Intestinal helminth parasites are responsible for a significant amount of pathology in both humans and farmed animals, resulting in a reduction in the quality of life, and occasionally lethal infection as well as causing decreases in livestock productivity. The importance of these parasites globally has resulted in efforts to understand the mechanisms of the host–parasite interaction epidemiology, and to develop methods for diagnosis and control.

(1) Staining methods using paraldehyde-fuchsin, chrome-haematoxylin, and alcian blue or astra blue following oxidation, have demonstrated the shape of the hook and other structures on the cephalic space of microfilariae. These structures are described for three species of the genus Brugia, B. malayi, B. pahangi and B. patei, and are compared with the related structures found in the genera Wuchereria, Loa, Cardiofilaria, Onchocerca, Mansonella, Dipetalonema and Litomosoides.

(2) In Brugia the hook of the microfilaria is V-shaped and is supported basally by a pair of transverse basal pieces which are closely associated with an oral ring. Similar structures are found in the microfilariae of Wuchereria and Loa except that in Loa the hook is supported below by a semi-circular arch. In Brugia there is a row of three spines transversely on the cephalic space opposite the hook complex, the spines being markedly shorter in B. patei than in the other two species; in Wuchereria there is a single transverse row of four spines, and in Loa there are two or three transverse rows of spines, No spines arranged opposite the hook complex were observed in the other genera. The hook and associated structures in Cardiofilaria are similar in arrangement to those of Loa, and the small structures in Mansonella can possibly be derived from a similar arrangement. In Onchocerca the hook has the appearance of a broad plate and in Dipetalonema perstans part of the surface of the cephalic space appears to be involved with the small pointed “hook”. In Litomosoides the tip of the cephalic space is covered by a helmet-like structure carrying a pointed beak-like projection.

(3) It is suggested, from their staining reactions, that the cephalic structures of microfilariae are particularly rich in disulphide bonds, suggesting the presence of cystine.

(4) The staining methods also demonstrate an internal thread of tissue in microfilariae which extends in Brugia from the tip of the cephalic space back to the innen korper. A similar thread is present in the microfilaria of Wuchereria, Loa, Cardiofilaria and Mansonella but was not observed in the other genera, although a short thread of tissue was stained in the cephalic space in Onchocerca and Litomosoides. In Brugia, the buccal capsule, the pharynx and the pharyngo-intestinal valve develop around the pharyngeal thread of the microfilaria. The extreme end of the thread, around which the pharyngo-intestinal valve develops, differs in its staining reactions from the rest of the thread.

(5) The staining reactions of the pharyngeal thread in the microfilaria of Brugia show resemblances to those of “elastic” fibres in other invertebrates and oxytalan fibres of vertebrates. The pharyngeal thread appears to contain an acid mucopolysaccharide component.

(6) The possible functions of the cephalic and pharyngeal structures in the microfilariae are discussed briefly.

(7) A staining routine for demonstrating the structures described in this paper is given in an appendix.

In the course of work undertaken in the preparation of the experimental field plots at Winches Farm it has been of interest to ascertain something about the nematode fauna of the place, especially that occurring in certain heaps of manure made at the farm and afterwards used on some of the plots. With regard to the worms recorded from sheep droppings collected from pastures these were obtained in Baermann extractions, set up by a colleague, in attempts to collect larvae of parasitic nematodes harboured by the stock. It became necessary for purposes of differentiation to determine the naturally occurring free-living nematodes which were found in great abundance. The worms described in the following pages have been encountered in the course of these investigations. Some are new to science and about others very little has previously been known so that additional information on them is here made available.

A total of 142 serum specimens from Croatian children aged 3–18 years, with peripheral eosinophilia and without any clinical symptoms, were tested for the presence of Toxocara canis IgG antibodies using an enzyme-linked immunosorbent assay (ELISA) and Western blot method. The overall T. canis seropositivity rate in the samples tested was 31%. There was no statistical difference in the seroprevalence rate between boys (32.1%) and girls (29.7%, χ2 = 0.092, P = 0.761). The T. canis seropositivity varied significantly between age groups both in boys (Fisher's test P < 0.001) and girls (Fisher's test P = 0.007). The highest seroprevalence rate was found in boys aged 11–14 (42.9%) and girls aged 7–10 (44.2%). Our results showed a high seroprevalence rate of T. canis infection among children with eosinophilia. It is important that testing for toxocariasis should be included in a differential diagnosis of eosinophilia, especially in children.

Human Taenia solium cysticercosis is common in developing countries due to poor sanitary conditions and economics based on breeding livestock, especially pigs, with low hygiene standards. Neurocysticercosis, caused by migration of the larvae of the tapeworm in the nervous system, is the leading cause of acquired epilepsy in adults in Central and South America, sub-Saharan Africa, and East and South Asia. This makes neurocysticercosis a large public health problem in developing countries. Two clinical cases of neurocysticercosis have been observed recently in Haiti. In order to evaluate the prevalence of human T. solium cysticercosis in this country, in 2007 we conducted a cross-sectional serological retrospective survey using a Western blotting test (LDBIO Diagnostics®) in Port-au-Prince, where sewage systems are rare and swine usually roam freely throughout the area. A total of 216 serum samples, obtained from healthy adults seen in the work setting of periodical medical visits, were tested after storage at − 20°C. The frequency of antibodies in serum samples of the study population was 2.8% (6/216). The immunodominant bands recognized in Western blots were 23–26 kDa (100%), 39 kDa (67%), 45 kDa and 6–8 kDa (50%), 50–55 kDa (33%). These results confirm for the first time an endemic situation of cysticercosis in humans in Haiti, with similar prevalence as that reported in other Latin American and African countries. It reinforces the urgent need for control and prevention measures to be taken by local public health services.

The members of the nematode genus Rhabdias present many features of great interest to the parasitologist. They are usually found inhabiting the lungs of amphibians and reptiles where their eggs or larvæ are produced. They have the general appearance of females and are either hermaphroditic or parthenogenetic in function (vide Goldschmidt, 1923, p. 176, on “Unisexual Monœcism”). Seurat (1920), p. 121, considers that the parasitic forms of R. dujardini and R. entomelas from the Slow worm Anguis fragilis are parthenogenetic females and not protandrous hermaphrodites because they lay an enormous number of eggs, whereas the hermaphroditic forms produce comparatively few eggs. Moreover, in R. entomelas he has been unable to find either receptacula seminis or spermatozoa.

Human strongyloidiasis is a deleterious gastrointestinal disease mainly caused by Strongyloides stercoralis infection. We aimed to study the possible transmission of S. stercoralis between humans and pet animals. We isolated Strongyloides from humans and domestic dogs in the same rural community in north-east Thailand and compared the nucleotide sequences of derived worms using portions of the mitochondrial cytochrome c oxidase subunit 1 (cox1) and 18S ribosomal RNA (18S rRNA) genes. Twenty-eight sequences from the 18S rRNA gene were obtained from worms derived from humans (n = 23) and dogs (n = 5), and were identical with S. stercoralis sequences (from Thailand, Cambodia, Lao PDR and Myanmar) published in the GenBank database. The 28 cox1 sequences from humans and dogs showed high similarity to each other. The available published cox1 sequences (n = 150), in combination with our 28 sequences, represented 68 haplotypes distributed among four clusters. The 28 samples from the present study represented eight haplotypes including four new haplotypes. Dogs and humans shared the same haplotypes, suggesting the possibility of zoonotic transmission from pet dogs to humans. This is of concern since dogs and humans live in close association with each other.

An enzyme-linked immunosorbent assay (ELISA) using antigenic β-galactosidase-Dirofilaria immitis recombinant fusion protein (FP) obtained by the recombinant DNA technique provided a useful diagnostic tool for human dirofilariasis. D. immitis-infected human sera reacted strongly with FP that was immobilized with anti-β-galactosidase monoclonal antibody on microplates. However, the FP did not react with sera from patients with other filariasis. In detection of anti-D. immitis IgG antibody. ELISA using FP was highly sensitive and specific compared to that using crude somatic antigen.

The morphologies of the adult worms and microfilariae of Ochocerca found in the neck and gastro-splenic region of cattle in southeast England were compared. It is concluded that they are forms of the same species.

The susceptibility of 13 different B. forskalii strains from Zaire, Cameroun, Gabon, Senegal, Rhodesia and Tanzania and B. reticulatus wrighti Aden has been tested to infection with Schistosoma intercalatum from Cameroun. The most common prepatent period was 23–28 days.

B. forskalii from Zaire, Cameroun and Gabon were excellent intermediate hosts with infection rates varying from 59–0 to 97–4% and with very low death rates, 0-28-4%. The strains from Senegal and Rhodesia had infection rates from 500 to 58.4%. B. forskalii from Tanzania was refractory. 53.0% of the exposed B. reticulatus wrighti was infected. The total cercariae production per snail varied from 1000–11000. The duration of the infection varied from 8 to 174 days.

The migration of infective larvae of Strongyloides ratti has been examined in C57B1/6 mice after percutaneous infection of the anterior abdominal wall. Lateral migration of larvae through the skin and subcutaneous tissues was not seen. Large numbers of larvae were recovered from the muscles between 2 and 24 hours after infection and larvae were seen in the cerebrospinal fluid 24 and 48 hours after infection. Insignificant numbers of larvae were seen in the blood, serosal cavities, liver, spleen, kidneys, brain or nasopharynx. Larvae arrived in the lungs between 24 and 72 hours after infection and worms were first noted in the small intestines at 48 hours. It is concluded that larvae migrate preferentially to the muscles and CSF before passing to the lungs, but the exact mode of travel is uncertain.

The distribution of glycogen in the adult common liver fluke, Fasciola hepatica, was studied by the periodic acid-Schiff reaction. As well as in the yolk cells, the peripheral muscle layers and to a lesser extent the parenchyma, glycogen was detected in fine tonofibrils in the tegument.

The glycogen of the peripheral muscle layers and of the tonofibrils of the tegument is drastically depleted if the flukes are kept for a few hours in Hédon-Fleig with insulin added, as compared to controls without insulin.

The effect of insulin raises the question whether this protein enters the tissues through the surface of the tegument, or conceivably but less likely, through the gut. Furthermore, the mechanism of its action in the parasite's tissues requires investigation

Despite the seriousness of schistosomiasis, its treatment depends only on praziquantel (PZQ), which has begun to lose its efficacy against the emergent Schistosoma mansoni-resistant strains. Therefore, the discovery of a novel schistosomicidal drug is an urgent priority. This study was designed to evaluate treatment with Cucurbita pepo L. (pumpkin) seed oil (PSO) alone and combined with PZQ against S. mansoni in experimentally infected mice. The study involved five groups: GI was the normal control; GII was the infected control; GIII was treated with an oral dose of PZQ of 500 mg/kg/day for two successive days, starting in the sixth week post infection; GIV was treated with an oral dose of PSO of 50 mg/kg/day for four weeks, starting in the fourth week post infection; and GV was treated with combined PSO–PZQ. Worm burden, tissue egg load and oogram pattern were estimated, and the ultrastructure alterations were examined. Histopathological examination of granuloma diameters, collagen deposition (Picro Sirius red stain), and angiogenesis (immunohistochemical expression of CD34+) was conducted and serum liver enzymes were measured to assess the liver condition. Moreover, the oxidative stress was evaluated by determining the amounts of malondialdehyde and superoxide dismutase in liver homogenates. The results revealed significant changes in all the assessed parameters with PSO administration. However, PZQ was significantly more effective as an antiparasitic agent, whereas PSO was better in terms of fibrosis and oxidative stress. The most significant results were obtained in group V, which may be attributed to a synergy between PZQ and PSO, with antiparasitic, antioxidant and antifibrotic properties.

The effect of cadmium exposure of the snail first intermediate host Lymnaea peregra on the incidence of encystment of Echinoparyphium recurvatum (Digenea: Echinostomatidae) cercariae without emergence from the snail was investigated. Exposure to 100 μg l−1 Cd for 72 h caused a significant increase in the incidence of first host encystment when compared to controls. In addition, autometallographic staining of E. recurvatum daughter rediae and developing cercariae showed that there was metal accumulation within their body tissues. The significance of these findings to parasite transmission in metal-polluted environments is discussed.

Dichloromethane and aqueous fractions from leaves and stems of Piper arboreum Aubl., P. aduncum L., P. amalago L., P. crassinervium H.B. & K., P. diospyrifolium Kunth, P. hispidum Sw. and P. xylosteoides (Kunth) Steud. were tested against adult worms of Schistosoma mansoni. The in vitro activity was evaluated in terms of mortality, number of separated worms and number of worms with reduced motor activity. Most dichloromethane fractions from all Piper species showed moderate schistosomicidal activity, but aqueous fractions were not active. The dichloromethane fraction of P. amalago leaves (at 100 μg/ml) showed the highest activity, resulting in worm mortality, the separation of worm pairs and reduced motor activity. Chromatographic fractionation of the dichloromethane fraction of P. amalago leaves led to the isolation of its major compound, which was also tested against adults of S. mansoni. The isolated piperamide N-[7-(3′,4′-methylenedioxyphenyl)-2(Z),4(Z)-heptadienoyl] pyrrolidine, at 100 μm, resulted in the mortality of all adult worms after 24 h of incubation. The findings suggest that species of Piper are potential sources of schistosomicidal compounds.

The cercarial shedding of Schistosoma bovis and S. haematobium were studied in single and mixed infections in the snail host Bulinus truncatus. The two species displayed a distinctive diurnal cercarial emergence with an earlier shedding pattern for S. bovis than S. haematobium (the average emergence peaks were respectively at 0800 h and 1200 h). In mixed infections, each species kept its own cercarial shedding rhythm with no marked alterations. The cercarial emergence pattern is proposed as a new method to identify natural mixed infections in the snail intermediate hosts. The interactions between the two parasites are discussed.

Entomopathogenic nematodes (EPN) are lethal parasites of insects, used as biocontrol agents. The objectives of this work were to survey the presence of EPN in continental Portugal and to characterize the different species. Of the 791 soil samples collected throughout continental Portugal, 53 were positive for EPN. Steinernema feltiae and Heterorhabditis bacteriophora were the two most abundant species. Analysis of EPN geographical distribution revealed an association between nematode species and vegetation type. Heterorhabditis bacteriophora was mostly found in the Alentejo region while S. feltiae was present in land occupied by agriculture with natural vegetation, broadleaved forest, mixed forest and transitional woodland-shrub, agro-forestry areas, complex cultivated patterns and non-irrigated arable land. Although no clear association was found between species and soil type, S. feltiae was typically recovered from cambisols and H. bacteriophora was more abundant in lithosols. Sequencing of the internal transcribed spacer (ITS) region indicated that S. feltiae was the most abundant species, followed by H. bacteriophora. Steinernema intermedium and S. kraussei were each isolated from one site and Steinernema sp. from two sites. Phylogenetic analyses of ITS, D2D3 expansion region of the 28S rRNA gene, as well as mitochondrial cytochrome c oxidase subunit I (COXI) and cytochrome b (cytb) genes, was performed to evaluate the genetic diversity of S. feltiae and H. bacteriophora. No significant genetic diversity was found among H. bacteriophora isolates. However, COXI seems to be the best marker to study genetic diversity of S. feltiae. This survey contributes to the understanding of EPN distribution in Europe.

Strongyloides fuelleborni is a soil-transmitted nematode parasite of non-human primates. The worm is prevalent also in human populations in Africa and South-East Asia. In this study, we amplified and sequenced a portion of the 18S ribosomal RNA gene (rRNA) and of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of Strongyloides adult males recovered from faecal samples from long-tailed macaques (Macaca fascicularis) in Thailand and Lao PDR. The prevalence in Thailand was 31.1% (55/177) and in Lao PDR it was 62.1% (41/66), with an overall prevalence of 39.5% (96/243). All 18S rRNA sequences that we obtained (n = 96) showed 100% identity with published S. fuelleborni sequences. The 96 cox1 sequences that we obtained represented 32 new haplotypes. When included with the 17 previously known haplotypes from S. fuelleborni, the cox1 sequences fell into four clusters, which had clear geographical structure. This is the first molecular confirmation of S. fuelleborni in long-tailed macaques in Thailand and Lao PDR. Clearly, awareness needs to be raised of the zoonotic potential of S. fuelleborni. A monitoring programme should be organized, taking into account the role of reservoir hosts (i.e. monkeys) in the natural background of human strongyloidiasis caused by S. fuelleborni.

1. Two snail species (Physa marmorata and Drepanotrema surinamensis), guppies (Poecilia reticulata), and tadpoles (Bufo marinus) prevented in various degrees the infection of susceptible B. glabrata by miracidia of S. mansoni.

8. When the animal decoys were used in “pure” groups, the snails were more efficient in reducing the infection in B. glabrata than the guppies and the tadpoles.

3. When the animal decoys were used in “mixed” groups, the combination of P. marmorata and D. surinamensis was the most efficient group in reducing the infection in B. glabrata.

The gullet worm (Gongylonema pulchrum) has been recorded from a variety of mammals worldwide, including monkeys and humans. Due to its wide host range, it has been suggested that the worm may be transmitted locally to any mammalian host by chance. To investigate this notion, the ribosomal RNA gene (rDNA), mainly regions of the internal transcribed spacers (ITS) 1 and 2, and a cytochrome c oxidase subunit I (COI) region of mitochondrial DNA of G. pulchrum were characterized using parasites from the following hosts located in Japan: cattle, sika deer, wild boars, Japanese macaques, a feral Reeves's muntjac and captive squirrel monkeys. The rDNA nucleotide sequences of G. pulchrum were generally well conserved regardless of their host origin. However, a few insertions/deletions of nucleotides along with a few base substitutions in the ITS1 and ITS2 regions were observed in G. pulchrum from sika deer, wild boars and Japanese macaques, and those differed from G. pulchrum in cattle, the feral Reeves's muntjac and captive squirrel monkeys. The COI sequences of G. pulchrum were further divided into multiple haplotypes and two groups of haplotypes, i.e. those from a majority of sika deer, wild boars and Japanese macaques and those from cattle and zoo animals, were clearly differentiated. Our findings indicate that domestic and sylvatic transmission cycles of the gullet worm are currently present, at least in Japan.