A Comprehensive Review of Alaria alata (Goeze 1782) (Platyhelminthes, Trematoda) in Different Animal Hosts

Abstract

This review provides a comprehensive overview of the occurrence of Alaria alata (Goeze 1782) trematodes in first, second, definitive, and paratenic hosts, including wild and do- mestic animals. This systematic review was conducted using two academic databases: Web of Science and Google Scholar. A total of 119 articles containing data on 18 different A. alata hosts from 30 countries were analyzed. Based on the literature review, the best-studied group were definitive hosts (Mustelidae, Canidae, and Felidae), followed by paratenic, first (snails), and second intermediate hosts (amphibians). For these key intermediate hosts—snails and frogs—the data remain sparse, highlighting a gap in understanding the possible scale of the spread of A. alata. Among definitive hosts, Canids showed a higher prevalence, reinforcing their significant role in the parasite’s spread. Additionally, some Procyonidae, Felidae, and Mustelidae have been identified as paratenic hosts, with mesocer- cariae localized in their muscle tissues. Considering that meat of unknown origin or meat that is insufficiently heat-treated may contribute to human infection, prevalence rates as high as 40–50% in wild boar highlight the critical need for complex research. Furthermore, this review clarifies the role of host groups in the life cycle and transmission of A. alata, providing key epidemiological information and emphasizing the importance of continued research to fill knowledge gaps.