A total of 984 snails, comprising nine species, were collected from six areas in the Kafue wetlands between August and October 2003 to assess larval trematode infections. Of these, 135 (13.7%) were positive. Most trematode infections were recorded from Lymnaea natalensis (42.8%), which harboured four of the five morphologically different cercariae found. No trematodes were recovered from Bellamya capillata, Biomphalaria pfeifferi, Melanoides tuberculata, Physa acuta and Cleopatra nswendweensis. One snail (0.2%) of 416 Bulinus snails shed brevifurcate-apharyngeate distome cercariae while three (0.7%) shed amphistomes. Gymnocephalous and longifurcate-pharyngeate distome were the commonest types of cercariae recorded while xiphidiocercaria was the least common. The highest prevalence rates of F. gigantica (68.8%) and amphistomes (50.0%) in cattle (n = 101) were in Chiyasa while those in Kaleya had the lowest (9.1 and 18.2%, respectively). In most habitats, infections were recorded in both cattle and snails. Critical determinants of infection may have been the distance of settlements and/or cattle kraals, the number of animals in nearby homesteads and the presence of susceptible host snails. This study suggests that fascioliasis and amphistomiasis could be major constraints of cattle production in the Kafue wetlands because favourable factors were available to introduce and maintain the infections. It further provides a starting point for some comprehensive studies on snail-related aspects of transmission and snail host ecology in Zambia.

A study on the prevalence and intensity of Toxocara canis (Werner, 1782) in dogs was carried out in Ile-Ife, Nigeria. Faecal samples were collected from 269 dogs between January and December 2004, processed by the Kato–Katz technique and then examined for T. canis eggs. The prevalence of T. canis obtained was 33.8%. The intensity of infection, measured as mean egg count per gram of faeces ( ± SEM) was 393.8 ± 83.4. The prevalence and intensity of T. canis in dogs aged 0–6 months were significantly higher (P < 0.05) than older age groups. The prevalence and intensity of T. canis infection were significantly higher in males than in female dogs (P < 0.05). Since T. canis is known to cause visceral larva migrans (VLM) in young children, there is the possibility that the high prevalence of T. canis infection obtained in this study might constitute an important risk factor for transmission to humans. Therefore, there is the need to educate the residents of Ile-Ife on the danger of close association of their children with household pets.

1. Observations carried out on four groups of sheep during the spring of 1954 are described.

2. A spring-rise in the worm-egg output was found to occur in all the groups studied.

3. The management of the animals precluded rcinfestation during the spring and, in two instances, from 8th January and 22nd, respectively.

4. Time of lambing and nutritional level appeared to influence the onset and magnitude of the spring increase.

Bithynids snails are a widespread group of molluscs in European freshwater systems. However, not much information is available on trematode communities from molluscs of this family. Here, we investigate the trematode diversity of Bithynia tentaculata, based on molecular and morphological data. A total of 682 snails from the rivers Lippe and Rhine in North Rhine-Westphalia, Germany, and 121 B. tentaculata from Curonian Lagoon, Lithuania were screened for infections with digeneans. In total, B. tentaculata showed a trematode prevalence of 12.9% and 14%, respectively. The phylogenetic analyses based on 55 novel sequences for 36 isolates demonstrated a high diversity of digeneans. Analyses of the molecular and morphological data revealed a species-rich trematode fauna, comprising 20 species, belonging to ten families. Interestingly, the larval trematode community of B. tentaculata shows little overlap with the well-studied trematode fauna of lymnaeids and planorbids, and some of the detected species (Echinochasmus beleocephalus and E. coaxatus) constitute first records for B. tentaculata in Central Europe. Our study revealed an abundant, diverse and distinct trematode fauna in B. tentaculata, which highlights the need for further research on this so far understudied host–parasite system. Therefore, we might currently be underestimating the ecological roles of several parasite communities of non-pulmonate snail host families in European fresh waters.

The work has demonstrated that one of the more important areas of Scotland where Dicrocoelium dendriticum is endemic carried infected colonies of Helicella itala which live in association with the ant Formica fusca. Workers of the ant were shown to acquire typical metacercarial cysts after the ingestion of slime balls, and the cysts gave rise to mature lancet flukes in sheep and hamsters, eggs appearing in the faeces after 56 and 48 days respectively. Higher egg counts were obtained from hamsters to which more cysts were administered. This is the first occasion on which an ant intermediate host has been demonstrated for Dicrocoelium in Britain.

From the known species occurring in crocodilians, the genus Dujardinascaris is redefined and found to be a homogenous group of species, with dujardini Travassos, 1920 as the type species. The following new species are described and added to the genus: gedoelsti, puylaerti, waltoni, mawsonae and taylorae. The following species are excluded from the genus: vandenbrandeni, australiensis, tasmani, alata and antipini. The distribution of the species in Dujardinascaris is as follows: in African crocodiles—dujardini, madagascariensis, gedoelsti, and puylaerti; in South American caimans—longispicula, paulista, and chabaudi (possibly a synonym of paulista); in North American alligator–waltoni; in Crocodylus acutus—helicina; in the Indian gavial—woodlandi; in crocodiles in Papua New Guinea and Australia—mawsonae and taylorae.

These species are differentiated mainly by the relative length of the spicules and the form of the guber naculum in the males and by the relative length of the vagina and the form of the vulva in the females.

Setaria digitata is a filarial parasite that causes fatal cerebrospinal nematodiasis in goats, sheep and horses, resulting in substantial economic losses in animal husbandry in the tropics. Due to its close resemblance to Wuchereria bancrofti, this nematode is also frequently used as a model organism to study human lymphatic filariasis. This review highlights numerous insights into the morphological, histological, biochemical, immunological and genetic aspects of S. digitata that have broadened our understanding towards the control and eradication of filarial diseases.

Terrestrial molluscs (Mollusca: Gastropoda) are important economic pests worldwide, causing extensive damage to a variety of crop types, and posing a health risk to both humans and wildlife. Current knowledge indicates that there are eight nematode families that associate with molluscs as definitive hosts, including Agfidae, Alaninematidae, Alloionematidae, Angiostomatidae, Cosmocercidae, Diplogastridae, Mermithidae and Rhabditidae. To date, Phasmarhabditis hermaphrodita (Schneider, 1859) Andrássy, 1983 (Rhabditida: Rhabditidae) is the only nematode that has been developed as a biological molluscicide. The nematode, which was commercially released in 1994 by MicroBio Ltd, Littlehampton, UK (formally Becker Underwood, now BASF) under the tradename Nemaslug®, is now sold in 15 different European countries. This paper reviews nematodes isolated from molluscs, with specially detailed information on the life cycle, host range, commercialization, natural distribution, mass production and field application of P. hermaphrodita.

Dietary feeding of drugs for 5 days to mice infected with Nematospiroides dubius and Hymenolepis nana detected all modern anthelmintics examined except stilbazium. A simple test using eggs of Nematodirus spathiger and adult Nippostrongylus brasiliensis to detect anthelmintics in vitro is reported.

Dirofilaria immitis is endemic in Portugal. Several studies have reported the presence of canine heartworm disease, although no previous studies on feline infections have been published. The aim of this study was to determine the prevalence of D. immitis in cats and dogs from central and northern Portugal. Blood samples from 434 cats were tested for circulating anti-D. immitis and anti-Wolbachia antibodies. Furthermore, 386 dogs were tested for circulating D. immitis antigens. Overall feline seroprevalence was 15%, while canine prevalence was 2.1%. The highest feline seroprevalences of 18.7% and 17.6% were found in Aveiro and Viseu, respectively, while the highest canine prevalences of 8.8% and 6.8% were found in Coimbra and Aveiro, respectively. Cats and dogs showing respiratory signs presented higher prevalences of 24.4% and 17%, respectively, while 50% of cats with gastrointestinal signs were seropositive. The present study confirms the seropositivity of D. immitis in the feline population in central and northern Portugal, and suggests the importance of including heartworm disease in the list of differential diagnoses of cats and dogs showing clinical signs compatible with the disease.

1. Metacercarial cysts of Echinoparyphium serratum occur in the pericardium of the snail Isidorella brazieri. Each cyst is surrounded by a nucleated, syncytial host capsule containing granules which are presumed to be melanin. The cyst wall consists of two layers and both contain acid and neutral mucopolysaccharide but little or no protein. No modification of the cyst wall coincident with the point of emergence of the metacercaria has been located.

2. Excystment of the metacercaria takes place in two main stages when pepsin is omitted from the initial pretreatment solution: stage I (emergence from the cyst wall through the escape aperture) is an active process (exogenous enzymes are not necessary), and a high percentage of specimens reaching this stage is dependent on the combined effects of a þH of 2, reducing conditions, elevated temperature (37–39°C) and sodium cholate. Temperature and sodium cholate are absolute requirements for this stage as is pretreatment of between þH 2 and 4 when sodium cholate is included with the reductant (sodium dithionite) rather than in the excystment medium with trypsin. The possibility that CO2 is involved has not been established.

Dactylogyrus legionensis n. sp., a monogenean parasite from the gills of Barbus barbus bocagei from the Esla river (León, NW Spain), is described and its population dynamics discussed. It differs from the closely related species, D. balistae, in the presence of vaginal armour and in the morphology of the copulatory organ. D. legionensis was found on 30·40% of barbel, with a mean intensity of 13·71 and maximum infection levels in autumn-winter. The prevalence and intensity of infection rose significantly with the age and length of the barbel, and were higher in females than in males. D. legionensis showed preference for the second and first gill arches, sector III and the internal zone of each hemibranch.

Biogenic amines regulate important behaviours in nematodes and are associated with pharyngeal activity in plant-parasitic nematodes. A robust behavioural assay based upon nematode body movements was developed to expand the study of these and other neuroregulators in plant-parasitic nematodes. Dopamine, octopamine and serotonin each had significant but differing effects on the behaviour of soybean cyst nematode Heterodera glycines and root-knot nematode Meloidogyne incognita juveniles. Body movement frequency was increased twofold in H.glycines by 5 mM dopamine (P = 0.0001), but decreased by 50 mM dopamine in H. glycines (88%) and M. incognita (53%) (P <  0.0001). Movement frequency in both species was increased by 50–70% (P <  0.0001) by 50 mM octopamine, and 5 mM octopamine increased M. incognita movement frequency more than twofold (P <  0.0001). Movement frequency in each species was reduced by more than 90% by 5 mM serotonin (P <  0.0001). While amplitude of body movement in H. glycines was unaffected by any amine, it was significantly reduced in M.incognita by all amines (P <  0.0006). Stylet pulsing frequencies in either species were unaffected by dopamine or octopamine, but 5 mM serotonin stimulated pulsing in H. glycines by nearly 13-fold (P <  0.0001) and in M. incognita by more than 14-fold (P <  0.0001). The invertebrate neuropeptide FLRFamide (N-Phe-Leu-Arg-Phe) increased M. incognita body movement frequency 45% (P = 0.02) at 1 mM but did not affect stylet activity. Finally, H. glycines egg hatch was completely suppressed by 50 mM serotonin, and partially suppressed by 50 mM dopamine (75%; P <  0.0001) and 50 mM octopamine (55%; P <  0.0001).

The immune response of hamsters to a chronic hookworm infection has been investigated. Ancylostoma ceylanicum caused long term infections in hamsters which were associated with prominent changes in secondary lymphoid organs. The mesenteric lymph nodes and spleens increased rapidly in size stabilizing at approximately 3–4 times the weight in control animals by weeks 3–7. Cells from both the mesenteric lymph node and spleen, after an initial period of increased blast cell activity, became less reactive in the latter stages of infection. Serum antibody responses were marked, commencing in weeks 3–4 and increasing in intensity throughout the 10 week period of measurement. The results are discussed in relation to their contribution to the understanding of human hookworm infection.

During the course of some experiments involving the Nematode worm Heterakis gallinæ, it became necessary to know the exact life history in order to interpret the results. On consulting the literature it became evident that the details of the life history had never been worked out accurately in either this worm or in any of its near relations. Further-more, there was considerable controversy on the subject. For this reason therefore the whole morphology and life history were investigated in detail and some interesting points came to light.

A technique for the recovery and counting of infective strongyle larvae from macerated herbage obtained through oesophageal fistulae is described. The method is also useful for examining samples of herbage gathered by hand.

The response of the free-living stages of Nippostrongylus brasiliensis, Nematospiroides dubius, Haemonchus contortus, Trichostrongylus colubriformis and Ostertagia ostertagi to a wide variety of antiparasitic agents in vitro was investigated.

All the major broad spectrum veterinary anthelmintics showed good activity against each of these worms with EC30 values varying from about 00002mg/1 for certain benzimidazoles and ivermectin to about 6–5 mg/1 for febantel. Of 22 known narrow spectrum anthelmintics useful only against H. contortus and/or helminths other than trichostrongyles, only 10% showed good activity at concentrations equal to or less than 100mg/1. Further, only one of 15 antiprotozoal agents showed good activity in these tests at the 100mg/1 level.

Seven calves, 5 sheep, 2 goats and one buffalo calf were exposed to S. bovis cercariae in the laboratory. The prepatent period varied from 44–45 days in calves, 47–50 days in sheep to 47–48 days in goats. The recovery rate of adult worms was 62.1% in calves, 41.4% in sheep and 67.3% in goats. The infection rates were much higher than those obtained by previous workers, possibly because of a superior technique. One buffalo calf was exposed to S. bovis cercariae but showed no signs of infection.

The mean daily egg output per gram of faeces was 75 in calves, 60 in sheep and 75 in goats. The daily egg output in the faeces per individual female worm was 106 in calves, 52 in sheep and 48 in goats at 9 weeks after exposure to cercariae. The number of eggs passed in the faeces decreased in calves and increased in sheep as the duration of infection was prolonged.

Metacercariae of Paragonimus spp. were obtained from field-collected freshwater crabs in Sri Lanka. Genomic DNA was extracted from single metacercariae. Two gene regions (partial mitochondrial cytochrome c oxidase subunit 1 (CO1) and the second internal transcribed spacer of the nuclear ribosomal gene repeat (ITS2)) were amplified using the polymerase chain reaction. Two differing sequences were obtained for each of these gene regions. Phylogenetic analyses placed the type 1 sequences as sister to a clade containing P. westermani and P. siamensis whereas the type 2 sequences were close to published sequences of P. siamensis from Thailand. The possible taxonomic status of these two types are discussed. This is the first report of molecular data about Paragonimus from Sri Lanka.