Epidemiology

Ultrasonography is very useful for epidemiological surveys of populations at risk of echinococcosis or schistosomiasis haematobium. Successful public health surveys and control of treatment have been carried out in many countries. However, as with all ultrasonography, time spent on checking the quality of the equipment and in teaching the operators will yield better and more reliable results. In surveys, it is not the number of active or chronic cases which is solely important: even more important are those patients in whom the infection has not been recognized. From them will come further spread to others, as well as their own increasing ill health. The World Health Organization has laid down guidelines for such surveys, providing not only clinical guidance but information for proper record keeping. These suggestions should be closely followed, if only to ensure that results are comparable with similar surveys elsewhere. (This information can be obtained from any regional office of the WHO or from the WHO Headquarters, 1211 Geneva 27, Switzerland).

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