Ultrastructure of the male reproductive system of the trematode Brachylaimus aequans.

The transmission electron microscopic studies of the trematode Brachylaimus aequans revealed that the seminal vesicle and ejaculatory duct are lined with syncytial epithelium with numerous lamellate processes. The cirrus and genital pore are covered with a spineless tegument, which is almost identical with the body tegument. The testes contain tailed spermatozoa developing during spermiogenesis from biflagellate spermatids whose flagella (9 + 1) fuse with the median cytoplasmic process. The lumina of seminal vesicle, ejaculatory duct and cirrus are filled with spermatozoa.

Ultrastructure of the excretory system of Brachylaimus aequans (Trematoda: Brachylaimoidea).

The ultrastructure of the flame cell, excretory capillaries, ducts, collecting ducts, excretory bladder, and excretory pore of Brachylaimus aequans was studied 6-8 days p.i. The excretory ducts, collecting ducts and excretory bladder are provided with numerous lamellae on the luminal side. The cilia of lateral flames in the excretory ducts have a triated rootlet. The excretory pore is covered by a tegument identical with the body tegument. The syncytium of the excretory bladder is connected with the tegument of the excretory pore by means of a septate desmosome. No lipid or excretory corpuscles have been demonstrated in the excretory system.

Rhabdovirus-like particles in the sporocyst of the trematode Brachylaimus fuscatus from terrestrial mollusc Ponsadenia duplocincta.

Rhabdovirus-like particles containing nucleoprotein in a helix with eight turns was demonstrated by transmission electron microscopy in subtegumental cells and syncytial layer of tegument in Brachylaimus fuscatus sporocyst. This is the first case of virus infection in trematodes. The possibility of transfer of the virus to intra-molluscan parasitic generations of the trematode is discussed with respect to the peculiarities of the life cycles of the family Brachylaimidae.

Scanning electron microscopy of the trematode Hasstilesia ovis.

The trematode Hasstilesia ovis parasitic in sheep was studied by scanning electron microscopy. A single type of sensory papillae was found on the surface of oral and ventral suckers and around the genital pore. The whole surface of body, except the oral and ventral suckers and vicinity of genital pore, is covered with spines. The mostly multipointed and rarely singlepointed spines are of variable size and distribution on different parts of body. They irritate mechanically the intestinal mucosa of the definitive host and thus increase the pathogenic effect of the trematode.

[Morphobiological characteristics of Hasstilesia ovis (Trematoda: Brachylaimidae) and the pathomorphological changes it causes in sheep intestines]. / Morfobiologicheskie osobennosti Hastilesia ovis (Trematoda: Brachylaimidae) i vyzyvaemye eiu patomorfologicheskie izmeneniia v kishechnike ovtsy.

Data on the life cycle of the trematode Hasstilesia ovis are given for the second time in order to point to the errors occurring in helminthological literature. The species has one intermediate host, the terrestrial molluscs Pupilla muscorum and Vallonia costata. Cercariae are turned into metacercariae without leaving molluscs. Pathomorphological changes in the intestine of the sheep caused by these parasites are described. The authors came to the conclusion that the parasites have a pathogenic effect upon the host and cause a disease which should be called hasstileosis.

[Land molluscs--intermediate hosts of trematodes of the family Microphallidae travassos, 1920]. / Nazemnye molliuski--promezhutochnye khoziaeva trematod semeistva Microphallidae travassos, 1920.

Encysted metacercariae of Microphallus sp. were found in the land mollusks Bradybaena duplocincta and Jaminia potaniniana asiatica collected on the slopes of Tien-Shan. The above mollusks are first reported as intermediate hosts of microphallids. The meta cercariae found were fed to white mice, golden hamsters, chickens and nestlings of sparrows and starlings. Maritae developed only in white mice and golden hamsters. Mature trematodes containing 14 to 35 eggs in the uterus were found in the small intestine 66-90 hours after the infection. Small mammals are assumed to be the definitive hosts of these trematodes. The trematodes of Microphallus sp. are characterized by a short life cycle with one intermediate host, land mollusk.