good immunogenicity; Utilize the duck BYD viral inactivation vaccine of its preparation to be applied to duck, can effectively help the infection of host duck opposing BYD virus, and security is good; Untoward reaction can be do not caused, the prevention and control of the duck egg drop syndrome that the infection of duck BYD virus causes can be widely used in.