Trichinella pseudospiralis an elusive nematode

Trichinella pseudospiralis is one of the three species whose larvae do not encapsulate after muscle cell differentiation, and the only one infecting both mammals and birds. More than 40 years after its discovery, the epidemiology remains, at least in part, still enigmatic. The aim of this work was to reconsider the current knowledge on the T. pseudospiralis epidemiology by collecting the information available in the literature and in the website of the International Trichinella Reference Center. Over the last decade, there was an increasing number of reports of T. pseudospiralis due to the increased use of the digestion tests. T. pseudospiralis was detected in 18 mammalian species (3 species of Dasyuridae; 2 species of Muridae; 4 species of Canidae; 3 species of Felidae; 2 species of Mustelidae; 1 species of Procyonidae; 1 species of Ursidae; and swine) including humans, and 8 avian species (3 species of Accipitridae; 1 species of Cathartidae; 1 species of Corvidae; 1 species of Tytonidae; 2 species of Strigidae) for a total of 249 isolates from Asia, America, Australia, and Europe. In the European Union, T. pseudospiralis has been documented in 19 out of 28 countries. The zoonotic role of this parasite was documented in 128 persons with trichinellosis. The number of mammals tested for Trichinella spp. by digestion has been much higher than that of birds, thus the role played by birds in the epidemiology of T. pseudospiralis still needs to be elaborated in more detail. The results may suggest that T. pseudospiralis, allowing to make up for the lower prevalence than that of the encapsulated species in the host populations, uses a wider host range.