W.A. Nizami

Seasonal reproduction in Paramphistomum epiclitum and Gastrothylax crumenifer, rumen paramphistomes of the Indian water buffalo, and comparison with the biliary paramphistome Gigantocotyle explanatum.

Abstract Hanna R. E. B. , Williamson D. S. , Mattison R. G. and Nizami W. A. 1988. Seasonal reproduction in Paramphistomum epiclitum and Gastrothylax crumenifer, rumen paramphistomes of the Indian Water Buffalo, and comparison with the biliary paramphistome Gigantocotyle explanatum. International Journal for Parasitology18: 513–521. Monthly in vitro egg-shedding experiments and morphometric analysis of reproductive structures were carried out from July 1985 until November 1986 for the two rumen paramphistome species Paramphistomum epiclitum and Gastrothylax crumenifer and the bile-duct inhabiting Giganlocotyle explanatum. The two rumen species showed marked seasonality in egg production, with peak activity during the monsoon and post-monsoon months. This correlated closely with the appearance of the gonads and other reproductive structures which developed rapidly from an incipient stage in May and June, and regressed in September and October. Worms of all size classes were present in the populations sampled each month, and the mean body size of the samples analysed (from which juveniles were omitted) did not vary significantly throughout the study period. The results supported the concept that individual worms reproduced during several consecutive seasons with only partial replacement of the older cohorts by incoming juveniles each year. The possible natures of the intrinsic or extrinsic ‘trigger’ stimuli which initiate gonad recrudescence and regression are considered. Giganlocotyle explanatum, the biliary species, showed no evidence of seasonal modulation in reproduction, with individual worms displaying the ability to produce relatively large numbers of eggs in all months. The implications of the contrasting reproductive strategies in the rumen and bile-duct inhabiting species are considered with reference to the locations occupied by the adult worms and the ecology of the molluscan intermediate hosts.

Observations on the suitability and importance of the domestic intermediate hosts of Echinococcus granulosus in Uttah Pradesh, India

The present study investigated the suitability and importance of buffaloes, camels, sheep, goats and pigs in maintaining the life-cycle of Echinococcus granulosus in Aligarh, India. A total of 565 (36%) of 1556 buffaloes, 20 (2%) of 1208 goats, 5 (1%) of 559 pigs, 6 (6%) of 109 sheep and two of three camels were found to harbour hydatid cysts. The frequency distribution of the hydatid cysts in each intermediate host species was over-dispersed and in buffaloes cyst fertility increased with increasing cyst size. Of 2171, 95 and four buffalo, goat, and camel cysts examined 327 (15%), two (2%) and three cysts respectively were fertile. No pig or sheep cysts were found to contain protoscoleces. The unfenced buffalo abattoir and the large number of dogs allowed access to the abattoir coupled to the number of buffalo slaughtered in comparison to the other potential hosts, indicates that the buffalo is the most significant host for maintaining the life-cycle of the parasite in this area of India. Applicable control measures for the region are suggested.

Ultrastructural and cytochemical observations on the tegument of three species of paramphistomes (Platyhelminthes:Digenea) from the Indian water buffalo, Bubalus bubalis.

Abstract The tegument of the paramphistomes Gigantocotyle explanatum, Srivastavaia indica and Gastrothylax crumenifer , basically resembles that described for other digeneans. It is folded into numerous furrows and ridges. Sensory papillae occur on the ridges and are particularly prevalent around the oral opening and acetabulum. Two types of tegumental secretory body are produced in separate tegument cells. Mitochondria are absent from the adult surface syncytium and tegumental cells, suggesting that the tegument is largely protective in function and probably has limited absorptive potential.

Biochemical characterization of Taenia hydatigena cysticerci from goats and pigs.

Analysis of the major biochemical components of Taenia hydatigena cysticerci collected from goats and pigs showed marked differences, particularly in glycogen, protein, lipid and DNA levels. Differences were also detected in the levels of cholesterol, triglycerides, free fatty acids and phospholipids. Furthermore, the profile of phospholipid fractions revealed quantitative differences between the two species. It is concluded that the cysticerci of goat and pig origin probably represent two different strains and possibly follow the same pattern of speciation as reported in the related taeniid, Echinococcus granulosus.

Ultrastructural and histochemical observations on the tegument of Gastrodiscoides hominis (Paramphistoma: Digenea)

The tegument of the paramphistome, Gastrodiscoides hominis, is basically similar to that of other digeneans. It is folded into concentrically arranged furrows and ridges bearing numerous tightly packed tubercules, and extends into the oral cavity. An area of specialized tegument is present on the ventral surface, anterior to the disc region. Mitochondria are absent from the tegumental syncytium and underlying tegumental cells, suggesting that the tegument may serve principally as a protective layer rather than in active uptake phenomena. However, extensions of the lymph and parenchyma systems are closely associated with the base of the tegumental syncytium and may provide ATP for active processes. Ciliated and non-ciliated sensory papillae are present, particularly around the oral opening. Numerous lymph channels are present in the sub-tegument and may be involved in osmoregulation.

Ultrastructural and histochemical observations on the foregut and gut caeca of Gigantocotyle explanatum, Gastrothylax crumenifer and Srivastavaia indica (Trematoda:Paramphistomidae) ☆

Abstract The fine structure and histochemistry of the gut is similar in Gigantocotyle explanatum, Gastrothylax crumenifer and Srivastavaia indica . The gut consists of two morphologically distinct regions; the foregut, comprising the pharynx and oesophagus, is tegument lined, while the two intestinal caeca are lined by a single layer of gastrodermal cells. The pharyngeal tegument resembles the external tegument and contains T1 and T2 secretory inclusions. The oesophagal tegument displays T1 and T3 bodies. The latter displays intense reactions for acid phosphatases and non-specific esterases and probably initiate extracellular digestion. Gastrodermal cells produce glycoprotein-containing secretory bodies which accumulate apically and following eccrine discharge are probably involved in further digestion of food. Endocytosis apparently does not occur. The apical membrane of each gastrodermal cell is greatly amplified by numerous elongate microvilli, which presumably compensate for the lack of a trans-tegumental route for asborption of nutrients in these flukes.

In vitro effects of mebendazole on the carbohydrate metabolism of Avitellina lahorea (Cestoda).

Mebendazole (3.3 mumol), causes in vitro glycogen depletion and inhibits glucose uptake in Avitellina lahorea. Inhibition of non-specific phosphomonoesterases and adenosine triphosphatase by mebendazole discussed in the light of the role of phosphatases in uptake mechanisms. Mebendazole has no effect on hexokinase which has broad substrate specificity but influences the activities of some glycolytic enzymes such as phosphorylase, phosphoglucomutase and glucose-6-phosphatase. Thus, it appears that mebendazole also acts to disrupt certain enzymes of carbohydrate metabolism which may ultimately cause death of the parasite.

Ultrastructure and histochemistry of the protonephridial system of juvenile Paramphistomum epiclitum and Fischoederius elongatus (Paramphistomidae: Digenea) during migration in indian ruminants

The protonephridial system of juvenile Paramphistomum epiclitum and Fischoederius elongatus consists of a bilaterally symmetrical arrangement of primary, secondary and tertiary ducts which connect individual flame cells with a simple common bladder. Primary and secondary ducts are formed from columns of adjoining cells which provide an epithelial lining, whose luminal surface is elaborated with either short tubercles or lamellae. Groups of cilia project from the luminal surface at frequent intervals along secondary ducts. By contrast, the tertiary ducts and bladder are lined with a nucleated syncytium which ends at a junctional complex formed with the terminal canal. The latter is continuous with the tegumental syncytium and opens at a nephridiopore on the postero-dorsal surface. Tertiary ducts of mature cercariae contain concretions which are voided by migrating juveniles in whose tertiary ducts lipids are progressively accumulated. Evidence for the role of protonephridia in excretion and possibly in osmoregulation and ionic balance is currently examined.

Ultrastructure and histochemistry of the tegument of juvenile paramphistomes during migration in Indian ruminants.

The tegument of juvenile Paramphistomum epiclitum and Fischoederius elongatus (Paramphistomidae: Digenea) resembles those of other digeneans. Seven types of papillae were observed, mostly on the oral and acetabular surfaces, and increase in number during migration. Also evident are two types of secretory body (T1 and T2) which are synthesized separately in tegumental cytons underlying the syncytium. Exocytosis of T2 bodies occurs at the apical membrane and appears to contribute to a fibrous glycocalyx. The tegumental syncytium lining the pharynx and acetabulum is thinner and has a higher capacity for vacuolation than the general tegument. These may represent important sites for osmoregulation. The absence of mitochondria from the tegument in migrating juveniles suggests limited involvement in energy demanding processes. Pigmentation of the subtegument is first evident in mature cercariae and is progressively eliminated during migration.

Ultrastructural and histochemical observations on the epidermis, presumptive tegument and glands of the miracidium of Gigantocotyle explanatum (Trematoda : Paramphistomidae)☆

Abstract Dunn T. S. , Hanna R. E. B. and Nizami W. A. 1987. Ultrastructural and histochemical observations on the epidermis, presumptive tegument and glands of the miracidium of Gigantocotyle explanatum (Trematoda: Paramphistomidae). International Journal for Parasitology 17 : 885–895. The miracidium is invested with 20 ciliated epidermal cells arranged in four tiers (6: 8: 4: 2 = 20). Non-ciliated ridges of cytoplasm, located between the epidermal cells, are continuous with an extensive multivesiculate syncytium which underlies the body musculature and comprises the main bulk of the miracidium. It is suggested that the syncytium represents the presumptive sporocyst tegument. Two distinct types of glands are present in the anterior region of the miracidium, viz . a large, syncytial apical gland and a single pair of small, unicellular lateral glands. The apical papilla is formed by the bounding membrane of the apical gland, which is elevated into a complex network of anastomosing lamellae. The lateral glands terminate in discrete rosetteshaped areas on the apical papilla. The possible function of glands in digenetic miracidia and the nature of their secretions are discussed.