A Fresh Look at the Final Countdown
By Claude E. Barton, DVM
USDA,APHIS,VS

The slogan "The Final Countdown" originated at a recent meeting of LCI and was formalized by resolution at last years meeting. It is appropriate that today we consider the current status of brucellosis eradication and the possibilities for the immediate future in this context. Within the state-federal cooperative brucellosis program, the goal for completing the eradication of brucellosis from domestic cattle by December 31, 1998, has been established. This afternoon, I want to review the current brucellosis situation and look at the possibilities and imperatives for achieving eradication by the end of 1998.

Let me begin by sharing with you a little about my role in this effort. Early in February I was appointed to the job of Assistant to the Deputy Administrator with the working job title of Brucellosis Program Director, USDA, APHIS, VS. This position was created as a result of recommendations from the state-federal task force established to identify program enhancements that would increase the chances of achieving the 1998 goal. Previously, there had been two national brucellosis program directors but the position was eliminated by attrition several years ago. On strong recommendation from the task force, the current position was created as a field position, rather than a staff position stationed in Riverdale, Maryland. The reasoning was that the director should be in the field, working closely with states that continue to experience brucellosis in cattle so that problems could be quickly identified and corrective action coordinated.

There are some who felt that a Brucellosis Program Director was not needed at this stage of the eradication effort and I respect their views. On the other hand, the job was created and I was selected to fill it. So, my personal commitment today is to put the shoulder to the wheel and do everything possible to achieve the eradication goal on schedule.

Let’s look for a moment at where we are today in the brucellosis program. There were 109 brucellosis affected herds in the entire country as of March 31, just a few days ago. The distribution of these herds is shown in Figure 1. Five of these herds (Figure 2) were dairy herds, with two being located in New Mexico and three in California. There are 33 Class-Free states and 17 Class A states, as detailed in Figure 3. Five of the Class A states are well into the yearlong countdown toward achieving Class-Free status. These numbers are remarkable compared to just five years ago when there were over 2,000 affected herds. On the other hand, there were 200 newly affected herds (Figure 4) disclosed in the US during the 12 month period preceding March 31. This statistic much more accurately reflects the true incidence of brucellosis in cattle, as well as a more accurate estimate of the effort that will be necessary to achieve its eradication.

Two years ago at the LCI Meeting in St. Louis, I shared my views on the critical elements in brucellosis eradication. These elements were derived from the Rapid Completion Plan that was implemented in 1989. The rapid progress in recent years is the result of individual state programs that have been conducted according to the Rapid Completion Plan. Considering its success to date, let’s briefly review its major components.

1. Depopulation.

2. Whole Herd Vaccination.

3. First Point Testing.

4. Increased Adjacent and Contact Herd Testing.

5. Increased Epidemiologic Testing. 6. State Program and Technical Reviews.

7. Use of Task Forces.

8. Increased Training.

In my view, within the framework of the Rapid Completion Plan, there are five basic critical elements that determine whether brucellosis will be eradicated from an area and, if so, relatively how long it will take. They are:

1. Surveillance

Affected herds must be identified before brucellosis can be eliminated from them. Therefore, a system for rapid identification and location of affected herds is probably the most critical element to eradication.

Let’s look for a moment at the two basic methods that have been the mainstay of surveillance for cattle brucellosis. They are the market cattle testing program and the brucellosis ring test. These two programs have served the brucellosis program well down through the years. However, they both are passive systems to a degree in that surveillance occurs at fixed points and brucellosis is not detected by these methods until it reaches the surveillance points.

It behooves us then to look at any and all methods of surveillance, being focused all the while on finding new cases, rather than just conducting routine surveillance. In this context, change of ownership testing, retest of imports, area testing, and testing high risk herds become valuable surveillance adjuncts in finding new cases of brucellosis.

2. Affected Herd Management

Affected herd management is the art of controlling and managing the disease situation. It involves the application of disease control and eradication measures, and those animal husbandry practices that will minimize spread within the herd and eliminate the disease in the shortest possible time. Good management also includes treating each new outbreak as a community problem rather than just a single herd problem. Important affected herd procedures are:

a. Depopulation.

b. Whole Herd Vaccination.

c. Herd Plans and Managing the Affected Herd.

d. Quarantines.

e. Herd Tests.

f. Calving Management.

3. Adjacent, Community and Contact Herd Testing

Experience has taught us time, and time again, that we must consider each outbreak of brucellosis as a community problem. Otherwise, we allow neighborhood herds to go undetected and leave brucellosis behind. Adjacent, community, and contact herds must be managed, along with the index herd, as part of the outbreak.

At the LCI Meeting two years ago, I shared some data with you from the states of Alabama and Tennessee. Because this data highlights a critical issue that must be resolved in a number of states if we are to reach the goal of eradication by the end of 1998, please allow me to share it with you again.

Figure 5 is a line graph that shows the number of new affected herds disclosed in Alabama by year, from 1972 to 1993. Alabama achieved Class A brucellosis status in 1987, yet continued to find field strain affected herds until about five months ago. True, the incidence has been low for a number of years, but brucellosis has managed to persist for about eight years since the state achieved Class A status.

Figure 6 is a line graph showing the same data from Tennessee. Superimposed, the two graphs are virtually identical, with both showing the long tail on the graph in recent years. Tennessee achieved Class A status in 1985, but continued to have brucellosis up to about six months ago.

The designated epidemiologists collaborated to determine the most probable sources of brucellosis from 1988 to 1993 in these two states. Figure 7 shows some of the comparative results. Please note the number of years in which 70 percent, or more, of new affected herds disclosed were thought to be due to recrudescence and spread to or from adjacent and neighborhood herds. It is true that the cattle industries and brucellosis programs in these two states are very similar. On the other hand, the fact that it has typically taken an average of seven to10 years for states to move from Class A to Class-Free status cannot be ignored.

The lesson here, in my view, is that where new brucellosis affected herds occur in the future, the overwhelming probability is that it will be due to recrudescence or to spread from previously affected adjacent or neighborhood herds. The 17 remaining Class A states must deal with this issue in diligent fashion if the 1998 goal is to be attained. Adjacent, community, contact, and epidemiologically traced herds must be tested and managed along with the index herd for as long as necessary to assure that brucellosis does not recur.

During the last few decades, epidemiology has emerged as the key element in determining the methods by which we evaluate and deal with animal disease outbreaks. This is certainly true in the case of brucellosis. Good epidemiologic support is essential if the program is to be brought to a successful conclusion.

Good epidemiologic support, not only involves the designated brucellosis epidemiologist, but also the veterinary medical officers and animal health technicians who are the key people that deal with locating and managing affected herds. All should be well trained in order to deal with the last vestiges of brucellosis. Continuing education should be provided in order to maintain a high level of competence in this area.

This critical element ultimately determines how well other elements of a brucellosis program are executed. The collective state-federal management determines the policies, procedures, goals, priorities, and field organization in each state. Program direction and urgency must be conveyed to program personnel at all levels and each new affected herd should be treated as urgent, if not as an outright emergency.

Affected herds that do not depopulate should be reviewed frequently by the program management team. This collective approach focuses all administrative and management resources on the affected herd, invariably resulting in the best and most credible management plan for the individual herd.

The program management team should foster program reviews, both internally and from outside program specialists. Each program deficiency should be promptly corrected. Likewise, ongoing quality controls should be in place to assure a high level of program success. Regular monitoring of key checkpoints and reports is essential.

In the spring of 1994, several specific enhancements were recommended by the state-federal task force that studied the brucellosis program from the perspective of achieving eradication by the end of 1998. These recommendations were submitted in the form of a white paper to the Deputy Administrator, APHIS, VS. Following are the seven recommended enhancements and their current status relative to implementation:

Whole herd depopulation has become the option of choice in dealing with cattle herds diagnosed as having active field strain brucellosis. In most states, however, the decision to depopulate is optional to the herd owner. As a result of the recommendation in the white paper and as an added incentive to depopulate, the federal indemnity was increased from $150 to $250, with the added option of paying full market value in specially designated cases. Several states also contribute funds toward depopulation. Since October 1, 1994, this combined effort has been very effective in quickly eliminating affected herds, thus driving the prevalence rate downward.

In those instances where affected herds are not depopulated, the recommendation is that whole herd vaccination be vigorously pursued as the alternate management option.

2. Strengthen State Program Reviews

The value of reviews in identifying program weaknesses and in remedying deficiencies has played an important role in the brucellosis program. Because of funding constraints, reviews have been conducted in only about five states per year for the past several years. The recommendation was that outside technical reviews be conducted on an annual basis in states that have active infection and that follow-up corrective action of deficiencies be monitored closely. Further, it was recommended that states that do not correct deficiencies in timely fashion be downgraded to the next lower class for lack of program progress.

Since constraints in funding are likely to continue, it is planned to direct those reviews that are done toward states that continue to find brucellosis affected herds; or that are not making anticipated progress; or that appear to have deficiencies in specific elements of the program. By selective focusing of reviews toward problem areas, it is anticipated that the process will be more effective in the identification and correction of program deficiencies.

Brucellosis is a complex disease and the program to eradicate it is likewise complex. Effective control and eradication of brucellosis requires knowledge and understanding by not only state-federal regulatory personnel, but by the entire cattle industry, including private veterinarians, producers, market operators, dealers, and packers.

In response to this recommendation, two continuing education courses are scheduled this year for 50-60 designated brucellosis epidemiologists across the country. A basic brucellosis epidemiology course for newly hired regulatory veterinarians is also scheduled this year. Two states have already had refresher brucellosis training in conjunction with work conferences and others are being planned. The best ways to disseminate information to the non-regulatory players in the eradication effort are being explored.

The critical importance of good brucellosis surveillance cannot be over emphasized. This element was addressed above in general fashion. It is well, however, to address first point testing specifically as the key component in market cattle surveillance. The traceback efficiency from first point testing dictates that it be continued in states were it is currently in use until the remaining Class A states are free of brucellosis. Consistently, first point testing, as a surveillance tool, has detected the highest percentage of new affected herds. In addition, most of the Class A states are in the area of the country that has experienced the most problems, for whatever reason, in bringing brucellosis under control to the point that eradication is a realistic goal. The need for continuation of first point testing cannot be overemphasized.

The task force strongly recommended that APHIS,VS, develop a national policy on the use of Strain 19 vaccine. A six point policy was developed. It has been published and distributed. The six points are:

a. Encourage calfhood vaccination in herds and areas where the risk of exposure to brucellosis is high.

b. Encourage States to rescind laws and regulations that mandate calfhood vaccination, such as for importation or sale.

c. Eliminate Federal funding for the purchase and administration of Strain 19 vaccine, except in infected or designated high-risk herds.

d. Encourage herd owners and veterinary practitioners to carefully weigh the advantages, disadvantages, and appropriateness of calfhood vaccination in herds under consideration.

e. Emphasize the importance of correct age, dosage, identification, and reporting when vaccinating with Strain 19.

f. Do not encourage routine calfhood vaccination in States that are classified as free of brucellosis.

The task force concluded that brucellosis in certain wildlife is an issue that needs timely attention because of the serious impact it can have on maintaining free status in domestic cattle herds. This conclusion was focused mainly on the situation in and around Yellowstone National Park. It was recommended that APHIS,VS work closely with other agencies to develop and implement an action plan for controlling and eradicating brucellosis in the Greater Yellowstone Area. It was further recommended that program authorities be expanded to regulate movement of infected and exposed animals of other species; particularly nontraditional carriers of infection like camelids and captive cervidae.

APHIS, VS has three representatives on committees that are working toward developing a plan for dealing with brucellosis in the Greater Yellowstone Area. In addition, an epidemiologist has been assigned to the area to monitor the brucellosis situation in wildlife and coordinate local agency activities. The brucellosis staff continues to work with the cervid industry in developing uniform methods and rules for cervidae.

This recommendation involved the creation of the position, National Brucellosis Program Director. It also included that the Director would be an Assistant to the Deputy Administrator, APHIS, VS, and would be stationed in the field rather than in the Riverdale, MD area. This has been implemented as was discussed above.

In conclusion, let’s discuss for a moment what the goal of eradication by December 31, 1998, really means. Do we mean total eradication from domestic cattle and bison so that it never recurs, or do we mean virtual eradication? Personally, it is my view that we will have achieved our goal if all states have no affected herds and are well into the countdown toward Class-Free status. Certainly, for several years to come, there could possibly be an isolated animal or herd in which brucellosis could reappear. Brucella abortus has proven to be a formidable foe, especially in the intracellular state. Fortunately, such recurrences can be dealt with very quickly and efficiently.

So, what are the imperatives to complete the eradication of brucellosis by the end of 1998? This year will be 41 years since the beginning of the National Cooperative Brucellosis Eradication Program. Between three and one-half and four billion dollars and much effort have been collectively expended thus far. It is reasonable then to assume that at this point we owe it to the long-suffering livestock industry to complete this job . We owe it to those in legislative and executive positions who have provided funds throughout the years. We owe it to the researchers and state-federal regulatory leaders that have provided the tools and technical expertise to make eradication possible.

Finally, we owe it to ourselves to complete this job. I asked one of our staff veterinarians a few weeks ago to research the countries of the world that have verifiably eradicated brucellosis from their livestock. There were about a dozen or so. When we complete the eradication of brucellosis we will have done so from more cattle, in more herds, and under more diverse circumstances than all the countries in the world combined, that lay claim to this achievement to date. What an awesome accomplishment that will be!

United States Brucellosis Information

Alabama, Tennessee Cattle Brucellosis

Alabama Brucellosis Report