Human infections due to nematode helminths nowadays: epidemiology and diagnostic tools.

An update on the epidemiology of intestinal and tissue roundworms, in the world as well as in Italy, is presented. This analysis indicates that the most important changes happened in developed countries, where two main phenomena have been registered. The improvements occurred in social, economic, hygienic and sanitary conditions resulted in decrease of intestinal geohelminth prevalence but, besides, the changes happened at level of other factors, like environment, climate and human behaviour, promote more and more the opportunity for infections due to animal nematode species, which in people induce tissue syndromes. Therefore, the easier circulation of zoonoses among humans constitutes the main remark, which has to be strongly taken into account in countries like Italy, in that it is an emerging sanitary problem, important both for the number of people involved, and for the difficulties induced by their diagnosis. The general trend of "traditional" and "new" nematode infections that can affect humans is analysed, changes in the distribution patterns are tentatively explained, and available diagnostic tools are summarised.