Dr. Murai Éva szerk.: Parasitologia Hungarica 13. (Budapest, 1980)
Parasit. Hung. 13. 1980. Recent Observations on the Developmental Cycle of Philometra obturans (Prenant, 1886) (Nematoda: Philometridae) Dr. Kálmán MOLNÁR Veterinary Medical Research Institute of the Hungarian Academy of Sciences, Budapest "Recent observations on the developmental cycle of Philometra obturans (Prenant, 1886) (Nematoda: Philometridae)" - Molnár, K. - Parasit. Hung. 13. 65-66. 1980. ABSTRACT. It was substantiated by infection experiments that nematode larvae parasitic in the vitreous body of the eye of the carrier host pikeperch (Stizostedion lucioperca) develop to Philometra obturans (Prenant, 1886) stages after transfer to the pike (Esox lucius) as final host. After the original incomplete description of Philometra obturans females by PRENANT (1886), the parasite has been studied recently in a greater detail. The first adequate information on the females of Ph. obturans was presented by MORAVEC (1971) and it was also MORAVEC (1978a) who gave a detailed description of the females and the single male specimen found. Prior to MORAVEC, MOLNÁR (1976) studied the developmental cycle of the parasite under experimental conditions. Cyclopeans experimentally infected with Ph. obturans larvae as intermediate hosts were fed to carp fry as carrier hosts, and the latter were placed with pike (Esox lucius) fry, which became infected with the parasite through ingestion of the carp. Ph. obturans stages recovered from the peritoneum of the pikes enabled me to describe the males of the species for the first time, along with subgravid females. MORAVEC (1978b) followed up the development of Ph. obturans in intermediate hosts, and was able to infect pikes directly, with copepodes containing infective larvae. The observations of MOLNÁR (1976) and MORAVEC (1978b) have shown that Ph. obturans may infect the pike both directly, through ingestion of infected cyclopeans, and indirectly, via mediation of carrier hosts. Taking into consideration the predatory habit of the final host, the indirect route of infection is in all probability prevalent. Until recently no data were presented on the location of Philometra larvae inside the body of carrier hosts. A progress in this field was made by MORAVEC and DVKOVA (1978) who demonstrated the occurrence of larvae, previously described by MOLNÁR (1970) as Agamospirura sp. , in the ocular vitreous body of the perch (Perca fluviatilis) and rudd (Scardinius erythrophthalmus), and presented morphological evidence in support of their identity with Ph. obturans larvae. The present experiments were performed to obtain biological evidence of the identity ©f the nematode larvae frequently found in the vitreous body of the pikeperch (Stizostedion lucioperca) with developmental stages of Ph. obturans. MATERIALS AND METHODS Pike fry hatched and reared in the laboratory were used as susceptible hosts. The pikes were fed on fish also reared in the laboratory, to furnish infection-free conditions. The vitreous bodies of 2-summer to 3-summer pikeperches, taken of the Lake Velence, were used as infectious material. The vitreous bodies contained 10-30 nematode larvae on the average. Larvae recovered from the eyes of pikeperches were placed in saline, and were injected into the abdominal cavity of the carp and grasscarp fry used to feed the pikes. The infected fry were exterminated and sectioned under a stereomicroscope. Impression smears of the organs were examined for the presence of parasite stages.
