Early warning, early reaction

The theory is straightforward and sounds simple; outbreaks of transmittable animal disease can be minimized with early warning and early reaction. In practice these require a degree of emergency preparedness that might, more usually, be associated with flood, drought or some other natural disaster. Even the most affluent countries struggle at times (see CSF - a communication crisis?) so how do less affluent developing countries prevent disease outbreaks from turning into disasters?

credit: FAO

Imagine a country that has recently declared provisional freedom from rinderpest, to take just one example of a transboundary disease. There may have been no sign of the disease for many years. Mass vaccination must cease and those for whom this has provided a remunerative workload in the past are worried that their income will disappear. Morale, for any number of other reasons, may be low and yet, upon this group of people, together with their livestock owning clients, the first line of defence against disease must rest - early detection. A planned programme of surveillance will be necessary using visual inspection and, at times, blood sampling. The extent and intensity of surveillance will depend upon the assessment of risk and, where veterinary resources are limited, most will be deployed at critical points such as border crossings, auction pens, slaughter slabs etc.. Those carrying out the work must be trained to recognize the clinical signs of diseases that may be unfamiliar to them. Laboratories must be equipped and technicians trained. The collected data must be recorded efficiently - and used. Vigilance is hard to sustain because, by definition, early warning means that for most of the time there will be no warning signs.

For early reaction to suspicion of disease to be effective, a pre-determined plan of action, that can be implemented without delay, must be in place and every player must know the part that they must play. They must have the tools, the training and authority to do the job. The first essential will be containment of the disease, the exact procedures to be followed depending on the disease concerned and the means by which it spreads. Surveillance and monitoring will be stepped up, the movement and contacts of actual or potentially infected animals will be traced. Vaccines may be needed as well as equipment and personnel to carry out slaughter of affected herds or flocks, disposal and decontamination. A compensation policy may apply. Technical contingency plans should be in place but procedures will be tailored to the nature of the disease concerned, the circumstances and location of the outbreak and the resources available for control.

The Food and Agriculture Organization is currently in the process of developing, through EMPRES, a computer model which will provide national veterinary authorities with alternatives for control depending, for example, upon the rate of infection or the size of the livestock population affected. Already available are Animal Health Manuals for use as reference books for establishing early warning, early reaction procedures. TADinfo, the FAO-designed software package for recording disease data, is now being deployed in some 16 countries in Africa and Asia and requests from other countries in Africa, the Near East and South America are being processed. TADInfo is GIS-based system which means that each observation of disease, with its date, the locality where it was seen, the species affected, etc., must be reported. It is inappropriate for countries where surveillance systems are poorly developed or where data is insufficient or of the wrong type to justify investing in computerized data input and analysis. Computer systems will surely supersede the abandoned and forgotten piles of dusty, yellowing forms that formerly recorded disease surveillance in many countries.

For the gatherers of information in the field to feel their work is valued as part of an effective national system of disease preparedness, must surely strengthen the line that they defend against disaster.

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