14
UWI TODAY
– SUNDAY 8 APRIL, 2018
To get a better understanding
of the nature of Brucellosis, I
asked two lecturers from the School of Veterinary Medicine at
The UWI, to explain its nature and impact on cattle, particularly
the Buffalypso. Dr. Michael Diptee, a veterinarian in the area
of veterinary medicine and surgery, lectures in Large Animal
Surgery. He has a special interest in Brucellosis. Dr. Winthrop
Harewood is a Senior Lecturer in Food Animal Medicine and
is Head of the Clinical Veterinary Department. The Livestock
Advisor to the Minister of Agriculture, Dr. Marlon Knights also
shared his position on some of the questions.
What is Brucellosis?
DR. DIPTEE:
It is an infectious disease caused by a gram-
negative bacteria that can persist in the environment
invariably depending on temperature, pH, and humidity. The
bacteria affect multiple species and can spread from animals
to humans. Humans acquire
brucellosis
when they come in
contact with contaminated animals or animal products, most
commonly from the ingestion of raw milk or cheese.
What does it mean for buffalo
infected with Brucellosis?
DR. DIPTEE:
Infected buffalo are prone to abortions,
low milk production and even infertility when infected.
It is caused by an intracellular bacteria and thus requires
prolonged treatment with clinically effective antibiotics. As
such there is no cost-effective treatment for infected livestock.
I understand it can be managed,
what does that entail?
DR. DIPTEE:
When Brucellosis is detected, infected animals
are identified and later slaughtered at a Brucellosis-approved
abattoir (at the Sugarcane Feed Centre).
DR. KNIGHTS:
What is the definition of ‘managed’ and to
what end and under what conditions? My suggestion that the
herd at Mora Valley should be culled is an actual management
strategy.
1.
Your management strategy will vary depending on how
widespread the disease is or conversely how localized.
Thankfully Brucellosis is localized and the best strategy
would be to ensure it does not spread even if that means
culling the herd.
2.
Your management strategy depends on what you see as
the potential role or function of that herd. Remember
it is probably nearly 25 years since this herd has been
infected. Certainly if the function of the herd is a
source of genetic material then over the last 25 years we
certainly have not been using it for that purpose. The
management strategy of test and cull and return to the
same environment has not worked, and the population
has continued to dwindle while still remaining as a
potential source of infection for animals outside of Mora
Valley.
3.
Your management strategy for Brucellosis must consider
the existing level of overall management of the animals.
Even after discovering the disease some 20-25 years ago
many basic practices was not put in place. Two of the
major deficiencies is the lack of controlled breeding and
animal identification. Additionally appropriate fencing is
still lacking. These are significant undertakings and still
will not be sufficient.
Source: A status report on the water buffalo (
Bubalus bubalis
Linnaeus, 1758) industry
in Trinidad. A. Mohammed, M. D.Diptee, A. Persad, R. Mohammed, N. Lambie and S.
Sieuchand.
4.
Some will suggest vaccination. There are risks involved
in with this, including the possibility of the vaccine
causing disease in humans if accidental injection
occurs. Moreover there is the issue of identifying
animals that were naturally infected from those who
were vaccinated. While the technology does exist
to do this, who will be the ones to guarantee that a
seropositive animal was actually due to vaccination
and will be willing to let that animal leave the farm?
Even the best vaccines are not 100% effective and there
still exist questions as to if and when animals need to
be revaccinated to maintain protection. We need to
be careful that we do not take a localized problem and
make it a national issue.
5.
Then there is the question of what is the true demand
for our water buffalo genetics. Yes we did supply
genetics in the past but in terms of development of the
animals, whether for growth or milk production, many
countries have much more developed animals. It is my
belief that the herd at ALS can adequately be managed
to meet the need for breeding stock locally.
Do we have the capacity
to treat/manage it locally?
DR. DIPTEE:
The simple answer to this question is no. We
lack the political commitment to deal with this problem.
Brucellosis was identified in water buffalo in 1998 and up to
today (20 years later) the problem exists. Depopulation was
not considered possible due to economic factors and the loss
of genetic variability.
DR. HAREWOOD:
I am not aware about any effective
treatment options for Buffalypso with Brucellosis. There
are options to manage Buffalypso herds which have been
exposed to Brucellosis. The option one uses will depend
upon what one wishes, this is usually related to the purpose
for which the animals are kept. One management option for
an infected herd or animal(s) at risk of getting infected is a
vaccination. This requires a vaccination protocol, and use
of a vaccine which increases the immunity of the animal(s)
to withstand the infection by the causative bacteria, with
minimal signs.
DR. KNIGHTS:
Based on what has occurred in the past
and what I identified above, I would say no.
Even if a vaccine is available and
administered, would that be relevant
to the herd at Mora Valley?
DR. DIPTEE:
No! The current vaccines used on cattle are
not effective in preventing Brucellosis in water buffalo. Test
and slaughter is the only means available to manage the
disease in T&T. It is also impossible to test the entire herd of
buffalo at Mora Valley because some wild buffalo live in the
forested area there.
DR. KNIGHTS:
Based on the above no. I do not believe the
Government should be in the business of beef production,
which is essentially the only purpose Mora Valley serves at
this time. To clean that herd up so that it can be used as a
source of breeding animals will be extremely difficult. In any
event the management at that site will eventually involve
depopulating even if potentially positive animals are moved
to another site. Moving animals from that site puts cattle
and buffalo production throughout Trinidad at risk
(
Dr Adesh Ramsubhag
, a microbiologist at The UWI,
has been exploring the efficacy of the vaccines.
“We need
to seriously explore alternative strategies for managing
Brucellosis in local herds. It appears that imported vaccines
currently used are not working. This may be due to the
occurrence of unique strains of the disease-causing agent in
this region. If we can confirm this by studying the disease in
more detail, we may be able to help with developing more
suitable and effective vaccines for protecting the animals in
Trinidad and Tobago,”
he said.)
How safe would it be for humans to consume
the meat and milk of infected cattle, even if
they are being treated?
DR. DIPTEE:
When milk is pasteurized and meat is
cooked, it is made safe by heating it just long enough to kill
the Brucellosis disease-causing germs. Infected Buffalypso
are slaughtered. The reproductive tract, mammary glands
and lymph nodes are removed to ensure that the meat is safe
for human consumption.
DR. HAREWOOD:
It really depends upon how you define
safe. Also on what is done with the meat and milk prior
to human consumption. I suspect it also depends upon
the state of one’s immune system. If you work with the
“one-size-fits-all” concept, you would most likely want to
advocate avoiding Brucella-infected food, milk and milk
products, especially when the alternative is readily available.
DR. KNIGHTS:
The Same procedure must be employed; all
animals must be slaughtered at the Sugarcane Feed Centre.
Buffalypso’s Last Stand
SPECIAL REPORT
BY VANEISA BAKSH
The Case for Culling
