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Human fascioliasis infection sources are analysed for the first time in front of the new worldwide scenario of this disease. These infection sources include foods, water and combinations of both. Ingestion of freshwater wild plants is the main source, with watercress and secondarily other vegetables involved. The problem of vegetables sold in uncontrolled urban markets is discussed. Distinction between infection sources by freshwater cultivated plants, terrestrial wild plants, and terrestrial cultivated plants is made. The risks by traditional local dishes made from sylvatic plants and raw liver ingestion are considered. Drinking of contaminated water, beverages and juices, ingestion of dishes and soups and washing of vegetables, fruits, tubercles and kitchen utensils with contaminated water are increasingly involved. Three methods to assess infection sources are noted: detection of metacercariae attached to plants or floating in freshwater, anamnesis in individual patients, and questionnaire surveys in endemic areas. The infectivity of metacercariae is reviewed both under field conditions and experimentally under the effects of physicochemical agents. Individual and general preventive measures appear to be more complicated than those considered in the past. The high diversity of infection sources and their heterogeneity in different countries underlie the large epidemiological heterogeneity of human fascioliasis throughout.

Before the 1990s, human fascioliasis diagnosis focused on individual patients in hospitals or health centres. Case reports were mainly from developed countries and usually concerned isolated human infection in animal endemic areas. From the mid-1990s onwards, due to the progressive description of human endemic areas and human infection reports in developing countries, but also new knowledge on clinical manifestations and pathology, new situations, hitherto neglected, entered in the global scenario. Human fascioliasis has proved to be pronouncedly more heterogeneous than previously thought, including different transmission patterns and epidemiological situations. Stool and blood techniques, the main tools for diagnosis in humans, have been improved for both patient and survey diagnosis. Present availabilities for human diagnosis are reviewed focusing on advantages and weaknesses, sample management, egg differentiation, qualitative and quantitative diagnosis, antibody and antigen detection, post-treatment monitoring and post-control surveillance. Main conclusions refer to the pronounced difficulties of diagnosing fascioliasis in humans given the different infection phases and parasite migration capacities, clinical heterogeneity, immunological complexity, different epidemiological situations and transmission patterns, the lack of a diagnostic technique covering all needs and situations, and the advisability for a combined use of different techniques, at least including a stool technique and a blood technique.