Comparative studies on the morphology, histology, and histochemistry of metacestodes (Hymenolepididae, Dilepididae and Dipylidiidae).

Histological and histochemical methods were used for the studies on 12 species of metacestodes of the genera Coronacanthus, Diorchis, Diplopylidium, Fimbriaria, Hymenolepis, Microsomacanthus, Rodentotaenia, and Triodontolepis. Two basic types of larvae, cysticercoid and cercoscolex, were found. The cyst structure is identical or similar in the cysticercoids using the same group of intermediate hosts (gammarus, planktonic crustaceans, coprophagous beetles, and terrestrial snails). The morphological structure of scolex and neck is the same as in adult cestodes. The length and number of hooks are definitive in morphologically differentiated metacestodes, while the scolex, rostellum and suckers grow still inside the definitive host. The excretory canals open separately at the end of neck in the cysticercoids and in a common opening at the body end of larva in the cercoscolex. Calcareous corpuscles are smaller and more numerous in the scolex and neck than in the cyst wall. Acid mucosubstances prevail in the tissues at the early stages of development. In morphologically differentiated metacestodes, the amount of neutral mucosubstances and glycogen increases. In ageing larvae, the amount of neutral mucosubstances and glycogen gradually decreases and later also decreases the amount of acid mucosubstances, proteins and lipids.

Parasitological investigation of children's sandboxes and dog faeces from public areas of housing development in Prague.

Two hundred sand samples from 50 children's sandboxes and 500 samples of dog faeces collected in 10 Prague housing developments were examined for the presence of parasites. Eggs of three helminth species were found in 28% of sandboxes and eggs and oocysts of 10 species of parasites were found in 10.4% of dog faeces. Toxocara canis occurred in 9 sandboxes and 3.2% of dog faeces, T. cati in 0.2% of dog faeces. The results from housing developments are compared with those from older estates.

Parasitological investigation of children's sand boxes and dog faeces from public areas in old housing districts of Prague.

Eggs and oocysts of 11 species of parasites were recorded in 21 of 50 sand boxes (200 samples) and in 66 (13.2%) of 500 dog faeces samples from parks and grassy areas in Prague. Toxocara canis was found in 12 sand boxes and in 4.2% of faeces samples and T. cati in one sand box and one sample of dog faeces.

Morphology of the cysticercoid of Hymenolepis erinacei (Gmelin, 1789).

The morphology of the cysticercoid of H. erinacei has been studied for the first time by histological methods. The cysticercoid consists of a tailed cyst enclosing the neck and scolex of the cestode. The outer limiting layer surrounds the surface of the cyst, neck and scolex. The tegument of the cyst is characterized by circular and longitudinal layers of fine connective tissue fibres. The tegument of the proximal part of neck and scolex is characterized by microtriches. The basement layer is of fibrous character. The subtegument of the cyst, neck and scolex is formed by outer circular and longitudinal muscle and connective tissue layers and a layer of pyriform cells. The subtegument of the cyst is further formed by an inner longitudinal muscle and connective tissue layer with distinctly prevailing connective tissue fibres forming a lamellar structure. Under the subtegument of the cyst is an inner zone consisting of oval nuclei and cytoplasmic processes, without distinct cellular borders. The parenchyma is situated under the subtegument of the neck and scolex. The inner edge of the cyst and neck is bordered by the inner limiting layer.

Demonstration of calcium salts in excretory corpuscles of larval stages of trematodes.

Calcium salts were demonstrated by Kóssa's method in excretory corpuscles of five species of cercariae and six species of metacercariae. The interference of calcium salts in excretory corpuscles in Gomori's method for the detection of alkaline phosphatase is discussed.

Multiciliate sensory endings in the redia of Echinostoma revolutum (Trematoda, Echinostomatidae).

In addition to uniciliate sensory endings, three types of multiciliate sensory endings have been demonstrated on the anterior end of Echinostoma revolutum redia using transmission and scanning electron microscopy. This is the first finding of multiciliate sensory endings in the parthenogenetic generation of trematodes. In the first type, 12 cilia are situated in a pit communicating with the tegument surface. In the second and third types, there are two and four short cilia, respectively. They protrude from the nerve bulb above the surface of the tegument. The significance of multiciliate sensory endings in rediae and their similarity to multiciliate sensory endings in miracidia and cercariae is discussed.

Ultrastructure of the tail of Echinostoma revolutum cercaria.

The ultrastructure of the tail fins and muscles of Echinostoma revolutum cercaria is described. The longitudinal muscles consist of a primitive type of transversely striated muscle fibres with a well-developed sarcoplasmic reticulum in the Z-band. The fins are formed by a longitudinal tegument fold containing the same components as the remaining part of the tail tegument. The difference between the body and tail tegument is discussed.

Histochemistry of the racemose form of Cysticercus cellulosae.

The racemose form of brain cysticercosis arises from an intense proliferation of the bladder wall after the scolex part has degenerated. The proliferating zones are 2-3 times thicker than the remaining parts of the bladder and are characterized by a densely folded tegument and thick subtegumental and parenchymal layers. The tegument and subtegumental cells contain a large amount of acid mucosubstances with sulpho groups and hydrophilic lipids, and exhibit a high activity of alkaline and acid phosphatases. The parenchyma contains a large amount of glycogen. With the gradual aging of the bladder wall and with the first signs of autolysis, the enzymatic activity as well as the amounts of glycogen, neutral and acid mucosubstances, and proteins decrease, and the hydrophobic lipids prevail over the hydrophilic ones. The results obtained are important for the differential diagnostics of cestode larval stages in the human brain.

Ultrastructural observations on the redia of Echinostoma revolutum (Froelich, 1802).

E. revolutum redia digestive and excretory system ultrastructure, as well as body wall tegument were studied in TEM. The body tegument protrudes in short microvilli and contains uni- and multiciliate sensory endings. The anterior part of the digestive system (pharynx, short oesophagus) is lined with body tegument, the caecum being covered with a flat epithelium with sporadic microvilli. Oesophageal gland cells are filled with minute electron-dense granules. The excretory capillaries joined to large flame cells are composed of spirally wrapped cells, in the cytoplasm of which there are clusters of microtubules. The special features of the digestive system of echinostome rediae, as well as their significance in the antagonistic relationship to the partenitae of other families of trematodes and their pathogenic effect on the intermediate host, are discussed.

Ultrastructure of a new type of sensory ending in Echinostoma revolutum cercaria (Trematoda: Echinostomatidae).

Two pairs of hitherto unknown multiciliate sensory endings have been demonstrated in free-swimming cercariae of Echinostoma revolutum using transmission and scanning electron microscopy. This type of receptor consists of a bundle of 36--40 short, conically projecting cilia ensheathed by a collar formed by a circular evagination of tegument in shape of a cup. The cilia projecting from the centre of a widened nerve fibre, filled with electron-lucid vesicles, possess a well developed basal body and do not contain a ciliary rootlet. The function of this receptor is discussed.

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.

[Biology of cestodes of domestic ducks and wild water birds]. / Biologie tasemnic domácích kachen a divokého vodního ptactva.

Life cycles of 16 cestode species of the families Hymenolepididae and Diploposthidae were studied in 52 ponds of the State Fishery in Bohemia and Moravia. The parasites were recovered from domestic ducks kept on the ponds and from wild birds, mostly of the genera Anas and Aythya, occurring in these water biotopes. Cestode larvae were found in 9 species of Copepoda (9669 out of 1 600 200 examined specimens, i. e. 0.6%) and 3 species of Ostracoda (500 out of 272 300 examined specimens, i. e. 0.18%). Five species of water snails serving as reservoir hosts harboured cysticercoids of 5 cestode species (680 out of 10 212 examined specimens, i. e. 6%). The studies of cestode life cycle under natural conditions were supplemented with 680 successful experiments with intermediate hosts and 179 successful experiments with definitive hosts. The development of larvae was related to the temperature and lasted approximately 13-20 days at 18-25 degrees C. The highest intensity of infection occurred incrustaceans under experimental conditions, a lower intensity was found in crustaceans from duck farms and the lowest in crustaceans from other parts of ponds (e. g., in the case of Fimbriaria fasciolaris in Copepoda, 37, 22 and 10 cysticercoids). The intermediate hosts infected with cestode larvae can live for 3-6 weeks (Copepoda) and 4-7 weeks (Ostracoda) and after invagination of cysticercoids for 20-25 days, on the average. The cysticercoids survive their hosts for 14-18 h at 4-6 degrees C, for 10-11 h at 12-14 degrees C, for 6-7 h at 18-20 degrees C and for 3-4 h at 24-26 degrees C. If they are swallowed by water snails at that time (dead crustaceans are a component of their food), they survive in their digestive tract even for two years (the longest period demonstrated experimentally) and after this time they are able to develop into an adult cestode in the definitive host. The infectivity of cysticercoids increases with their age. It is the lowest immediately after invagination (10-15%), during the stay of cysticercoids in crustaceans it gradually increases (30-60% on days 10-20 after invagination) and it is the highest in cysticercoids from snails (45-55% after 20-50 days in snails, 60-80% after 50-100 days in snails and 70-90% after more than 100 days in snails).

[Distribution of cestodes among domestic ducks and free-living aquatic birds]. / Cirkulace tasemnic mezi domácími kachnami a volne zijcím vodním ptactvem.

In 1959-1975, 3404 water birds of 18 species belonging to six orders were examined for the presence of cestodes. The birds came from 52 localities (ponds) in Bohemia and Moravia where domestic ducks were kept by the State Fishery and where also wild water fowl occurred. Cestodes of 31 species of the families Hymenolepididae, Dilepididae, Amabiliidae and Diploposthidae were found. The total number of examined birds included 2476 domestic ducks (1406 of them, i. e. 56.8%, were positive for cestodes) and 928 free-living water birds (873 of them, i. e. 94.1%, were 30 cestode species. Eight free-living bird species of the orders Anseriformes and Ralliformes (Anas platyrhynchos, Aythya ferina, A. fuligula, Fulica atra, Aythya nyroca, Anas crecca, A. querquedula and A. strepera) are significant for the circulation of cestodes as they harbour 16 cestode species also occurring in Anas platyrhynchos dom.

[Human sparganosis]. / Lidská sparganóza.

Endemic subcutaneous sparganosis was described in right pectoral region of a 29-year-old male Vietnamese. It was caused by 2nd larval stadium (plerocercoid, sparganum) of a tapeworm Spirometra mansoni. Lesion was discovered during the patient's 2nd month in this country, surgery was made 7 months later. Description is the first in Czech Republic.