HRP20000774A2 - Immunization of chickens against new castle disease in hatchery - Google Patents

Description

Field of invention

A 61 D 7/00 Devices or procedures for administering drugs in solid, liquid or gaseous state or other substances into or onto the body of animals

A 61 K 39/17 Newcastle disease virus

Technical problem

Newcastle disease represents an exceptional health and economic problem in all countries of the world, regardless of whether it is intensive, farm or extensive, rural production. The pathogenic virus threatens all domestic poultry, but chickens and turkeys are the most susceptible (Alexander, 1997). Also, significant damage (death, drop in laying capacity) occurs in the conditional farming of feathered game. The disease is controlled by law, and on the list of the most important diseases that threaten the health of poultry, Newcastle disease is on the first place.

The disease is prevented by the use of non-specific technological procedures, but the most important is the specific immunoprophylaxis with the use of vaccines. "Live" strains of weakened (attenuated) viruses are used, which by themselves can cause a milder form of the disease, but not death. They are most suitable for giving to chickens or older poultry that have inherited or acquired specific antibodies, thus avoiding the possible harmful effect of vaccine strains. With regard to the method of administration, there are different methods of instillation of the vaccine virus through the oculonasal route, administration with drinking water, and the method of dispersing the aqueous suspension of the vaccine. Oculonasal application is avoided because it is individual and requires a lot of manpower, while the other two methods are mass procedures. The effect of oculonasal vaccination is very favorable, and specific resistance to the pathogenic virus occurs in seven days (Allan et al., 1978).

Application in drinking water is satisfactory only if there is no immediate danger from the disease, because resistance occurs after more than ten days, and contamination of water with chlorine or metals can reduce the concentration of the virus and interfere with the effect of the vaccine (Gramenzi, 1964).

The spraying procedure using aerosol particles with a diameter of 10 to 100 microns was found to be the most favorable (Narvaes, 1976). This procedure achieves the fastest protection in just 60 hours. Aerosol vaccination achieves entry of the virus and its adsorption in the front parts of the respiratory system, so the size of the particle is adapted to this need. It has been shown that droplets smaller than 10 μm are unacceptable because they enter deeper into the respiratory system and will cause clogging of respiratory capillaries in the lungs, often suffocation of chickens, or be the basis for the action of conditionally pathogenic microorganisms (Villegas et al., 1976; Gross, 1961. ). A very small particle with a diameter of less than 10 microns is not used in the vaccination of chickens for the already mentioned reasons, although it is described that the MASTERDROP® device, a mechanical device that forms particles with a size of less than 7 microns, and the aerosol is polydisperse and contains both larger and smaller particles than those listed . Meszaros et al. achieved satisfactory success with this device using their own strain of the NDV-6/10 virus (Meszaros et al., 1995). This virus is adapted to the digestive system in order to eliminate vaccine reactions of the respiratory system with its application. There is no description of administration of other lentogenic strains of Newcastle disease virus in the form of very small particles to newly hatched chicks.

PUBLICATIONS

1. Aleksander D.J. (1997): Newcastle Disease and other Avian Paramyxoviridae Infections., 541-569, in: Diseases of poultry, 10th Edition, Mosby-Wolfe, Iowa, USA.

2. Allan W.H. (1978): Nev/castle disease vaccines: Their production and use. FAO Animal Production and Health Series No. 10.

3. Gross, W.B. (1961): Escherichia coli as a complicating factor of Newcastle disease vaccination. Avian Diseases, 5.

4. Meszaros J., E. Horvath, E. Nagy (1995): Immunization Trials against Newcastle Disease with the VITAPEST® Vaccine Administered by Different Routes. Hungarian Agriculture Research.

5. Narvaez, P.V. (1976): Aerosol vaccination against Newcastle disease. Diss. Abstr. Int., 36B(9).

6. Villegas, P., S.H. Kleven, D.P. Anderson (1976): Effect of route of Newcastle disease vaccination on the incidence of airsacculitis in chickens infected with Mycoplasma synoviae. Avian Diseases, 20.

State of the art

Newcastle disease (NB) threatens poultry especially in areas where it is caused by highly velogenic strains of the virus. Chickens become infected already in the first days of life, regardless of the presence of inherited antibodies. The specific prevention of Newcastle disease comes down to the use of active and inactivated vaccines. Individual strains of the NB virus differ less genomically and more in terms of tropism and pathogenicity. That is why, in order to suppress the diseases that cause them, it is necessary to adapt the type of vaccine to them. This especially applies to the tropism of the virus because, for example, enterotropic vaccine viruses NB do not protect the respiratory system, but only the digestive system. The process of dispersing lentogenic vaccines against NB particles of size 20-150 μ is the most effective, but already La Sota or B1 strains can cause vaccine reactions, while milder ones, such as Ulster C2, are not suitable for vaccinating chickens with maternal antibodies. In the area where vrio velbgenic strains of VNB predominate, the early application of lentogenic strains is not enough for the specific protection of poultry until the end of fattening, and they should be revaccinated.

FOREIGN PATENTS

Patent US4235876, 25/11/1980, Gits, J., N. Zygraich: Live Newcastle disease virus vaccine.

Patent US4279893, 7/21/1981, Kreimer, J.K., Lj.S. Ageeva: Vaccine against Newcastle fowl disease, method for preparation and use thereof.

Patent US5250298, 5 October 1993, Gelb, J.: Live attenuated Newcastle disease virus vaccines and preparations thereof.

Patent US 5427791, 27.6.1995, Ahmad, J., J.M. Sharma: Embryonic vaccine against Newcastle disease.

Patent US5750111, 12.5.1998, Schrier, C.C.: Mild Newcastle disease virus vaccine.

The essence of invention

Until now, it was not known that day-old commercial chickens vaccinated with NB strain La Sota could survive the causative infection on the 42nd day after vaccination. It was also not known that day-old chicks could withstand exposure to vaccine aerosol for 300 seconds without any respiratory response. Fine particles of virus suspension produced in an ultrasonic nebulizer can penetrate very deep into the respiratory system by increasing the resorptive surface. Maternal antibodies do not inhibit the vaccine virus, and this keeps the level of HI antibodies relatively high/over a longer period. The resistance of chickens to the causative infection with the pathogenic VNB strain Herts 33 on the 42nd day after vaccination proves that the aerosol of fine particles opens up new possibilities in the control of ND, especially in regions where it is endemic. Day-old chicks vaccinated with the NB strain La sota virus can be successfully distributed to large farms or small producers (individual farmers or peasants).

APPLICATION

The purpose of these experiments is to demonstrate that the VNB strain La Sota can be safely administered to day-old commercial chickens in the form of an aerosol of particle size 2 to 5 μm in diameter, to prevent infection with the pathogenic virus NB strain Herts 33 at 42 days of age.

EXPERIMENT 1.

A study was conducted with the aim of proving that strains of the Newcastle disease virus (VNB) La Sota and B1 (Hitchner) can be given to newly hatched (0-24 hours) commercial chickens using an ultrasonic nebulizer SONOVAC 095®, which produces particles with a diameter of 2 -. 5 p,, safely protect chickens from the causative infection at the age of 42 days of life. The chickens were exposed to the aerosol of the aqueous suspension of the commercial vaccine PESTIKAL SPF LASOTA for 30 and 300 seconds, and the commercial vaccine PESTIKAL B1 SPF for 30 seconds, without negative clinical reactions. Chickens infected at the age of 21 and 42 survived i.m. infection with 6 log10 embryo LD VNB strain Herts 33.

The device SONOVAC 095® is an ultrasonic nebulizer that produces a monodisperse aerosol of an aqueous suspension of the Newcastle virus with 95% of particles with a diameter of 2 - 5^1. The nebulization intensity was adjusted to 5 ml per minute.

Eight vials of PESTIKAL® SPF LA SOTA vaccine, 1000 doses each, were suspended in 200 ml of distilled water. The virus content in 1 ml of the suspension thus amounted to 107.6 EID50. The vaccine is stabilized with PPGF stabilizer. Four vials of PESTIKAL® B1 SPF vaccine of 1000 doses were suspended in 100 ml of distilled water.

A total of 280 one-day-old (newly hatched) chicks were used in the experiment. 140 commercial broiler chickens (TP) were vaccinated with the PESTIKAL SPF LA SOTA vaccine, 70 commercial broiler chickens (TP) with the PESTIKAL B1 SPF vaccine, while 70 unvaccinated chickens served as controls. Chickens vaccinated with the PESTIKAL® SPF LA SOTA vaccine were divided into two subgroups of 70 chickens each and exposed to the vaccine aerosol for 30 seconds (TP1) and 300 seconds (TP2). Chickens vaccinated with the PESTIKAL B1 SPF vaccine are exposed to the vaccine aerosol for 30 seconds (TP3). Considering the nebulizing intensity of the device, chickens exposed to the aerosol for 30 seconds received 2.5x107.6 EID50 and those exposed for 300 seconds received 25x107.6 EID50 of the Newcastle disease virus.

Blood samples for serological tests (HI-test) were taken on the day of vaccination, and at weekly intervals until the 42nd day of age.

The challenging infection was carried out i.m. Day 21 (10 chickens from each group) and day 42 (15 animals from each group), including controls, using 106 LD50 Newcastle disease virus strain Herts 33. Blood samples were taken from surviving chickens 14 days after infection.

Exposure of chickens to an aerosol of Newcastle disease vaccine for either 30 or 300 seconds did not induce a negative vaccine reaction. The HI-titer of specific maternal antibodies was relatively high (3.5 log2).

In vaccinated chickens, the HI-titer dropped from 3.5 log2 on the day of vaccination to about 2.1 at day 7 of age in TP1, 2.0 in TP2 and 2.2 in TP3. After that, in the TP group of chickens, the titer increased on day 49 to 4.67 log2 in TP1, 4.13 log2 in TP2 and 4.58 in TP3. Chickens from the control group at the age of 14 days were free of specific antibodies.

Figure 1. HI-titer of specific antibodies in the sera of chickens after vaccination with PESTIKAL SPF LA SOTA 30 and 300 seconds.

HI titer (log 2)

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There was no difference between the challenge infection results on day 21 and day 42 after vaccination. All vaccinated chickens survived infection with 6 log10 LD50 VNB strain Herts 33, while control chickens died. The antibody titer determined after both challenge infections increased significantly to a value of 7.0 to 9.0 log2 in chickens infected on day 21, reaching a maximum value of 10.0 to 11.0 log2 in chickens infected on day 42.

EXPERIMENT 2.

An experiment was conducted with a vaccine against Newcastle disease strain La Sota given to one-day-old (newly hatched) chickens using an ultrasonic nebulizer SONOVAC 095®, which produces particles with a diameter of 2 - 5 μ (95%). Seven vials of PESTIKAL® SPF LA SOTA vaccine, 1000 doses each, were suspended in 175 ml of distilled water. The virus content in 1 ml of the suspension thus amounted to 107.6 EID50. The vaccine is stabilized with PPGF stabilizer.

A total of 250 one-day-old chicks were used in the experiment. 200 male light hybrid chickens were vaccinated, while 50 non-vaccinated chickens served as controls. Vaccinated chickens were divided into two groups of 100 chickens each and exposed to the vaccine aerosol for 30 seconds (LP1) and 300 seconds (LP2). Considering the nebulizing intensity of the device, chickens exposed to the aerosol for 30 seconds received 2.5x107.6 EID50 and those exposed for 300 seconds received 25x107.6 EID50 of Newcastle disease virus. Blood samples for serological tests (HI-test) were taken on the day of vaccination, and at weekly intervals until the 49th day of age.

The challenging infection was carried out i.m. Day 21, and day 42 (40 chickens from each vaccinated group), and 20 animals from the control group, using 106 LD50 Newcastle disease virus strain Herts 33. Blood samples were taken from surviving chickens 14 days after infection.

Exposure of chickens to an aerosol of Newcastle disease vaccine for either 30 or 300 seconds did not cause a negative vaccine reaction. The HI-titer of specific maternal antibodies was quite high (5.0 log2).

Both LP1 and LP2 groups of chickens had a similar HI-titer until day 21 after vaccination, which reached values of 5.11 and 4.7 log2, and until day 42 when the titer values dropped to 3.6 and 3.2 log2. Chickens from the control group at the age of 35 days were free of specific antibodies.

Figure 1. HI-titer of specific antibodies in the sera of chickens after vaccination with PESTIKAL® SPF LA SOTA 30 and 300 seconds vaccine

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There was no difference between the results of the causative infection on the 21st and 42nd days after vaccination. All vaccinated chickens survived the infection with 6 log10 LD50, while control chickens died. The antibody titer determined after both challenge infections increased significantly to a value of 7.0 to 9.0 log2 in chickens infected on day 21, reaching a maximum value of 10.0 to 11.0 log2 in chickens infected on day 42.

EXPERIMENT 3.

In the described study, an ultrasonic nebulizer SONOVAC® 095 was used to administer the vaccine, which produces particles of size 2-5 μ.

Five vials of each virus strain were dissolved in 100 ml of distilled water so that the virus content in 1 ml of the suspension was 106.5 EID50. Chickens are exposed to an aerosol for 60 seconds, i.e. an amount of 5x106.5 EID50 of the corresponding vaccine virus. The control group of chickens was exposed to the same procedure as the experimental groups, only distilled water was used.

One-day-old male chickens were divided into three groups and vaccinated with the original lentogenic strains of VNB, obtained from Nat. Vet. Crisp. Service Labs Ames Iowa. Group A with 103 chickens was vaccinated with lentogenic strain VNB, mark IRELAND-ULSTER-1968; group B with 105 chickens was vaccinated with the lentogenic strain VNB, designation NJ-LASOTA-1946; group C with 103 chickens was vaccinated with the lentogenic strain VNB, mark AUSTRALIA-QUEENSLAND-V4-1966. Group K served as an unvaccinated control.

Blood samples for serological tests (ELISA-test) were taken on the day of vaccination (20 chickens) to determine the titer of maternal antibodies, and then every week until the 56th day of age.

The ELISA antibody titer from the initial 3151, immediately after lying down, fell on the 21st day after vaccination in group A to 436, in group B to 308 and in group C to 1183, and then increased to 3999 in group A, 3328 in group B and 3291 in group C. The control group was free of specific antibodies on the 35th day of the experiment.

Figure 1. HI-titer of specific antibodies in chicken sera after vaccination with lentogenic strains of Newcastle disease virus.

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15 chickens from each group were separated at weekly intervals until day 49 and infected with 106 ELD5o velogenic Newcastle disease virus strain Herts 33 oculonasally.

Until the age of 49 days, the chickens of vaccinated groups A - Ulster (88%), group B - La Sota (98%) and group C - Queensland V4 (88%) survived the causative infection. The deaths were not caused by the causative infection.

In the control group, 56% of the chickens died, with the number of dead chickens increasing during the experiment.

The nebulization process did not cause any adverse reactions. Maternal antibodies in a high titer did not hinder the effect of the applied Newcastle disease virus strains, but induced long-term specific protection against the pathogenic virus. The difference in the tropisms of the viruses used, apparently due to the method of administration, did not affect the immune response.

EXPERIMENT 4.

An experiment was conducted with a vaccine against Newcastle disease strain La Sota, given to newly hatched (0-24 hours) broilers using an ultrasonic nebulizer SONOVAC 095®, which produces particles with a diameter of 2 - 5 μ (95%).

An aqueous suspension of Newcastle disease virus strain La Sota was prepared so that 1 ml contained 107 EID50 viruses. 180 one-day-old (newly hatched) chickens were used in the experiment. An experimental group with 90 chickens was exposed to the vaccine aerosol for 30 seconds. The control group with 90 chickens was exposed to the same procedure as the experimental group, except that distilled water was used.

Blood samples for serological tests (ELISA test) were taken on the day of vaccination (20 chickens) to determine the titer of maternal antibodies, and weekly until the 49th day of age.

The challenging infection was carried out i.m. every week (10 animals from both groups) until day 42 of age, including controls, using 106 LD50 of Newcastle disease virus strain Herts 33. Blood samples were taken from surviving animals on day 10 post-infection.

Out of 90 vaccinated chickens, 88 survived the causative infection, while one chicken died and one showed signs of disease, which was not related to Newcastle disease or vaccination. In the control group with 90 chickens, 49 survived the causative infection, 39 died, and 2 chickens showed clinical signs of Newcastle disease.

In vaccinated chickens, the ELISA antibody titer increased during the first week, then decreased until day 21 with an increase on day 35 after vaccination. In the control group, the chickens were free of specific antibodies on the 28th day. The challenge infection induced antibody production in both groups, with a maximum ELISA-titer value of 30014 in chickens infected on day 28 after vaccination.

Newcastle disease virus strain La Sota, applied in the form of an aerosol using the ultrasonic nebulizer SONOVAC 095® is a safe and highly effective procedure for the specific protection of day-old chicks with inherited maternal antibodies. Chickens are protected from infection with Newcastle disease virus strain Herts 33 until the age of at least 42 days.

Claims (7)

1. Procedure for immunization of chickens against Newcastle disease in the hatchery, indicated by the fact that one-day-old chicks originating from immune parents are vaccinated using the lentogenic strain of the Newcastle disease virus La Sota (VNB) sprayed in the form of a flue aerosol with a droplet size of 2-5 μm. 2. The process of immunization of chickens against Newcastle disease in the hatchery, indicated by the fact that one-day-old chicks originating from immune parents are vaccinated using the lentogenic strain B1 of the Newcastle disease virus (VNB) sprayed in the form of a fine aerosol with a droplet size of 2-5 μm. 3. Procedure for immunization of chickens against Newcastle disease in the hatchery, indicated by the fact that one-day-old chicks originating from immune parents are vaccinated using the lentogenic strain of the Ulster 2C Newcastle disease virus (VNB) sprayed in the form of a fine aerosol with a droplet size of 2-5 μm. 4. Procedure for immunization of chickens against Newcastle disease in the hatchery, indicated by the fact that newly hatched chickens (aged 0-24 hours) originating from immune parents are vaccinated using the lentogenic strain of Queensland V4 Newcastle disease virus (VNB) sprayed in the form of a fine aerosol with the size droplet 2-5 μm. 5. The method, according to patent claims 1 - 4, characterized in that a fine aerosol with a droplet size of 2 - 5 μm is created using an ultrasonic nebulizer. 6. The method, according to patent claims 1 - 4, characterized in that the chickens are exposed to a fine aerosol in a chamber in which the space is saturated with aerosol, for a duration of 5 to 120 seconds, most often 15-30 seconds. 7. The method according to patent claims 1 - 4, characterized in that the concentration of vaccine viruses ranges from 106 to 109 EID50, most often 107.5 to 108 EID50.