Drug – bio-affecting and body treating compositions – Antigen – epitope – or other immunospecific immunoeffector – Parasitic organism or component thereof or substance...
Reexamination Certificate
1997-12-01
2002-12-31
Saoud, Christine J. (Department: 1647)
Drug, bio-affecting and body treating compositions
Antigen, epitope, or other immunospecific immunoeffector
Parasitic organism or component thereof or substance...
C424S265100, C424S269100
Reexamination Certificate
active
06500438
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of vaccinating domesticated birds against coccidiosis. In particular, the invention relates to the in ovo administration of live Eimeria spp sporozoites or merozoites, or mixtures thereof, into the developing eggs of domesticated birds in order to immunize the hatched chicks against coccidiosis.
Coccidiosis is an enteric disease of domesticated birds caused by infection with intracellular protozoan parasites of the genus Eimeria. Coccidiosis is the most economically devastating parasitic disease of domesticated birds. It is estimated that anticoccidial medications and losses due to coccidiosis cost the poultry industry hundreds of millions of dollars every year.
Various attempts to vaccinate domesticated birds against coccidiosis have been reported since the early 1950's. Current vaccination methods include administering live Eimeria oocysts to birds through feed or water. These methods, however, are inconvenient and inefficient because not all birds get the intended oocyst dose and many are either unprotected by the vaccine or receive a pathogenic infection.
In J. M. Sharma and B. R. Burmester, Avian Dis. 26: 134-149, 1981, the authors reported that chickens vaccinated in ovo with herpesvirus of turkey developed immunity against subsequent challenge with Marek's disease virus. In European patent publication no. 291173, an immunization process is referred to wherein a nonreplicating immunogen is administered in ovo. The immunogens specifically referred to in the European patent are a genetically engineered Eimeria antigen and an Eimeria oocyst extract. The European patent specifically excludes live parasite stages such as those used in the vaccination method claimed herein.
The present vaccination method involves in ovo administration of live Eimeria sporozoites or merozoites, or a mixture thereof, into the developing eggs of domesticated birds. The available literature suggests that such a vaccination method would be ineffective in ovo and should be applied post-hatch. In T. K. Jeffers and G. E. Wagenbach, J. Parasit. 56(4): 656-662, 1970, the authors reported that in ovo injection of
E. tenella
sporozoites on day 10 of incubation provided no significant immunological protection against subsequent challenge with
E. tenella
oocysts. In fact, they reported that chicks that received no treatment had a greater survival rate against subsequent challenge with
E. tenella
oocysts than chicks that had been treated in ovo with sporozoites. In K. L. Watkins et al., Proc. VI th. International Coccidiosis Conf., Abstract E1-2, Ontario, Canada, 1993, the authors described in ovo inoculation with live
E. maxima
sporocysts and sporulated oocysts and concluded that their study provided no evidence that in ovo exposure protects against subsequent coccidial challenge with
E. maxima
oocysts 10 days post-hatch. Watkins et al. further concluded that significant immunological protection is provided if inoculation is done soon after hatch rather than in ovo. Contrary to this teaching, the in ovo vaccination method of the present invention provides unexpected immunity that protects the hatched birds against subsequent coccidial challenge.
SUMMARY OF THE INVENTION
The present invention, also referred to herein as the “present vaccination method”, relates to a method of vaccinating a domesticated bird against coccidiosis comprising administering in ovo, during the final quarter of incubation, an effective immunizing dose of live Eimeria sporozoites or merozoites, or a mixture thereof.
The term “domesticated bird(s)”, as used herein, unless otherwise indicated, includes chickens, turkeys, ducks, game birds (including, but not limited to, quail, pheasants, and geese) and ratites (including, but not limited to, ostrich).
The term “in ovo”, as used herein, unless otherwise indicated, means into a domesticated bird egg containing a live, developing embryo.
The term “administering in ovo” or “in ovo administration”, as used herein, unless otherwise indicated, means administering the vaccine described herein to a domesticated bird egg containing a live, developing embryo by any means of penetrating the shell of the egg and introducing the vaccine. Such means of administration include, but are not limited to, injection of the vaccine.
The term “final quarter of incubation”, as used herein, unless otherwise indicated, means the final quarter of incubation of a developing egg of a domesticated bird.
The term “Eimeria”, as used herein, unless otherwise indicated, means one or more species of the genus Eimeria that infect domesticated birds. Such Eimeria species include those that are found in chicken, including
E. tenella, E. acervulina, E. maxima, E. necatrix, E. mitis, E. praecox,
and
E. brunetti,
and also those that are found in turkeys, including
E, meleagrimitis, E. adenoeides, E. gallopavonis, E. disperse, E. meleagridis, E. innocua,
and
E. subrotunda,
and also Eimeria species that infect other domesticated birds as defined above. The term “Eimeria” also includes all strains of the foregoing species of Eimeria, including, but not limited to, precocious strains, and attenuated strains, which includes strains that have been irradiated, or otherwise treated, so that they fail to complete development. The term Eimeria also includes any newly-discovered strains or species of Elmeria that infect domesticated birds as defined above.
The terms “sporozoites”, “sporocysts”, “oocysts”, and “merozoites”, as used herein, unless otherwise indicated, mean live Eimeria sporozoites, sporocysts, oocysts, and merozoites.
The term “effective immunizing dose”, as used herein, unless otherwise indicated, means a number of sporozoites or merozoites, or, when mixed, a number of sporozoites and merozoites, sufficient to provide immunological protection in the hatched birds that is greater than the inherent immunity of non-immunized birds. As used herein, the terms “immunize” and “vaccinate” are synonymous and are used interchangeably.
A preferred dose to be administered in accord with the method of the invention comprises 10 to 10
6
sporozoites or merozoites, or a mixture thereof wherein the total number of said sporozoites and merozoites ranges from 10 to 10
6
.
A more preferred dose comprises 10
3
to 10
6
sporozoites or merozoites, or a mixture thereof wherein the total number of said sporozoites and merozoites ranges from 10
3
to 10
6
.
Another preferred dose comprises 10
2
to 10
5
sporozoites or merozoites, or a mixture thereof wherein the total number of said sporozoites and merozoites ranges from 10
2
to 10
5
.
A preferred domesticated bird to be vaccinated in accord with the method of the invention is a chicken.
A preferred dose to be administered in ovo to chicken eggs comprises sporozoites or merozoites, or a mixture thereof, of two or more species of Eimeria selected from the group consisting of
E. tenella, E. acervulina, E. maxima, E. necatrix, E. mitis, E. praecox,
and
E. brunetti.
The dose preferably includes from 10 to 10
6
sporozoites or merozoites, or a mixture thereof, for each species that is included in the dose.
Another preferred domesticated bird to be vaccinated in accord with the method of the invention is a turkey.
A preferred dose to be administered in ovo to turkey eggs comprises sporozoites or merozoites, or a mixture thereof, of two or more species of Eimeria selected from the group consisting of
E. meleagrimitis, E. adenoeides, E. gallopavonis, E. dispersa, E. meleagridis, E. innocua,
and
E. subrotunda.
The dose preferably includes from 10 to 10
6
sporozoites or merozoites, or a mixture thereof, for each species that is included in the dose.
Other preferred domesticated birds to be vaccinated in accord with the method of the invention are game birds, ducks and ratites.
The method of the invention further comprises, in combination with the present vaccination method, administering in ovo an immune stimulant at any time during incubation.
A preferred method of administering the immune stimul
Evans Nigel A.
Findly Robert Craig
Weber Frederick H.
Myers Bigel Sibley & Sajovec P.A.
Pfizer Incorporated
Saoud Christine J.
Turner Sharon
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