L. Forró - É. Murai szerk.: Miscellanea Zoologica Hungarica 5. 1989 (Budapest, 1989)

Murai, É., Tenora, F.; StanÄ›k, M.: Atypical strobilocercus (Cestoda: Taeniidae) – a parasite in experimental stocks of Ondatra zibethicus (Rodentia)

Reports about abnormal larval stages of the species H. taeniaeformis have been published by DOLLFUS (1953) and BERNARD (1959, I960!. Their papers indicate, that our material (formation 2) is related to the finding of the big common cysts in the abdominal cavity of two Arvicola terrestris Linne, 1758 specimens in the experimental stock of BERNARD (Belgium, 1960) which contained 42 and 60 H. taeniaeformis larvae, covered with individual envelope. Polystrobilocercus cysts, similar to our formation 3, have not been observed before our findings. In these cases neither polyembryony (e.g. Multiceps)

, nor exogenous larval multiplication by budding (e. g. Taenia crassiceps) were observed. We presume, that the development of each strobilocercus could originate from separate oncosphere. The formation of a teratologic common cyst'without individual envelopes of larvae! is the consequence of repeated heavy invasions. The teratologic cysts of H. taeniaeformis should not be confound with the polycephalic metacestodes of another Taenia (Hydatigera

) species. Several general reports were published about the known polycephalic Taenialarvae (BERNARD 1963; DOLLFUS 1953; KAMIYA et al. 1987; MAHON 1954; MAS-COMA and FELIU 1977; SCHULZ and LANDA 1934; SLAIS 1973; etc. ). The post-oncospheral development of any of this taeniid species is related to H. taeniaef

ormis (excluding Multiceps and another cysticerci with parthenogenetic multiplications). Taenia parva Baer, 1925; Hydatigera krepkogorski Schulz et Landa, 1934; as well as the bicephalic cysticerci of a probably distinct species "

Taenia sp. " from Malaysian Rattus spp. (KAMIYA et al. 1987) are of similar morphology, having pseudostrobila with evaginated scoleces, characteristic hook-crown, specific intermediate and definitive hosts, typical predilection-sites in the intermediate hosts, and geographical distribution. The most important features of these species are summarized in the Table 1. During the post-oncospheral development all the taeniid species with pseudostrobilalike metacestodes have a cyst whith transudate from the host-tissue. The young cysticerci are freely enclosed in the translucent blastocyst and the scoleces are invaginated at first. Further on the metacestode becomes a pseudosegmented body and the scolex evaginates, with hook-crown identical to the adult worm. In normal cases H. taeniaeformis develops only one strobilocercus; in the teratologic cases many strobilocerci are enclosed in a common cyst. In the three taeniid species mentioned above with polycephalic metacestodes the development of larvae in the blastocyst (named coenurostrobilocercus by AGAPOVA 19 50) are the same as in H. taeniaeformis. The tissue of cyst can disappear, or the endbladders can fuse, constituting a common basis for strobilocerci. Figs 16-18. Taenia sp. from Malaysian Rattus spp. (16= bicephalic strobilocercus-like metacestodes from the thoracic cavity; 17= form of the large hooks; 18= form of the small rostellar hooks) (After KAMIYA et al. 19871