The following citations highlight the facts
that: 1. Bison vaccine is disputed, 2.
Does not prevent brucellosis infection, only marginally protects
from abortion, and is not longterm, 3. Single
shot vaccine showed no difference with non-vaccinated, 4.
Commitment to booster vaccinations and long term programs (30
years) would be necessary and would be at great cost and manpower
hours with limited results, 5. Vaccinated bison
would still contract field strains of Brucella abortus,
requiring slughter and loss to program, 6. Vaccination
during mid-gestation induces greater abortions, 7.
Bison vaccination, in an attempt to lower seroprevalence, will
have no effect on reducing seroprevalence in the elk population
currently the transmission risk vector to the cattle, 8.
Efficacy of RB51 vaccine has not been tested in field conditions,
9. Test and slaughter/vaccine programs are not
efficient or socially acceptable management tools for wildlife.
Also, Brucellosis Science Review Workshop Panelists Report 2013
"Many serologic tests have been produced
to aid in diagnosis of B. abortus infections; however,
all currently-used diagnostic methods were developed and validated
for use only in cattle. When applied to wildlife, many cattle
tests have shown to be inaccurate and unpredictable (pg. 13)"
- A
Risk Analysis of Brucella abortus Transmission Among Bison, Elk,
and Cattle in the Northern Greater Yellowstone Area, 2010.
"The efficacy of RB51 in bison remains
in dispute. Olsen et al. (2003) reported that RB51 was efficacious
as a calfhood vaccine, whereas data reported by Elzer and Davis
(2002) were contradictory. However, there does appear to be consensus
that EB51 vaccine is safe as a calfhood vaccine for bison. Also,
informatin about effects on individual bison from vaccination
during pregnancy is limited, and there are concerns about abortigenic
responses in bison. (pg.20)... However, because bison rarely transmit
B. abortus to elk, management alternatives such as vaccination
that reduce bison seroprevalence are unlikely to reduce transmission
from elk to cattle (pg. 81)... Bison vaccination did not meaningfully
reduce B. abortus transmission risk to cattle (97)...
Bison vaccination and the resultant lowering of bison seroprevalence
also was not an effective risk reduction strategy...Delaying cattle
grazing turn-on dates showed the largest absolute reduction in
B. abortus transmission incidence between wildlife and
cattle. Delay the earliest cattle turn-on date to 6/21 reduced
transmission incidence to one case every 3.3 years and further
delaying the turn-on date to 6/30 resulted in only one case every
30.4 years (pg.107)." - A
Risk Analysis of Brucella abortus Transmission Among Bison, Elk,
and Cattle in the Northern Greater Yellowstone Area, 2010.
"Bison in single-vaccination treatment
groups (hand RB51 and dart RB51) did not differ (P>0.05) from
the control group in the incidence of abortion or recovery of
S2308 from uterine, mammary, fetal, or maternal tissues at necropsy."
- Efficacy of Dart or Booster Vaccination with Strain RB51 in
Protecting Bison against Experimental Brucella abortus
Challenge, pg. 886, 2012
"As implementation of a vaccination
program for free-ranging wildlife will be expensive and require
long-term commitment of human and financial resources for success,
the failure of the vaccination strategies evaluated in the current
study to provide sterile immunity may be of concern to some individuals.
However, one model for brucellosis estimated a 24 to 66% reduction
in seroprevalence in bison over a 30-year period, using an estimation
of vaccine efficacy of 0.5 and an estimation of vaccination coverage
of 1 to 29% of the population. As abortins are the most significant
mechanism for horizontal transmission of B. abortus in
ruminants, it should be noted that the current study found that
booster vaccination reduced abortions by 83%, uterine infection
by 60%, and colonization in uterine placentomes by 78% after experimental
challenge in comparison to results for control bison. Using a
similar comparison, a single hand vaccination with RB51 in our
study was associated with a 33% reduction in abortions, a 34%
reduction in uterine infection, and a 48% reduction in placentome
colonization after experimental challenge compared to those in
nonvaccinated animals. ..
Recognizing that the numbers of experimental units in the current
study were relatively small, additional studies are warranted
to more accurately define the efficacy of booster vaccination
of bison with RB51...
In summary, our study suggests that an initial vaccination of
calves followed by booster vaccination as yearlings should be
a more effective strategy for brucellosis control in bison than
a single calfhood vaccination." - Efficacy of Dart or Booster
Vaccination with Strain RB51 in Protecting Bison against Experimental
Brucella abortus Challenge, pg. 889, 2012
"There is a need to improve brucellosis
vaccines for bison, as overall data from our labratory suggest
that the RB51 vaccine is not as efficacious in protecting bison
against experimental challenge when compared to similar data from
vaccinated cattle. Any vaccination program for YNP bison will
most likely be of long duration and require commitment of significant
financial and human resources. Therefore, this study was initiated
to characterize the safety, immunogenicity, and efficacy of a
second dose of RB51 vaccine in bison and evaluate pneumatic darts
as an option fo remote delivery of brucellosis vaccine (pg.642)...Responses
of nonvaccinates and single vaccinates did not differ (P> 0.05)
in any samplings obtained after the booster vaccination (60 to
84 weeks after the initial vaccination)... In conclusion, our
study found relatively small differences in immunologic responses
of bison after single RB51 vaccination delivered by parenteral
or dart delivery or when comparing single and booster parenteral
vaccinations (pg. 647)." - Immune Responses and Safety after
Dart or Booster Vaccination of Bison with Brucella abortus Strain
RB51, 2012.
"Traditional test-and-slaughter programs
have been effective for managing diseased livestock but these
practices may not be realistic or socially acceptable for wildlife...The
success of a vaccination program is influenced by vaccine efficacy
and the proportion of the population innoculated. Our ability
to deliver efficacious vaccines and monitor their effectiveness
is restricted in free-ranging wildlife. Additionally, we will
seldom have all the information necessary to predict the effectiveness
of a wildlife vaccination program, but management actions will
need to move forward despite these uncertainties (pg. F64)...The
live B. abortus strain RB51 (SRB51) is the official brucellosis
vaccine for cattle in the U.S., but has the potential to induce
abortions in pregnant bison vaccinated in mid-gestation...There
is uncertainty about the level of protection (i.e., efficacy)
SRB51 will provide Yellowstone bison based on experimental studies...However,
SRB51 was found to have little efficacy in adult and calf bison
despite repeated vaccinations. Thus, the duration of protection
provided by a single dose of SRB51 is unknown and older cows may
need to be booster-vaccinated to extend the protection of the
vaccine (pg. F66)... Vaccine-protected bison that were subsequently
exposed to B. abortus were expected to react positively on serologic
tests and, consequently, be removed during management operations
(pg. F69)...Model simulations suggest that syringe vaccination
of females captures at the park boundary will provide only a small
decrease in brucellosis infection due to low vaccination rates
that rely on out-of-the-park migrations...The current vaccine,
SRB51, is not expected to provide lifetime protection and female
bison may need booster vaccinations...Because the antibody responses
to B. abortus are long lived, the proportion of actively
infected bison would be exprected to decrease faster in response
to vaccination than population seroprevalence. Also, vaccinated
bison that are subsequently exposed to field strain Brucella
will react positively on serologic tests even though they may
be protected from further transmission. These bisaon would be
removed during boundary operations, thereby impeding the reduction
of brucellosis infection...Thus, a delay in seroprevalence decrease
is expected in the first 10 years of initiating a vaccination
program because of high population seroprevalence (pg.70), long-lived
antibodies, and the removal of vaccinated, seropositive bison...
Thus, a consistent long-term investment in vaccination will be
required to meet the objective of he Interagency Bison Management
Plan for reducing brucellosis transmission risk to cattle by reducing
infection within Yellowstone bison... The efficacy of vaccine
SRB51 has not been tested under field conditions and research
is needed to estimate its efficacy within the Yellowstone system.
Also, the duration of vaccine protection offered by SRB51 is unknown,
but undoubtedly plays an important role in reducing infection
and transmission... In addition, realistic group responses of
bison to vaccination are largely unknown, and disturbances from
remote vaccination may make bison difficult to vaccinate with
this method over the long term. Remote vaccination effort will
be (pg. F71) unable to compensate for vaccine efficacy if bison
are difficult to vaccinat. (pg. F72)." - Vaccination
strategies for managing brucellosis in Yellowstone bison, 2010.
"The effectiveness of Strain RB51 vaccine
against field strain B. abortus is not conclusive and mixed results
have been reported by various research projects. The USDA–Agricultural
Research Service has published results of research showing that
only 15% of vaccinated bison aborted pregnancies when experimentally
challenged by a virulent strain of B. abortus, while 62% of non-vaccinates
aborted their pregnancies. Conversely, experiments conducted by
Texas A&M University concluded that vaccination with Strain
RB51 provides no protection from aborted pregnancies. The results
are not comparable because methods were not consistent (pg. vi)."
- Brucellosis Remote Vaccination Program for Bison in Yellowstone
National Park DRAFT Environmental Impact Statement, 2010. |