The histopathological response of carp to Sanguinicola inermis was investigated by serial sectioning laboratory infected fish up to 90 days post infection (d p.i.). Juvenile flukes and adults caused mechanical damage to tissues during invasion and migration up to 28 d p.i. Adults partially occluded blood vessels and may have reduced blood circulation. In the initial phase of egg production (28–42 d p.i.), eggs and emigrating miracidia in gill tissue caused breakdown of vascular integrity, necrosis, hyperplasia, haemorrhage and eosinophilic infiltration of epithelial tissue. After 42 d p.i. the host granulomatous inflammatory response encapsulated eggs lodged in the gills, visceral sites and connective tissue displacing normal tissue. Encapsulation and subsequent degradation of eggs and miracidia within granulomata was highly developed by 90 d p.i. Laboratory infections of S. inermis can induce respiratory distress and therefore impair respiration of fish. The parasite also caused pathological changes in osmoregulatory, excretory and haemopoietic tissue and may impair function in these organ systems.

Most studies of helminth communities in the European eel Anguilla anguilla have been undertaken in the British Isles, and there are very few analyses of community composition and structure from continental Europe. To fill this gap and test the hypothesis that helminth communities in freshwater eels in the British Isles are not typical of those of continental Europe, helminth communities of eels in the River Tiber below Rome were analysed by season using data collected in 1980 and new data from 1996. The intestinal helminth communities in the Tiber eels were species poor and characterized by low diversity. Most eels harboured one or no parasite species and communities were heavily dominated by the acanthocephalan Acanthocephalus clavula. Intestinal helminth infra-community richness and diversity did not differ between seasons within a year or between the same seasons in 1980 and 1996, although some changes in composition were apparent. Intestinal infracommunities from Tiber eels were very similar in characteristics to those analysed from the British Isles, and their temporal changes also showed close similarities to those reported from rivers in the UK. It seems likely therefore that conclusions derived from British studies can be applied to helminth communities of eels on the continent.

Centrocestus armatus (Trematoda: Heterophyidae) develops rapidly and produces eggs at 3 days postinfection in albino rats. Excysted metacercariae are pear-shaped and concave ventrally, with 42–44 peg-like circumoral spines. The entire body surface is densely covered with scale-like serrated spines. On juveniles, serration of the tegumental spines is greatest in the middle of the ventral and dorsal surfaces, and decreases anteriorly and posteriorly. Ciliated sensory papillae are concentrated around the oral sucker. Several nonciliated sensory papillae (type II papillae) occur equidistantly on the acetabulum and are arranged in a linear symmetry on the dorsal surface. On adults, the serration of the tegumental spines decreases to 14–17 tips on the ventrolateral surface. The high density of tegumental spines on posterior half of the body and the distribution of type II papillae on dorsal surface are considered to be characteristic of C. armatus.

In a survey carried out during the period May 1995 to November 1996, in communities of various ethnic groups in northern Israel, 206 dogs were examined for Echinococcus granulosus and other intestinal helminth parasites by arecoline hydrobromide purges and the coproantigen-ELISA. The arecoline test was performed close to the owners' homes, using plastic sheets secured to the ground. From 56 dogs examined in the Muslim town of Tamra, six (10.7%) were found to be infected with E. granulosus. Four of them also had a mixed infection of Taenia hydatigena and Dipylidium caninum (two dogs), and the remaining two dogs were infected with either D. caninum or Taenia pisiformis. An additional 18 dogs were infected with either T. pisiformis (eight dogs), D. caninum (seven dogs), or T. hydatigena (three dogs). Two of these dogs harboured mixed infections whereas the remaining 32 dogs were free of helminths. In the Jewish villages, none of the 150 dogs examined were infected with E. granulosus, although 26 (17.3%) were infected with D. caninum, four (2.7%) with Ancylostoma spp. and one (0.7%) with Toxocara canis. Only one of the 22 stray dogs and none of the 15 jackals examined were infected with E. granulosus. However, 21 (95.4%) of the dogs and 12 (80%) of the jackals harboured helminth infections, including: D. caninum (16 dogs and seven jackals), Ancylostoma spp. (five jackals), T. hydatigena (three dogs), and T. canis (one dog). Approximately 18% of the dogs and 33% of the jackals showed mixed infections with two or more of the above helminths. In the abattoirs, 52 (5.9%) of the 874 sheep and 33 (5.3%) of the 616 goats from 17 herds slaughtered in the Muslim and Druze villages were found to be infected with E. granulosus, compared with a 0% infection rate observed in 93 sheep from two herds in Jewish villages.

Of the 13 species of helminths that parasitize stream fishes in Hawai'i, seven species are considered to be native to the archipelago and the remaining six species to be introduced by man. Sources of colonization for native species are piscivorous birds for three species, and marine fishes for four species. Non-native helminths have been brought to Hawai'i in association with the importation of parasitized exotic species of poeciliids introduced into streams for mosquito control and as aquarium releases. Many of these introduced parasites have broad host specificity and now infect the five species of native gobioid stream fishes. Exotic parasites, including a roundworm Camallanus cotti, a tapeworm Bothriocephalus acheilognathi and a leech Myzobdella lugubris, are more widely distributed among Hawaiian streams than are native species.

Specimens of 12 helminth species were collected from carcasses of eight Lynx pardinus (Temminck, 1827), a carnivore endemic to the Iberian Peninsula. These species included: Brachylaima sp. (12.5%) (Trematoda); Taenia pisiformis (12.5%), T. polyacantha (25%), T. taeniaeformis (25%) and Mesocestoides litteratus (37.5%) (Cestoda); Eucoleus aerophilus (12.5%), Ancylostoma tubaeforme (12.5%), Toxocara cati (37.5%), Toxascaris leonina (62.5%), Vigisospirura potekhina potekhina (12.5%), Mastophorus muris (12.5%) and Physaloptera praeputialis (12.5%) (Nematoda). The helminth fauna in Iberian lynx is compared with that of L. canadensis and L. rufus in America, and for L. lynx in Eurasia. The potential relationships between the parasitological data and some geographical, historical and dietary factors are discussed.

The influence of soil texture (silt, sand and laterite) and flotation solutions (saturated NaCl, sucrose, NaNO3 and ZnSO4) upon the recovery of Toxocara ova from seeded soil samples with the centrifugal flotation technique was investigated. Soil samples of different texture were artificially seeded with Toxocara spp. ova and subjected to a centrifugal flotation technique which used various flotation solutions. The results showed significant (P<0.001) interactions between the soil types and the flotation solutions. The highest percentage of ova recovery was obtained with silty soil (34.9−100.8%) with saturated NaC1 as the flotation solution (45.3−100.8%). A combination of washing of soil samples with 0.1% Tween 80, and flotation using saturated NaCl and a 30 min coverslip recovery period was used to study the prevalence of contamination of soil samples. Forty-six soil samples were collected from up to 24 public parks/playgrounds in urban areas of Petaling Jaya and suburban areas of Serdang. The prevalence of Toxocara species in the urban and suburban areas was 54.5% and 45.8% respectively.

The lipid composition of three batches of single generation cysts of Globodera rostochiensis, stored dry at 4°C for 1,7 and 13 years, comprised 81%, 74% and 53% neutral lipids, 14%, 18% and 27% non-acidic phospholipids and 5%, 8% and 20% free fatty acids, respectively. Lipids in eggs from two batches of G. pallida cysts, stored for 3 and 7 years, comprised 80% and 67% neutral lipids, 15% and 23% non-acidic phospholipids and 5% and 10% free fatty acids, respectively. All batches contained the same fatty acids which were dominated by C18:l, C20:l and C20:4. The fatty acid profiles of hatched J2 of G. rostochiensis from two batches, stored for 1 and 9 years, differed only in their free fatty acid fractions. Thus, while it is not possible to determine the age of cysts by their fatty acid profile, it may be possible to use the relative amounts of the main lipid classes as an indicator of age. Four batches of hatched J2 of G. pallida were investigated, with sample A hatched during the second week in potato root diffusate, B during week 3, C during week 4 and D during weeks 5 and 6 and stored for 3.5 days (on average) after hatching. Total lipid content was 27.2%, 31.5%, 18.5% and 6.3% of the dry weight for A, B, C and D, respectively. In the neutral lipid fraction of D an increase in C18:l and to a lesser extent C18:2 was observed. In the free fatty acid fraction of sample D, the percentages of C18:l, C18:2 and C18:3 were greater but the percentages of C20:3 and C20:4 were smaller compared with sample C. Fresh early hatched J2 of G. rostochiensis were compared with later hatched and stored (for 13 days on average) individuals for their lipid content and fatty acid composition. The lipid content was 26.1% and 11.4% in fresh and stored J2, respectively. Total lipid consisted of 77% and 70% neutral lipid, 18% and 26% non-acidic phospholipid and 6% and 4% free fatty acid in fresh and stored J2, respectively. In the neutral lipid fraction of stored J2 C18:l, C16:0 and C18:0 increased, whereas C20:4, C20:l and C20:3 decreased. Therefore, both neutral lipid and free fatty acid fractions showed changes in their fatty acid profiles after long delayed hatching and/or storage in both PCN species.

An erratic parasitism was observed in the lungs of sheep experimentally infected with Fasciola gigantica at autopsy 14 weeks after inoculation. Macro-scopically, several hyperaemia of 7.5–12.5 mm in diameter were found on the surface of the lungs. Juvenile flukes detected in the lungs were much smaller than those in the liver of the same sheep. A slight inflammatory reaction was observed in the lungs and it is likely that the flukes had migrated in the pleural cavity for some time. Occasionally, a mixed thrombus with many eosinophils was found in the blood vessels adjacent to the bronchia, although no cough was observed clinically. This suggests that diagnosis of juvenile fluke is difficult not only by parasitological but also serological methods.

The length and width of 1297 Fasciola hepatica eggs shed in cattle hosts, 337 in sheep and 199 in nutria, were measured from several parts of France. The data were compared with those obtained from other studies in Spain, France (where rats were also investigated), Germany and the Netherlands. One way analysis of variance and discriminant analysis were used to assess differences between host origins. The distribution of length and width of eggs were analysed using skewness and kurtosis Fisher coefficients. The eggs recovered from sheep, cattle, rodents and lagomorphs were different in size: the eggs found in rodents (length L × width W in μm: 8592) and lagomorphs (L × W in μm: 9100) were smaller than those found in sheep and cattle (L×W in μm: 10,000). These morphological differences in F. hepatica eggs were host-induced in rats (L×W in μm: 9709 in cattle to 8949 in rats) and rabbits (L×W in μm: 9709 in cattle to 8432 in rabbits). These differences in size of eggs might correspond to their being less able to develop into miracidia in less frequent hosts such as rodents and rabbits.

The influence of dietary protein supplementation upon resistance to haemonchosis was examined in Dorsimal (Polled Dorset × Malin) lambs offered two levels of protein. Lambs were offered either a complete basal ruminant diet (15% crude protein (CP)) or the same diet supplemented with fish meal as a source of rumen bypass protein (19% CP). Lambs from each dietary treatment group were given either a 7-week trickle infection with Haemonchus contortus infective larvae (L3) or remained uninfected. All lambs were drenched with anthelmintic at week 8 post-infection (PI), challenged with a single dose of 5000 H. contortus L3 one week later, and killed 14 days post-challenge (PC). Lambs on the supplemented diet that were trickle infected showed a significant reduction in egg output. Supplementation and previous infection did not affect either growth rate, worm burden, worm development or haematological parameters. There was a trend for enhanced growth among supplemented non-infected lambs in comparison to lambs which received the basal ration.

Calves and lambs heavily infected with Strongijloides papillosus develop cardiac arrest by ventricular fibrillation which is preceded by continuous sinus tachycardia and prolongation of the PQ interval during the patent infection. In the present study, cardiac rhythms following anthelmintic treatment were investigated in lambs infected with S. papillosus to ascertain whether cardiac disorders due to the infection are based on a reversible and curable change. Eight lambs were given a lethal dose of S. papillosus. Five of the animals were injected with ivermectin when they developed continuous sinus tachycardia and prolongation of the PQ interval. The other three animals served as untreated controls. In the treated animals, elevated heart rates and PQ intervals began to decrease between 10 and 21 h, then continuous sinus tachycardia and prolongation of PQ interval disappeared within 39 h of treatment. No arrhythmias were detected after the disappearance of sinus tachycardia. Faecal egg counts became negative within 61 h of treatment. Only a few worms were collected from the small intestine at necropsy. The control animals developed ventricular fibrillation by 349 h after infection, having high faecal egg counts and intestinal worm burdens. These results indicate that cardiac disorders generated by S. papillosus infection are reversible and curable following worm elimination.

Excretory/secretory antigens (ES) of larval Taenia solium were obtained by maintaining the bladder worms in Medium 199 for 3 days. Analsysis by SDS-PAGE showed that ES antigens consisted of at least 19 polypeptides, with Mrranging from 14–116 kDa. Analytical isoelectric focusing revealed eight bands with acidic pI. An immunocytolocalization study using the peroxidase method demonstrated the presence of ES epitopes on the tegument of the wall of the spiral canals of bladder worms. The specificity of ES antigens was evaluated by EITB, ELISA and FAST-ELISA using antisera against the common parasites of Chinese pigs and man. ES antigens cross-reacted with the antiserum against larval T. hydatigena of pigs. However, these antigens were generally more specific in diagnosing human cysticercosis. Three host-like molecules with molecular masses 43, 58 and 66 kDa were present in the ES products.

Lymnaea tomentosa, the intermediate host of a schistosome which causes schistosome dermatitis in Lake Wanaka, was found to depths of 16 m. The snail recruits in January, lives for up to 21 months, is associated with all water plant species and is found in areas devoid of macroscopic plants. It is host to several trematode species. Avian schistosome infections appear in the spring when echinostome prevalence is low, and a decrease in schistosome prevalence may be correlated with an increase in echinostome prevalence during the summer. A multiple-kind lottery model analysis of parasite species richness implies that interspecific interactions may be occurring in the host snail during the months of December and January.

Three hundred and twenty seven European lynx (Lynx lynx) were examined forTrichinella sp. larvae using the muscle digestion method. The animals were of both sexes, various ages, and collected between 1989 and 1994 in different locations in Finland. Forty percent of them (132) were found to be infected. Infection was overdispersed, so that the majority of infected lynx only harboured small amounts of larvae, while a minority had higher densities of infection, but never significantly exceeding 40 larvae per gram of muscle (lpg). The median density of infection was 1.04 lpg. To find factors statistically associated with the risk of infection, multivariate logistic regression analysis was performed. Male sex, increasing age, and the density of raccoon dog population in the area were all significantly associated with infection. However, the association with age was not linear and prevalence did not increase after middle age. The mean density of infection decreased slightly with age. The association with the density of the raccoon dog population leads to a tentative hypothesis that the raccoon dog might be an important reservoir of sylvatic trichinellosis in Finland.

During studies on the ecology of fish helminths, the tapeworm Proteocephalus torulosus (Batsch, 1786) was frequently found in the intestine of the blue bream (Abramis ballerus) from the Oder River (Germany/Poland). In total, 633 fish, ranging between two and 16 years old, were sampled at monthly intervals over a two year period during 1993–1995. Statistically significant differences in the seasonal occurrence of the parasite in its fish host were observed. In 1993, the prevalence remained at a high level, ranging between 61.9 and 100%. During the summer of 1994, this value decreased to 5.5% and remained low for the rest of the year. The pattern of mean intensity of infection was similar to that of the prevalence. In 1993, the mean intensity varied between 8.4 and 31.8 worms per infected fish, with a continual loss of worms being observed in the summer of 1994. Changes in the amount of suspended particulate matter in water have been identified as the main cause of these observed differences in the course of infection of blue bream.

The strobila of an adult tapeworm represents a continual gradient of developmental stages from immature to gravid proglottids. The purpose of this study was to determine if organogenesis (as measured by the develop mental gradient) in tapeworms within a single host and among different hosts occurred at the same rates. Rats were infected with Hymenolepis diminuta and the tapeworms were recovered 20 days post-infection. The total number of proglottids in each worm was determined, and five “benchmarks” of organogenesis were quantified. The data demonstrated that organogenesis in worms from a single host occurred at a relatively constant rate, but that rates in tapeworms from different hosts were different.

Following oral administration to sheep, chlamydospores of a Mexican isolate of Duddingtonia flagrans (FTHO-8) survived passage through the digestive tract and subsequently grew on corn meal agar plates. The fungus was able to catch and destroy free-living nematodes and third-stage larvae of Haemonchus contortus added to these plates. Chlamydospores of Arthrobotrys sp. showed a poor resistance to the digestive processes of sheep, although conidia of A. superba survived following oral inoculation in one of two animals.

The study describes methods developed for using video-imaging technology to record and measure the velocity of Schistosoma mansoni miracidia. The efficacy of the classical bioassay procedure (a qualitative behavioural assay) was compared with that of the new quantitative protocol, for assessing the sub-lethal impact of a larvicidal dichloromethane extract of the seeds of Millettia thonningii on miracidia. The new technique confirmed the efficacy of the classical bioassay for rapid determination of the lethal and sub-lethal impact of larvicides but also provided quantitative information on sub-lethal impacts on miracidial velocity and shape.

Miracidia of Echinostoma caproni were exposed to solutions varying in salinity, pH, and temperature in 1 ml concavity slides. Half-lives of the miracidial populations were determined and longevity curves constructed to find maximum life spans of the miracidia in the different conditions. Control miracidia in aquarium water at pH 7.2 and 22°C. had a half-life of 3.6 h and a maximum life span of 9 h. Miracidia of E. caproni were not very tolerant of saline solutions from 0.1% to 0.4%, the latter being lethal within an hour. A bimodal effect was found with exposure to aquarium water of varying pH, with a peak at pH 5 in acid solutions and pH 9 in alkaline solutions. Miracidia tolerated pH ranges from 3 to 11 exhibiting half-lives of 2.4 h or greater in these solutions. At lower than ambient temperatures, E. caproni miracidia lived longer, the greatest being a half-life of 5.0 h and a maximum life span of 15h at 5°C. At warmer temperatures, the half-life was reduced until lethality was reached at 40°C. ANCOVA analysis of log transformed longevity curves supported the observation that in pH trials many miracidia survived initially with a major die-off after 3.3 h. The opposite trend of early die-off and gradual mortality of the survivors was supported in the temperature trials.