Public-private partnerships in blindness prevention: reaching beyond the eye.

The control of river blindness (onchocerciasis) has been one of the major public health achievements of recent decades. Initially, vector control was used to stop transmission of the parasite Onchocerca volvulus by blackflies (Simulium) but the introduction of ivermectin (Mectizan) as a means of morbidity control enabled new strategies of distribution to be developed based on community directed treatment. The donation of Mectizan by Merck & Co. Inc. for onchocerciasis control in 1987 'as long as needed' was a public health landmark to be followed by a donation from GlaxoSmithKline of albendazole in 1997 for lymphatic filariasis to which Merck also responded by agreeing to extend their donation to include the coadministration of Mectizan and albendazole. Both the drugs, however, have wider impacts than those specific to filarial parasites and are effective against a range of intestinal parasites, whilst ivermectin has an important effect on ectoparasites. The wider benefits of the annual public health intervention-collateral benefits--therefore include deworming, improved nutritional status, increased growth, improved school performance and attendance, and improved haemoglobin status as a result of the impact of albendazole on hookworm, a major cause of anaemia. More recently, studies suggest that worm-free children have a significantly reduced frequency of malaria specific episodes of fever and Ascaris-infected children have a two-fold higher frequency of cerebral or severe malaria than those without Ascaris. These findings suggest that programmes based on annual interventions to control river blindness and lymphatic filariasis can contribute disproportionately more to a range of public health problems than has been hitherto recognized, thereby assisting in attaining the millennium development goal targets.