A rare ascaridoid species, Mawsonascaris australis (Johnston & Mawson, 1943), is reported from the Taiwan Strait for the first time, and the brown guitarfish Rhinobatos schlegelii Müller & Henle (Rhinopristiformes: Rhinobatidae) represents a new fish host. The detailed morphology of M. australis was studied using light and scanning electron microscopy (SEM) based on the newly collected specimens. The results revealed some important, but previously unreported or erroneous, morphological features, including the lateral alae starting well posterior to the base of the ventrolateral lips, the presence of one pair of double paracloacal papillae and a single, small precloacal median papilla on the anterior margin of the cloaca. In addition, in order to determine whether the morphometric difference in the relative lengths of the right and left spicules represents intraspecific or interspecific variation, specimens of M. australis were characterized using molecular approaches by sequencing and analysing the ribosomal internal transcribed spacer (ITS) and mitochondrial cox1 genes. The results indicate that this morphometric difference represents intraspecific variability.

Migration and development of the larvae of Gnathostoma nipponicum in the rat as second intermediate or paratenic host and the weasel as definitive host were examined to clarify the pathogenesis in each animal. The advanced third-stage larvae (AdL3) given orally to rats remained in the stomach for 12 h post-infection (PI). After that, larvae transiently invaded various organs and finally moved into the muscle within 48 h. The percentage of eosinophils in the blood taken from the jugular vein of rats infected with AdL3 reached a maximum (about 6%) on day 20 PI and then decreased. IgG antibody titre for G. nipponicum measured by ELISA began to increase on day 5 PI and reached a plateau on day 20 PI. The AdL3 given orally to weasels moved from the stomach into the muscle and then increased in size. Half of them invaded the muscle within 5 days, whereas the majority of them invaded the muscles within 20 days PI. Morphology of worms which invaded the muscles indicated that they were still the larval form with three rows of hooklets on the head bulb. The larvae in the muscles developed to young adult worms with seven rows of hooklets on the head bulb within 40 days PI. These young adult worms invaded the oesophageal wall and formed a tumour within 60 days PI. It was presumed that worms invaded the oesophageal wall though the adventitia. Ferret and mink were shown to be potential final hosts of G. nipponicum.

Rodents, particularly those belonging to the family Muridae, form the largest group of mammals in Malaysia. They are also a group that has been well studied because of their medical and economic importance. Yet, comparatively little is known, in Malaysia, about the helminths that are associated with them; far less the types of terrain in which these are prevalent. An attempt is now made to survey the nematodes parasitic in these rodents, with a view to assessing the potential risk from those that are harmful to man and domestic animals, and to studying those that are harmless, but nevertheless form an enlightening contribution to the knowledge of Malaysian parasitic fauna.

Parasite composition can be affected by physiological and ecological changes during host ontogeny. Intertidal fish do not travel long distances and live in the same area throughout their lifetimes, meaning that parasite communities can differ across geographic ranges. The objective of this study was to analyse the parasite communities of three fish species (Hypsoblennius sordidus, Helcogrammoides cunninghami and Scartichthys viridis) collected from the Chilean coast. The composition of parasite species was compared among host ontogenetic stages (larvae, juveniles and mature fish) and geographic areas. A total of 184 larval, 252 juveniles and 217 mature individuals were collected in the northern area (c. 24°S), and 186 larval, 192 juveniles and 112 mature individuals from the central area (c. 33°S). Ectoparasites were most prevalent in fish from the central area, whereas endoparasites were most prevalent in the northern area. The parasite species richness varied significantly between geographical areas for H. sordidus and H. cunninghami, but the parasite composition varied significantly between geographical areas for all fish species analysed. Therefore, the geographical area was the most important factor determining the parasite composition of intertidal fish species. The absence of endoparasites in fish larvae and the increased infestation in juvenile and mature fish may be explained by the shift in habitat from the water column to intertidal pools where prey abundance and availability are higher. On the other hand, hydrographic barriers affecting prey distributions may also offer an explanation as to the differences in parasite composition.

Schistosomiasis represents a public health problem and praziquantel is the only drug used for treatment of all forms of the disease. Thus, the development of new anti-schistosomal agents is of utmost importance to increase the effectiveness, reduce side effects and delay the emergence of resistance. The present study was conducted to report the therapeutic efficacy of PPQ-8, a new synthetic quinoline-based compound against Schistosoma mansoni. Mice were treated with PPQ-8 at day 49 post infection using two treatment regimens (20 and 40 mg/kg). Significant reductions were recorded in hepatic (62.9% and 83.6%) and intestinal tissue egg load (57.4% and 73.5%), granuloma count (75.4% and 89.1%) and diameter (26.2% and 47.3%), in response to the drug regimens, respectively. In addition, both treatment regimens induced significant decrease in liver (23.3% and 32.8%) and spleen (37.5% and 45.3%) indices. Also, there were significant reductions in mature ova, total worm and female count, which were more prominent with the higher dose. The reduction in the level of nitric oxide in the liver by both therapeutic regimens to 22.5% and 47.2% indicates the anti-oxidant activity of PPQ-8. Bright field microscopic examination of worms recovered from infected and PPQ-8-treated mice showed nearly empty intestinal caeca with no observable changes in the tegument. Our findings hold promise for the development of a novel anti-schistosomal drug using PPQ-8, but further in vitro and in vivo studies are needed to elucidate the possible mechanism/s of action and to study the effect of PPQ-8 on other human schistosomes.

Dictyocaulus viviparus were harvested from calves treated daily with albendazole at dose-rates sub-lethal to this parasite and from matched untreated calves. Male and female reproductive tracts from the worms were examined by light and transmission electron microscopy. A first description of the testis of this nematode is provided. Cell division in the germinal zone of both male and female worms was arrested by in vivo exposure to albendazole metabolites and the cytoplasmic threads connecting the germinal cells to the rachis disappeared. In male worms from treated calves, the rachis was absent from the growth zone and severe ultrastructural damage of spermatogonia, spermatocytes and spermatozoa was apparent. In female worms, the rachis remained intact in the growth zone, obvious abnormalities being confined to the germinal zone, where the cytoplasm of the oogonia was disrupted and few nuclei seen, and to the uteri and ovijector which contained only undifferentiated ova. The detrimental effects of albendazole metabolites on male and female worms were quickly reversed after withdrawal of medication.

Fish-borne zoonotic trematodes (FZTs) can cause major human health problems. The aim of this study was to quantify the transmission of parapleurolophocercous cercariae to common carp (Cyprinus carpio) and to study the effect of the density of cercariae and the density of fish on transmission with respect to the volume of water and surface area of the bottom. Fish were kept individually either as controls (n= 91) or were exposed to 250 cercariae in tubes with a volume of 25, 50, 100, 250 or 500 ml water (n= 190) with a surface area of 4, 12, 21, 30 or 49 cm2 (n= 195). The dose to which the fish were exposed was kept constant. Infection occurred in 94–100% of fish, with a mean of 15–18 metacercariae per fish and the proportion of FZTs established at 0.06–0.07 metacercariae per cercariae per fish. Neither the prevalence of infection with FZTs nor the number of metacercariae per fish nor the proportion of FZTs established were significantly associated with differences in the density of cercariae or the density of fish per ml water or per cm2 surface area. Thus, it was concluded that the transmission of cercariae to fish is independent of density.

Environmental changes and ecological disturbances can have large and unpredictable effects on parasite dynamics. Increasing human impacts on freshwater ecosystems through land use may thus modify the distribution and abundance of parasites and have cascading effects on host populations. Here we tested the effects of small-scale riparian forest management on the nematode Cystidicoloides ephemeridarum and its insect intermediate host Ephemera danica in forested streams. We assessed the impacts of harvesting riparian trees on parasite prevalence and abundance concomitantly with host densities. We also looked at upstream and downstream reaches to document potential cascading effects on unaltered stream sections mediated by aerial dispersal of adult mayfly or downstream drift of E. danica larvae. We show that host densities and parasite levels (prevalence and abundance) increased significantly following riparian tree removal. Overall, parasite densities showed a 6- to 66-fold increase in harvested reaches compared to upstream, pristine reaches. Similar effects were also clear downstream of the disturbance. Thus, despite the small extent of riparian forest alteration along the study streams, both parasite and intermediate host were strongly affected. Small-scale riparian forest management may thus have large, unforeseen impacts on some aspects of freshwater ecosystem structure and functioning that are often ignored. Generally, understanding how human perturbations influence parasites is vital when trying to predict overall impacts on ecosystem structure and functioning, and how changes in infection dynamics may further affect host species.

Until 1934 the life history of Syngamus trachea was usually considered to be direct though Walker in 1886 and Waite in 1920 had both tentatively suggested that earthworms play a part in the dissemination of the parasite. In that year, however, I was able to show conclusively in this laboratory that the rôle they play in transmitting the nematode is a very important one, for by means of this annelid it was possible to effect with certainty heavy infections in various birds of domestic importance. The following year it was shown also that Syngamus from starlings can easily be transmitted to chickens by earthworms: this method apparently overcomes the resistance due to a different “host strain” such as Taylor had previously encountered when he tried to infect chickens directly with material obtained from starlings. In 1938 using earthworms as vectors chickens, pheasants and partridges were easily given definite infections with various other “strains” of Syngamus. Consideration of these results made it no longer possible to ignore the importance of earthworms in the life cycle of “Gapes.”

The effect of calcium and ammonium chloroacetates in increasing the yield of potatoes grown in Ayrshire fields infected with Heterodera schachtii is demonstrated.

From the examination of roots of treated and untreated plants it is believed that this increase in yield is due to a reduction in the eelworm infection, and from hatching experiments this reduction is thought to be the result of the action of calcium chloroacetate in retarding and reducing the hatching of larvae from the cysts.

In a previous paper the writer (1929) has given an account of the initiation and earlier work on a field plot experiment at Winches Farm devoted to the study of the stem eelworm, Anguillulina dipsaci, in its attacks on potato tubers. For the trials carried out in 1928 the original plot, which was 200 ft. long by about 21 ft. 9 ins. wide, was divided up into 30 smaller plots, each measuring 12 ft. long by 10 ft. 9 ins. wide, and 10 varieties of potatoes were tested, each variety being grown in triplicate. Following an inoculation of the soil with diseased tubers, it was found that all the varieties grown, whether earlies, second-earlies or main-crops, became infected. Since 1928 the plot has been cropped each year with potatoes and the purpose of the present paper is to put on record observations made and results obtained in subsequent years and to advance certain conclusions arrived at as a result of this work.

An optimum protocol for the cryopreservation of third-stage larvae (L3) of Angiostrongylus cantonensis was determined by: (i) use of different dimethyl sulphoxide (DMSO) concentrations; (ii) use of different FBS concentrations in RPMI-1640 medium; and (iii) variation in the thawing temperature. Studies showed that with Concentrations of DMSO at 4·8% and FBS at 40% and a thawing temperature of 43°C, L3 survival assessed by motility was highest at 56%. The infectivity of the cryopreserved L3 of A. cantonensis was 20% compared to controls obtained from slugs.

On 23/3/43 a small experiment was sown with commercial onion seed at Kirton, being one of a series laid down at county oentres in order to study the effect of different times of lifting on the development of wastage in store. Four varieties, which may be designated A, B, R, U, were sown in strips of three rows 10in. apart, in triplicate, the rows being 41 yards long and forming three randomised blocks. The liftings were also in randomised block pattern, 3 × 3, across the length of the rows. Two sub-plots of each variety were taken for convenience, consisting of adjacent six-foot lengths across the three rows, the produce of each sub-plot being put into a separate box immediately on lifting.

Elevated serum lipids are associated with infections of laboratory rodents with plerocercoids of Spirometra mansonoides. The effect of infection with these larval tapeworms on triglyceride degradation and hepatic de novo fatty acid synthesis was investigated in Syrian hamsters. Serum lipoprotein electrophoresis revealed a consistent elevation in very low density lipoproteins in the infected animals. Lipoprotein lipase activity was enhanced in the infected animals. After seven days of plerocercoid infection the activity of acetyl-CoA carboxylase (E.C. 6.4.1.2) was significantly elevated after 6,12 and 18 hours of fasting. Fatty acid synthetase was significantly increased after 0,6,12,18 and 24 hours of fasting. Therefore, a chronic insulin-like activity on lipid metabolism of hamsters is associated with plerocercoid infection.

1. Evidence is given which confirms the hypothesis of Peters (1941) that nematode eggsin McMaster slides are distributed according to the Poisson series.

2. No significant variation in egg counts due to the time of sampling was found in any of four sheep observed over a period of ten days.

3. A significant negative correlation of egg concentration with faeces output was found in three of the sheep (in the fourth it was negative but not significant).

4. The variation from day to day was relatively much less marked when the counts were expressed as total daily output than when expressed simply as eggs per gram.

5. No significant correlation was found between egg concentration and the dry matter proportion of the faeces.

6. A table derived from the Poisson formula is given to aid in the determination of the range of populations from which an egg count might reasonably have been drawn.

Velacumantus australis is a common mollusc along the easter and southern coast of Australia. A study of the incidence of larval trematodes in several populations of V. australis showed that the incidence of the various infections varied considerably with time and place. Heterophyids were usually the commonest infection, while schistosomes and echinostomes were frequently absent. In one population, seasonal changes in the incidence of philophthalmids and schistosomes were found to be positively correlated, and seasonal changes in the incidence of philophthalmids and echinostomes were found to be negatively correlated. These results are discussed.

Several taxonomic studies of the entomopathogenic nematode family Steinernematidae have reported on the minute tail projections on the tail tips of females of the first generation; however, the occurrence and morphology of these traits in other steinernematid species and their taxonomic significance are still unclear. In the present study, the tail projections in females of seven steinernematid species belonging to four phylogenetic clades were examined. The projections are present in all of the tested species and their number and shape is consistent within species but significantly differs among species. It thus seems that these structures may have taxonomic significance at the species level. Based on these results, we suggest that every description of a new species in the family Steinernematidae should contain a precise morphology of the female tail, focused on these projections, using both light and scanning electron microscopy.

Schistosomosis and amphistomosis are the two economically important and widely prevalent snail-borne trematode infections in grazing cattle of southern India. Acute infections are symptomatically similar and difficult to detect by routine microscopy for eggs. The present study was directed towards the development of a copro-polymerase chain reaction (copro-PCR) for detection of bovine schistosome species, using custom-designed primers targeting 18S and 28S ribosomal RNA as well as mitochondrial DNA. The study demonstrated the enhanced diagnostic specificity of mitochondrial DNA markers over ribosomal RNA genes as genus-specific probes to detect schistosomes. We developed a sensitive PCR assay using primers designed from mitochondrial DNA sequences targeting the partial rrnl (16S rRNA), tCys (transfer RNA for cysteine) and partial rrnS (12S rRNA) genes of Schistosoma spindale to specifically detect schistosome infection from faecal samples of naturally infected bovines. The salient findings of the work also throw light on to the high similarity of the ribosomal RNA gene sequences of schistosomes with those of Gastrothylax crumenifer and Fischoederius elongatus, the most prevalent pouched amphistomes of the region. Further investigation has to be directed towards unravelling the complete gene sequences of 18S and 28S ribosomal RNA as well as mitochondrial DNA sequences of amphistome isolates from India.

About the middle of July, 1932, red galls were discovered on blades of grass in a meadow at Winches Farm, St. Albans, by Mr. W. A. Macdonald, who drew the attention of the writer to the presence of nematodes within them. Subsequent search on this and an adjoining meadow proved that the galls were widely distributed, on the same kind of grass, over the whole area, whilst some days later similar galls were found on a bank by the side of the main road from St. Albans to Hatfield. The grass was identified as Agrostis tenuis Sibth. (Agrostis vulgaris With.), popularly called Fine Bent-grass.

Flubendazole given orally at 50mg kg to mice inoculated with 50, 250 or 500 larvae of Angiostrongylus cantonensis showed almost complete larvicidal effect, irrespective of the worm burden.