THE HUMAN FILARIASES - NEW UNDERSTANDINGS, NEW THERAPEUTIC STRATEGIES

The discovery of techniques to localize and recover Wuchereria bancrofti parasites from patients and the use of molecular toots to probe the genomes of all the filariae have permitted unprecedented advances in understanding the biology of these parasites. Recognition that the immune responses of most infected patients are 'contrainflammatory' suggests that their primary role is to contain or limit inflammation around the parasite, not promote it. Pathology appears to develop either in response to parasite products or when the host is unable to contain local inflammation- around dying microfilariae in the skin of onchocerciasis patients or in response to bacterial or fungal super-infection of tissues with compromised lymphatic function in patients with lymphatic filariasis. Therapeutic strategies to control morbidity associated with these infections are focused on decreasing both the parasite burden and the inflammatory burden caused by super-infecting microorganisms. Effective treatment of affected populations is now possible with single annual doses of ivermectin (onchocerciasis) or diethylcarbamazine with or without ivermectin (lymphatic filariasis).