Laboratory support of tropical disease control programs

Preventive Veterinary Medicine, 2 (1984) 487--492

487

Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands

LABORATORY SUPPORT OF TROPICAL DISEASE CONTROL PROGPAMS

J.F. FRANK Consultant to the Canadian International Development Agency, P.O. Box 291, Manotick,

Ontario, Canada, K0A 2N0

ABSTRACT Frank, J.F., 1984. Laboratory support of tropical disease control programs. Prev. Vet. Med., 2: 487-492. The availability of accurate and precise identification of animal disease is vital to the success of any disease surveillance program. This can only be achieved through the availability and use of an adequate laboratory service. The main requirements that make up an effective laboratory service are discussed. These are facilities, personnel, the availability of reagents and arrangements for the collection of samples. It is most important that there be close cooperation with field officers so that a sufficient volume of adequate specimens are made available for laboratory testing. All diagnostic laboratories, regardless of where they are located, continually face problems of staff shortages, deficiency of appropriate reagents, and the appearance of previously undiagnosed diseases requiring the rapid adoption of new test procedures. Laboratories in tropical areas face additional problems, such as those related to temperature and humidity, transportation, and equipment maintenance.

INTRODUCTION It need hardly be stated that an adequate laboratory service is essential to the support of livestock development programs by aiding in effective disease control and surveillance.

Yet the availability of such services is often

forgotten when livestock programs are developed and it is only after disease problems cause serious disruptions are considered.

in the program that laboratory facilities

It is not uncommon for livestock development programs and

even disease control programs to be planned without considering what laboratory support is required to carry out the testing that is necessary in such programs. The availability of an accurate and precise diagnosis is vital to the identification of a disease outbreak and this is especially important when the disease is being identified for the first time in a country.

I could readily point to

many examples where an important disease outbreak could not be definitely identified until a laboratary examination was conducted.

I could cite the out-

break of African swine fever in Brazil or our own Canadian experience with foot and mounth disease in 1952 or our outbreak of hog cholera in the early 1960's. In fact, many national disease control systems have their origin in laboratory

488 findings. In the Americas the importance of diagnostic laboratories to the health and well being of the livestock industry was recognized at the Second Inter-American Meeting of the Directors of Animal Health (EEDISA II) in September, 1980.

As a

result of discnssions at this meeting, the Inter-American Institute for Cooperation in Agriculture (IICA) appointed a commission which carried ont an assessment of veterinary diagnostic laboratories in all the Americas in 1981 with the ultimate objective of upgrading the diagnostic capabiJities of veterinary laboratories throughout the region.

Arellano e t a ] .

(1982) reported

on the commission's findings to the Third Inter-American Meeting of the Directors of Animal Health in Buenos Aires in August, 1981. Basically, the requirements for laboratory support for the control and surveillance of animal diseases in tropical areas are not much different than in other areas.

There may be a few more problems related to temperature and

humidity, and more emphasis on certain types of diseases such as those caused by blood parasites.

However, the major problems are usually related to a shor-

tage of financial and personnel resources.

STAGES IN THE DEVELOPYENT OF L±XBOPATORY SUPPORT The d e v e l o p m e n t has

a high

and growth of an effective

probability

of survival

passes

laboratory

through

three

support

service

that

stages.

The first consists of the provision of simple diagnostic procedures such as the determination of parasitism by ova identification and simple serum agglutination tests for diseases such as brucellosis.

Gradually, more complex

well defined diagnostic procedures are adopted as the personnel develop greater expertise and laboratory facilities are expanded. The second stage in the development of laboratory support consists of conducting surveys on the incidence of various diseases in support of, or in deciding on, disease control programs.

Again, this begins with simple sur~eys

using fairly simple techniques and gradually more and more complex procedures are used in survey programs. In the third stage, research is undertaken to study disease conditions which are not readily identified by common test procedures. This development is paralleled by the continuous and gradual upgrading of personnel and laboratory facilities.

With this gradual progression a more

permanent laboratory support system is developed, one whose benefits are recognized by the supporting authorities and which develops slowly or quickly in line with the support that can be given to it by the livestock industry of the country which it serves.

489 FACTORS TO BE CONSIDERED IN PROVIDING FOR AN EFFECTIVE LABORATORY SERVICE There are four essential requirements in providing for an effective laboratory service: i. Adequate facilities. 2. A knowledgeable and well trained staff. 3. The availability of laboratory supplies and reagents. 4. Adequate arrangements

for the collection and receipt of samples.

The laboratory should be so located that it is most convenient for the shipping and receipt of specimens,

close to the centre of the livestock industry

and within easy reach by a good public transportation system, road and air. A suitable building site should be selected that provides ample space for the laboratory and ancillary buildings,

good drainage to allow for safe

disposal of laboratory wastes, and the ready availability of public utilities such as electricity and water. Desirable amenities for staff such as proximity to schools, stores, transportation services,

etc., should be kept in mind.

The staff selected should have an interest in, and an aptitute for, laboratory work. Adequate salary and incentive programs should be developed for the staff, as it requires full time devotion to this type of work in order to keep up to date with rapidly developing changes in laboratory procedures. A systematic program for training and updating laboratory staff should be put in place.

This should apply to both professional and technical staff

and should include access to suitable texts, scientific journals and other sources of current technical information. A specific budget should be set aside for the operation of the laboratory so that the Director may be able to plan the activities of the laboratory with greater efficiency.

The budget should be developed in parallel with that of

the field staff so that the laboratory might be prepared to handle samples submitted by any proposed field program. It is important that there be regular and continuous consultation and a close working relationship between the staff of the laboratory and the animal health regulatory personnel as well as with livestock owners, livestock associations and practicing veterinarians.

Without this it is impossible to

achieve the optimum disease surveillance. In order for a diagnostic laboratory to make a worthwhile contribution to the health of the livestock of the country,

it must receive recognition by the

senior agricultural authorities of the country and be given adequate support. I can only point to the development of diagnostic laboratories

in the USA, New

Zealand and Canada over the last 30 years as examples of how support for these

490 has contributed considerably to the well being of the livestock industry in these countries. A laboratory specializing in the diagnosis of exotic diseases has certain special requirements.

These were described by Frank and Bannister (1973) at

the 6th Inter-American Meeting of Foot and f~outh Disease and Zoonoses Control in Medellin, Columbia in 1973.

LABORATORY SERVICES REQUIRED TO SUPPORT DISEASE CONTROL PROGRAMS The actual tests and services provided by any laboratory will vary with the development of the livestock industry in the country and with the support given to the laboratory by the authorities in control of the budget.

Generally, in

order to provide adequate support in tropical areas a laboratory should be able to carry out: I. Complete post mortem examinations of carcasses. 2. Examinations for blood parasites. 3. Examinations for other endo- and ecto-parasites. 4. Bacterial culturing for pathogenic bacteria. 5. Histophathological examinations of tissues. 6. Virological culturing and tests to identify viruses. 7. Serological tests to identify antibodies to various diseases. 8. Chemical tests to identify toxicities and nutritional deficiencies. The complexity of the tests conducted will vary with the development of the laboratory, as described earlier.

Where a laboratory has not developed to the

stage where it can carry out the more complex tests, arrangements should be made to have them done in a reference laboratory.

There is a definite need for

regional reference laboartories in many parts of the world which would be available to all countries in a region, as many countries do not have a sufficiently developed laboratory service to carry out all the complex tests that may be required, nor is it practical for all countries to have such facilities. A method of rating the capabilities of diagnostic laboratories was described by Arellano et al. (1982), in their study of the laboratories in the Americas, and their findings illustrate the great variety of diagnostic capability that might be found in any given region.

PROBLEMS ENCOUNTERED IN VETERINARY LABORATORIES IN TROPICAL AREAS All veterinary laboratories, no matter where they are located, are continually facing obstacles that restrict their operations.

However, laboratories

in tropical areas are burdened with additional problems and those problems common to all laboratories seem to occur in a more acute form.

491 Most of the problems specific to these areas relate to high temperatures and humidity.

These have an adverse effect on the working environment for per-

sonnel, they affect the condition of specimens which may have to be moved over considerable distances,

they reduce the shelf-life of reagents,

they affect

culturing procedures and cause other specific problems such as mould growing on microscopic slides and on the lenses of microscopes. One problem, which is becoming more and more evident as developing countries increase their diagnostic activities, are the restrictions placed on the movement of specimen and sample material from one country to another when seeking aid in diagnosis. It appears that, with a few exceptions, supported laboratories,

including the internationally

the majority of laboratories in tropical areas suffer

from a severe lack of sufficient funding.

Personnel are badly underpaid,

funds

are not available for materials and supplies, transportation of specimens is difficult and often delayed, power outages are common, and refrigeration

is

limited. One of the major problems noted in these laboratories is a very critical deficiency in the maintenance of equipment and buildings.

Training of techni-

cal staff in equipment and building maintenance should have top priority in international training programs. The chronic shortage of various antigens is another serious problem.

This

is very often aggravated by long delays in clearing items through customs, thus resulting in unnecessary deterioration of perishable materials.

MISGUIDED ASSISTANCE In view of the problems listed above, laboratory facilities should be kept simple in design, meeting basic needs but within the financial means of the country or industry that will have to provide continuous on-going support. We have all seen facilities that were very elaborate, built by some donor who was very generous, but the laboratory falls upon hard times when it is left to the support of the local industry. Similarly well-meaning scientists,

supported by generous donor agencies,

introduce a wide variety of complex disposable materials and gadgets which leave the laboratory with no means of continuing operation after the supply is used up and no further contributions are forthcoming.

Items such as disposable

syringes, disposable needles, plastic petri plates, disposable scalpels, prepackaged, ready-to-use bactiological

identification kits, etc., are all very

convenient but what does one do when these have all been used and foreign exchange is not available to replenish the supply? Cooperators should attempt to introduce reusable materials and make more use

492 of local resources, including labor, which is often more readily available than funds to import disposable supplies. When the installation of air conditioning is considered it is felt that, in most cases, because of the difficulties encountered in maintaining and servicing equipment, it is more effective to install individual room air conditioners than a central system.

Such units can be changed by personnel with a

minimum of training and, should one fail, it does not affect the use of a complete building.

COMMENT It is not uncommon to find that a laboratory has been established, equipped and staffed to service a local livestock industry but that it is not being used to anywhere near its capacity to support the industry and carry out disease surveillance.

Often this has been found to be due to a lack of

communication between laboratory personnel and field personnel or regulatory staff.

Both sides must make a continual effort to involve the other in their

planning and activities so that a joint effort can be mounted in disease control programs and surveillance. In many countries there is no field staff and no large private practitioner group as exist in some of the developed countries.

It is therefore necessary

for the laboratory service to provide all the information needs in support of animal health, right down to the farm level or to the level of animal health assistants where such personnel are available. systems often fail.

This is where laboratory

Laboratory veterinarians and organizers of veterinary

laboratories must recognize and strive to fill such needs if they are to obtain adequate political and financial support. Every specimen received at a diagnostic laboratory provides information for disease surveillance and, during slack periods in laboratory work, survey material is readily available in slaughtering facilities, often located within reasonable distance of laboratories.

If the laboratory is functioning

effectively and is receiving adequate quantities of diagnostic material from the field, this material will provide a good indication of the disease incidence in the country.

It is of course important to keep adequate records on each

specimen and these can be kept in such a manner that they may be easily summarized, even with the use of a very simple record keeping system.

REFERENCES Arellano, C., Frank, J., Howarth, J.Ao, Palacios, C., Seaton, V.A., Acha, P.N., Murnane, T., 1982. Animal Health, Scientific Publication No. 2, InterAmerican Institute for Cooperation in Agriculture, San Jose, Costa Rica,81 pp. Frank, J.F., and Bannister, G.L., 1973. The Diagnostic Laboratory for Exotic Diseases: Organization and Function. Proceedings of VI Inter-American Meeting of Foot and Mouth Disease and Zoonoses Control. ~!edellin, Columbia Scientific Publication No. 281, Pan American Health Organization, Washington, D.C., pp 80-84.