Various cooling (01–5.100 Cmin−1) and warming (2O–6,8OO½Cmin−1) rates, stepped cooling schedules and four cryoprotective additives (dimethyl sulphoxide, methanol, ethanediol and glycerol) were investigated in cryopreservation studies with Dictyocaulus viviparus third-stage larvae. Exsheathment with sodium hypochlorite was essential to achieve significant survival. With uninterrupted cooling, highest survival (30% normally motile) was achieved with rates of 10–70½C min−1. Survival was higher (50–75%) using 1 ½C min−1 to — 10½C followed by plunging into liquid nitrogen. The optimum warming rate was 6,8OO½C min−1. The use of cryoprotectants led to marginally lower survival while varying the suspending media had no significant effect on survival. X-irradiated, exsheathed third-stage larvae cryopreserved by the optimum protocol yielded 38–3 ±4–2% survival. Two calves each infected with 45,000 (15,000 viable) exsheathed, unirradiated, C“ryopreserved third-stage larvae harboured 494 worms (11% infectivity) and 355 worms (0-8%) at necropsy. Numbers of first-stage larvae in the faeces reached 420/G and 105/G respectively 27 days after infection.

1. “Chlorphenol” and “dichlorphenol”are shown to be highly toxic to eelworms, both in the active and quiescent stages. Comparisons are made between these chemicals and iodine solutions in this respect.

2. Treatments of clover and teazle seed with “chlorphenol” and iodine solutions are described and it is shown that infesting eelworms may be controlled without affecting germination or subsequent growth.

3. The use of “chlorphenol,” with the addition of a wetting agent is recommended for the hot-water treatment of narcissus bulbs, as an additional insurance for the control of the “wool” stage of bulb eelworm.

4. The phytocidal action of “chlorphenol” is discussed and it is shown that such action is not marked.

5. Some preliminary experiments on the use of “chlorphenol” against potato root eelworm are described.

Here we report findings to optimize and standardize conditions to attenuate metacercariae of Opisthorchis viverrini by ionizing radiation to elicit protective immune responses to challenge infection. Metacercariae were gamma-irradiated and the ability of irradiated metacercariae to prevent patent infection of challenge metacercariae in hamsters was determined, as well as their ability to induce a host antibody response. Metacercariae irradiated in a dose-dependent manner, with 3, 5, 10, 12, 20, 25 and 50 Gray, were used to infect Syrian golden hamsters by stomach gavage to ascertain the effect of irradiation on ability of the worms to establish infection. In addition, other hamsters were infected with metacercariae irradiated with 20–50 Gray, followed by challenge with intact/wild-type (non-irradiated) metacercariae to determine the protective effect as established by the numbers of adult flukes, eggs of O. viverrini in hamster faeces and anti-O. viverrini antibody titres. Significantly fewer worms were recovered from hamsters immunized with metacercariae irradiated at 20, 25 and 50 Gray than from control hamsters infected with intact metacercariae or 0 Gray, and the worms showed damaged reproductive organs. Faecal egg numbers were decreased significantly in hamsters immunized with 25 and 50 Gray metacercariae of O. viverrini. Moreover, hamsters administered metacercariae that were protected elicited a robust, specific anti-fluke immunoglobulin G response compared to control hamsters, suggesting a role for antibody in protection elicited by radiation-attenuated metacercariae.

The macrofilaricidal activity of diethylcarbamazine (DEC) was confirmed in jirds infected with Brugia pahangi. Seventy jirds were inoculated subcutaneously with 100 infective larvae. At 20 weeks post-infection, the microfilaraemic jirds were divided into two groups, untreated and treated. For the treated group, 200 mg kg−1 of DEC was injected intraperitoneally for 5 consecutive days. One, 4, 8, 12, 16 and 27 weeks after the final treatment, 4–7 jirds in each group were sacrificed to measure adult worm burdens. The number of adult worms recovered from treated jirds was comparable to controls at earlier necropsy (1 and 4 weeks post-treatment). However, at late necropsy (8 weeks and later) the recovery rate of adult worms in treated jirds was significantly lower than that in untreated controls, indicating an adultcidal effect of DEC. The present study demonstrates that DEC requires 8 weeks to kill B. pahangi adult worms in jirds and that the Mongolian jird is a useful model for screening antifilarial activity.

The digenean trematode Diphtherostomum brusinae (Stossich, 1888) Stossich, 1903 presents a complex life cycle that may involve more than one intermediate host. The present study represents the first description of the metacercariae from D. brusinae infecting the labial palps of a new intermediate host, Mytilus galloprovincialis, in the Aveiro estuary, Portugal. The morphology of this parasitic stage was studied by light (LM) and scanning electron microscopy (SEM) and some differences were reported (body and sucker sizes, and spine distribution and shape). In this work, the 18S partial region of the ribosomal DNA was sequenced from D. brusinae metacercariae isolated from M. galloprovincialis collected in different localities of the Aveiro estuary. In addition, sequences from the same region of the 18S rDNA were obtained from D. brusinae cercariae and metacercariae, hosted by Nassarius reticulatus and Cerastoderma edule, respectively. No intraspecific polymorphism was detected in the 18S partial region, since there was 100% homology among all the sequences analysed. The same comparison was made for the ITS1, and we observed intraspecific polymorphism in this region. To our knowledge, this is the first report of D. brusinae metacercariae infecting the mussel M. galloprovincialis with support from morphological and molecular data.

A striking was difference was found in the responses of Schistosoma mansoni and S. haematobium miracidia to the intensity and direction of light and to gravity. S. mansoni miracidia were found to be positively phototactic and sensitive to small changes in light intensities. They were indifferent to gravity. S. haematobium miracidia however were negatively phototactic and unable to distinguish low light intensities from darkness. They showed a strong positive geotaxis.

Both S. mansoni and S. haematobium miracidia could successfully find and infect snails to a depth of 2 metres of water: the significance of these findings in relation to transmission of schistosomiasis in the field is discussed.

Camallanus fotedari n.sp. is described from the intestine of Nemachilus from Kashmir. This is a new host record for the genus. The new species is characterised by the presence of 14–16 pairs of papillae of which 6–8 pairs are precloacal, 2 pairs are adcloacal and 6 pairs are postcloacal. The tail in females is rounded.

Studies on the seasonal population dynamics of Neoechinorhynchus qinghaiensis (Acanthocephala: Neoechinorhynchidae) in its fish host Gymnocypris przewalskii przewalskii in the Qinghai Lake, China, were carried out with samples taken in May 1991, August 1992, November 1992 and February 1993. Prevalences were higher than 44% in all seasons. The mean intensity of infection was above 124 worms per fish. The maximum intensity of worms recovered from a single fish was 1402 in the autumn of 1992. Differences in the mean abundance, mean intensity and prevalence are not statistically significant relative to season and this is likely to be related to the stable temperatures recorded at the bottom of Qinghai Lake. Over-dispersed distributions of N. qinghaiensis in the host population, due to heterogeneity and feeding habits, were observed in all seasons. The size composition of both sexes of N. qinghaiensis showed males to be less than 3.5 mm and females between 0.5 and 4.25 mm, with the main recruitment phase in the worm populations occurring in the autumn, extending through winter and spring with the lowest recruitment occurring in the summer. The maturation and copulation of worms were mainly focused in the summer season. The sex ratio of female to male was both high in winter (1.51:1) and spring (1.48:1). The higher proportion of females and the change in the worm sex ratio in winter can be attributed to the reduced longevity of male worms. As immature male worms exhibit a higher proportion of the worm population than females in all seasons, further studies are needed to determine if such a situation compensates for the shorter life span of males.

1. The paper deals with nematodes of the genus Aphelenchus causing diseases in cultivated plants. A list of these, with the main pathological conditions to which they give rise, is set out on page 144.

2. Each parasite and the disease due to it is dealt with, and particulars are given concerning the structure of the worm, together with the symptoms and biology in each case.

3. A general discussion on the problem of the appropriate treatment of these diseases is given, and the suggestion is made that some form of heat treatment of infective soils is likely to give the best results, owing to the fact that comparatively low temperatures are lethal to the parasites.

Adult Lymnaea truncatula were subjected to 10 days of experimental desiccation and then remained in water for 1 or 8 days before each was exposed to a single miracidium. The infection rate was lower in these snails than in infected controls that were not exposed to stress (52–54% vs 73%). The redial burden clearly decreased in stressed snails (18–25 rediae per snail) than in controls (43 rediae). This numerical decrease concerned essentially: i) live independent rediae of the first generation and the first cohort of the second generation, and ii) dependent rediae of subsequent generations. Mature rediae were more numerous in the first cohort of the second generation than in the other generations. Desiccation before exposure limited the size of the redial burden but placement in water for 8 days just after the stress attenuated the effects of this factor.

A new species of Moniliformis Travassos, 1915 (Acanthocephala: Moniliformidae) is described from the hairy-tailed bolo mouse, Necromys lasiurus Lund, 1840 (Cricetidae: Sigmondontinae), captured in the Brazilian Cerrado, in Uberlândia, state of Minas Gerais, Brazil. The specimens were studied by light and scanning electron microscopy. Molecular phylogenies were inferred from partial nuclear large subunit ribosomal RNA gene sequences and partial mitochondrial cytochrome c oxidase subunit I gene. The new species is distinguished from other moniliformid species by the number of rows and number of hooks per row, size of the proboscis, size of the eggs, host species and geographical distribution. Molecular phylogenies and genetic distances analyses demonstrated that Moniliformis necromysi sp. n. forms a well-supported monophyletic group with sequences of other species of Moniliformis and is distinguished from them, which agrees with the morphological characteristics, allocating the new species to this genus and to the family Moniliformidae Van Cleave, 1924. This is the first moniliformid acanthocephalan described from a wild rodent in Brazil.

Eurytrema coelomaticum is a digenean flatworm of ruminants that is the causative agent of eurytrematosis, a disease of veterinary health concern. Although modern techniques of morphological analysis have provided new insights about the morphology and anatomy of parasitic helminths, most studies on E. coelomaticum adults are based on conventional light microscopy. In the present study, a combined approach using brightfield, fluorescence, confocal and scanning electron microscopies (SEMs), together with the cryofracture technique, have updated morphological data on E. coelomaticum recovered from cattle in Rio de Janeiro State, Brazil. Light microscopy confirmed the presence of several structures present in the current description, such as suckers, pharynx, oesophagus, intestinal bifurcation and the cirrus-sac. Fluorescence stereomicroscopy revealed for the first time the cubic crystal protein inclusions in the forebody, which were further detailed by confocal and SEMs. Confocal microscopy provided detailed information of the muscular architecture associated with the attachment structures (suckers), digestive system (pharynx and oesophagus), egg-forming complex (ovary, Mehlis’ gland and Laurer's canal) and male reproductive system, which are similar to those found in other digenean flukes. SEM images of cryofractured parasites showed mucus and developing eggs within uterine loops. It was demonstrated that the combination of advanced tools generated complementary information, confirming the importance of experimental morphology in parasitology. Therefore, the knowledge of the adult structural organization of E. coelomaticum was improved and this work has contributed to propose new morphological criteria to evaluate the effects of antiparasitic drugs on flukes of medical and veterinary importance.

A description and the molecular characterization of two new species in the Haploporidae and Haplosplanchnidae families are provided herein. Parasaccocoelium armatum n. sp. was collected from the intestine of a Mugil cephalus Linnaeus, 1758 from the Primorsky region, Russia, and Pseudohaplosplanchnus catbaensis n. g. n. sp. was collected from Moolgarda seheli (Forsskål, 1775) in the coastal waters of Cat Ba Island, Vietnam. The morphological features of P. armatum n. sp. closely resemble those of Parasaccocoelium polyovum, but these species differ from one another by hermaphroditic sac and vitellaria area length and by maximal egg size. The main difference between P. armatum n. sp. and P. polyovum is the presence of an armed hermaphroditic duct in the new species. Molecular data support the case for inclusion of the studied trematodes in P. armatum n. sp. Worms P. catbaensis n. g. n. sp. from the mullet from Vietnam are morphologically close to Haplosplanchnus (Haplosplosplanchninae). The only difference between P. catbaensis n. g. n. sp. and species of Haplosplanchnus is the presence of few (1–7) large eggs, measuring 135–142 × 92–104 μm, versus numerous small eggs with a maximal size of 75 × 50 μm. Phylogenetic analysis showed that there is a contradiction between the morphological similarity of the worms and their position in the Haplosplanchnidae system, based on the genetic data. Results of this study indicate that P. catbaensis n. g. n. sp. is genetically distant from other representatives of Haplosplanchnus, despite their morphological similarity. According to the molecular data, P. catbaensis n. g. n. sp. is close to Hymenocotta mulli Manter, 1961 (Hymenocottinae). However, these species are considerably different to each other morphologically. Molecular data argue for the possibility of establishing a new subfamily for P. catbaensis n. g. n. sp. However, considering earlier studies of Haplosplanchnidae, we support the view that creating new subfamilies within this family is unreasonable because of the lack of molecular data for most haplosplanchnid species, which are necessary to resolve the problematic systematics and phylogeny of this family.

In the present study, the nematicidal activity of a Moringa oleifera ethyl acetate leaf extract against the eggs and larvae of Haemonchus contortus and Nacobbus aberrans, nematodes of agricultural importance, was evaluated. The experimental design for the evaluation of the effects against both nematodes consisted of eight treatments (n = 4). Distilled water, Tween (4%) and a commercial anthelmintic agent (ivermectin, 5 mg/mL) were used as controls, and for treatments 4–8, the concentrations of the extract were 20, 10, 5, 2.5 and 1.25 mg/mL, respectively. Readings were taken at 12 h and 24 h for N. aberrans and 48 h and 72 h for H. contortus post-treatment under an optical microscope (10× and 40×). The data obtained were analysed by analysis of variance through a completely randomized factorial design using the SAS V9 program. The results show that, for H. contortus egg hatching, 85.88% inhibition was obtained at a concentration of 20 mg/mL at 48 h, while for third-stage larva (L3) mortality, the highest percentage was 68.19% at 1.25 mg/mL at 72 h. In the case of N. aberrans, the greatest inhibition of egg hatching was 90.69% at 5 mg/mL at 12 h post-treatment, and for larval mortality, it was 100% at 10 mg/mL at 24 h post-treatment. The main major compounds identified by qualitative analysis and by gas chromatography coupled to mass spectrometry were 9,12,15-octadecatrienoic acid, (Z,Z,Z)-, n-hexadecanoic acid and 2,4-di-tert-butylphenol, and the minor compounds included phytol, γ-sitosterol and α-tocopheryl acetate. It was demonstrated that the ethyl acetate leaf extract of M. oleifera Lam. shows great potential for combating agricultural nematodes.

1. Ten dogs were given infective larvae of Dracunculus medinensis, originally from human cases in Western Nigeria, and bred in the laboratory in Cyclops leuckarti (Claus).

2. Parasites were found in seven of the dogs when dissected at intervals between 4 hours and 36 days. From an examination of the location of the larvae obtained, both by direct search and by the use of intravenous Evans' blue, it was concluded that they migrated directly through the tissues via the intestinal wall (about 13 hours), abdominal mesenteries (found at 7 and 10 days), and muscles of the abdominal and thoracic wall (15 days). A similar route of migration is believed to take place in cats from an examination of three positive kittens.

3. Almost no increase in length of the larvae occurred during the migration; these measured an average of 0·59 mm. in length after 15 days.

4. No moult was observed up to 36 days but one may have been missed.

This study used Balb/c mice to examine the longevity of Echinostoma caproni. Five mice each exposed to 75 encysted metacercariae (cysts) were necropsied at 23 weeks postinfection (PI) (160 days PI). Two of the 5 were infected with a total of 33 worms; 23 in one mouse and 10 in the other. Body and organ area measurements showed that these worms were robust and normal in appearance. No signs of atrophy of any of the genital structures were observed. The mean ± SE of eggs/uterus per worm (n = 10) was 243 ± 6. This strain of mouse will be suitable to study the effect of long-term survival on the host–parasite relationship of E. caproni in Balb/c mice.

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.

Single and double infections of juvenile Omphiscola glabra (Gastropoda: Lymnaeidae) with Paramphistomum daubneyi and/or Fasciola hepatica were carried out to determine the redial burden and cercarial production in snails dissected at day 60 or at day 75 post-exposure (p.e.) in the laboratory at 20°C. The results were compared with those obtained with single-miracidium infections by Fascioloides magna. Compared to F. hepatica, low values were noted at day 75 p.e. for the prevalence of snail infections with P. daubneyi (4.6–8.3% instead of 23.6–25.9%), the total number of free rediae (10.7–17.9 per snail instead of 26.3–34.7), and that of free cercariae (112.8–136.9 per snail instead of 177.8–248.5). Despite a greater number of free rediae at day 75 p.e. (36.2–45.6 per snail), the prevalences of snail infections with F. magna and cercarial production were similar to those noted for F. hepatica. The results concerning F. hepatica and P. daubneyi might partly be explained by a progressive adaptation of O. glabra to sustain the larval development of these digeneans over the years, as this snail is a natural intermediate host of F. hepatica and P. daubneyi in central France since 1995. Compared with the high number of fully-grown rediae of F. magna in O. glabra, cercarial production seemed limited and this might be explained by the presence of high numbers of rediae which reduced the avaibility of nutrients for cercarial differentiation within the snail.

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.