INTRODUCTION. Rodents represent intermediate hosts of several cestodes, including Echinococcus multilocularis and other taeniid species (Husák et al., 2025. Front Vet Sci., 12:1571082). Among these, the taxonomy of Hydatigera (formerly Taenia) taeniaeformis sensu lato (s.l.) was revised based on molecular and morphological analyses, reclassifying H. taeniaeformis s.l. into H. taeniaeformis sensu stricto (clade A), H. kamiyai (clade B) as a new species, and Hydatigera sp. (clade C). In particular, the name H. kamiyai n. sp. was attributed to a “cryptic lineage” predominant in northern Eurasia using voles and the genus Apodemus as intermediate hosts, while the specific status of clade C from the Mediterranean remained unresolved due to a lack of data on morphology and intermediate hosts (Lavikainen et al., 2016. Int J Parasitol., 46: 361–374). MATERIALS AND METHODS. A total of 144 rodents were trapped in 18 locations within the Apuan Alps Regional Park in Tuscany as part of a zoonotic pathogen monitoring project conducted by the University of Udine. Target specimens were processed for organ collection under controlled laboratory conditions following biosafety protocols. Livers were examined for the presence of cysts, which were isolated and stored at −20 °C. Ten cysts (0.5–1 cm) were isolated from eight Apodemus sylvaticus. Cysts were dissected under a stereomicroscope, and a metacestode was found in all of them. In nine cysts, a strobylocercus-type larva was identified, while in one cyst a cysticercus-type larva was found. Metacestodes were morphologically analysed, then DNA was extracted and PCR amplification was conducted using primers Cest3-Cest5seq (Trachsel et al., 2007. Parasitology, 134: 911–920). RESULTS AND CONCLUSION. The strobylocercus-type metacestodes measured 4–13 cm in length and showed a protoscolex with large rostellar hooks, four suckers, and a prominent segmented strobila. The cysticercus-type metacestode measured approximately 1 cm. Three sequences obtained so far (approximately 220 bp) showed 99.5% identity with the reference sequence of Hydatigera sp. clade C (LC008533), originally obtained from an adult cestode found in Felis silvestris in France (Lavikainen et al., 2016). These results need to be further validated with a larger number of samples and longer sequences. However, considering that Hydatigera sp. clade C is believed to be confined to the Mediterranean, that its intermediate hosts are unknown, and that further studies are needed to classify Hydatigera sp. either as a distinct species or a variant of H. kamiyai (Lavikainen et al., 2016), this work could contribute to clarifying these taxonomic and epidemiological issues.
OCCURRENCE OF HYDATIGERA SPP. (CLADE C) IN LIVER CYSTS OF APODEMUS SYLVATICUS FROM APUAN ALPS, ITALY
Daniele Fabbri;Paola Beraldo
2026-01-01
Abstract
INTRODUCTION. Rodents represent intermediate hosts of several cestodes, including Echinococcus multilocularis and other taeniid species (Husák et al., 2025. Front Vet Sci., 12:1571082). Among these, the taxonomy of Hydatigera (formerly Taenia) taeniaeformis sensu lato (s.l.) was revised based on molecular and morphological analyses, reclassifying H. taeniaeformis s.l. into H. taeniaeformis sensu stricto (clade A), H. kamiyai (clade B) as a new species, and Hydatigera sp. (clade C). In particular, the name H. kamiyai n. sp. was attributed to a “cryptic lineage” predominant in northern Eurasia using voles and the genus Apodemus as intermediate hosts, while the specific status of clade C from the Mediterranean remained unresolved due to a lack of data on morphology and intermediate hosts (Lavikainen et al., 2016. Int J Parasitol., 46: 361–374). MATERIALS AND METHODS. A total of 144 rodents were trapped in 18 locations within the Apuan Alps Regional Park in Tuscany as part of a zoonotic pathogen monitoring project conducted by the University of Udine. Target specimens were processed for organ collection under controlled laboratory conditions following biosafety protocols. Livers were examined for the presence of cysts, which were isolated and stored at −20 °C. Ten cysts (0.5–1 cm) were isolated from eight Apodemus sylvaticus. Cysts were dissected under a stereomicroscope, and a metacestode was found in all of them. In nine cysts, a strobylocercus-type larva was identified, while in one cyst a cysticercus-type larva was found. Metacestodes were morphologically analysed, then DNA was extracted and PCR amplification was conducted using primers Cest3-Cest5seq (Trachsel et al., 2007. Parasitology, 134: 911–920). RESULTS AND CONCLUSION. The strobylocercus-type metacestodes measured 4–13 cm in length and showed a protoscolex with large rostellar hooks, four suckers, and a prominent segmented strobila. The cysticercus-type metacestode measured approximately 1 cm. Three sequences obtained so far (approximately 220 bp) showed 99.5% identity with the reference sequence of Hydatigera sp. clade C (LC008533), originally obtained from an adult cestode found in Felis silvestris in France (Lavikainen et al., 2016). These results need to be further validated with a larger number of samples and longer sequences. However, considering that Hydatigera sp. clade C is believed to be confined to the Mediterranean, that its intermediate hosts are unknown, and that further studies are needed to classify Hydatigera sp. either as a distinct species or a variant of H. kamiyai (Lavikainen et al., 2016), this work could contribute to clarifying these taxonomic and epidemiological issues.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
