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.
- 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.
- 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.
- 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.
- 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.
- 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.
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