The surface topography of 15-day-old adult Echinoparyphium recurvatum (Von Linstow, 1873) sensu stricto, from an isolate of the parasite utilizing Lymnaea peregra as first intermediate host in southern England, is described and illustrated using scanning electron microscopy, and is compared to those of other Echinoparyphium species from Europe, and with those of E. recurvatum of East Asian origin. The general morphology of tegumental features was found to be very similar to that of worms of the same age observed in a previous study on a Korean isolate of E. recurvatum. Comparison of collar and body spination of E. recurvatum with other 45-collar-spined members of the genus in Europe revealed some significant differences in morphology. Collar spines of E. recurvatum were found to be shorter and more pointed than those of Echinoparyphium mordwilkoi. The body spines of E. recurvatum are rounded and scale-like, extending just beyond the ventral sucker, contrasting with the pointed, thorn-shaped body spines of E. mordwilkoi, extending posteriorly to the level of the second testis. Body spine shape and distribution in E. recurvatum were found to be more similar to those of Echinoparyphium pseudorecurvatum. The value of SEM studies in elucidating the relationship between members of the genus Echinoparyphium in Britain/Europe and those in Africa, Asia and North America is suggested.

Here the intestinal helminth infracommunities of 218 double-crested cormorants (Phalacrocorax auritus) from 11 locations in Alabama, Minnesota, Mississippi and Vermont are documented. Trematode infections were present in 98% of hosts; 65% of cormorants carried cestode infections, 4% were infected with acanthocephalans and 66% had nematode intestinal parasites. Parasite infracommunities of hosts collected on wintering grounds had higher richness and diversity than did birds collected on breeding grounds. Differences in parasite richness and diversity between male and female P. auritus were also detected, but not between immature and mature bird hosts. Parasite intensity did not differ by sex, maturity, or between breeding and wintering season. The most common parasite was Drepanocephalus auritus (spathans), which is recognized as a disease agent that negatively impacts the catfish aquaculture industry in the US. Echinochasmus sp. in double-crested cormorants is documented for the first time in the United States. We suggest that the differences observed among parasite infracommunities could be associated with the foraging distances travelled by P. auritus during breeding and wintering seasons, which is limited by allocation of parental care during the breeding season.

A morphological and immunohistochemical study of larval migration patterns was performed in gerbils that were infected once (primary infected group) or twice (secondary infected group) with 1500 eggs of Toxocara canis. Animals from the primary infected and the re-infected group were killed at different times after infection, and larvae were counted in the intestines, liver, lungs and brain. Fragments of all organs were formalin fixed and paraffin embedded for histology and immunohistochemistry analyses (using polyclonal anti-Toxocara serum raised in rabbits infected with T. canis). In the primary infected group, larvae were more abundant in the intestine at 24 h, in the liver and lungs between 24 and 72 h and in the brain after 96 h; larvae predominated in the brain for up to 60 days after infection. In the re-infected group, an increase in the number of larvae in the liver and a reduction in the number of larvae in the brain was observed up to 60 days after re-infection. Inflammatory reactions were absent or limited. Eosinophils and loose granulomata were observed around the larvae and their antigens in the primary infected group and were more severe. Many eosinophils and typical epithelioid granulomata were observed around larvae in the re-infected group. These results demonstrate that the migration pattern of T. canis larvae in gerbils is similar to that in mice and rats, exhibiting a late neurotropic stage. In the re-infected group, there was histological evidence of an adaptive T-helper 2 (Th-2) response, and larvae were apparently retained within granulomata in the liver, without obvious signs of destruction.

Early studies by light microscopy provided preliminary data on the fine structure of Strongylus vulgaris (Looss 1900). The present study employed transmission electron microscopy to investigate particular structures in the buccal capsule especially the dorsal gutter (DG) and teeth. The DG is a tube containing the terminal duct of the dorsal oesophageal gland (DOG) surrounded by two concentric canals. Putative pores indicated in the wall of the DG seen in other studies are revealed as honey-combed, fibrous, structures on each side of the ventral lamella. This lamella is formed by the wall of the DG internal canal running the length of the DG. Secretions of the DG canals are released through the dorsal gutter duct (DGD) which passes through the teeth bases at the base of the buccal capsule. Teeth have a vesicular cytoplasmic core containing various organelles.

An aggregative dispersive dichotomy (ADD) model is presented to describe the distribution of parasites in host populations. The ADD model is a mathematical construct which provides two complementary measures extracted from a reformulated negative binomial (NBD) and an inequality model, which combine to capture observed patterns of a parasitic infection. The dispersion element is modelled using the NBD with the threshold set at a parasite level above zero. By applying binomial dichotomy, the host community is divided into two sub-populations, one including hosts harbouring parasites up to the threshold and the other with parasites above the threshold level. The k parameter, derived from the NBD, provides a cumulative probability. However, k is relatively insensitive to variations in the degree of aggregation, a known feature of the NBD model. The aggregation of parasites above the threshold in the host sub-population is evaluated by using an inequality model which is indexed by a scale-free parameter δ(δ ≥ 1) and provides an accurate measure of parasite aggregation. Applications of this model are made from field and simulated data in wood mouse populations infected with the trichostrongylid nematode Heligmosomoides polygyrus from a woodland site in Surrey.

Viktorocara torea and Sciadiocara tarapunga n. spp. are described from specimens from the gizzards of Haematopus ostralegus finschi and Larus novaehollandiae scopulinus respectively. All hosts were collected in the South Island, New Zealand. V. torea is characterised by the possession of the doubly bifid apices to the long spicule and absence of a subterminal spicular spur; presence of six preanal papillae, the first and second widely spaced: the muscular region of the oesophagus constituting about one quarter of the total length of the oesophagus. S. tarapunga is similar to S. umbellifera, but differs in having the muscular region of the oesophagus shorter than the glandular region, a more slender body in both sexes, much smaller spicules (78–91 μm and 275–359 μm) with the right spicule not more than one-third as long as the left one. The long spicule bears a pair of similar, rounded, laterally placed spatulate apices. It is suggested that Sciadiocara umbellifera of previous authors may encompass more than one species.

Ninety-seven cliff swallows, Petrocheilidon pyrrhonota, were examined from North-eastern Colorado. Five species of nematodes (Hadjelia pyrrhonotae sp. n., Acuaria sp., Microtetrameres inermis, Splendidofilaria sp., Diplotriaena sp.); four species of trematodes (Concinnum minor sp. n., Brachylecithum marinholutzi, Plagiorchis maculosus, Stomylotremagratiosus); and two species of acanthocephala.(Mediorhynchusgrandis, Mediorhynchus papillosus (juveniles)) were recovered. All eleven species of helminths represent new host records. Six new records (Hadjelia pyrrhonota, Microtetrameres inermis, Concinnum minor, Brachylecithum marinlwlutzi, Plagiorchis maculosus, Stomylotrema gratiosus) were established for Colorado. Five new records (Hadjelia pyrrhonota, Microtetrameres inermis, Concinnum minor, Brachylecithum marinlwlutzi were established for North America.

An average of 11% of adult Schistosoma curassoni were recovered from 200 albino mice which had been infected subcutaneously with 150–250 cercariae. Worms were primarily found in the portal veins. The average number of intrauterine eggs per female during the first 100 days p.i. was 13 and the average number of eggs produced per female worm was 103 per day for the first 60 days post oviposition. The majority of eggs were recovered from the liver (98·3%). The oograms were determined until day 95 p.i. For screening of antischistosomal drugs it is recommended not to use infections older than 60 d.p.i.

In 1911 Looss wrote as follows : “ Up to the present time Agchylostoma duodenale is known to occur with certainty only in Man. It is true that the older works and text-books state that it has also been found in various species of animals (some species of apes, the tiger, the dog, the horse, etc.). In opposition to these statements, attempts made on various occasions to infect adult dogs, cats, rabbits, guineapigs, rats, mice, etc., with the parasite yielded entirely negative results. Only with quite young dogs and cats (not more than three or four months old) was the infection partly successful. The results of all these attempts at artificial infection thus support the view that the older statements as to the natural occurrence of Agchylostoma duodenale in animals are founded on a confusion of this species with others …”

The present communication evaluates the antigen B (AgB) family of bubaline isolates of Echinococcus granulosus with respect to their conformational propensity and also discusses the stretches of agretope. AgB, which is abundantly present in hydatid cyst fluid, is encoded by a gene family, AgB1–AgB5. Hydatidosis is of zoonotic and economic importance in India. Buffaloes serve as the intermediate host. However, to date the AgB family has not been fully analysed. During the present study two different primers used for amplification of AgB1 revealed homology to Echinococcus canadensis (G8) as well as E. granulosus sensu stricto (G1/G2). The sequence of AgB3 is homologous to that of the well-defined species, Echinococcus ortleppi (G5), and the predicted amino acid sequence of AgB4 is homologous to bovine isolates identified earlier. α- and β-amphipathic structures were recorded in all the antigens designated as T-cell receptor sites. The antigenic index of different stretches correlated with hydrophilicity because the hydrophobic residues are not accessible to the cells. In this study, we investigated the binding propensity of AgB to MHC II in order to determine stretches of agretope. Agretopes began with four hydrophilic residues. Two to three additional hydrophilic residues were present in the internal motif. This comparison of AgB and its family of bubaline isolates, with respect to their sequence information, α- and β- amphipathic regions, antigenic index and stretches of agretope is the first such report from India.

The prevalence of onchocercosis was determined in three Local Government Areas (Ezeagu, Oji-River and Uzo-Uwani) in Enugu State, Eastern Nigeria between March 1989 and June 1990. Enugu State was shown to be mesoendemic for onchocercosis. A total of 7472 (26.9%) persons out of 27,831 examined were positive for skin microfilariae. There was no significant difference in infection rates between males (27.6%) and females (26.2%). Of the 118 villages surveyed only five had no inhabitant with skin microfilariae. There was a progressive increase of prevalence to the second decade of life, although 96.6% of cases with skin microfilariae had only a light infection. Onchocercomata prevalence was recorded as 27.3% which tallies with the prevalence of skin microfilariae at 26.9% hence onchocercomata prevalence may be used as a yardstick for predicting skin microfilariae prevalence.

Two types of neurosecretory cells (NSC), large a cells and small β cells were detected on the basis of their size and characteristics as shown by aldehyde fuchsin and chrome haematoxylin-phloxin staining. A histochemical survey of the neurosecretory material indicates that it is a glycoprotein. Phosphatases and esterases present in NSC probably help in the transfer of metabolites and their hydrolysis and in the control of secretory material produced in a NSC, while SDH provides the necessary energy for the synthetic activity of the latter. The role of neurosecretion in governing the reproduction of this parasite is discussed.

Specimens of elasmobranchs, collected in the State of Santa Catarina, Brazil, were parasitized with Poecilacanthoidea trypanorhynch cestodes. Sharks of the species Prionace glauca harboured Callitetrarhynchus gracilis and Floriceps saccatus, and those of the species Sphyrna zygaena were infected with Callitetrarhynchus speciosus. Details of the proglottids of F. saccatus, provided by bright-field, and/or scanning electron microscopy, are described. Adults of F. saccatus are reported for the first time in the Brazilian coast.

In 1925 Chapin reviewed the genera Syngamus and Cyathostoma and in the review described a new species of Syngamus which he had obtained from the American Crow, Corvus brachyrhynchos: this, he called Syngamus gracilis. It had been found in a bird from the Zoological Gardens at Philadelphia. He was of the opinion that this species had probably been recovered before from the American Crow but that its specificity had not been recognised. He assumes, in fact, that some if not all of the records of the occurrence of S. trachea in this species of host, and by inference probably in other Corvidae also, are incorrect and that S. gracilis is the species found. He bases this assumption on the physiological reactions of the parasite. It is a well known fact that S. trachea does not establish itself well in chickens and can in fact only reach maturity in young or very sick birds. The turkey is generally assumed to be the natural host of this helminth and Chapin is of the opinion that if S. trachea cannot establish itself satisfactorily in the chicken, then it is highly improbable that it can do so in the crow. For the chicken and the turkey are closely related phylogenetically, both being gallinaceous birds while the crow belongs to the Corvidae, which has no near kinship with the Galliformes.

The catchment area of the Volta River covers an area of 153,000 sq. miles of which approximately 64,000 sq. miles is located in Ghana. This forms about 70 per cent of the total area of the country. Most of the catchment area in Ghana consists of savanna; including the Guinea savanna of the Northern region, the derived savanna of Northern Ashanti adjacent to it on the south, and the coastal savanna which is separated from the interior savanna by a broad belt of tropical forest. With the exception of some of the headwaters of the Afram the tropical forest is drained by smaller rivers including the Tano, Ankobra and the Pra which are not part of the Volta Basin. Most of the Volta catchment area lies in an area with a well defined wet season occurring between June and September.

In May 1964, the huge dam across the Volta River at Akosombo was completed and the dendritic Volta Lake began to form. It reached its full size after the rainy season of 1968 when it covered an area of approximately 3,275 sq. miles.

Four new species of digenetic trematodes of birds from Palawan Island, Philippines, are described: Galactosomum palawanense (Heterophyidae) from Ceyx r. rufidorsus; Euamphimeruspalawanensis (Opisthorchiidae) from Gallus g. gallus; Strigea palawanensis (Strigeidae) from Strix seluputo wiepkeni; Paramonostomum palawanense (Notocotylidae) from Centropus sinensis bubttlus. Stephanoprora sp. (Echinostomatidae) from Spilornis cheela palawanensis and Euamphimerus sp. from Chalcophaps i. indica are briefly described but not allocated to species as the specimens are incomplete.

Protective immunity to the subperiodic human filariid, Brugia malayi, was explored in the rodent host, Mastomys coucha after vaccination with subcellular fractions derived from the adult stage of the parasite. The highest level of protection was conferred in animals vaccinated with the ‘mitochondria rich’ (MT) fraction, in which microfilaraemia and worm burden were markedly reduced by 67.2 and 65.9%, respectively, followed by the ‘nucleus rich’ (NR) fraction, showing reductions of 62 and 52.3%, respectively, over the non-immunized control group. Mastomys vaccinated with MT and NR, displayed a significant increase in the level of antigen-specific serum immunoglobulin G (IgG). The levels of IgG2a, IgG2b and IgM antibody isotypes were remarkably elevated in both the MT and NR immunized groups, while IgG1 and IgG3 levels were low. Apart from antibodies, both these fractions also led to marked antigen-specific lymphoproliferation in vitro, along with enhanced release of nitric oxide by peritoneal macrophages. There was an increased population of CD4+ and CD8a+T-cells in MT immunized animals, as measured by flow cytometry, accompanied by elevated levels of proinflammatory cytokines; interferon gamma (IFN-γ), tumour necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) in the culture supernatants of the activated splenocytes. The results suggest that both NR and MT contain proinflammatory molecules which evoke a protective Th1 type of immune response.

A specimen of Cysticercus tenuicollis is described, which contained many daughter cysts in various stages of development. One of these cysts was a well developed daughter cysticercus.

The daughter cysts at all stages of development, are lined internally by a distinct cuticle, and have no scolices. The daughter cysticercus, like the parent bladder, has an outer cuticle and a well developed scolex and receptacular appendage.

There is evidence for regarding the daughter cysticercus as having been formed from a daughter cyst by a process of evagination of the latter in such a way that the cuticle has come to lie on the outside, rather than by a process of vesiculation of a scolex.

The daughter cysts appear to be homologous with the brood-capsules of Echinococcus. They are not strictly homologous with daughter hydatids or daughter coenuri.

A retrospective analysis of slaughterhouse records during the pre-veterinary-organized meat inspection era (before 1970) for cysticercosis and hydatidosis in food animals showed that parasitic cysts were documented but not identified and that the numbers of slaughtered animal species harbouring various parasitic cysts were not recorded. Since the various parasites which the meat inspectors observed were not identified, the prevalence of species encountered could not be determined.

An analysis of abattoir records during the veterinary meat inspection era showed that Cysticercus bovis and C. cellulosae infections were documented in cattle and pigs respectively. Moreover, hydatid cysts were detected in cattle, pigs, sheep, goats and camels.

The data obtained from this survey cannot be wholly relied upon as accurate, but it can be used as a baseline for the proper evaluation of the status of these zoonotic parasitic diseases in future co-ordinated researches.