1975
NEW ZEALAND VETERINARY JOURNAL
85
VACCINATION OF YOUNG CHICKENS WITH LIVE VACCINE AGAINST SOME NEW ZEALAND ISOLATES OF INFECTIOUS BRONCHITIS VIRUS H.~J.
BENGELSDORFP* and J. E. LOHRt
INTRODUCTION
THE ISOLATION Df infectious bronchitis (IB) virus of chickens in New Zealand (PoW, 1967, 1968) has been fDllDwed by reports Dn the frequency Df IB virus isolatiDn at the Ruakura Animal Health Laboratory (McCausland, 1972) and clinical symptoms and pathology Df IB in New Zealand (McCausland et ai., 1972). MDre recently a serological pilot survey (Lom, 1974) has given further indications of the extent of the disease in New Zealand. Von Bulow ( 1969) cDmpared several German field iSDlates, of IB virus with Massachusetts and Connecticut types, the Australian T strain ( Cumming, 1963) , and N.Z. 103, the first New Zealand isolate of IB virus (Poh!, 1967), designated "Massey" strain. He found the N.Z. 103 (Massey) strain to be significantly different from all strains of IB virus examined, including the Australian T strain. He therefore concluded that a IDeal virus strain might have to' be attenuated in New Zealand fDr vaccine production if further studies on other New Zealand IB virus isolates confirmed the prevalence Df serologically distinct strains, and if the disease was found to' playa significant role in this country. New Zealand isolates, other than the MaS'sey strain have not yet been studied in detail, but the published reports as well as personal experience: of one of the authors (J.E.L.) have shown that IB is of significance in this country. Both killed and live vaccines against IB have been de:veloped. This laboratory's:!: experience with a beta-propiolac~ tone (BPL) inactivated vaccine has confirmed the view that killed vaccines are *H.-J. Bengelsdorff, Dr.Med.vet., Behringwerke AG, Marburg/Lahn (W. Germany). tJ. E. Lahr, Dr.Med.Vet., Department of Veterinary Pathoiogy and Puhlic Health, Massey University, Palmerst01l North. :j:Behringwerke AG, Marburg/Lahn (W. Germany).
of unsatisfactory immunogenicity. UnsatisfactO'ry results with inactivated IB vaccines have alsO' be'en reported by Winterfield (1967), Swarbrick et ai. (1967), McDougall (1968), Cumming (1969), Box et al. (1973), and others. Other authors (Christian and Mack, 1957; Woernle, 1961; Berry, 1965) have noticed some protection in laying birds, but never at a totally satisfactory level. The! difference,s appear to' be due largely to' the criteria employed in evaluating the vaccines. Thus, McMartin (1968) found that an inactivated vaccine induced some resistance in the reproductive tract but not in the respiratory system. Generally live vaccines engender a more reliable and durable immunity than killed vaccines, particularly in the respiratory tract, and even when stimulatin~ only low serum antibody levels (Hofstad, 1967). Their usual route of administration via the drinking water O'r as a spray is easier than the inoculation of individual birds with inactivated vaccine. It also allows direct contact between the live virus and the: respiratory tract for the induction of local immunity. However, the use of live vaccines is not without problems. Live vaccines may induce signs of a respiratory infection with or without the usual growth retardation and damage to the oviduct. The protection engendered by the var.:cine varies, considerably 'according to the antigenic relationship between the: vaccine and the challenge strain (Raggi and Lee, 1958, 1965; Bengelsdorffand Schneider, 1964a; Bengelsdorff, 1965: Berrv, 1967; McFerran et al., 1972; Chubb, 1973). As a rule the immunity produced in oldelr birds is better and more persistent than that in vounger birds. Raggi and Leel (1958} found that 100% of birds vaccinated at the 'age of 2 months but only 80.9% of "sus~ ceptible" birds vaccinated at 6 days of age were resistant to challenge with a Mas~:achusetts type IB virus. Bengelsdo,rff (1965) found that between 45 and
86
NEW ZEALAND VETERINARY JOURNAL
100% of chicks vaccinated 'at the age of 2 ~ weeks showed some clinical symptoms of IB when challenged with several European isolates 4 weeks: after vaccination. In comparison, 10 to' 70% of birds showed clinical signs of IB upon challenge if vaccination occurred at the: age of 4V2 weeks. Chubb (1973), working with the Australian A and T isolates of IB virus, foound that immunity to the virusinduced kidney failure coincided with the chicks' ability to produce precipitating antibody, not with the; level Df maternal antibody. The degree of immunity against challenge infection with a respiratory type of IB virus cannoot be accurately determined by the serum-neutralization test (Raggi and! Lee:, 1957, 1958; HQfstad, 1961). The latter author recommended the use Qf challenge infection rather than the serum-neutralizatiDn test to' determin:e the prote:ction afforded by a vaccine because the very important factor Qf local immunity at the tracheal mucosa cannot be measured by the serumneutralization test. Live, attenuated IB vaccines are commonly used in many overseas countries but not in New Zealand. This is because the production of a IDeally manufactured vaccine hithertO' had been c;onsidered uneconomic by the major local vaccine firms. In the absence Qtf any knQwledge about the, types Qf IB virus prevalent in New Zealand, permission to import a live IB vaccine from overseas was de" dined by the Animal Health Division of the Ministry of Agriculture and Fisheries. Nevertheless, after re:ceiving seveTal New Zealand isolates of IB virus in 1969, wQrk was commenced to' eNaluate the efficacy' Df a recQmmended vaccination prO'gramme 'asemplo~yed in We:st Germany a~ainst some New Zealand isolates as challenge virus. The vaccination trials were preceded by the agar gel-precipitin and cross-neutralization tests be.tween a Massachusetts type and the Massey strain to see whether the first, used for revaccination, was capable of producing a satisfactory neutralizing antibody ::esponse -against the Massey stram. Fur1
NEW ZEALAND VETERINARY JOURNAL
85
VACCINATION OF YOUNG CHICKENS WITH LIVE VACCINE AGAINST SOME NEW ZEALAND ISOLATES OF INFECTIOUS BRONCHITIS VIRUS H.~J.
BENGELSDORFP* and J. E. LOHRt
INTRODUCTION
THE ISOLATION Df infectious bronchitis (IB) virus of chickens in New Zealand (PoW, 1967, 1968) has been fDllDwed by reports Dn the frequency Df IB virus isolatiDn at the Ruakura Animal Health Laboratory (McCausland, 1972) and clinical symptoms and pathology Df IB in New Zealand (McCausland et ai., 1972). MDre recently a serological pilot survey (Lom, 1974) has given further indications of the extent of the disease in New Zealand. Von Bulow ( 1969) cDmpared several German field iSDlates, of IB virus with Massachusetts and Connecticut types, the Australian T strain ( Cumming, 1963) , and N.Z. 103, the first New Zealand isolate of IB virus (Poh!, 1967), designated "Massey" strain. He found the N.Z. 103 (Massey) strain to be significantly different from all strains of IB virus examined, including the Australian T strain. He therefore concluded that a IDeal virus strain might have to' be attenuated in New Zealand fDr vaccine production if further studies on other New Zealand IB virus isolates confirmed the prevalence Df serologically distinct strains, and if the disease was found to' playa significant role in this country. New Zealand isolates, other than the MaS'sey strain have not yet been studied in detail, but the published reports as well as personal experience: of one of the authors (J.E.L.) have shown that IB is of significance in this country. Both killed and live vaccines against IB have been de:veloped. This laboratory's:!: experience with a beta-propiolac~ tone (BPL) inactivated vaccine has confirmed the view that killed vaccines are *H.-J. Bengelsdorff, Dr.Med.vet., Behringwerke AG, Marburg/Lahn (W. Germany). tJ. E. Lahr, Dr.Med.Vet., Department of Veterinary Pathoiogy and Puhlic Health, Massey University, Palmerst01l North. :j:Behringwerke AG, Marburg/Lahn (W. Germany).
of unsatisfactory immunogenicity. UnsatisfactO'ry results with inactivated IB vaccines have alsO' be'en reported by Winterfield (1967), Swarbrick et ai. (1967), McDougall (1968), Cumming (1969), Box et al. (1973), and others. Other authors (Christian and Mack, 1957; Woernle, 1961; Berry, 1965) have noticed some protection in laying birds, but never at a totally satisfactory level. The! difference,s appear to' be due largely to' the criteria employed in evaluating the vaccines. Thus, McMartin (1968) found that an inactivated vaccine induced some resistance in the reproductive tract but not in the respiratory system. Generally live vaccines engender a more reliable and durable immunity than killed vaccines, particularly in the respiratory tract, and even when stimulatin~ only low serum antibody levels (Hofstad, 1967). Their usual route of administration via the drinking water O'r as a spray is easier than the inoculation of individual birds with inactivated vaccine. It also allows direct contact between the live virus and the: respiratory tract for the induction of local immunity. However, the use of live vaccines is not without problems. Live vaccines may induce signs of a respiratory infection with or without the usual growth retardation and damage to the oviduct. The protection engendered by the var.:cine varies, considerably 'according to the antigenic relationship between the: vaccine and the challenge strain (Raggi and Lee, 1958, 1965; Bengelsdorffand Schneider, 1964a; Bengelsdorff, 1965: Berrv, 1967; McFerran et al., 1972; Chubb, 1973). As a rule the immunity produced in oldelr birds is better and more persistent than that in vounger birds. Raggi and Leel (1958} found that 100% of birds vaccinated at the 'age of 2 months but only 80.9% of "sus~ ceptible" birds vaccinated at 6 days of age were resistant to challenge with a Mas~:achusetts type IB virus. Bengelsdo,rff (1965) found that between 45 and
86
NEW ZEALAND VETERINARY JOURNAL
100% of chicks vaccinated 'at the age of 2 ~ weeks showed some clinical symptoms of IB when challenged with several European isolates 4 weeks: after vaccination. In comparison, 10 to' 70% of birds showed clinical signs of IB upon challenge if vaccination occurred at the: age of 4V2 weeks. Chubb (1973), working with the Australian A and T isolates of IB virus, foound that immunity to the virusinduced kidney failure coincided with the chicks' ability to produce precipitating antibody, not with the; level Df maternal antibody. The degree of immunity against challenge infection with a respiratory type of IB virus cannoot be accurately determined by the serum-neutralization test (Raggi and! Lee:, 1957, 1958; HQfstad, 1961). The latter author recommended the use Qf challenge infection rather than the serum-neutralizatiDn test to' determin:e the prote:ction afforded by a vaccine because the very important factor Qf local immunity at the tracheal mucosa cannot be measured by the serumneutralization test. Live, attenuated IB vaccines are commonly used in many overseas countries but not in New Zealand. This is because the production of a IDeally manufactured vaccine hithertO' had been c;onsidered uneconomic by the major local vaccine firms. In the absence Qtf any knQwledge about the, types Qf IB virus prevalent in New Zealand, permission to import a live IB vaccine from overseas was de" dined by the Animal Health Division of the Ministry of Agriculture and Fisheries. Nevertheless, after re:ceiving seveTal New Zealand isolates of IB virus in 1969, wQrk was commenced to' eNaluate the efficacy' Df a recQmmended vaccination prO'gramme 'asemplo~yed in We:st Germany a~ainst some New Zealand isolates as challenge virus. The vaccination trials were preceded by the agar gel-precipitin and cross-neutralization tests be.tween a Massachusetts type and the Massey strain to see whether the first, used for revaccination, was capable of producing a satisfactory neutralizing antibody ::esponse -against the Massey stram. Fur1
