Because of the negative binomial distribution of filarial third stage larvae (L3) in their vectors, under natural conditions only a few are usually transferred per bite. After an inoculation of 5 L3 per animal into eight host animals at least one developed a long lasting patency based on one reproductive female only. After an inoculation of 15 L3, three of eight animals developed long lasting patency, harbouring between two and five fertile females. The rates of adult stages recovered were 0·43 and 0·30 respectively. The parasitaemias of the six patent animals in both experimental groups increased with the number of reproductive females present (r=0·89, p=<0·005). All non-patent animals which were mf-negative in the pleural fluid and lung blood as well had a single sex or no worm load. In only one animal was there an apparently normal but non-reproductive pair of worms without any pathological alterations of the host animal. Encapsulated adult worms were found rarely, but independent of the final worm load or inoculation dose and always beside normal adults. In three of the 16 animals inoculated with 5 or 15 L3 patency passed after 10–12 weeks p.i., in two others it seemed to pass soon. After inoculation of 30, 40 or 60 L3 per animal patency passed early in about one half of 105 animals, when they were observed up to 24–36 weeks p.i. In conclusion all types of host defensive reactions are already visible after inoculation with such small doses. Nevertheless even a single inoculation of 5 L3 may give rise to a patent animal and its microfilaraemia is sufficient for transmission under natural conditions. Higher inoculation doses increase the defensive reactions which nevertheless remain unable to destroy all invasive stages.

No article involving the nematode cuticle can ignore the work of Donald Lee. Since the publication of his book Physiology of nematodes (Lee, 1965), he has provided us with an extensive knowledge of the structure, composition, maintenance and growth of a variety of nematode cuticles and has undoubtedly contributed a great deal to our understanding of this unique and diverse structure.

The present paper consists of descriptions of an encysted developing stage of Asymmetricostrongylus dissimilis, and of four newz species, Globocephaloides trifidospicularis, Pharyngostrongylus longibursaris, Zoniolaimus cobbi and Labiostrongylus australis. With the exception of L. australis, which is doubtfully recorded from Python spilotus, all the species came from the alimentary canal of the Australian wallaby, Macropus rufogrisea fruticus.

Metacestodes of Taenia crassiceps were cultured in laboratory rats and mice, washed in glycine/hydrochloric acid (Gly/Hcl) buffer pH 2·4 and phosphate buffered saline (PBS) pH 7·2 and a soluble extract of the metacestodes (SEM) was prepared from larvae washed in both buffers. The SEM and the original washings were examined for host IgG and a common host antigen (CHA). CHA was present in both the SEM and Washings but IgG only in the washings and, in metacestodes from mice only in the Gly/HCl washings). Metacestodes washed in Gly/HCl were not viable.

Metacestodes were also maintained in vitro in a peptide nutrient agar and 0·9% saline at 37°C and a SEM was prepared from these; metacestodes from mice had neither host IgG nor CHA but those from rats had CHA but not IgG. SEM prepared from ‘normal’ metacestodes showed that the CHA consisted of at least two entities, only one having a common identity with the IgG. These results suggest that molecules of both host IgG and a common host antigen are present on the tegument of these parasites.

Japanese observers have found the encysted cercarire of Heterophyesnocens in the Japanese mullet which belongs to the genus Mugil. In Egypt, Heterophyes heterophyes is a fairly common parasite of man, dog and cat. The genus Mugil “Egyptian mullet” is represented in Egypt by three species.

A biological test to estimate the numbers of infective metacercariae of F. hepatica on pastures is described. The test is shown to be successful provided a snail site can be determined. Results from samples collected from field outbreaks are described and the possible applications of the test are discussed.

In 1890, Müller described, from the lung of the cat, a species of nematode which is now known as Aelurostrongylus abstrusus. In 1928, I was able to show that its true habitat was not the lung substance, but the pulmonary artery and its branches, and that its pathogenic action, was mainly, if not entirely, due to the presence of the developing eggs and larvae distributed throughout the lung tissue by the blood stream.

In their preliminary paper (Fenwick and Franklin, 1942) on the identification of the cyst-forming species of the nematode Heterodera by means of the length of the larvae, the present authors studied methods of preparing the larvae for measurement and of making the measurements, and considered the form of sample to be taken from a population of Heterodera larvae which would give the most reliable estimate of the mean length of the whole population. Those studies were made on the larvae of H. rostochiensis only, but the ultimate purpose was to obtain strictly comparable estimates of the mean lengths of the larvae of all the known species of Heterodera in order to find out whether larvae of the different species could be identified by their length.

The alimentary tract of adult Sanguinicola inermis Plehn, 1905 (Digenea: Sanguinicolidae) was studied by transmission electron microscopy. A highly developed muscular region, likely to be a modified sucker, is present anteriorly to the oesophagus. The tegumental oesophagus, on the basis of the characteristics of the surface cytoplasm, is differentiated into anterior, median and posterior regions with the apical cytoplasm of the median oesophagus drawn into extracellular vesicles from which arise surface knobs. The oesophagus leads to a cellular intestine composed of a single layer of epithelial cells. The apical surface of the intestine is drawn into short luminal projections and the intestinal cells contain numerous organelles and secretory granules. No host cells or cell debris were evident within the alimentary tract, although the intestinal lumen was filled with electron-dense material.

The effect of niclosamide on the tegument of adult Haplorchis taichui (Trematoda: Heterophyidae) exposed in vitro was observed by scanning electron microscope. Adult worms were incubated in Tyrode's solution containing 0.01, 0.1, 1.0, and 10 μg ml− 1 of niclosamide for 30 min, 1, 6, 12 and 24 h. Control groups were incubated in Tyrode's solution without niclosamide and worms remained active until 24 h. In 0.01 μg ml− 1 of niclosamide, worms showed slightly active movements up to 1 h after incubation, while in 0.1 μg ml− 1 solution a few worms showed only slightly active movements after 30 min. Tegumental changes were determined by scanning electron microscopy. Swelling and blebbing of the tegument were observed on both ventral and dorsal sides. After longer periods, extensive swelling and blebbing of the tegument became more severe and there was a loss of the apical plasma membrane in some regions. Empty spine sockets occurred, and small perforations penetrated the basal lamina, followed by some lesions. Destruction of both surfaces was more pronounced on the posterior compared with the anterior regions.

The present study examined sequence variation in three mitochondrial DNA (mtDNA) genes, namely cytochrome c oxidase subunit 3 (cox3) and NADH dehydrogenase subunits 1 and 4 (nad1 and nad4), among Ascaridia galli isolates from different geographical localities in China. A portion of cox3 (pcox3), nad1 (pnad1) and nad4 (pnad4) genes were amplified by polymerase chain reaction (PCR) separately from adult A. galli individuals and the amplicons were subjected to sequencing from both directions. The length of the sequences of pcox3, pnad1 and pnad4 were 408 bp, 471 bp and 333 bp, respectively. The intraspecific sequence variations within A. galli were 0–1.7% for pcox3, 0–2.8% for pnad1 and 0–3.4% for pnad4. The A+T contents of the sequences were 67.16–67.65% (pcox3), 67.09–67.94% (pnad1) and 69.91–71.77% (pnad4). The interspecific sequence differences among members of the Ascaridida were significantly higher, being 13.2–30.9%, 12.8–29.0% and 15.1–34.1% for pcox3, pnad1 and pnad4, respectively. Phylogenetic analyses using combined sequences of pcox3, pnad1 and pnad4, with three different computational algorithms (Bayesian analysis, maximum likelihood and maximum parsimony), all revealed distinct groups with high statistical support. These findings demonstrated the existence of intraspecific variation in mitochondrial DNA (mtDNA) sequences among A. galli isolates from different geographical regions in China, and have implications for studying molecular epidemiology and population genetics of A. galli.

Cathepsin L proteinases (CL1 and CL2), the major components of Fasciola hepatica excretion/secretion products (E/S) are considered potential antigens of a vaccine against fascioliasis. The humoral response elicited by CL1 and CL2 in rats either immunized with the enzymes or infected with F. hepatica has been analysed, examining specific IgE and IgG subclass dynamics. The experiment was continued for 10 weeks and peripheral blood eosinophilia was also determined. Infected rats presented peaks of eosinophilia at weeks 3 and 7 post-infection, while those immunized with CL1 and CL2 were no different from controls. Total IgE in infected rats increased up to week 5, reaching 30 μg -1 in some cases, then decreased slowly and rising again towards the end of the experiment. Determination of specific IgE, carried out in sera previously absorbed with Protein G-Sepharose, reached a peak in infected rats between weeks 2 and 5, depending on the individual. In immunized rats both total and specific IgE levels remained around the pre-immunization values. With regard to the IgG subclass responses to E/S products, in infected rats IgG1 predominated over IgG2a, and the reverse was true in rats immunized with CL1 and CL2 and tested against the respective antigens. In all cases an increase in IgG1 and IgG2a antibody titres was seen, with maximum levels being reached later (weeks 6–7) in infected rats than in immunized ones (weeks 4–5). No IgG2b or IgG2c responses were detected in any of the groups studied.

Epilepsy is one of the most common neurological disorders, while neurocysticercosis caused by Taenia solium infection of the central nervous system currently represents the leading cause of secondary epilepsy in Central and South America, East and South Asia, and sub-Saharan Africa. As a result of increased migration from these endemic regions, neurocysticercosis and subsequent epilepsy are becoming a growing public health problem in developed countries as well. In order to determine the prevalence of T. solium infection in patients with epilepsy in Croatia, a retrospective serological study was conducted. A total of 770 serum samples were tested for the presence of T. solium IgG antibodies using a commercial qualitative enzyme immunoassay. The Western blot technique was used as a confirmatory test for the diagnosis. The overall seroprevalence rate of T. solium infection in patients with clinically proven epilepsy was 1.5%. Although the results have shown that infection with this tapeworm is rare in Croatia, this study hopes to increase awareness about the importance of preventive measures and benefits of accurate and timely diagnosis. Intervention measures for infection control are crucial, namely sanitation improvement, control of domestic pig-breeding, detailed meat inspection, detection and treatment of tapeworm carriers, hand washing and health education.

A total of 687 adult nematomorphs of four species of Gordiida: Chordodes brasiliensis (393 specimens), Noteochorododes cymatium (47 specimens), N. talensis (162 specimens) and Pseudochordodes dugesi (85 specimens) were collected during a period of 1 year from El Simbolar stream, Argentina. Free-living worms were abundant during autumn and spring, but their number decreased during winter and summer. Males were shorter and significantly more abundant than females. The presence of N. cymatium, N. talensis and P. dugesi was correlated with water temperature and these species were most abundant in winter and spring. The presence of C. brasiliensis was correlated with flow rate and pH; this species was more abundant in autumn and winter. These four species are sympatric.

The variations in the oxygen uptake, reduced weight, metabolic rate and the number of contained, fully formed, healthy, autolysed or dead metacercariae, recorded during starvation in sea water, in vitro, suggest that first mainly stored carbohydrates, then mainly lipids and, in the final stages of starvation, mainly proteins are broken down and metabolised, by the sporocysts of Microphallus pygmaeus.

Some 250 substances were assessed for larvicidal activity against the free-living stages of Haemonchus contortus. Most of them were either plant products or chemical compounds found in plants.

Results indicate that promising chemical types worth further investigation are ketones of low molecular weight, alkyl di– and trisulphides, and organic isothiocyanates. Compounds whose molecular structures include the allyl group (e.g. anethole) and the methylenedioxy ring system are potentially active, safrole being particularly effective. Alkaloids as a group were not very effective, but eserine (physostigmine) was outstandingly active, and nicotine sulphate and arecoline hydrobromide showed pronounced activity. Other substances worthy of mention were phenyl mercuric phthalate, galegine sulphate, 8-hydroxy quinoline, methyl salicylate, 10-allyl phenothiazine, guaiacol, thymol, l-limonene and sabinol.

Most of the plant products tested were essential oils: these generally were active, the lowest activity being noted in those oils rich in sesquiterpenes. Activity in the essential oils could be correlated with that of the known compounds.

A number of these nematodes were sent to this Department for identification early in 1958 by Dr. J. F. B. Edeson from the Institute for Medical Research at Kuala Lumpur. The specimens were collected from the peritoneal cavity of Macaca irus. Since then, several further collections of the same species have been sent to this Department from time to time. The latter collections came from several laboratories using monkeys caught in Malaya and Siam for the production of poliomyelitis vaccines.

Pelecitus galli n.sp. is described from the Malayan jungle fowl Gallus gallus spadiceus. It differs from other species of the genus in the size of the spicules, number and arrangement of caudal papillae in the male, and the relative position of the vulva. It is also the first species of Pelecitus described from the genus Gallus.

Three types of microfilariae were seen in blood and lung smears of two jungle fowls trapped in Tasek Bera in Pahang State. One of these microfilariae is indisguishable from that described by Dissanaike (1963) from the Ceylon jungle fowl. One of the other two resembles the microfilaria of Pelecitus ceylonensis described from Ceylon (Dissanaike, 1967) and adults were found between the tendons at the bases of the legs of one of the jungle fowls examined.

Euparadistomum heischi n.sp., the sixth species in the genus, was recovered from a domestic cat on Pate Island, Kenya. In the Dicrocoeliidae, a new subfamily Euparadistominae is proposed for two genera, Euparadistomum Tubangui, 1931 and Stromitrema Skrjabin and Evranova, 1944.