The main goal of the current work was to develop and validate an in vitro fluke egg hatch test, as a method for the detection of albendazole (ABZ) resistance in the liver fluke, Fasciola hepatica. Fluke eggs (200/ml, n= 5) from six different isolates were used in the current experimental work. They were obtained from different geographical locations and named Cullompton (UK), CEDIVE (Chascomus, Argentina), INTA-Bariloche (Bariloche, Argentina), Rubino (Uruguay), Cajamarca (Perú) and Río Chico (Catamarca, Argentina). The fluke eggs were incubated (25°C) for a 12-h period in the presence of either ABZ or its sulphoxide metabolite (ABZ.SO) (5, 0.5 or 0.05 nmol/ml). Untreated eggs were incubated as a control. Incubated eggs (with or without drug present) were kept in darkness at 25°C for 15 days. Afterwards, the trematode eggs were exposed to daylight over a 2-h period. Hatched and unhatched eggs were evaluated using an optical microscope, and the ovicidal activity was assessed for each fluke isolate. A very low ovicidal activity ( ≤ 13.4%) was observed in the ABZ-resistant CEDIVE isolate for both ABZ and ABZ.SO. Conversely, in the INTA-Bariloche and Río Chico isolates, which are suspected to be susceptible to ABZ, ovicidal activities ≥ 70.3% were observed after incubation with ABZ at the lowest concentration tested (0.05 nmol/ml). This finding correlates with that previously described for the ABZ-susceptible Cullompton. Finally, the Cajamarca and Rubino isolates behaved as ABZ resistant, since no ovicidal activity was observed after eggs were incubated with ABZ at 0.5 nmol/ml. Considering the specific results obtained for each isolate under assessment, the egg hatch test described here may be a suitable method for detection of ABZ resistance in F. hepatica.

Tænia echinococcus has always been recognised as one of the most important tapeworms of carnivores, both from the human and the economic point of view. Its intermediate stage, or Hydatid, assumes many forms, but most modern workers believe that all these forms—with one possible exception, the alveolar form from Central Europe—are merely the manifestations of a single species.

Climate oscillations and episodic processes interact with evolution, ecology and biogeography to determine the structure and complex mosaic that is the biosphere. Parasites and parasite–host assemblages are key components in a general explanatory paradigm for global biodiversity. We explore faunal assembly in the context of Quaternary time frames of the past 2.6 million years, a period dominated by episodic shifts in climate. Climate drivers cross a continuum from geological to contemporary timescales and serve to determine the structure and distribution of complex biotas. Cycles within cycles are apparent, with drivers that are layered, multifactorial and complex. These cycles influence the dynamics and duration of shifts in environmental structure on varying temporal and spatial scales. An understanding of the dynamics of high-latitude systems, the history of the Beringian nexus (the intermittent land connection linking Eurasia and North America) and downstream patterns of diversity depend on teasing apart the complexity of biotic assembly and persistence. Although climate oscillations have dominated the Quaternary, contemporary dynamics are driven by tipping points and shifting balances emerging from anthropogenic forces that are disrupting ecological structure. Climate change driven by anthropogenic forcing has supplanted a history of episodic variation and is eliminating ecological barriers and constraints on development and distribution for pathogen transmission. A framework to explore interactions of episodic processes on faunal structure and assembly is the Stockholm Paradigm, which appropriately shifts the focus from cospeciation to complexity and contingency in explanations of diversity.

Schistosoma mansoni cercariae labelled with 75Se-methionine were used to study host-finding capacity by determining the radioactivity of exposed mouse “target” tails. Possible interfering effects of some aquatic vertebrates and invertebrates, plants and algae and secretions and excretions of aquatic organisms were examined.

A marked interferent effect due to predatory behaviour was produced by Cyclops strenuus (Copepoda), Daphnia pulex and D. longispina (Cladocera), Notodromas monacha and Cypria ophthalmica (Ostracoda) and Lebistes reticulatus (guppy). Bufo bufo (Amphibia) and Planaria lugubris (Turbellaria) interfered significantly, presumably by secreting cercaricidal toxins. Several other organisms apparently produced no interference. The interferent effect of the plant species Ceratophyllum demersum, Elodea canadensis, Lemna minor, Ranunculus aquaticus, Holcus lanatus (grass) and Botryococcus braunii was particularly pronounced when they were confined to the surface layer of the water. Several other species did not interfere with host-finding.

The present study describes Demidospermus spirophallus n. sp. and Demidospermus prolixus n. sp. (Monogenea, Dactylogyridae) from the siluriform catfish Loricaria prolixa Isbrücker & Nijssen, 1978 (Siluriformes, Loricariidae) from the state of São Paulo, Brazil, supported by morphological and molecular data. In addition, notes on the circumscription of the genus with a redescription of Demisdospermus anus are presented. Demidospermus spirophallus n. sp. differed from other congeners mainly because of the morphology of the male copulatory organ (MCO), which exhibited 2½ counterclockwise rings, a tubular accessory piece with one bifurcated end and a weakly sclerotized vagina with sinistral opening. Demidospermus prolixus n. sp. presents a counterclockwise-coiled MCO with 1½ rings, an ovate base, a non-articulated groove-like accessory piece serving as an MCO guide, two different hook shapes, inconspicuous tegumental annulations, a non-sclerotized vagina with sinistral opening and the absence of eyes or accessory eyespots. The present study provides, for the first time, molecular characterization data using the partial ribosomal gene (28S) of two new species of Demidospermus from Brazil (D. spirophallus n. sp. and D. prolixus n. sp.), and Demidospermus anus from Loricariichthys platymetopon Isbrücker & Nijssen, 1979 collected in the Upper Paraná River floodplain, Brazil. Additionally, a revision of the species composition of this genus and others that occur in catfish is proposed to elucidate problems with their circumscription. The Brazilian species of Demidospermus clustered together as sister taxa among Neotropical dactylogyrids from siluriforms. The morphological characterization of D. spirophallus n. sp. and D. prolixus n. sp., and the molecular data of the three species in the present study will extend knowledge about this monogenean genus from the Neotropical region, and provide new information for future phylogeny studies.

1. The life-cycle of Filaria ozzardi was studied in St. Vincent, B.W.I.

2. Culicoides furens Poey, a common sandfly in Calliaqua, where a 37·7% human infection was found, was used in the experimental infections.

3. Two hundred sand-flies, collected at Calliaqua, were given an infective feed of blood of F. ozzardi carriers. Of these flies, fifty-five, i.e., 27·5%, were subsequently found to be infected with developing stages of the parasite. The ingested microfilariae migrated within 24 hours to the thorax, where the entire morphological development takes place. In flies which were kept alive for seven or eight days, advanced stages were found in the thorax and head, and their emergence from the proboscis was induced by slight pressure on the head.

4. The development in the sandfly consists of a metamorphosis from the 1st stage or “sausage” larva to a 2nd stage larva during the first 3 to 4 days, and from this stage to a 3rd stage or infective larva on the fifth or sixth day. Two ecdyses occur during these metamorphoses, which are discussed in relation to the other human filarial parasites.

5. Five per cent. of C. furens caught at Calliaqua were found to be naturally infected with developing larvae, apparently F. ozzardi.

6. The possibility that C. paraensis, another species in Calliaqua, may also act as a vector, is not excluded.

A prospective multicentric study was carried out to assess both the performance of Western-blot (WB) detecting specific anti-Toxocara IgG and that of CAP™ measuring specific IgE titre for the immunodiagnosis of ocular toxocariasis. For 14 outpatients presenting ophthalmic symptoms (choroiditis, chorioretinitis, papillar oedema, hyalitis, retinal detachment and/or uveitis), samples of serum and aqueous fluid (AF) were sent to the Department of Parasitology, University Hospitals, Toulouse, France. All patients but two tested positive with WB on the serum; 13 WB tests were performed on the AF, 12 of which were positive. The two patients who had a negative WB serum result tested positive for the AF. Specific IgE detection was considered as a complementary test of WB. Two patients showed a greater specific IgE titre in the AF than in the serum, and one had a positive result in the AF, but not in the serum. These six patients were considered as clear cases of ocular toxocariasis. Western-blot coupled with specific anti-Toxocara IgE detection appeared therefore to be an accurate procedure for the immunodiagnosis of ocular toxocariasis, provided the testing was simultaneously performed on the serum and AF.

Three commercially available entomopathogenic nematode (EPN) strains (Steinernema feltiae and Heterorhabditis bacteriophora Hb1 and Hb2) and two local species (S.jeffreyense and S. yirgalemense) were evaluated for the control of the codling moth (Cydia pomonella). In field spray trials, the use of S. jeffreyense resulted in the most effective control (67%), followed by H. bacteriophora (Hb1) (42%) and S. yirgalemense (41%). Laboratory bioassays using spray application in simulated field conditions indicate S. feltiae to be the most virulent (67%), followed by S. yirgalemense (58%). A laboratory comparison of the infection and penetration rate of the different strains showed that, at 14°C, all EPN strains resulted in slower codling moth mortality than they did at 25°C. After 48 h, < 15% mortality was recorded for all species, whereas, at the warmer temperature, >98% mortality was recorded for all species involved. However, the washed codling moth larvae, cool-treated (at 14°C) with S. feltiae or S. yirgalemense, resulted in 100% mortality 24 h later at room temperature, whereas codling moth larvae treated with the two H. bacteriophora strains resulted in 68% and 54% control, respectively. At 14°C, S. feltiae had the highest average penetration rate of 20 IJs/larva, followed by S. yirgalemense, with 14 IJs/larva. At 25°C, S. yirgalemense had the highest penetration rate, with 39 IJs/larva, followed by S. feltiae, with 9 IJs/larva. This study highlights the biocontrol potential of S. jeffreyense, as well as confirming that S. feltiae is a cold-active nematode, whereas the other three EPN isolates tested prefer warmer temperatures.

Angiostrongylus vasorum is a nematode that parasitizes domestic dogs and wild canids. We compared the predatory capacity of isolates from the predatory fungi Duddingtonia flagrans (AC001), Monacrosporium thaumasium (NF34), Monacrosporium sinense (SF53) and Arthrobotrys robusta (I31) on first-stage larvae (L1) of A. vasorum under laboratory conditions. L1A. vasorum were plated on 2% water-agar (WA) Petri dishes marked into 4 mm diameter fields with the four grown isolates and a control without fungus. Plates of treated groups contained each 1000 L1A. vasorum and 1000 conidia of the fungal isolates AC001, NF34, SF53 and I31 on 2% WA. Plates of the control group (without fungus) contained only 1000 L1A. vasorum on 2% WA. Ten random fields (4 mm diameter) were examined per plate of treated and control groups, every 24 h for 7 days. Nematophagous fungi were not observed in the control group during the experiment. There was no variation in the predatory capacity among the tested fungal isolates (P>0.05) during the 7 days of the experiment. There was a significant reduction (P < 0.05) of 80.3%, 74.5%, 74.2% and 71.8% in the means of A. vasorum L1 recovered from treatments with isolates AC001, NF34, SF53 and I31, respectively, compared to the control without fungi. In this study, the four isolates of predatory fungi were efficient in the in vitro capture and destruction of A. vasorum L1, confirming previous work on the efficiency of nematophagous fungi in the control of nematode parasites of dogs and as a possible alternative method of biological control.

Measurements were made of gravid worm lengths, scolex diameter, rostellum diameter, sucker diameter, and large and small rostellar hooks of adult Taenia hydatigena, T. multiceps, T. ovis and T. pisiformis obtained from dogs in North Wales. Values recorded agreed closely with published values. None of these characters could be used to differentiate reliably between the species except that, of the worms examined, those with large rostellar hooks greater than 228 μim were T. pisiformis and those with large hooks less than 168 μm were T. multiceps. The range of hook lengths of the different species overlapped considerably.

Reliable identification required examination of mature proglottis morphology of specimens which were relaxed before fixation. Relaxed mature proglottides often showed a characteristic shape.

Lengths of rostellar hooks of scolices from T. multiceps coenuri followed the same frequency distribution as adult worm hooks. A strong correlation was shown between coenurus volume and the number of scolices on the coenurus membrane, with a poor correlation between coenurus age and volume.

A survey was conducted in 150 households owning 1756 pigs in the rural areas of Mayo-Danay division in the north of Cameroon. A questionnaire survey was carried out to collect information on the pig-farming system and to identify potential risk factors for Taenia solium cysticercosis infection in pigs. Blood samples were collected from 398 pigs with the aim of estimating the seroprevalence of T. solium cysticercosis. The results showed that 90.7% of the pigs are free roaming during the dry season and that 42.7% of households keeping pigs in the rural areas have no latrine facility. Seventy-six per cent of the interviewed pig owners confirmed that members of the household used open-field defecation. Enzyme-linked immunosorbent assay (ELISA) for antigen and antibody detection showed an apparent prevalence of cysticercosis of 24.6% and 32.2%, respectively. A Bayesian approach, using the conditional dependence between the two diagnostic tests, indicated that the true seroprevalence of cysticercosis in Mayo-Danay was 26.6%. Binary logistic regression analysis indicated that a lack of knowledge of the taeniasis–cysticercosis complex and the absence of a pig pen in the household were associated with pig cysticercosis.

The platinum group metals (PGM) Pt, Pd and Rh are emitted into the environment mainly by catalytic exhaust gas converters of cars. As PGM accumulate in sediments of aquatic ecosystems, the study was focused on the uptake of the noble metals by European eels, Anguilla anguilla infected with the acanthocephalan Paratenuisentis ambiguus. Eels were exposed to ground catalytic converter material for six weeks. After exposure Pt and Pd were detected in the liver and kidney of the eels and in the parasites. Palladium was also found in fish muscle and intestine. No Rh uptake by the eel tissues and the parasites occurred. Paratenuisentis ambiguus contained the highest levels of both metals with 40 times higher Pt concentrations and four times higher Pd concentrations than the liver of its host. Due to its accumulation capacity for PGM, P. ambiguus can be applied as a sensitive accumulation indicator in field studies to assess the degree of environmental PGM contamination in aquatic ecosystems.

The success of ring-necked pheasant (Phasianus colchicus) restocking in Asturias, northern Spain was assessed, and the role of parasites and predators in the mortality of released birds was studied. The experimental release of 56 radio-tagged pheasants showed that 98% of birds died within 12 days. As soon as 72 h after release, 67.5% of males and 55.0% of females were found dead. Foxes (Vulpes vulpes) killed 63% of the birds. The survival of those birds killed by foxes was lower than for birds which died due to other causes, and pheasants depositing eggs of the nematode Eucoleus contortus (Creplin, 1839) survived less than those apparently non-parasitized. No impact of the parasite on the pheasants' condition was found, but foxes preyed upon parasitized birds more than expected by random. The results suggest that: (i) the current pheasant releases in this area are unsuccessful and need to be improved; (ii) this is mainly due to intense predation by red foxes; and (iii) parasites could have some influence on the predation of released birds by foxes. However, the way parasites affect pheasant vulnerability remains unclear.

The compatibility between strains of Schistosoma mansoni from Egypt, Kenya, Sudan, Uganda, the West Indies, and Zaire (two strains which came from Katanga and from Kinshasa), and various species and strains of Biomphalaria, i.e., Biomphalaria pfeifferi, B. alexandrina, B. glabrata and B. camerunensis was investigated. Data as mortality, rate of infection of the surviving snails, duration of infection, cercarial production per day per positive snail, etc., were observed. The main emphasis was placed on determining the total cercarial production per 100 exposed snails for each snail population.

It was possible to infect all the tested populations of B. pfeifferi with the various strains of S. mansoni, but the observation as e.g. TCP/100 exposed snails varied greatly according to the population of snail and the strain of S. mansoni. The results for the remaining species of Biomphalaria varied greatly, depending on the combination, e.g. B. alexandrina was only susceptible to the local S. mansoni from Egypt.

The highest TCP/100 exposed snails was more than 1 million for the strains of S. mansoni from Egypt, Kenya and the West Indies in B. alexandrina, B. pfeifferi and B. glabrata, respectively. The next group, with a TCP/100 exposed snails on 7 – 800 000 consists of S. mansoni from Sudan, Uganda and Zaire (Katanga) all in B. pfeifferi. The last tested strain of S. mansoni, Zaire (Kinshasa) yielded a cercarial production on 500 000 per 100 exposed snails in B. pfeifferi and B. camerunensis.

The shortest prepatent period, 19 days, was observed for S. mansoni from Kinshasa, Zaire, in B. camerunensis, and the longest prepatent period, 25 days, was found for strains from Egypt and from the West Indies in B. alexandrina and B. glabrata, respectively.

In general, a very long duration of infection, lasting up to 200 days, was observed.

The utility of the IgG fraction of human filarial serum immunoglobulin in detecting circulating antigen by sandwich enzyme linked immunosorbent assay (ELISA) was studied. 27 of 33 sera from persons with microfilaracmia, 19 of 30 sera from clinical cases of filariasis, 4 of 30 sera from normal persons from a region endemic for filariasis showed the presence of circulating filarial antigen. All the 20 normal sera from the area where filariasis was not endemic gave negative reaction for filarial antigen. Those sera from persons with microfilaracmia that showed the presence of circulating antigen also showed an apparent positive correlation between the microfilarial density and the antigen titre.

Angiostrongylus vasorum infection was detected for the first time in eight foxes (Dusicyon vetulus) captured in the south of the State of Minas Gerais, Brazil. Two crossbred dogs were successfully infected orally with larvae from the foxes' faeces.

A modification of gDNA extraction was developed for the polymerase chain reaction (PCR) technique, intended for the detection and differentiation of Toxocara spp. eggs in soil or sediments. Sand samples from sandpits confirmed as being contaminated with Toxocara spp. eggs by the flotation technique were analysed by PCR. The use of proteinase K made it possible to obtain genomic DNA from the sample without needing to isolate eggs using flotation or to inactivate PCR inhibitors present in the sand. Specific primers in the PCR reaction allowed discrimination between T. canis and T. cati eggs. The modification simplified the procedure, thanks to eliminating the step of gDNA isolation from eggs, which is both laborious and difficult.

1. The behaviour and development of Brugia patei has been followed in the mosquito host, Mansonia uniformis, from ingestion of the microfilariae to the development of the infective stages.

2. The microfilariae penetrated very rapidly out of the stomach into the abdomen of the mosquito; 80% of them escape from the stomach during the first 50 minutes after a blood meal.

3. The microfilariae migrate from the abdomen to the thorax through fat body cells and the heart during the first 140 minutes followed engorgement and begin to penetrate the indirect flight muscles within 15 minutes from engorgement. During this migration microfilariae were found in close association, suggesting that they follow similar pathways of migration through the body of the mosquito.

4. Most microfilariae (98%) have settled in the indirect flight muscles within 2 hours of engorgement. In these muscles the larvae digest away the muscle surrounding them but do not begin to elongate until the third or fourth day after the blood meal. The rate of development varies from one mosquito host to another, but about 80% of the larvae have developed to the infective stage by the ninth to tenth days after the infective feed. The infective stages concentrate in the head and proboscis of the mosquito vector. The development of B. patei is faster than that of B. pahangi in mosquitoes from the same colony.

5. The efficiency of M. uniformis as a vector of B. patei is compared with the similar efficiency of M. longipalpis as a vector of B. malayi. In both mosquitoes the majority of the microfilariae ingested develop to the infective stage. M. uniforms is also an efficient vector of B. pahangi.

6. The development of the parasite is discussed briefly with reference to knowledge of the physiological events within the mosquito host subsequent to the blood meal.

In an attempt to demonstrate experimentally the life cycle of Fasciola gigantica, the snails Lymnaea natalensis were exposed to newly hatched miracidia of this trematode.

Faecal cultures were established using bovine faeces containing known numbers of eggs from either Oesophagostomum radiatum, Haemonchus placei, Cooperia pectinata or a mixture of all three. A substantially greater percentage of larvae was recovered from cultures of O. radiatum and C. pectinata than was recovered from cultures of H. placei. The same pattern was observed in mixed cultures although yields of larvae from all species in mixed cultures were significantly reduced (p<0·001). The lower recovery of H. placei was not associated with a lower viability of H. placei eggs. Of the three different methods of harvesting larvae, the jar and mesh recovery technique was the least effective and significantly fewer larvae were recovered with this technique than with the Baermann and inversion techniques (p<0·05). The results are discussed with reference to the use of faecal culture and larval differentiation in the diagnosis of mixed species nematode infections of cattle.