A comparative study on the pathogenicity of two strains of Schistosoma mansoni one from Bor District and the other from the Gezira in the Sudan, using Cercopithecus aethiops monkeys as experimental hosts. The results, which were based on the assessment of various clinical, parasitological and pathological parameters, indicated that Bor strain was responsible for a more severe type of disease than its Gezira counterpart. Monkeys infected with Bor parasite generally revealed higher worm and egg loads, more marked changes inHb content and body weight gain and more extensive lesions in the liver and two monkeys died.

In the Sudan, it has often been noted that the disease produced by Schistosoma mansoni, as observed among patients from Bor District in the Southern Region, is far more severe than that usually encountered in those from the Gezira in the northern part of the country. These two areas which are about 500 miles apart differ widely in their climate, indigenous population, and social and economic status. It has been suspected that differences in the pathogenicity of the local S. mansoni strains may be one of the important factors determining the clinical presentation of the disease. Accordingly, a comparison of these two strains was undertaken, using the green monkey, Cercopithecus aethiops, as an experimental model. These animals varied in their response to the schistosomal infection, irrespective of the strain used, but the group infected with the Bor strain generally suffered from a more severe illness than their counterparts infected with the Gezira form of the parasite. This was evidenced by the higher worm and egg loads, and consequently the more severe clinical and pathological effects shown by the former group.

In reviewing the literature on helminthology one finds that a great deal of attention has been given to the study of the physiology of parasites. Investigations of such a nature are valuable, in that they enable one to approach the problem of anthelmintic treatment in a scientific manner. Most of the early work that was carried out on lungworms in general was concerned either with their life histories or with their morphology, and little work has been done on their physiological characteristics.

A detailed redescription of Gazellostrongylus lerouxi and Paracooperia serrata was given from specimenscollected from antelopes in Kenya. It was felt that there was no justification for the synonymy of the genus Gazellostrongylus with Paracooperia. Gazellostrongylus was placed in the tribe Ostertagiea.

The proteins of homogenized adult Opisthorchis viverrini were separated by polyacrylamide gel electro-Phoresis and isoelectric focusing in the presence of detergents. By far the most abundant component(s) had a Mr of 18,000 to 19,000, represented about 47% of the total parasite protein, and did not separate in isotypes.

Owing to the comparatively little use made of the flesh of the goat in this country, the helminthic parasites of this host have been far less studied than those found in other domestic animals. In other countries, where the goat plays a far greater economic rôle, a large number of parasitic worms have been recorded.

Five Macaca mulatta were each inoculated with 200 larvae of Brugia pahangi. One monkey showed no microfilariae and the other 4 only low and transient microfilaraemias. Another group of 5 monkeys were each given an original 200 larvae and 11 further infections with 50 larvae but no better microfilaraemias were obtained. These monkeys were killed between 176 and 185 days later and no adult worms could be found. A few adult worms were found in two further monkeys killed 60 days after infection.

Brugia pahangi infects mammalian hosts of several orders but the only primate found naturally infected is Nycticebiis coucang (Laing et al., 1960, Ash and Riley, 1970). Edeson et al. (1960) tried to infect Macaca inis, M. nemestrina, M. mulatta and N. coucang but were only able to detect microfilariae in N. coucang. On the other hand, B. malayi (sub-periodic strain) infects primates much more readily (Laing et al., 1960) in nature. Fredericks and Ramachandran (1968) successfully infected 26 of 27 M. mulatta with B. malayi.

Methods are discussed for greatly increasing the cyst content of Helerodera-intested soil, so that very little soil need be “floated” to provide the number of cysts necessary to form a replicate in bioassay. Such a “float” contains very little debris and may be used directly, thus avoiding the laborious and time-consuming step of separating the cysts from the debris. An apparatus for quick recovery of the “float” is described.

Dissolved carbon dioxide was deemed not to be an important factor in the activation of Taenia taeniaeformis oncospheres. Rabbit bile was found to provide the most appropriate whole bile for in vitro activation of oncospheres

Isozyme patterns of six enzymes, glucose-6-phosphate dehydrogenase, glucosephosphate isomerase, hexokinase, malate dehydrogenase, 6-phosphate dehydrogenase and phosphoglucomutase were examined in electrophoresed homogenates of adult male worms of Schistosoma japonicum and S. mansoni. In general, enzyme patterns obtained from the parasite homogenates differed from that of host (mouse) blood and muscle, indicating that electrophoretic patterns from parasite extracts are most probably of parasite origin. Adult male and female S. mansoni worms yielded identical patterns. However, all six enzyme patterns showed distinct differences between S. japonicum and S. mansoni. These results suggest that S. japonicum is clearly distinguishable from S. mansoni at the molecular level.

Experimental completion of the life-cycle of Paragonimus westermani (Trematoda: Troglotrematidae) (diploid type) from egg to adult has been achieved in the laboratory for the first time. A dog was fed metacercariae of P. westermani from naturally infected freshwater crabs, Geothelphusa dehaani. The adult flukes were recovered and their eggs were incubated in water at 28°C, hatching after 20 days. Laboratory reared marsh snails, Semisulcospira libertina, were exposed to miracidia from embryonated eggs. One of 47 snails became infected with a large number of 2nd generation rediae containing fully mature cercariae 245 days after exposure. Paragonimus-free crabs (G. dehaani) were then infected with the intramolluscan larvae. Of the 40 crabs examined 34–70 days after infection, 17 were infected with a total of 84 metacercariae. A cat and 4 dogs were fed with 55 metacercariae obtained. Eighty to 100 days later, a total of 40 flukes was recovered; 39 flukes were adults with eggs in their Uteri.

Root-lesion nematodes (Pratylenchus spp.) are a group of economically important pathogens that have caused serious economic losses in many crops. In 2019, root-lesion nematodes were recovered from tomato (Solanum lycopersicum) root samples collected from Sichuan Province, People's Republic of China (PRC). Extracted nematodes were disinfected, and one individual female was cultured on a carrot disc for propagation at 25 °C by parthenogenesis and designated the SC isolate. Afterwards, the isolate was identified on the basis of morphometric and molecular markers. Both morphometric characters and molecular analysis of the internal transcribed spacer region gene (ITS) of ribosomal DNA, the D2-D3 expansion region of the 28S rDNA gene and the mitochondrial cytochrome oxidase I (mtDNA-COI) gene revealed that the species of root-lesion nematode was Pratylenchus scribneri. The Bayesian tree inferred from the ITS rDNA, 28S rDNA and mtDNA-COI gene sequences also showed that this isolate formed a highly supported clade with other P. scribneri isolates. The pathogenicity of the root-lesion nematode SC isolate on tomato was assessed, showing that tomato was a suitable host for P. scribneri. To the best of our knowledge, this is the first report of P. scribneri on tomato in Sichuan Province, PRC. These are also the first molecular data obtained from P. scribneri on tomato in the PRC, and the pathogenicity of P. scribneri to tomato was studied for the first time. This study provides scientific data for the detection, identification and control of tomato root-lesion nematode disease.

Lungworms of the genus Metastrongylus are parasitic nematodes in the respiratory tract of swine. Although they infect both wild boars and domestic pigs, studies on Metastrongylus infections in wild boars in Europe, the Americas and Africa are numerous, while those in domestic pigs are few. There are several studies analysing the molecular phylogenetic relationships of few individual Metastrongylus species with other nematode taxa, but there are no studies on the phylogenetic relationships of species within the genus Metastrongylus. In Southeast Asia, reports on swine lungworms are extremely scarce and do not include any nucleotide sequence data. Therefore, the aim of the present study is to survey Metastrongylus infection in domestic pigs raised in Dien Bien Province, Northern Vietnam, and to analyse the molecular phylogenetic relationships of Metastrongylus species. Based on morphological and molecular data, we identified two species: Metastrongylus apri and Metastrongylus pudendotectus. The prevalence of the former species was found to be significantly higher than the latter one (24.1% vs. 2.3%). We observed pigs exhibiting a coinfection with the two lungworm species or a single infection with only M. apri. However, we did not observe any pigs being infected with just M. pudendotectus. Vietnamese Metastrongylus specimens showed slight morphological and molecular differences compared to those from other countries. The molecular analyses revealed a close genetic relationship between M. apri and Metastrongylus salmi, while both these species were far distant from M. pudendotectus. The present study highlights the needs for further studies to clarify the morphological features and ecological and phylogenetic relationships of Metastrongylus species at the global scale.

Aphelenchus ritzemabosi is known as a serious parasite of greenhouse plants such as chrysanthemums and gloxinias but the number of records of its attacks on plants grown out of doors is increasing. Disease due to it has been observed in the open on chrysanthemums and dahlias in this country and in the present paper a new out-of-door host is added to the list of plants attacked by it.

Comparative ultrastructural studies have been made of newly excysted metacercariae and worms recovered from abnormal (rats) and normal definitive hosts (dogs). Worms from rats survived for prolonged periods without any growth or development in muscles of the host. They appeared to resemble metacercariae in general features, although ultrastructural observations revealed differences in the composition of tegumental granules and the development of the excretory bladder and caeca. Worms from dogs showed well-developed morphology in association with active energy metabolism and biosynthesis.

A number of helminths from a small bat from a cave in Northern Rhodesia were presented by Dr. P. L. leRoux to the author for study. The collection of consisted of about twenty specimens of one species of trematode, Prosthodendrium cordiforme; the rest were nematodes, namely, two males and three females of Molinostrongylus pseudornatus sp. nov., at least one species of filarial worm, one species of Capillaria and one or two species of trichostrongylid nematodes. Only the first two helminth species mentioned above were studied in detail. The others, for one reason or another, were inadequate for detailed study.

The authors describe Trichosomoides nasalis n.sp., parasitic in the nasal cavities of Epimys norvegicus and propose to modify slightly the definition of the family Trichosomoididae Yorke and Maplestone, 1926, especially in relation to the definition of the habitat (considered till now to be exclusively in the urinary tract).

A number of these specimens were available for study. They were collected from the stomach of Galago crassicaudatus agisymbanus (Coquerel) in Tanganyika Territory by Dr. W. H. R. Lumsden whom I wish to thank for the material.

These stout worms have a thick cuticle which is finely striated. The well-developed lateral lips are smooth, hemispherical, each possessing a large triangular external tooth and three smaller internal teeth. There are two prominent papillae towards the dorsal and ventral margins of each lip. The cervical cuticle forms a collar round the anterior end.

Factors which influence the establishment of tetrathyridia of Mesocestoides corti in mice following inoculation per os were examined. Only a proportion of the tetrathyridia penetrate the gut wall and gain access to the peritoneal cavity and liver, and most of these penetrate through the wall of the small intestine. It appears that tetrathyridia must attach to the intestinal mucosa and commence penetration immediately or they pass into the large intestine and are voided. Establishment was not influenced by strain, sex or age of host. However, the temperature at which tetrathyridia were maintained before inoculation did influence their ability to penetrate the intestinal wall. Additionally it appears that tetrathyridia have to undergo a morphological change before or during, this penetration phase.

The activities of selected enzymes of carbohydrate metabolism were measured in tetrathyridia of Mesocestoides corti and in adult females and males of Heterakis spumosa. When the species were compared, only lactate dehydrogenase and phosphoenolphyruvate carboxykinase activities were considerably higher in M. corti. Activities of other enzymes were higher in H. spumosa, with malate dehydrogenase activity being considerable so. In H. spumosa, enzyme activity was higher, and succinate dehydrogenase markedly so in males, when compared with females. Tetrathyridia aged 170 and 210 days show relatively stable malate and lactate dehydrogenase activities, and mice of ICR and BALB/c strains are suitable for the maintenance of tetrathyridia.