Scientists at the US-based National Institute of Allergy and Infectious Diseases recently suggested a new vaccine for blood flukes (Schistosoma mansoni) that cause snail fever in humans. The disease manifests itself by an excessive deposition of connective tissue in the liver, a condition known as fibrosis; the research team has succeeded in reducing fibrosis in mice by sensitising them with eggs of the parasite alongwith Interieukin-12 (Nature, Vol 376, No 6541). The vaccine has been found to prevent the formation of lesions of inflammatory tissues and restrict the growth of fibrous connective tissue in the liver.