Dr. Murai Éva szerk.: Parasitologia Hungarica 13. (Budapest, 1980)
The first infection experiment was performed in the spring, 1979. Two 4 cm long pikes were infected with larvae collected from vitreous bodies, by the mediation of 2 carps fed to each, and were exterminated 20 days later. One pike host harboured in the ocular cavity one 2. 1 mm long Philometra female, which showed the same morphological features as the Ph. obturans females seen in our earler infection experiments (MOLNÁR, 1976). In the second experiment, performed in the autumn, 1979, three 12 cm long pikes were infected with the parasite, each on four occasions, through feeding on carp and grasscarp fry carrying larvae. On extermination at 4, 6 and 8 weeks after experimental infection, respectively, all three hosts proved to be negative in respect of Ph. obturans infection. DISCUSSION The results of the infection experiments were not unequivocal, as only one of the five infected hosts harboured a Ph. obturans stage, but this finding has in itself substantiated the observation of MORAVEC and DYKOVA (19 78) that the larvae parasitic in the vitreous body of Percidae and Cyprinidae did in fact represent larval stages of Ph. obturans, which were capable of continuing their life cycle in the pike host. The Philometra female found by us did originate from the experimental infection; it no longer showed larval features, and with its 2. 1 mm long body it was three times as large as the stages harboured by the intermediate hosts or carrier hosts. It follows that this stage not only established itself in the new host, but also continued its developmental cycle. As on the basis of earlier findings (MOLNÁR, 1976) we expected to detect developing stages on the peritoneum and around the swimming bladder of the pikes, it was rather surprising to find the parasite in the vitreous body. Regarding, however, that the single male found by MORAVEC (1978a) also originated from the vitreous body of pike it has to be supposed that the early developing stages of Ph. obturans pass through the eye bulb while migrating. REFERENCES MOLNÁR, K. (1970): Beiträge zur Kenntnis der Fischparasitenfauna Ungarns VI. Cestoda, Nematoda, Acanthocephala, Hirudinea. - Parasit. Hung., 3. 51-76. MOLNÁR, K. (1976): Data on the developmental cycle of Philometra obturans (Prenant, 1886) (Nematoda: Philometridae). - Acta Vet. Acad. Sei. Hung. 26. 183- 188. MORAVEC, F. (1971): Nematodes of fishes in Czechoslovakia. - Acta Sc. Nat. Brno, 5. 1-49. MORAVEC, F. (1978a): Redescription of the nematode Philometra obturans (Prenant, 1886) with a key to the philometrid nematodes parasitic in European freshwater fishes. Folia Parasit. (Praha), 25. 115-124. MORAVEC, F. (1978b):The development of the nematode Philometra obturans (Prenant, 1886) in the intermediate host. - Folia Parasit. (Praha), 25. 303-315. MORAVEC, F. - DYKOVA, I. (1978): On the biology of the nematode Philometra obturans (Prenant, 1886) in the fishpond system of Mâcha Lake, Czechoslovakia. - Folia Parasit. (Praha), 25. 231-240. PRENANT, L. A. (1886): Recherches sur les vers parasites des poissons. - Bull. Soc. Sc. Nancy. (1885), ser 2, 7. 89-130. Received: 15 January, 1980 Dr. MOLNÁR, K. Veterinary Medical Research Institute of the Hungarian Academy of Sciences H-1143 Budapest , Hungária krt. 21.
