Only three of the four species assigned to the genus Cooperioides are considered valid and are redescribed. The fourth species Cooperioides kenyensis Daubney, 1933 is considered a synonym of Cooperioides hamiltoni (Mönnig, 1932) Mönnig, 1933. A key to the species of the genus is given and their hosts and geographical localities are listed.

1. Skrjabinotaenia cricelomydis n.sp. is described from 18 specimens taken from Cricetomys gambianus Waterhouse, near Ibadan, Nigeria.

2. Apolytic proglottides are described and also some details of development of the eggs.

3. Details of the anatomy are given and their significance in deciding the relationship with other genera and species is discussed.

4. The regrouping of a number of species into the genus Skrjabinotaenia is proposed.

5. The diagnostic features of the genera Catenotaenia and Skrjabinotaenia are restated.

In order to characterize GATA transcription factors in Echinococcus granulosus, a PCR-based cloning strategy was developed. Degenerate oligonucleotides were designed for the most conserved sequence in GATA proteins that include 20 amino acids of the zinc domain. A 60 bp fragment was isolated that had high homology among this sequence and those reported in other species. An analogous sequence was obtained by performing the same procedure with DNA from the free living platyhelminth Dugesia tigrina. High stringency Southern blotting experiments confirmed the presence of this sequence in the parasite genome.

It is demonstrated that Schistosoma curassoni, a parasite of sheep, cattle and goats in parts of West Africa, will live for at least 8 years 5 months in a sheep. The sheep was exposed to 500 cercariae of S. curassoni liberated from infected Bulinus wrighti. The sheep died of natural causes, and at post-mortem 28 pairs of adult S. curassoni were removed from the mesenteric and rectal veins. All female worms were gravid, and eggs were hatched from faeces to produce miracidia. The development of immune responses of the host had apparently little or no effect on the viability of the eggs. Histological studies of the liver, small and large intestines revealed mild pathological symptoms. The longevity of S. curassoni is the first record of longevity of schistosomes to be based on worm counts.

Oxysomatiinae: Sexual dimorphism not marked; mouth with three lips; body delicate; pharynx short and muscular; females with ovaries much reduced, uteri divergent, amphidelph, contain a reduced number of eggs arranged in moniliform manner and towards the centre eggs with well developed larvae or even free larvae may be present; vulva behind middle of body; males with subequal or equal spicules of moderate size; accessory piece present. Parasites of amphibians and reptiles. Type species: R. simples (Travassos, 1925) Travassos, 1927.

Nondenatured and denatured total RNA from the tapeworm Diphyllobothrium dendriticum (Cestoda) was analysed by agarose gel electrophoresis. It was found that the large subunit ribosomal RNA (lrRNA) is 28.0S and the small subunit ribosomal RNA (srRNA) is 19.5S. Following denaturation the 28.0S rRNA was disrupted into a 19.5S subfragment and a 20.7S subfragment due to the presence of a centrally located hidden break. By hybridization of Northern blot membranes with oligonucleotide probes specific for the 5′- and 3′-ends of the lrRNA respectively, we have shown that the 19.5S sub-fragment is from the 5′-end (the α-subfragment) and the 20.7S subfragment from the 3′-end (the β-subfragment) of the 28.0S rRNA of D. dendriticum.

The humoral response of guinea pigs infected with doses of 500, 1000, and 1500 infective Toxocara canis ova were measured by counterimmunoelectrophoresis and indirect haemmagglutination tests one to five weeks after infection. The antigens used in these measurements were prepared from adult T. canis. Counterimmunoelectrophoresis showed lower titres than haemagglutination method, but it was performed rapidly and with case. The possible use of these techniques for immunodiagnosis of human visceral larval migrans is discussed.

Schistosomiasis is a disease caused by parasitic flatworms of the genus Schistosoma, whose diagnosis has limitations, such as the low sensitivity and specificity of parasitological and immunological methods, respectively. In the present study an alternative molecular technique requiring previous standardization was carried out using the polymerase chain reaction (PCR) for the amplification of a 121-bp highly repetitive sequence for Schistosoma mansoni. DNA was extracted from eggs of S. mansoni by salting out. Different conditions were standardized for the PCR technique, including the concentration of reagents and the DNA template, annealing temperature and number of cycles, followed by the determination of the analytical sensitivity and specificity of the technique. Furthermore, the standardized PCR technique was employed in DNA extracted, using Chelex®100, from samples of sera of patients with an immunodiagnosis of schistosomiasis. The optimal conditions for the PCR were 2.5 mm MgCl2, 150 mm deoxynucleoside triphosphates (dNTPs), 0.4 μm primers, 0.75 U DNA polymerase, using 35 cycles and an annealing temperature of 63°C. The analytical sensitivity of the PCR was 10 attograms of DNA and the specificity was 100%. The DNA sequence was successfully detected in the sera of two patients, demonstrating schistosomiasis transmission, although low, in the community studied. The standardized PCR technique, using smaller amounts of reagents than in the original protocol, is highly sensitive and specific for the detection of DNA from S. mansoni and could be an important tool for diagnosis in areas of low endemicity.

The structure and affinities of the progenctic larva of Echinobothrium reesae Ramadevi, 1969, are described and discussed.

Hexatylus viviparus, a spear-bearing nematode superficially resembling Aiiguillulina dipsaci, was originally described by the writer (1926) from a diseased potato tuber. In a second note published the same year (1926a), further details of its structure were given; the organisms in this case being obtained from a gladiolus corm affected with an internal soft rot.

Since the appearance of these papers the writer has encountered this species on several occasions both in potato tubers and gladiolus corms. The receipt of a gladiolus corm in February, 1937, the brown rotten centre of which contained numerous specimens of the worm, provided further material for detailed observations on the structure of the worms. Some of the decayed central tissues of the corm also served as an inoculum for the cultivation of the nematode, along with a fungus, on slope cultures of a malt extract agar. Subcultures from the original slopes have been made from time to time and on these the worms have been successfully maintained for more than twelve months.

One of the peculiarities of the eelworm Heterodera schachtii which makes it a very difficult parasite to control is the length of time it can survive in a dormant condition in the soil. In this state the embryonated eggs are protected by the resistant cyst wall, and, in the case of the potato strain of the eelworm, the larvae only hatch in large numbers in the presence of the host plant. On account of this property, land infected with the parasite remains infected even though the host plant is not grown. It is however well known that if “potato sick” land is rested from potatoes for a few years it is then sometimes possible to grow a potato crop giving a fairly good yield and showing little or no sign of sickness in the overground parts. In these cases, however, it is often found that the roots of the plants are heavily infested with eelworm. These and other observations have led to suggestions that other factors may be associated with H. schachtii in giving rise to the condition known as “potato-sickness.” Such factors may be due wholly or in part to soil conditions, climate, fungal attack or the time of attack by the eelworm. In some cases more than one factor may operate in addition to the nematode, and in different cases it is probable that different factors come into play.

Cysticercosis is caused by infections with embryonated eggs of the tapeworm Taenia pisiformis. Knowledge of the genetic characteristics of T. pisiformis could be applied to study the epidemiology and transmission of this parasite. In this study, 61 isolates of intraperitoneal cysticerci from eight geographically distinct regions in Sichuan province, China, were subjected to a molecular analysis in order to determine their intra-regional genetic characteristics. Partial sequences of the mitochondrial cytochrome c oxidase subunit I (cox1, 1427 bp) and NADH dehydrogenase 1 (nad1, 738 bp) were concatenated. Five haplotypes were identified, and 89.04% of total genetic variation was found in collections of T. pisiformis isolates from a single region. According to the phylogenetic reconstruction, the T. pisiformis isolates from eight regions did not form geographical clusters. Our study highlights the genetic characteristics of T.pisiformis with the aim of accelerating the genetic research and control of cysticercosis.

Pharmacological studies carried out on protoscoleces in vitro to standardize conditions that would permit a preliminary estimate of the efficacy of drugs with potential activity against Echinococcus granulosus are reported. Media such as PBS and Hanks solution, maintenance temperature, different pH values and concentrations of various solvents have been tested to check the effects on protoscolex survival in tubes in vitro. Mebendazole has been used as the pharmacological standard reference. Changes in the viability of protoscoleces have been used to demonstrate pharmacological activity. Best conditions were obtained employing Hanks solution and propylene glycol at low concentrations. Mebendazole was not completely effective at the concentrations achievable in human therapy. Linear, reproducible results demonstrated that Hanks solution provides an ideal medium for pharmacological studies. Among tested solvents, propylene glycol and dimethyl sulphoxide showed no lethal activity at low concentrations. At concentrations similar to those normally obtained in human sera, mebendazole, as in vivo, demonstrated only partial lethality for protoscoleces. The present study represents a new experimental approach to chemotherapy of hydatid disease.

A total of 21 amino acids were detected in the present investigations on three species of Gangesia (Cestoda: Proteocephalata) viz. G. bengalensis Woodland, 1924, G. hanumanthai Seth & Capoor, 1982 and G. sanehensis Malhotra et al., 1981. The study was conducted in a sub-humid region around Allahabad, India. The implications of amino acid utilization in metabolic activities of fish tapeworms have been discussed.

Experiments were performed to study the effect of age and lifespan on the infection success of Diplostomum spathaceum miracidia. Specimens of Lymnaea peregra and L. stagnalis were individually exposed to single miracidia of D. spathaceum of different ages under conditions of constant illumination at 20°C. The life-span of the free-swimming miracidium of D. spathaceum is 24 h at 20°C. It was observed that as the miracidium ages, its ability to successfully infect snails declines rapidly.

Four muscle groups are responsible for the eversion and retraction of the apical denticles and enlarged pseudolabia in Skrjabinoptera goldmanae (Nematoda: Physalopteridae), which occurs in the lizards Chlamydosaurus kingii, Pogona spp. and Varanus gouldii in Australia. These muscles enable the nematode to bury its anterior portion in the gastric submucosa of its hosts. They comprise three sets which are derived from the somatic musculature and are inserted in the oesophagus and associated organs, and a fourth set of muscles which appears to be derived from the muscular oesophagus itself. These accessory muscle groups are described and illustrated, and from this their mode of action in everting and retracting the pseudolabia is derived. Possible selection pressures which led to their evolution are reviewed.

Primitive epithelium and outer tegumental layer formation during early cercarial development was studied in Prosorhynchoides borealis using electron microscopy. It demonstrated that germinal cells freely floating in the sporocyst body cavity divide to give rise to naked cell aggregates. These early embryos are highly irregular in outline and are composed of blastomeres differing in size and structure. In embryos consisting of about 12–14 cells a few (possibly only two) superficial macromeres become concave and produce thin extensions which envelop the embryonic mass before fusing to form a syncytial primitive epithelium. This primitive epithelium forms syncytial connections with underlying embryonic cells. Primordial tegumental cells become apparent in late germinal balls below the primitive epithelium. These cells expand and fuse to give rise to an embryonic nucleated tegument. The embryonic tegument is connected to peripheral embryonic cells by thin cytoplasmic bridges until the basement lamina is formed. Subsequently, the primitive epithelium is shed by the embryos and the nuclei in the embryonic tegument undergo pyknotic degeneration. These results are analysed and compared with data from studies on other trematode species and it is concluded that the primitive epithelium is derived from the embryo in at least the majority of digeneans.

It was observed in laboratory experiments that the lethal action of dilute solutions of calcium cyanamide on the larvae of Heterodera schachtii was more rapid when these solutions were rendered slightly acid. This might be due to the rate of decomposition of calcium cyanamide in aqueous solutions of varying þH. The changes which cyanamide undergoes in acid and alkaline media have been described by Crowther & Richardson (1932). Solutions of commercial calcium cyanamide are moderately alkaline because of their lime content, and in this alkalinity any free cyanamide which is formed tends to polymerise to dicyanodiamide. Experiments with solutions of dicyanodiamide showed that this substance has very little toxic action on H. schachtii larvae. In acid solution, on the other hand, cyanamide is hydrolysed to urea. This substance becomes toxic when it decomposes to ammonia, but in the slightly acid solutions used the change would be a slow process. It is probable, therefore, that the degree of toxicity of calcium cyanamide solutions would be greatest where the cyanamide radicle could be retained unchanged for the longest period.

From the researches of Onchi and Nishio it is known that the encysted larva of Heterophyes nocens Onchi et Nishio is found in the Japanese mullet. H. nocens is closely allied to H. heterophyes v. Siebold, which is found commonly in. man, dog and cat in Egypt. It may be assumed that the larva of the Egyptian Heterophyes will be found likewise in certain fishes allied to the mullet. On the homeward voyage from my tour in Europe I examined some specimens of mullet in Port Said, for the purpose of finding the young larva in them, and was fortunate enough to discover encysted larva. I carried back with me some of these fishes fixed by formalin. After returning to Chosen (Korea) I examined the parasite, and found that it certainly belongs to a species of Heterophyes. Its morphological description is given in the present short communication.