960
M. A. MACKENZIE AND B. S. BAINS
serotypes to the organization. Dissemination of Salmonella to the carcases would be effectively reduced, resulting in a subsequent reduction of the carcase contamination rates. REFERENCES Bains, B. S., and M. A. MacKenzie, 1974. Transmission of Salmonella through an integrated poultry organization. Poultry Sci. 53: 1114-1118. Morris, G. K., B. L. McMurray, M. M. Galton and J. G. Wells, 1969. A study of the dissemination of Salmonellosis in a commercial broiler chicken operation. Am. J. Vet. Res. 30: 1413-1421. Snoeyenbos, G. H., B. A. McKie, C. F. Smyser and C. R. Weston, 1970. Progress in identifying and maintaining Salmonella-free commercial chicken breeding flocks. 1. 1967-1969. Av. Dis. 14: 683-696. Woodburn, M., 1964. Incidence of Salmonellae in dressed broiler-fryer chickens. Appl. Microbiol. 12: 492-495.
Vaccination of Chickens Against Marek's Disease with the Turkey Herpesvirus Vaccine Using a Pneumatic Vaccinator C. S. EIDSON AND S. H . KLEVEN
Poultry Disease Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30601 (Received for publication August 12, 1975)
ABSTRACT A pneumatic vaccinator has been successfully used to administer cell-associated turkey herpesvirus (HVT) vaccine without a loss in titer due to the pressure required to administer the vaccine. Laboratory studies have also shown that chickens vaccinated with graded doses of the HVT vaccine using doses as low as 41 PFU offered protection against Marek's disease (MD) when compared to the unvaccinated controls. The pneumatic vaccinator has also been successful in administering a combination of HVT vaccine and tissue culture fowl pox vaccine. Vaccinated birds were protected against challenge with virulent MD virus as well as fowl pox virus. Antibiotics such as spectinomycin pentahydrate or lincomycin hydrochloride monohydrate and spectinomycin sulfate tetrahydrate were used in combination with the HVT and fowl pox vaccine and none of the antibiotics appear to have an adverse effect on the efficacy of either vaccine. POULTRY SCIENCE 55: 960-969, 1976
INTRODUCTION KAZAKI et al. (1970) using a turkey herpesvirus (HVT) isolated from turkeys by Witter et al. (1970), and Eidson and Anderson (1971) using a turkey herpesvirus
O
isolated by Kawamura et al. (1969) found that HVT, administered intraabdominal^ or subcutaneously protected chickens against Marek's disease (MD). This vaccine is most effective when inoculated parenterally at 1 day of age (Eidson et al., 1971, 1973a, b).
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
isolated from the grains; Salmonella typhimurium from wheat was responsible for a number of clinical outbreaks of salmonellosis in day-old broiler flocks, resulting in S. typhimurium isolations from carcases in this period (Bains and MacKenzie, 1974). Salmonella levels on carcases may therefore be reduced by restricting the dissemination of serotypes throughout the organization from contaminated meals and grains. This is achieved to some extent by the pelletizing of all feeds, including breeder rations. However, the risk of cross contamination from infected raw ingredients stored in the vicinity is high. If raw feed ingredients could be rendered Salmonella-free prior to arrival at the feed plant, this, in combination with the pelletizing of all feeds, would reduce to a minimum the risk of introducing Salmonella
PNEUMATIC VACCINATOR
The object of this report is to present data on a pneumatic vaccinator which was used to vaccinate one-day-old chickens with HVT and fowl pox vaccines or in combination with antibiotics (spectinomycin pentahydrate or lincomycin hydrochloride and spectinomycin sulfate tetrahydrate). MATERIALS AND METHODS Source of HVT Vaccine. The HVT used throughout this study was the FC 126 strain,
which was supplied by Dr. William Okazaki, East Lansing, Michigan. The cell-associated HVT vaccine was prepared as previously described by Eidson et al. (1973a). Each ampule contained approximately 3.6 x 106 plaque forming units (PFU) of HVT. The cell-free HVT vaccine was prepared by suspending HVT-infected chicken embryo fibroblasts in a stabilizer designated as SPA (Calnek et al., 1970). The cellular suspension was treated by sonication and lyophilized. The lyophilized HVT vaccine contained approximately 3.9 x 106 PFU of HVT per vial. Virus Assay. The cell-associated and cellfree HVT vaccines were titrated as previously described by Eidson et al. (1973a). The titers of the cell-associated HVT vaccine were determined after 5 days incubation; whereas, the titers of the cell-free HVT vaccine were obtained after 6 to 7 days. A mean plaque count from 2 plates from the virus dilution was used to determine the titer. Source of Chickens. A flock of White Leghorn chickens derived from Poultry Disease Research Center stock was maintained in a filtered-air, positive-pressure poultry house. These birds were free of most recognized poultry pathogens, including resistant-inducing factor (RIF) viruses and MD virus. Pneumatic Vaccinator.1 The vaccinator consists of a compressor, control box and jet applicator. The air pressure of an individual vaccinator is produced by a one-half horsepower compressor. The control box contains an activator switch, a counter which records the number of chicks vaccinated, and a pressure regulator which can adjust the air pressure from 0 to 4,000 pounds per square inch (p.s.i.). The sensitivity tolerance of the triggering mechanism is maintained at 1 and 2 ounces. 1. Avijet, Mizzy, Inc., New York, N.Y.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
Although vaccination against MD with the HVT vaccine has proven to be safe, effective and economically useful, interest continues in finding more desirable and less expensive methods of vaccine administration. Zander et al. (1972) isolated an avirulent MD virus from the blood of otherwise specific pathogen-free chickens. This virus was safe and provided effective protection against the virulent MD virus. The avirulent MD vaccine when administered subcutaneously as a suspension of freshly drawn citrated blood was effective whether all or only a small percentage of the flock was inoculated indicating that the virus was readily transmitted within the flock. A vaccine such as described by Zander would be beneficial in reducing the cost of administering the vaccine as well as reducing the cost of the vaccine itself, since only a portion of each flock would be vaccinated; however, the vaccine has not been licensed by the U.S.D.A. Unless a vaccine of this type is approved, it is unlikely that a less expensive MD vaccine will be available in the near future. Therefore, attention must be given to reducing the cost of administering presently available vaccines. In an attempt to reduce administration cost, Eidson et al. (1973b) showed that some antibiotics could be mixed with the HVT vaccine for simultaneous inoculation into day-old chicks without interfering with the performance of the HVT vaccine.
961
962
C. S. ElDSON AND S. H . KLEVEN
EXPERIMENTAL DESIGN Trial 1. To determine the effect of the pneumatic vaccinator on the titer of the cell-associated HVT vaccine, one vial of HVT vaccine was mixed in 200 ml. of tryptose phosphate broth and immediately titrated. Two ml. of the diluted HVT were passed through the pneumatic vaccinator at 950 p.s.i. through a 0.006 inch orifice and immediately titrated. For comparative purposes the diluted HVT vaccine was passed through a 2 ml. tuberculin syringe fitted with a 20 gauge needle. Two ml. of the vaccine were collected and the HVT virus was titrated. The above procedures were repeated 5 times with the same vial of vaccine, and the results of each treatment group for the 5 experiments were averaged. All of the vaccine samples were titrated on 18 hour chick embryo fibroblast monolayers as described above. Trial 2. In this study 12 groups of day-old chicks (20/group) were vaccinated with either the pneumatic vaccinator (intraabdominal) or by the conventional syringe and needle method (subcutaneous) with graded doses (41
to 1,500 PFU/0.1 ml.) of cell-associated HVT vaccine. Two groups (20/group) of chickens served as unvaccinated controls. All of the chickens were challenged at 2 weeks of age with 0.2 ml. of MD-infective plasma. The trial was terminated at the 6th post-challenge week, and the chickens were examined for gross MD lesions. Trial 3. Two groups of day-old chicks (20/group) were vaccinated subcutaneously with 1,000 PFU of cell-associated HVT vaccine with the conventional syringe and needle. Two groups (20/group) were infected intraabdominally with 1,000 PFU of HVT vaccine with the pneumatic vaccinator while two other groups (20/group) of chickens were injected intramuscularly with 1,000 PFU of HVT vaccine with the pneumatic vaccinator. The birds vaccinated with the pneumatic vaccinator were injected with 0.1 ml. of HVT vaccine at 950 p.s.i. The 2 remaining groups (20/group) of chickens served as unvaccinated controls. All of the chickens were challenged at 2 weeks of age with 0.2 ml. of MD-infective plasma. The trial was terminated 6 weeks post vaccination and all birds were examined for macroscopic lesions of MD. Trial 4. To evaluate the efficacy of the cell-free and cell-associated HVT vaccines administered by the pneumatic vaccinator, 4 groups of day-old chicks (20/group), were vaccinated with 1,000 PFU of the cell-free HVT vaccine with either the pneumatic vaccinator (2 groups) or conventional syringe and needle (2 groups). Four other groups of chickens (20/group) were vaccinated with 1,000 PFU of the cell-associated HVT vaccine with either the pneumatic vaccinator (2 groups) or the conventional syringe (2 groups). The remaining 2 groups of chickens (20/group) served as unvaccinated controls. One group of birds from each treatment group was challenged subcutaneously at 2
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
The jet applicator has an orifice opening of 0.006 inches which can deliver from 0 to 0.5 ml. of vaccine. The amount of fluid dispersed by the jet is easily regulated by a micrometer. The head of the jet contains the triggering mechanism and injection is achieved by placing the breast of the chick to the pressure sensitive trigger muzzle. In order to determine whether the jet has fired, a red light mounted on the side of the jet applicator flashes as the triggering head is depressed. The vaccinator has a cyclic rate of 3600 shots per hour; whereas, the device with two heads is capable of 7200 shots per hour. The device equipped with 2 jet applicators can be used by a single operator in conjunction with a chick debeaker.
PNEUMATIC VACCINATOR
weeks of age with MD-infective plasma. The remaining groups of birds were exposed at 2 weeks of age to MD virus by contact exposure to infected chickens. The infected chicks were hatchmates that had been inoculated subcutaneously with MD-infective plasma at one day of age. Five of the 2-week-old infected birds were placed with the test birds. All of the birds were killed at the 9th postchallenge week and were examined for macroscopic lesions of MD.
Trial 6. The design of this experiment was the same as in Trial 5 with the exception that a combination of 2-1/2 mg. lincomycin hydrochloride monohydrate and 5 mg. spectinomycin sulfate tetrahydrate was used in
2. Sterwin Laboratories, Inc., Millsboro, Delaware 19966. 3. Spectam, Abbott Laboratories, North Chicago, Illinois 60064.
place of spectinomycin dihydrochloride pentahydrate. 4 One group of chickens (30/group) from each of the treatment groups were challenged with 0.2 ml. of MD-infective plasma at 3 weeks of age while the remaining groups of chickens were challenged at 3 weeks of age with virulent fowl pox virus. All of the birds in Trials 5 and 6 challenged at 3 weeks of age with fowl pox virus were examined for lesions 5 to 10 days postchallenge while those challenged with MD virus were necropsied at the 6th postchallenge week and were examined for macroscopic MD lesions. Trial 7. Farms with two poultry houses were selected for these field trials so that birds vaccinated with the pneumatic vaccinator could be compared with those vaccinated with the conventional syringe and needle. On each farm each treatment group was placed in separate houses to eliminate mixing of birds vaccinated by either the pneumatic vaccinator or by syringe and needle. All of the houses used in this study were of conventional curtain-type with dirt floors. No attempt was made to change the usual husbandry procedures. None of the houses were cleaned prior to the placement of the chicks except for the addition of a layer of new shavings on the old litter. All of the birds were vaccinated at 1 day of age with 1,000 PFU of cell-associated HVT vaccine. The chickens vaccinated with the pneumatic vaccinator were either vaccinated intraabdominally or intramuscularly; whereas, those vaccinated with the syringe and needle were injected subcutaneously. No unvaccinated controls were used in this study because of the inevitable losses that would be incurred as a result of MD. All of the birds were processed between 7-1/2 and 8
4. LSSJ, TUCO, Division of the Upjohn Company, Kalamazoo, Mich. 49001.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
Trial 5. In this study, day-old chicks (30/group) were vaccinated with tissue culture fowl pox vaccine (EID J 0 10 5 3 /ml., 500 dose ampule was administered to 1000 chickens), cell-associated HVT vaccine (1,000 PFU) or a combination of tissue culture fowl pox vaccine, 2 HVT and 5 mg. spectinomycin pentahydrate. 3 The antibiotic was added because the severity of some diseases can be lessened if the antibiotic is administered at one day of age. The tryptose phosphate broth diluent was buffered to pH 6.8 with sodium bicarbonate following the addition of the antibiotic. After the antibiotic and sodium bicarbonate were in suspension, the fowl pox vaccine (EID 50 103 °, one-half bird dose) and 1,000 PFU of HVT per bird dose were added to the diluent. Chickens from each of the test groups were vaccinated with each of the vaccines or combination of vaccines and antibiotics with either the pneumatic vaccinator or the conventional syringe and needle.
963
C. S. ElDSON AND S. H. KLEVEN
964
weeks of age. Each group of chickens was identified separately as the birds were loaded and transported to the processing plant. Personnel of the Consumer and Marketing Service of the U.S.D. A. provided the inspection data. RESULTS
Trial 2. Data presented in Table 2 shows that birds vaccinated by the pneumatic vaccinator with 1,500 or 750 PFU of HVT/bird dose did not have any gross lesions of MD at the end of the 8 week experimental period; however, birds receiving 325, 163, 82 or 41 PFU had MD lesions in 2/20, 2/18, 2/20 and 4/20 birds, respectively. Chickens vaccinated by the syringe and needle with the same levels of HVT vaccine had similar results. The results show that all levels of the
TABLE 1.—Effect of the pneumatic vaccinator on the titer of cell-associated HVT vaccine Treatment
PFU/bird dose' 3800 3740
None Passage through 20 gauge needle Passage through pneumatic vaccinator 3660 'Average of 5 trials with same vial of HVT vaccine.
PFU/bird Vaccination dose equipment Pneumatic vaccina1500 tor Pneumatic vaccina750 tor Pneumatic vaccina375 tor Pneumatic vaccina188 tor Pneumatic vaccina94 tor Pneumatic vaccina47 tor Conventional 1500 syringe Conventional 750 syringe Conventional 375 syringe Conventional 188 syringe Conventional 94 syringe Conventional 47 syringe 0 Not vaccinated 0 Not vaccinated
No. MD lesions / n o . started 0/172 0/20 2/20 2/18 2/20 4/20 1/20 0/20 1/19 2/20 3/20 4/20 9/19 8/18
'All birds were challenged subcutaneously at 2 weeks of age with 0.2 ml. MD-infective plasma. 2 Not including birds dying before 2 weeks of age.
vaccine were effective regardless of the method used to vaccinate the birds since 9/19 and 8/18 of the nonvaccinated birds developed gross lesions of MD after challenge. Trial 3. In an attempt to ascertain the most effective site for administering the HVT vaccine with the pneumatic vaccinator, chickens were vaccinated either intraabdominally or intramuscularly. In chickens vaccinated intraabdominally 1 /17 and 2/19 developed MD lesions after challenge while 2 of 20 and 0/20 of those vaccinated intramuscularly were susceptible to MD challenge during the 8 week experimental period. Similarly, 1/18 and 0/20 of the chickens vaccinated subcutaneously with the syringe
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
Trial 1. Results presented in Table 1 show that immediately after the HVT vaccine was resuspended in tryptose phosphate broth the titer was 3,800 PFU/bird dose. This was the average of 5 titrations with the same vial of vaccine. Two ml. of the diluted HVT vaccine collected after passage through a 2 ml. syringe fitted with a 20 gauge needle had a titer of 3,740 PFU/bird dose. In comparison 2 ml. of diluted vaccine was passed through the pneumatic vaccinator and the average of the 5 titrations was found to be 3,660 PFU/bird dose.
TABLE 2.—MD lesions at 8 weeks of age in chickens vaccinated (0.1 ml.) with graded doses of HVT with the pneumatic vaccinator or conventional syringe method at 1 day of age1
965
PNEUMATIC VACCINATOR
TABLE 3.—Efficacy of HVT vaccine in day-old chicks when administered intraabdominal or intramuscularly with the pneumatic vaccinator or subcutaneously with a needle and syringe
and needle developed macroscopic lesions. However , 9 / 1 8 and 8 / 20 of the unvaccinated controls developed MD lesions (Table 3). Trial 4. In comparing the efficacy of the cell-free HVT vaccine with the cell-associated HVT vaccine when administered with either the pneumatic vaccinator or syringe
Trial 5. Chickens vaccinated by the pneumatic vaccinator with fowl pox vaccine were protected against challenge by virulent fowl pox virus; however, 19 of 29 chickens vaccinated with fowl pox but not the HVT vaccine developed gross lesions of MD. None
TABLE 4.—MD lesions at 11 weeks of age in chickens vaccinated at 1 day of age by the pneumatic vaccinator or needle and syringe with cell-associated or cell-free HVT vaccine
Vaccination equipment
Vaccine'
Method of challenge 2
No. MD lesions/no. started
C-F3 0/19 Contact Pneumatic vaccinator C-F 0/20 Plasma Pneumatic vaccinator C-A" 1/19 Contact Pneumatic vaccinator C-A 0/20 Plasma Pneumatic vaccinator C-F 0/18 Contact Conventional syringe C-F 1/20 Plasma Conventional syringe C-A 0/17 Contact Conventional syringe C-A 0/20 Plasma Conventional syringe None 8/20 Contact Not vaccinated None 11/19 Plasma Not vaccinated 'Birds vaccinated with approximately 1,000 PFU of cell free or cell-associated HVT vaccine. 2 All birds were challenged at 2 weeks of age either by contact exposure to MD infected chickens or 3by injecting the birds subcutaneously at 2 weeks of age with 0.2 ml. of MD-infective plasma. C-F = cell-free HVT vaccine. 4 C-A = cell-associated HVT vaccine.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
No. MD lesions/no. Route of vaccination started' Intraabdominal2 1/17 Intraabdominal 2/19 Intramuscular2 2/20 Intramuscular 0/20 Subcutaneous3 1/18 Subcutaneous 0/20 Not vaccinated 9/18 Not vaccinated 8/20 'All birds were challenged at 2 weeks of age with 0.2 ml. of MD-infective plasma. The trial was terminated at 8 weeks of age. 2 Birds vaccinated with 1,000 PFU of HVT vaccine with the pneumatic vaccinator (950 P.S.I.). 3 Birds vaccinated subcutaneously with 1,000 PFU of HVT vaccine with the conventional syringe and needle.
and needle, the results in Table 4 show that 1,000 PFU of either vaccine was effective in preventing gross lesions of MD regardless of the method used in administering the vaccine. None of the 3 groups of chickens vaccinated by the pneumatic vaccinator with the cell-free HVT had gross MD lesions and only one chicken from the 2 groups vaccinated with cell-associated HVT had gross lesions of MD. One bird from the group vaccinated by the needle and syringe with cell-free HVT had gross lesions, while none of the birds vaccinated with the cell-associated HVT had gross lesions of MD. Eight of twenty of the unvaccinated control birds exposed by contact exposure to the MD virus had gross lesions by 9 weeks postchallenge. Eleven of nineteen of the unvaccinated control chickens exposed to the MD virus by subcutaneous inoculation developed gross lesions.
C. S. ElDSON AND S. H. KLEVEN
966
TABLE 5.—Marek's disease or fowl pox challenge results in chicks vaccinated against HVT, fowl pox, or spectinomycin (alone or in combination) with the pneumatic vaccinator
Vaccine ppi
FP4 FP FP FP FP MDV 5 MDV MDV MDV
—
No. + / no. started Fowl pox
MD
0/30 28/28 1/30 0/27 29/30
— — — — —
— — — — —
19/29 0/28 1/26 0/30 21/30
i FP = Tissue culture fowl pox, 1 /2 broiler dose was injected intramuscularly at one day of age. HVT was injected subcutaneously at one day of age.
2 1,000 PFU of 3 5 mg. /bird. 4
Birds challenged by scarifying the comb at 3 weeks of age with fowl pox. 'Birds challenged at 3 weeks of age with 0.2 ml. of MD-infective plasma.
TABLE 6.—Marek's disease or fowl pox challenge results in chicks inoculated with HVT or fowl pox vaccine or spectinomycin (alone or in combination) by needle and syringe No. + / n o . started Vaccine ppi
HVT 2 FP + HVT FP + HVT + Spectinomycin 3 Control FP HVT FP + HVT FP + HVT + Spectinomycin Control
Challenge
Fowl pox
MD
FP4 FP FP FP FP MDV 5 MDV MDV MDV MDV
1/30 28/29 0/30 1/30 30/30
— — — — —
— — — — —
18/28 0/29 0/27 0/24 24/29
'FP = Tissue culture fowl pox, 1/2 broiler dose was injected subcutaneously at one day of age.
2 l,000PFU/birddose. 3 5 mg./dose. 4 Birds challenged by scarifying 5
the comb at 3 weeks of age with fowl pox. Birds challenged at 3 weeks of age with 0.2 ml. of MD-infective plasma.
of the chickens vaccinated with HVT vaccine were protected against fowl pox; whereas, all of the birds vaccinated with the HVT vaccine were protected against challenge with the MD virus. The results in Table 5 also show that birds vaccinated simultaneously at one day of age with fowl pox and HVT vaccine or a combination of fowl pox, HVT and spectinomycin pentahydrate were protected against MD virus as well as virulent fowl pox virus. Twenty-nine of 30 of the
unvaccinated control chickens challenged with fowl pox developed lesions within 10 days postchallenge. Also, 21 of 30 of the unvaccinated controls challenged with the MD virus developed MD lesions. Results of birds vaccinated with a needle and syringe (Table 6) are essentially the same as the results shown in Table 5. Trial 6. The results in this trial (Tables 7 & 8) were essentially the same as those
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
HVT 2 FP + HVT FP + HVT + spectinomycin 3 Control FP HVT FP + HVT FP + HVT + spectinomycin Control
Challenge virus
967
PNEUMATIC VACCINATOR
TABLE 7.—Marek's disease of fowl pox challenge results in chicks vaccinated against HVT, fowl pox or lincomycin-spectinomycin (alone or in combination) with the pneumatic vaccinator No. + / n o . started
Vaccine
hallenge
Fowl pox
MD
— — — — — 16/29 0/28 1/26 0/30 19/30
day of age.
TABLE 8.—Marek's disease or fowl pox challenge results in chicks inoculated with HVT or fowl pox or lincomycin-spectinomycin by the needle and syringe
Vaccine
hallenge
No. + / n o . started Fowl pox MD
FP1 FP 4 4/30 — HVT2 FP 28/29 — FP + HVT FP 3/30 — 3 FP + HVT + LS50 Fp 2/30 — FP Control 30/30 — 15/28 MDV 5 FP — 0/20 MDV HVT — 0/29 MDV FP + HVT — 0/30 MDV FP + HVT + LS 50 — 21/28 MDV Control — i FP = Tissue culture fowl pox, 1 /2 broiler dose was injected subcutaneously at one day of ; 2 1,000 PFU/bird dose. 3 5 mg. spectinomycin + 2-1/2 mg. lincomycin/dose. "Birds challenged by scarifying the comb at 3 weeks of age with fowl pox. 5 Birds challenged at 3 weeks of age with 0.2 ml. of MD-infective plasma.
obtained in trial 5. The results indicated that chicks vaccinated with a combination of fowl pox, HVT or lincomycin hydrochloride monohydrate and spectinomycin sulfate tetrahydrate were protected against MD challenge as well as challenge with the virulent fowl pox virus. Trial 7. Table 9 gives results from the field trial in which all birds were vaccinated with
1,000 PFU of cell-associated HVT vaccine administered by either the pneumatic vaccinator or by syringe and needle. Chickens vaccinated with the pneumatic vaccinator had an average MD incidence of 0.07% and a range of 0.0 to 0.19% for all of the farms in the trial. Condemnations from all causes was found to be 1.93%. In contrast, chickens vaccinated with the conventional needle and syringe had an average incidence of 0.6%
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
FP> FP 4 0/30 HVT2 FP 28/28 FP + HVT FP 1/30 FP 0/27 FP + HVT + LS503 FP 29/30 Control MDV 5 FP — MDV HVT — MDV FP + HVT — MDV FP + HVT + LS 50 — MDV — Control 'FP = Tissue culture fowl pox, 1/2 broiler dose was injected intramuscularly at one 2 1,000PFU/bird dose. 3 5 mg. spectinomycin + 2-1/2 mg. lincomycin/dose. 4 Birds challenged by scarifying the comb at 3 weeks of age with fowl pox. 5 Birds challenged at 3 weeks of age with 0.2 ml. of MD-infective plasma.
968
C. S. ElDSON AND S. H. KLEVEN TABLE 9.—Effect
Vaccination equipment Pneumatic vaccinator Conventional syringe
of vaccination of chicks with HVT vaccine at one day of age with pneumatic vaccinator or by needle and syringe (field trial)1 No. birds
Average weight
76,480 84,000
4.04 4.02
Leukosis condemnation
Total condemnation
No.
%
No.
%
56 136
0.07 0.16
1,480 1,428
1.93 1.82
'All birds vaccinated with approximately 1,000 PFU of cell-associated HVT vaccine.
DISCUSSION Eidson et al. (1973a) in conducting field studies to determine the efficacy of the HVT vaccine in broilers instructed vaccinating crews in the correct way to vaccinate oneday-old chicks subcutaneously with HVT vaccine. The vaccination equipment consisted of an automatic 2 ml. syringe fitted with a 20 gauge, one-half inch needle. The vaccinator's only job was to vaccinate chickens. A new innovation in vaccination equipment for poultry was recently developed with chickens being vaccinated without the aid of a needle. The vaccination equipment is placed so that the operator can debeak and vaccinate each bird. Concern had arisen as to whether the cell-associated HVT vaccine would be inactivated with the use of the pneumatic vaccinator since the cells may be ruptured as they passed through the 0.006 inch orifice at a pressure of 950 pounds per square inch. However, laboratory studies have revealed that the titer of the HVT vaccine was not reduced by the pressure used to administer the vaccine. Also, chickens vaccinated by the pneumatic vaccinator with the HVT vaccine were protected against challenge to the virulent MD virus. These studies have also shown that chickens vaccinated with graded doses of HVT vaccine, using doses as low as 41 PFU, offered protection against MD
when compared to the unvaccinated controls that were challenged at 2 weeks of age with MD-infective plasma. The results were essentially the same regardless of whether the pneumatic vaccinator or the conventional syringe and needle were used to administer the graded doses of HVT vaccine. The HVT vaccine was effective regardless of whether the vaccine is administered intraabdominally or intramuscularly. The pneumatic vaccinator has proven to be successful in administering the cell-free HVT vaccine as well as the cell-associated HVT vaccine; however, one of the disadvantages of the pneumatic vaccinator is that if the cell-associated HVT vaccine has large clumps of cells, the orifice of the pneumatic vaccinator may become clogged and only a partial dose of vaccine or no vaccine at all will be delivered. Birds vaccinated with a combination of fowl pox (500 dose ampule was administered to 1000 chickens) and HVT (1000 PFU/bird dose) vaccine were protected against challenge from virulent MD virus or the fowl pox virus for the 8 week experimental period. One-half broiler dose of the tissue culture fowl pox was administered because this is the level of the fowl pox being used in the field by many companies to vaccinate broiler chicks. The fowl pox vaccine derived from chick embryos has been used in the pneumatic vaccinator, but with the clumps of cellular material in the vaccine the vaccinator often clogs and will not operate properly. Spectinomycin pentahydrate (5 mg./bird dose) or lincomycin hydrochloride monohydrate (2-
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
and a range of 0.03 to 0.34% for all of the farms in this trial. The total condemnations rate for this group was 1.82%.
969
PNEUMATIC VACCINATOR
1/2 mg./bird dose) and spectinomycin sulfate tetrahydrate (5 mg./bird dose) was used in combination with the HVT (1,000 PFU/bird dose) and fowl pox (500 dose ampule was administered to 1000 chickens) vaccine, and neither of the antibiotics had an adverse effect on the efficacy of the HVT or fowl pox vaccines as determined by the challenge results with virulent fowl pox or Marek's disease virus.
During this study it was found that there were several mechanical deficiencies in the pneumatic vaccinator. It was found that if the birds were moved during vaccination, the skin could be torn. It was also found that the triggering mechanism could be released by the feet of the chick resulting in unsatisfactory vaccination. Also, if the instrument became clogged there was no safety device to warn the vaccinator. All of these deficiencies were corrected during these field studies.
Calnek, B. W., S. B. Hitchner and H. K. Adldinger, 1970. Lyophilization of cell-free Marek's disease herpesvirus and herpesvirus from turkeys. Appl. Microbiol. 20: 723-725. Eidson.C. S.,andD.P. Anderson, 1971. Immunization against Marek's disease. Avian Dis. 15: 68-81. Eidson, C. S., D. P. Anderson, S. H. Kleven and J. Brown, 1971. Field trials of vaccines for Marek's disease. Avian Dis. 15: 312-322. Eidson, C. S., D. D. King, H. E. Connell, D. P. Andersonand S. H. Kleven, 1973. Efficacy of turkey herpesvirus vaccine against Marek's disease in broilers. Poultry Sci. 52: 1482-1491. Eidson, C. S., S. H. Kleven and D. P. Anderson, 1973a. Efficacy of cell-free and cell-associated herpesvirus of turkeys vaccines in progeny from vaccinated parental flocks. Am. J. Vet. Res. 34: 869-872. Eidson, C. S., S. H. Kleven and D. P. Anderson, 1973b. Effect of antibiotics on turkey herpesvirus vaccine. Poultry Sci. 52: 755-760. Kawamura, H., D. J. King, Jr. and D. P. Anderson, 1969. A herpesvirus isolated from kidney cell cultures of normal turkeys. Avian Dis. 13: 853-863. Okazaki, W., H. G. Purchase and B. R. Burmester, 1970. Protection against Marek's disease by vaccination with a herpesvirus of turkeys. Avian Dis. 14: 413-429. Witter, R. L., K. Nazerian, H. G. Purchase and G. H. Burgoyne, 1970. Isolation from turkeys of a cell-associated herpesvirus antigenically related to Marek's disease virus. Am. J. Vet. Res. 31:525-538. Zander, D. V., R. W. Hill, R. G. Raymond, R. K. Balch, R. W. Mitchell and J. W. Dunsing, 1972. The use of blood from selected chickens as an immunizing agent for Marek's disease. Avian Dis. 16: 163-186.
NEWS AND NOTES (Continued from page 935) CARGILL NOTES Edward E. Reynolds has been elected Corporate Vice President in charge of the Poultry Products Division of Cargill, Inc. He joined Cargill at Minneapolis in 1966 and was appointed Assistant Vice President and General Manager of the Food Products Department. He became Division Vice President in
1972. He is a Director of the National Broiler Council and the Poultry and Egg Institute of America. Previously he was a Vice President for Central Soya Company. COMMITTEE ON REGULATORY PROGRAMS Secretary of Agriculture Earl L. Butz has appointed
(Continued on page 974)
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
Limited field trials indicate that birds vaccinated by the pneumatic vaccinator were as well protected against MD as those vaccinated with the conventional syringe and needle method. One of the weaknesses of these field trials is that there were no unvaccinated controls. Birds vaccinated with the pneumatic vaccinator were placed on the same farm with birds vaccinated with the conventional syringe and needle, but they were placed in separate houses.
REFERENCES
M. A. MACKENZIE AND B. S. BAINS
serotypes to the organization. Dissemination of Salmonella to the carcases would be effectively reduced, resulting in a subsequent reduction of the carcase contamination rates. REFERENCES Bains, B. S., and M. A. MacKenzie, 1974. Transmission of Salmonella through an integrated poultry organization. Poultry Sci. 53: 1114-1118. Morris, G. K., B. L. McMurray, M. M. Galton and J. G. Wells, 1969. A study of the dissemination of Salmonellosis in a commercial broiler chicken operation. Am. J. Vet. Res. 30: 1413-1421. Snoeyenbos, G. H., B. A. McKie, C. F. Smyser and C. R. Weston, 1970. Progress in identifying and maintaining Salmonella-free commercial chicken breeding flocks. 1. 1967-1969. Av. Dis. 14: 683-696. Woodburn, M., 1964. Incidence of Salmonellae in dressed broiler-fryer chickens. Appl. Microbiol. 12: 492-495.
Vaccination of Chickens Against Marek's Disease with the Turkey Herpesvirus Vaccine Using a Pneumatic Vaccinator C. S. EIDSON AND S. H . KLEVEN
Poultry Disease Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30601 (Received for publication August 12, 1975)
ABSTRACT A pneumatic vaccinator has been successfully used to administer cell-associated turkey herpesvirus (HVT) vaccine without a loss in titer due to the pressure required to administer the vaccine. Laboratory studies have also shown that chickens vaccinated with graded doses of the HVT vaccine using doses as low as 41 PFU offered protection against Marek's disease (MD) when compared to the unvaccinated controls. The pneumatic vaccinator has also been successful in administering a combination of HVT vaccine and tissue culture fowl pox vaccine. Vaccinated birds were protected against challenge with virulent MD virus as well as fowl pox virus. Antibiotics such as spectinomycin pentahydrate or lincomycin hydrochloride monohydrate and spectinomycin sulfate tetrahydrate were used in combination with the HVT and fowl pox vaccine and none of the antibiotics appear to have an adverse effect on the efficacy of either vaccine. POULTRY SCIENCE 55: 960-969, 1976
INTRODUCTION KAZAKI et al. (1970) using a turkey herpesvirus (HVT) isolated from turkeys by Witter et al. (1970), and Eidson and Anderson (1971) using a turkey herpesvirus
O
isolated by Kawamura et al. (1969) found that HVT, administered intraabdominal^ or subcutaneously protected chickens against Marek's disease (MD). This vaccine is most effective when inoculated parenterally at 1 day of age (Eidson et al., 1971, 1973a, b).
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
isolated from the grains; Salmonella typhimurium from wheat was responsible for a number of clinical outbreaks of salmonellosis in day-old broiler flocks, resulting in S. typhimurium isolations from carcases in this period (Bains and MacKenzie, 1974). Salmonella levels on carcases may therefore be reduced by restricting the dissemination of serotypes throughout the organization from contaminated meals and grains. This is achieved to some extent by the pelletizing of all feeds, including breeder rations. However, the risk of cross contamination from infected raw ingredients stored in the vicinity is high. If raw feed ingredients could be rendered Salmonella-free prior to arrival at the feed plant, this, in combination with the pelletizing of all feeds, would reduce to a minimum the risk of introducing Salmonella
PNEUMATIC VACCINATOR
The object of this report is to present data on a pneumatic vaccinator which was used to vaccinate one-day-old chickens with HVT and fowl pox vaccines or in combination with antibiotics (spectinomycin pentahydrate or lincomycin hydrochloride and spectinomycin sulfate tetrahydrate). MATERIALS AND METHODS Source of HVT Vaccine. The HVT used throughout this study was the FC 126 strain,
which was supplied by Dr. William Okazaki, East Lansing, Michigan. The cell-associated HVT vaccine was prepared as previously described by Eidson et al. (1973a). Each ampule contained approximately 3.6 x 106 plaque forming units (PFU) of HVT. The cell-free HVT vaccine was prepared by suspending HVT-infected chicken embryo fibroblasts in a stabilizer designated as SPA (Calnek et al., 1970). The cellular suspension was treated by sonication and lyophilized. The lyophilized HVT vaccine contained approximately 3.9 x 106 PFU of HVT per vial. Virus Assay. The cell-associated and cellfree HVT vaccines were titrated as previously described by Eidson et al. (1973a). The titers of the cell-associated HVT vaccine were determined after 5 days incubation; whereas, the titers of the cell-free HVT vaccine were obtained after 6 to 7 days. A mean plaque count from 2 plates from the virus dilution was used to determine the titer. Source of Chickens. A flock of White Leghorn chickens derived from Poultry Disease Research Center stock was maintained in a filtered-air, positive-pressure poultry house. These birds were free of most recognized poultry pathogens, including resistant-inducing factor (RIF) viruses and MD virus. Pneumatic Vaccinator.1 The vaccinator consists of a compressor, control box and jet applicator. The air pressure of an individual vaccinator is produced by a one-half horsepower compressor. The control box contains an activator switch, a counter which records the number of chicks vaccinated, and a pressure regulator which can adjust the air pressure from 0 to 4,000 pounds per square inch (p.s.i.). The sensitivity tolerance of the triggering mechanism is maintained at 1 and 2 ounces. 1. Avijet, Mizzy, Inc., New York, N.Y.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
Although vaccination against MD with the HVT vaccine has proven to be safe, effective and economically useful, interest continues in finding more desirable and less expensive methods of vaccine administration. Zander et al. (1972) isolated an avirulent MD virus from the blood of otherwise specific pathogen-free chickens. This virus was safe and provided effective protection against the virulent MD virus. The avirulent MD vaccine when administered subcutaneously as a suspension of freshly drawn citrated blood was effective whether all or only a small percentage of the flock was inoculated indicating that the virus was readily transmitted within the flock. A vaccine such as described by Zander would be beneficial in reducing the cost of administering the vaccine as well as reducing the cost of the vaccine itself, since only a portion of each flock would be vaccinated; however, the vaccine has not been licensed by the U.S.D.A. Unless a vaccine of this type is approved, it is unlikely that a less expensive MD vaccine will be available in the near future. Therefore, attention must be given to reducing the cost of administering presently available vaccines. In an attempt to reduce administration cost, Eidson et al. (1973b) showed that some antibiotics could be mixed with the HVT vaccine for simultaneous inoculation into day-old chicks without interfering with the performance of the HVT vaccine.
961
962
C. S. ElDSON AND S. H . KLEVEN
EXPERIMENTAL DESIGN Trial 1. To determine the effect of the pneumatic vaccinator on the titer of the cell-associated HVT vaccine, one vial of HVT vaccine was mixed in 200 ml. of tryptose phosphate broth and immediately titrated. Two ml. of the diluted HVT were passed through the pneumatic vaccinator at 950 p.s.i. through a 0.006 inch orifice and immediately titrated. For comparative purposes the diluted HVT vaccine was passed through a 2 ml. tuberculin syringe fitted with a 20 gauge needle. Two ml. of the vaccine were collected and the HVT virus was titrated. The above procedures were repeated 5 times with the same vial of vaccine, and the results of each treatment group for the 5 experiments were averaged. All of the vaccine samples were titrated on 18 hour chick embryo fibroblast monolayers as described above. Trial 2. In this study 12 groups of day-old chicks (20/group) were vaccinated with either the pneumatic vaccinator (intraabdominal) or by the conventional syringe and needle method (subcutaneous) with graded doses (41
to 1,500 PFU/0.1 ml.) of cell-associated HVT vaccine. Two groups (20/group) of chickens served as unvaccinated controls. All of the chickens were challenged at 2 weeks of age with 0.2 ml. of MD-infective plasma. The trial was terminated at the 6th post-challenge week, and the chickens were examined for gross MD lesions. Trial 3. Two groups of day-old chicks (20/group) were vaccinated subcutaneously with 1,000 PFU of cell-associated HVT vaccine with the conventional syringe and needle. Two groups (20/group) were infected intraabdominally with 1,000 PFU of HVT vaccine with the pneumatic vaccinator while two other groups (20/group) of chickens were injected intramuscularly with 1,000 PFU of HVT vaccine with the pneumatic vaccinator. The birds vaccinated with the pneumatic vaccinator were injected with 0.1 ml. of HVT vaccine at 950 p.s.i. The 2 remaining groups (20/group) of chickens served as unvaccinated controls. All of the chickens were challenged at 2 weeks of age with 0.2 ml. of MD-infective plasma. The trial was terminated 6 weeks post vaccination and all birds were examined for macroscopic lesions of MD. Trial 4. To evaluate the efficacy of the cell-free and cell-associated HVT vaccines administered by the pneumatic vaccinator, 4 groups of day-old chicks (20/group), were vaccinated with 1,000 PFU of the cell-free HVT vaccine with either the pneumatic vaccinator (2 groups) or conventional syringe and needle (2 groups). Four other groups of chickens (20/group) were vaccinated with 1,000 PFU of the cell-associated HVT vaccine with either the pneumatic vaccinator (2 groups) or the conventional syringe (2 groups). The remaining 2 groups of chickens (20/group) served as unvaccinated controls. One group of birds from each treatment group was challenged subcutaneously at 2
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
The jet applicator has an orifice opening of 0.006 inches which can deliver from 0 to 0.5 ml. of vaccine. The amount of fluid dispersed by the jet is easily regulated by a micrometer. The head of the jet contains the triggering mechanism and injection is achieved by placing the breast of the chick to the pressure sensitive trigger muzzle. In order to determine whether the jet has fired, a red light mounted on the side of the jet applicator flashes as the triggering head is depressed. The vaccinator has a cyclic rate of 3600 shots per hour; whereas, the device with two heads is capable of 7200 shots per hour. The device equipped with 2 jet applicators can be used by a single operator in conjunction with a chick debeaker.
PNEUMATIC VACCINATOR
weeks of age with MD-infective plasma. The remaining groups of birds were exposed at 2 weeks of age to MD virus by contact exposure to infected chickens. The infected chicks were hatchmates that had been inoculated subcutaneously with MD-infective plasma at one day of age. Five of the 2-week-old infected birds were placed with the test birds. All of the birds were killed at the 9th postchallenge week and were examined for macroscopic lesions of MD.
Trial 6. The design of this experiment was the same as in Trial 5 with the exception that a combination of 2-1/2 mg. lincomycin hydrochloride monohydrate and 5 mg. spectinomycin sulfate tetrahydrate was used in
2. Sterwin Laboratories, Inc., Millsboro, Delaware 19966. 3. Spectam, Abbott Laboratories, North Chicago, Illinois 60064.
place of spectinomycin dihydrochloride pentahydrate. 4 One group of chickens (30/group) from each of the treatment groups were challenged with 0.2 ml. of MD-infective plasma at 3 weeks of age while the remaining groups of chickens were challenged at 3 weeks of age with virulent fowl pox virus. All of the birds in Trials 5 and 6 challenged at 3 weeks of age with fowl pox virus were examined for lesions 5 to 10 days postchallenge while those challenged with MD virus were necropsied at the 6th postchallenge week and were examined for macroscopic MD lesions. Trial 7. Farms with two poultry houses were selected for these field trials so that birds vaccinated with the pneumatic vaccinator could be compared with those vaccinated with the conventional syringe and needle. On each farm each treatment group was placed in separate houses to eliminate mixing of birds vaccinated by either the pneumatic vaccinator or by syringe and needle. All of the houses used in this study were of conventional curtain-type with dirt floors. No attempt was made to change the usual husbandry procedures. None of the houses were cleaned prior to the placement of the chicks except for the addition of a layer of new shavings on the old litter. All of the birds were vaccinated at 1 day of age with 1,000 PFU of cell-associated HVT vaccine. The chickens vaccinated with the pneumatic vaccinator were either vaccinated intraabdominally or intramuscularly; whereas, those vaccinated with the syringe and needle were injected subcutaneously. No unvaccinated controls were used in this study because of the inevitable losses that would be incurred as a result of MD. All of the birds were processed between 7-1/2 and 8
4. LSSJ, TUCO, Division of the Upjohn Company, Kalamazoo, Mich. 49001.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
Trial 5. In this study, day-old chicks (30/group) were vaccinated with tissue culture fowl pox vaccine (EID J 0 10 5 3 /ml., 500 dose ampule was administered to 1000 chickens), cell-associated HVT vaccine (1,000 PFU) or a combination of tissue culture fowl pox vaccine, 2 HVT and 5 mg. spectinomycin pentahydrate. 3 The antibiotic was added because the severity of some diseases can be lessened if the antibiotic is administered at one day of age. The tryptose phosphate broth diluent was buffered to pH 6.8 with sodium bicarbonate following the addition of the antibiotic. After the antibiotic and sodium bicarbonate were in suspension, the fowl pox vaccine (EID 50 103 °, one-half bird dose) and 1,000 PFU of HVT per bird dose were added to the diluent. Chickens from each of the test groups were vaccinated with each of the vaccines or combination of vaccines and antibiotics with either the pneumatic vaccinator or the conventional syringe and needle.
963
C. S. ElDSON AND S. H. KLEVEN
964
weeks of age. Each group of chickens was identified separately as the birds were loaded and transported to the processing plant. Personnel of the Consumer and Marketing Service of the U.S.D. A. provided the inspection data. RESULTS
Trial 2. Data presented in Table 2 shows that birds vaccinated by the pneumatic vaccinator with 1,500 or 750 PFU of HVT/bird dose did not have any gross lesions of MD at the end of the 8 week experimental period; however, birds receiving 325, 163, 82 or 41 PFU had MD lesions in 2/20, 2/18, 2/20 and 4/20 birds, respectively. Chickens vaccinated by the syringe and needle with the same levels of HVT vaccine had similar results. The results show that all levels of the
TABLE 1.—Effect of the pneumatic vaccinator on the titer of cell-associated HVT vaccine Treatment
PFU/bird dose' 3800 3740
None Passage through 20 gauge needle Passage through pneumatic vaccinator 3660 'Average of 5 trials with same vial of HVT vaccine.
PFU/bird Vaccination dose equipment Pneumatic vaccina1500 tor Pneumatic vaccina750 tor Pneumatic vaccina375 tor Pneumatic vaccina188 tor Pneumatic vaccina94 tor Pneumatic vaccina47 tor Conventional 1500 syringe Conventional 750 syringe Conventional 375 syringe Conventional 188 syringe Conventional 94 syringe Conventional 47 syringe 0 Not vaccinated 0 Not vaccinated
No. MD lesions / n o . started 0/172 0/20 2/20 2/18 2/20 4/20 1/20 0/20 1/19 2/20 3/20 4/20 9/19 8/18
'All birds were challenged subcutaneously at 2 weeks of age with 0.2 ml. MD-infective plasma. 2 Not including birds dying before 2 weeks of age.
vaccine were effective regardless of the method used to vaccinate the birds since 9/19 and 8/18 of the nonvaccinated birds developed gross lesions of MD after challenge. Trial 3. In an attempt to ascertain the most effective site for administering the HVT vaccine with the pneumatic vaccinator, chickens were vaccinated either intraabdominally or intramuscularly. In chickens vaccinated intraabdominally 1 /17 and 2/19 developed MD lesions after challenge while 2 of 20 and 0/20 of those vaccinated intramuscularly were susceptible to MD challenge during the 8 week experimental period. Similarly, 1/18 and 0/20 of the chickens vaccinated subcutaneously with the syringe
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
Trial 1. Results presented in Table 1 show that immediately after the HVT vaccine was resuspended in tryptose phosphate broth the titer was 3,800 PFU/bird dose. This was the average of 5 titrations with the same vial of vaccine. Two ml. of the diluted HVT vaccine collected after passage through a 2 ml. syringe fitted with a 20 gauge needle had a titer of 3,740 PFU/bird dose. In comparison 2 ml. of diluted vaccine was passed through the pneumatic vaccinator and the average of the 5 titrations was found to be 3,660 PFU/bird dose.
TABLE 2.—MD lesions at 8 weeks of age in chickens vaccinated (0.1 ml.) with graded doses of HVT with the pneumatic vaccinator or conventional syringe method at 1 day of age1
965
PNEUMATIC VACCINATOR
TABLE 3.—Efficacy of HVT vaccine in day-old chicks when administered intraabdominal or intramuscularly with the pneumatic vaccinator or subcutaneously with a needle and syringe
and needle developed macroscopic lesions. However , 9 / 1 8 and 8 / 20 of the unvaccinated controls developed MD lesions (Table 3). Trial 4. In comparing the efficacy of the cell-free HVT vaccine with the cell-associated HVT vaccine when administered with either the pneumatic vaccinator or syringe
Trial 5. Chickens vaccinated by the pneumatic vaccinator with fowl pox vaccine were protected against challenge by virulent fowl pox virus; however, 19 of 29 chickens vaccinated with fowl pox but not the HVT vaccine developed gross lesions of MD. None
TABLE 4.—MD lesions at 11 weeks of age in chickens vaccinated at 1 day of age by the pneumatic vaccinator or needle and syringe with cell-associated or cell-free HVT vaccine
Vaccination equipment
Vaccine'
Method of challenge 2
No. MD lesions/no. started
C-F3 0/19 Contact Pneumatic vaccinator C-F 0/20 Plasma Pneumatic vaccinator C-A" 1/19 Contact Pneumatic vaccinator C-A 0/20 Plasma Pneumatic vaccinator C-F 0/18 Contact Conventional syringe C-F 1/20 Plasma Conventional syringe C-A 0/17 Contact Conventional syringe C-A 0/20 Plasma Conventional syringe None 8/20 Contact Not vaccinated None 11/19 Plasma Not vaccinated 'Birds vaccinated with approximately 1,000 PFU of cell free or cell-associated HVT vaccine. 2 All birds were challenged at 2 weeks of age either by contact exposure to MD infected chickens or 3by injecting the birds subcutaneously at 2 weeks of age with 0.2 ml. of MD-infective plasma. C-F = cell-free HVT vaccine. 4 C-A = cell-associated HVT vaccine.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
No. MD lesions/no. Route of vaccination started' Intraabdominal2 1/17 Intraabdominal 2/19 Intramuscular2 2/20 Intramuscular 0/20 Subcutaneous3 1/18 Subcutaneous 0/20 Not vaccinated 9/18 Not vaccinated 8/20 'All birds were challenged at 2 weeks of age with 0.2 ml. of MD-infective plasma. The trial was terminated at 8 weeks of age. 2 Birds vaccinated with 1,000 PFU of HVT vaccine with the pneumatic vaccinator (950 P.S.I.). 3 Birds vaccinated subcutaneously with 1,000 PFU of HVT vaccine with the conventional syringe and needle.
and needle, the results in Table 4 show that 1,000 PFU of either vaccine was effective in preventing gross lesions of MD regardless of the method used in administering the vaccine. None of the 3 groups of chickens vaccinated by the pneumatic vaccinator with the cell-free HVT had gross MD lesions and only one chicken from the 2 groups vaccinated with cell-associated HVT had gross lesions of MD. One bird from the group vaccinated by the needle and syringe with cell-free HVT had gross lesions, while none of the birds vaccinated with the cell-associated HVT had gross lesions of MD. Eight of twenty of the unvaccinated control birds exposed by contact exposure to the MD virus had gross lesions by 9 weeks postchallenge. Eleven of nineteen of the unvaccinated control chickens exposed to the MD virus by subcutaneous inoculation developed gross lesions.
C. S. ElDSON AND S. H. KLEVEN
966
TABLE 5.—Marek's disease or fowl pox challenge results in chicks vaccinated against HVT, fowl pox, or spectinomycin (alone or in combination) with the pneumatic vaccinator
Vaccine ppi
FP4 FP FP FP FP MDV 5 MDV MDV MDV
—
No. + / no. started Fowl pox
MD
0/30 28/28 1/30 0/27 29/30
— — — — —
— — — — —
19/29 0/28 1/26 0/30 21/30
i FP = Tissue culture fowl pox, 1 /2 broiler dose was injected intramuscularly at one day of age. HVT was injected subcutaneously at one day of age.
2 1,000 PFU of 3 5 mg. /bird. 4
Birds challenged by scarifying the comb at 3 weeks of age with fowl pox. 'Birds challenged at 3 weeks of age with 0.2 ml. of MD-infective plasma.
TABLE 6.—Marek's disease or fowl pox challenge results in chicks inoculated with HVT or fowl pox vaccine or spectinomycin (alone or in combination) by needle and syringe No. + / n o . started Vaccine ppi
HVT 2 FP + HVT FP + HVT + Spectinomycin 3 Control FP HVT FP + HVT FP + HVT + Spectinomycin Control
Challenge
Fowl pox
MD
FP4 FP FP FP FP MDV 5 MDV MDV MDV MDV
1/30 28/29 0/30 1/30 30/30
— — — — —
— — — — —
18/28 0/29 0/27 0/24 24/29
'FP = Tissue culture fowl pox, 1/2 broiler dose was injected subcutaneously at one day of age.
2 l,000PFU/birddose. 3 5 mg./dose. 4 Birds challenged by scarifying 5
the comb at 3 weeks of age with fowl pox. Birds challenged at 3 weeks of age with 0.2 ml. of MD-infective plasma.
of the chickens vaccinated with HVT vaccine were protected against fowl pox; whereas, all of the birds vaccinated with the HVT vaccine were protected against challenge with the MD virus. The results in Table 5 also show that birds vaccinated simultaneously at one day of age with fowl pox and HVT vaccine or a combination of fowl pox, HVT and spectinomycin pentahydrate were protected against MD virus as well as virulent fowl pox virus. Twenty-nine of 30 of the
unvaccinated control chickens challenged with fowl pox developed lesions within 10 days postchallenge. Also, 21 of 30 of the unvaccinated controls challenged with the MD virus developed MD lesions. Results of birds vaccinated with a needle and syringe (Table 6) are essentially the same as the results shown in Table 5. Trial 6. The results in this trial (Tables 7 & 8) were essentially the same as those
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
HVT 2 FP + HVT FP + HVT + spectinomycin 3 Control FP HVT FP + HVT FP + HVT + spectinomycin Control
Challenge virus
967
PNEUMATIC VACCINATOR
TABLE 7.—Marek's disease of fowl pox challenge results in chicks vaccinated against HVT, fowl pox or lincomycin-spectinomycin (alone or in combination) with the pneumatic vaccinator No. + / n o . started
Vaccine
hallenge
Fowl pox
MD
— — — — — 16/29 0/28 1/26 0/30 19/30
day of age.
TABLE 8.—Marek's disease or fowl pox challenge results in chicks inoculated with HVT or fowl pox or lincomycin-spectinomycin by the needle and syringe
Vaccine
hallenge
No. + / n o . started Fowl pox MD
FP1 FP 4 4/30 — HVT2 FP 28/29 — FP + HVT FP 3/30 — 3 FP + HVT + LS50 Fp 2/30 — FP Control 30/30 — 15/28 MDV 5 FP — 0/20 MDV HVT — 0/29 MDV FP + HVT — 0/30 MDV FP + HVT + LS 50 — 21/28 MDV Control — i FP = Tissue culture fowl pox, 1 /2 broiler dose was injected subcutaneously at one day of ; 2 1,000 PFU/bird dose. 3 5 mg. spectinomycin + 2-1/2 mg. lincomycin/dose. "Birds challenged by scarifying the comb at 3 weeks of age with fowl pox. 5 Birds challenged at 3 weeks of age with 0.2 ml. of MD-infective plasma.
obtained in trial 5. The results indicated that chicks vaccinated with a combination of fowl pox, HVT or lincomycin hydrochloride monohydrate and spectinomycin sulfate tetrahydrate were protected against MD challenge as well as challenge with the virulent fowl pox virus. Trial 7. Table 9 gives results from the field trial in which all birds were vaccinated with
1,000 PFU of cell-associated HVT vaccine administered by either the pneumatic vaccinator or by syringe and needle. Chickens vaccinated with the pneumatic vaccinator had an average MD incidence of 0.07% and a range of 0.0 to 0.19% for all of the farms in the trial. Condemnations from all causes was found to be 1.93%. In contrast, chickens vaccinated with the conventional needle and syringe had an average incidence of 0.6%
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
FP> FP 4 0/30 HVT2 FP 28/28 FP + HVT FP 1/30 FP 0/27 FP + HVT + LS503 FP 29/30 Control MDV 5 FP — MDV HVT — MDV FP + HVT — MDV FP + HVT + LS 50 — MDV — Control 'FP = Tissue culture fowl pox, 1/2 broiler dose was injected intramuscularly at one 2 1,000PFU/bird dose. 3 5 mg. spectinomycin + 2-1/2 mg. lincomycin/dose. 4 Birds challenged by scarifying the comb at 3 weeks of age with fowl pox. 5 Birds challenged at 3 weeks of age with 0.2 ml. of MD-infective plasma.
968
C. S. ElDSON AND S. H. KLEVEN TABLE 9.—Effect
Vaccination equipment Pneumatic vaccinator Conventional syringe
of vaccination of chicks with HVT vaccine at one day of age with pneumatic vaccinator or by needle and syringe (field trial)1 No. birds
Average weight
76,480 84,000
4.04 4.02
Leukosis condemnation
Total condemnation
No.
%
No.
%
56 136
0.07 0.16
1,480 1,428
1.93 1.82
'All birds vaccinated with approximately 1,000 PFU of cell-associated HVT vaccine.
DISCUSSION Eidson et al. (1973a) in conducting field studies to determine the efficacy of the HVT vaccine in broilers instructed vaccinating crews in the correct way to vaccinate oneday-old chicks subcutaneously with HVT vaccine. The vaccination equipment consisted of an automatic 2 ml. syringe fitted with a 20 gauge, one-half inch needle. The vaccinator's only job was to vaccinate chickens. A new innovation in vaccination equipment for poultry was recently developed with chickens being vaccinated without the aid of a needle. The vaccination equipment is placed so that the operator can debeak and vaccinate each bird. Concern had arisen as to whether the cell-associated HVT vaccine would be inactivated with the use of the pneumatic vaccinator since the cells may be ruptured as they passed through the 0.006 inch orifice at a pressure of 950 pounds per square inch. However, laboratory studies have revealed that the titer of the HVT vaccine was not reduced by the pressure used to administer the vaccine. Also, chickens vaccinated by the pneumatic vaccinator with the HVT vaccine were protected against challenge to the virulent MD virus. These studies have also shown that chickens vaccinated with graded doses of HVT vaccine, using doses as low as 41 PFU, offered protection against MD
when compared to the unvaccinated controls that were challenged at 2 weeks of age with MD-infective plasma. The results were essentially the same regardless of whether the pneumatic vaccinator or the conventional syringe and needle were used to administer the graded doses of HVT vaccine. The HVT vaccine was effective regardless of whether the vaccine is administered intraabdominally or intramuscularly. The pneumatic vaccinator has proven to be successful in administering the cell-free HVT vaccine as well as the cell-associated HVT vaccine; however, one of the disadvantages of the pneumatic vaccinator is that if the cell-associated HVT vaccine has large clumps of cells, the orifice of the pneumatic vaccinator may become clogged and only a partial dose of vaccine or no vaccine at all will be delivered. Birds vaccinated with a combination of fowl pox (500 dose ampule was administered to 1000 chickens) and HVT (1000 PFU/bird dose) vaccine were protected against challenge from virulent MD virus or the fowl pox virus for the 8 week experimental period. One-half broiler dose of the tissue culture fowl pox was administered because this is the level of the fowl pox being used in the field by many companies to vaccinate broiler chicks. The fowl pox vaccine derived from chick embryos has been used in the pneumatic vaccinator, but with the clumps of cellular material in the vaccine the vaccinator often clogs and will not operate properly. Spectinomycin pentahydrate (5 mg./bird dose) or lincomycin hydrochloride monohydrate (2-
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
and a range of 0.03 to 0.34% for all of the farms in this trial. The total condemnations rate for this group was 1.82%.
969
PNEUMATIC VACCINATOR
1/2 mg./bird dose) and spectinomycin sulfate tetrahydrate (5 mg./bird dose) was used in combination with the HVT (1,000 PFU/bird dose) and fowl pox (500 dose ampule was administered to 1000 chickens) vaccine, and neither of the antibiotics had an adverse effect on the efficacy of the HVT or fowl pox vaccines as determined by the challenge results with virulent fowl pox or Marek's disease virus.
During this study it was found that there were several mechanical deficiencies in the pneumatic vaccinator. It was found that if the birds were moved during vaccination, the skin could be torn. It was also found that the triggering mechanism could be released by the feet of the chick resulting in unsatisfactory vaccination. Also, if the instrument became clogged there was no safety device to warn the vaccinator. All of these deficiencies were corrected during these field studies.
Calnek, B. W., S. B. Hitchner and H. K. Adldinger, 1970. Lyophilization of cell-free Marek's disease herpesvirus and herpesvirus from turkeys. Appl. Microbiol. 20: 723-725. Eidson.C. S.,andD.P. Anderson, 1971. Immunization against Marek's disease. Avian Dis. 15: 68-81. Eidson, C. S., D. P. Anderson, S. H. Kleven and J. Brown, 1971. Field trials of vaccines for Marek's disease. Avian Dis. 15: 312-322. Eidson, C. S., D. D. King, H. E. Connell, D. P. Andersonand S. H. Kleven, 1973. Efficacy of turkey herpesvirus vaccine against Marek's disease in broilers. Poultry Sci. 52: 1482-1491. Eidson, C. S., S. H. Kleven and D. P. Anderson, 1973a. Efficacy of cell-free and cell-associated herpesvirus of turkeys vaccines in progeny from vaccinated parental flocks. Am. J. Vet. Res. 34: 869-872. Eidson, C. S., S. H. Kleven and D. P. Anderson, 1973b. Effect of antibiotics on turkey herpesvirus vaccine. Poultry Sci. 52: 755-760. Kawamura, H., D. J. King, Jr. and D. P. Anderson, 1969. A herpesvirus isolated from kidney cell cultures of normal turkeys. Avian Dis. 13: 853-863. Okazaki, W., H. G. Purchase and B. R. Burmester, 1970. Protection against Marek's disease by vaccination with a herpesvirus of turkeys. Avian Dis. 14: 413-429. Witter, R. L., K. Nazerian, H. G. Purchase and G. H. Burgoyne, 1970. Isolation from turkeys of a cell-associated herpesvirus antigenically related to Marek's disease virus. Am. J. Vet. Res. 31:525-538. Zander, D. V., R. W. Hill, R. G. Raymond, R. K. Balch, R. W. Mitchell and J. W. Dunsing, 1972. The use of blood from selected chickens as an immunizing agent for Marek's disease. Avian Dis. 16: 163-186.
NEWS AND NOTES (Continued from page 935) CARGILL NOTES Edward E. Reynolds has been elected Corporate Vice President in charge of the Poultry Products Division of Cargill, Inc. He joined Cargill at Minneapolis in 1966 and was appointed Assistant Vice President and General Manager of the Food Products Department. He became Division Vice President in
1972. He is a Director of the National Broiler Council and the Poultry and Egg Institute of America. Previously he was a Vice President for Central Soya Company. COMMITTEE ON REGULATORY PROGRAMS Secretary of Agriculture Earl L. Butz has appointed
(Continued on page 974)
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on June 12, 2015
Limited field trials indicate that birds vaccinated by the pneumatic vaccinator were as well protected against MD as those vaccinated with the conventional syringe and needle method. One of the weaknesses of these field trials is that there were no unvaccinated controls. Birds vaccinated with the pneumatic vaccinator were placed on the same farm with birds vaccinated with the conventional syringe and needle, but they were placed in separate houses.
REFERENCES
