Eradication and elimination: facing the challenges, tempering expectations

The words eradication, elimination and control have been regularly defined in attempts to avoid inappropriate use of terminology while addressing the realities and challenges of public health programmes. Whitty has recently outlined the dangers of raising expectations in the face of political, financial, biological and logistical efforts of eradication or elimination programmes, emphasising these risks in search of a holy grail. Bockarie et al. noted five categories that defined the elimination or endgame challenges—biological, socio-geographic, logistic, strategic and technical—providing examples from current programmes. These have created significant strategic and resource impediments to progress in implementation, requiring changes in approach often with significant financial implications. A variety of strategies are used to reduce incidence and prevalence of infectious diseases: vaccination (smallpox, polio, measles), chemotherapy (onchocerciasis, lymphatic filariasis, schistosomiasis), vector control, (onchocerciasis, malaria, schistosomiasis) and provision of improved clean water and sanitation (trachoma, guinea worm, soil transmitted helminths, schistosomiasis). Such strategies are more effective when combined, for example, chemotherapy, vector control and behaviour change, thereby achieving proportionately greater and more rapid impact on transmission. Eradication as a concept is specifically defined as a reduction to zero global incidence of a specific pathogen, not a disease, which results from such an infection. This represents a crucial distinction—the words disease and infection are often used interchangeably but incorrectly. Even WHO reporting recently on the yaws programme in India entitled their publication ‘Eradication of yaws in India.’ Thus, even WHO are unable to consistently use correct terminology. Another example is the call for the eradication of malaria. However, eradication is defined as the removal from the planet of a specific infection; raising the question, which of the five human species of Plasmodium is to be targeted? This is yet to be specified.