SAFETY AND EFFICACY OF ADVENT®
COCCIDIOSIS VACCINE
Julia.
J. Dibner, Marco. A. Quiroz, and Chris D. Knight
Novus International, Inc., 20 Research Park Dr., St.
Charles, MO 63304
marco.quiroz@novusint.com
This paper describes
a series of experiments to determine the safety and
efficacy of a new coccidiosis vaccine. ADVENT®
Coccidiosis Control contains sporulated viable oocysts
from the three commercially relevant species in broilers,
E. acervulina (strain VND-A10), E. maxima (strain
VND-M27), and E. tenella (strain VND-T49). The strains
have been selected to have the robust protection necessary
for today’s broilers without including any unnecessary
species, they were also selected for broad immunogenicity
and undiminished oocyst yield. A unique methodology
has been developed that inactivates extraneous agents
without the need to use any hazardous substances such
as potassium dichromate which is used as preservative
in other coccidiosis vaccines. Ability of the sterilent
and the processing methodology to inactivate viruses
was evaluated using two viruses; chicken anemia virus
(CAV) and infectious bursal disease virus (IBDV),
selected for their stability, resistance to disinfectants,
and importance to the poultry industry. It was demonstrated
that the sterilent and procedures used were sufficient
in eliminating at least 4-5 log10 of IBDV and CAV.
It was proven that the procedures also inactivate
extraneous bacterial contaminants such as Salmonella
spp. Extensive screening for anticoccidial drugs resistance
confirmed sensitivity of the strains to ionophores
and chemical drugs. An in vitro potency method –
the VIACYST® Assay – was used to determine
the viability of sporocysts of each of the three Eimeria
strains. Studies confirm that the in vitro viability
assay correlates to the ability to confer resistance
to a coccidiosis challenge and permits accurate and
consistent vaccine formulation. Different studies
confirmed the safety of the minimum immunization dose
for each species as well as a dose approximately 10
times that for each species administered ether via
spray cabinet or spray on the feed. Oral immunization
with ADVENT results in resistance to significant challenges
of oocysts: at least 300,000 viable sporulated oocysts
of E. acervulina, and 40,000 viable sporulated oocysts
of E. maxima or E. tenella. Doses resulting in immunity
have been evaluated both on the basis of lesion score
reduction and post challenge broiler performance.
The special sanitation and purification process along
with the exclusive viability assay used in the formulation
of the ADVENT vaccine results in coccidiosis control
that is consistent from lot to lot and vial to vial.
The resulting vaccine provides protection without
excess immune stimulation and is a consistent and
pure source of contemporary coccidial oocysts.
®ADVENT is a trademark
of Viridus Animal Health, LLC, and is registered in
the United States and other countries
® VIACYST is a service mark of Viridus Animal
Health, LLC, and is registered in the United States
and other countries.
