The structuring process of the macroparasite community of caged Cichlasoma urophthalmus was studied over time using sentinel fish. Three thousand uninfected cichlids were stocked in floating cages introduced into a quarry in which a wild population of the same species was present. Caged and wild cichlids were sampled monthly over 6 and 7 months, respectively. Seventeen macroparasite species were found in the wild C. urophthalmus population, ten of which were detected in the caged population after 6 months. Early infections were by those species that were more frequent and abundant in the wild population, while helminths with a low prevalence and abundance in the wild appeared later in the caged fish population. The results suggested that the structuring process of the macroparasite community of caged C. urophthalmus followed a predictable pattern, in which those species that were most frequent and abundant in the wild were the first to establish in sentinel fish.

Enterobius vermicularis infection remains one of the most common parasitic infections, particularly prevalent in children. Enterobiasis, although not usually dangerous, may cause significant morbidity. Elimination of the parasite from a family or an institution often poses problems, either because of an incomplete cure or re-infection. While there have been limited reports of ectopic enterobiasis throughout the world, ours is probably one of the rarest reports of recurrent vaginal E. vermicularis infection in the absence of any gastrointestinal symptoms despite complete treatment. A 4-year-old girl presented with recurrent episodes of vulval itching on 3–4 occasions over 2 years. There was no pruritis ani nor urinary/gastrointestinal complaints. The vulva was inflamed with 4–5 living worms, 6–7 mm in length, emerging from the anterior vaginal fornix, but with no vaginal discharge. Direct microscopic examination of vaginal swabs revealed adult worms of Enterobius but no eggs. Repeated stool samples from the patient, parents and a sibling were negative. The patient was treated orally with 100 mg of mebendazole for 3 days followed by two more courses at 3-week intervals over a period of 3 months. Recurrent vaginal enterobiasis despite complete treatment and in the absence of any gastrointestinal involvement suggests that the vagina is a potential reservoir for E. vermicularis, which supports the theory of rare ectopic enterobiasis through the ascending pathway of the female genital tract.

Although Oxyuris vermicularis occurs very frequently in children, material from which to study the early development, mature female worms, was difficult to obtain.

Specimens were found both in the normal stool and in the stool after treatment with santonin. Egg-laying began as soon as the worms came into contact with air; those which happened to be on the surface very quickly became surrounded by a white deposit of eggs and the worms themselves became reduced to fine threads, which were difficult to detect: Egg-laying was also induced by bringing females into water at body temperature.

The present paper deals with investigations on the occurrence in Netherlands' fresh water fishes and host specificity of tapeworms belonging to the genus Proteocephalus. The species involved are:

P. tetrastomus (Rudoiphi, 1810) in smelt, Osmerus eperlanus.

P. longicollis (Zeder, 1800) in smelt, Osmerus eperlanus.

P. cernuae (Gmelin, 1790) in pope, Acerina cernua.

P. ocellatus (Rudolphi, 1802) in perch, Perca fluviatilis.

P. macrocephalus (Creplin, 1825) in eel, Anguilla anguilla.

Seasonal cycles were found in P. telrastomus and P. ocellalus; in the latter species this was certainly induced by low winter temperatures.

Experimental infections showed that a high degree of host specificity exists in all species considered. Infections of an alien host were never successful. Two kinds of infections were carried out: (a) feeding plerocercoids (in the intermediate host), coming from a known source, to a number of fishes, belonging to several species including the original host species, and (b) transplanting worms, collected from the intestine of a fish, to the intestines of a number of other fishes, belonging to several species including the original host species.

Notwithstanding the high degree of host specificity, worms may survive for one or two days, but usually in a bad condition, in the intestine of an alien host. Occasionally they survived up to 14 days: e.g. P. tetratomus in Anguilla anguilla. Consequently sometimes dissections of predator fishes or carrion eating fishes may produce dubious host records because actually Proteocephalus from their prey are recorded. We are convinced that P. tetrastomus found in Salmo trutta, Platichihys flesus and Perca fluviatilis originate from Osmerus eperlanus having been eaten by these species.

Additionally cannibalism may be responsible for the fact that large specimens of some fish species, e.g. smelt, are heavily infected with Proteocephalus while they hardly eat any Cyclops, the intermediate host. This is clearly demonstrated by the transplantation experiments, transplanting worms to the proper host.

From the data recorded it is apparent that representatives of the genus Proteocephalus are not harmful to commercially important fishes in the Netherlands. In these fishes natural infection with the proper species of Proteocephalus is low and successful infection with other species, showing a high incidence in less valuable fishes, is prevented by the high degree of host specificity. Additionally worms of the species studied did not injure the tissues of the intestinal wall by the action of their suckers and piercing of the intestinal wall never occurred. Even smelts infected with large numbers of worms-more than 50 in a single 20 cm. specimen-did not show any abnormalities in genital development or in the amount of fat in the body cavity.

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.

Histochemical glycogen and neutral lipid studies were conducted on Echinostorna trivolvis cercariae maintained in artificial spring water (ASW) at 24–25°C for up to 24 h after emergence from host snails. Treatment of whole cercariae by the periodic acid Schiff (PAS) reagent with or without 1% malt diastase showed that cercariae depleted glycogen mainly from the tail by 6 to 24 h postemergence. The posterior tip of the tail remained PAS positive and diastase fast suggesting the presence of mucopolysaccharides there. Fresh cercariae or those stained up to 24 h postemergence with Oil Red 0 showed the presence of neutral lipid droplets in the excretory system. There was no discernible difference in the size, abundance, or distribution of these droplets in fresh or aged cercariae. Cercariae maintained in ASW plus 1% glucose for 12 or 23 h showed no evidence of resynthesizing glycogen. Nevertheless, cercariae survived longer in 1% glucose than in either 0.0, 0.1 or 0.5% glucose; but only at 23 h were any differences statistically greater (one way ANOVA, P <0.05).

The migratory pathway of Toxocara canis larvae was determined by infecting mice with a low, medium or high dose of embryonated T. canis eggs and determining numbers of larvae present in the brain, liver, lungs, kidneys and muscle on days 5, 14 and 26 post infection. Variation was seen in the numbers of larvae recorded in the organs of mice which had received the same number of eggs and were at the same stage of infection. This variation was particularly marked in the brain indicating that, for the purposes of behavioural studies, the actual numbers of larvae found in the brain rather than the number assumed from the dose would have to be taken into account when analysing the behaviour of infected mice.

Batches of 10 Anisakis larvae from Greenland salmon (Salmo salar) were labelled with radioiodcin and fed to 10 haddock (Melanogrammus aegiefimis). Similar batches of larvae from herring (Clupea harengus) were fed to 8 whiting (Merlangius merlangus). At post-mortem from 15 to 190 hours after infection, 0 to 6 larvae were recovered from whiting (over-all recovery rate 18.8%) and 0 to 4 larvae were recovered from haddock (over-all recovery rate 27%). Larvae penetrated the wall of the stomach or of a pyloric caecum. They were first seen in the body-cavity 24 hours after infection and a delicate capsule was present around some of them by 34 hours. Most larvae were recovered from the body-cavity but, in haddock, two had penetrated the epaxial musculature.

Blood samples from 50 dogs with episodic weakness and 50 clinically normal dogs, all belonging to hunting breeds, were examined for microfilariae using the modified Knott's method. The prevalence of microfilaraemia in dogs belonging to the episodic weakness group was 10% for Dirofilaria immitis, 30% for Dirolfilaria repens and 8% for Acanthocheilonema reconditum. In the clinically normal group, the figures were 14% for Dirofilaria repens and 4% for Acanthocheilonema reconditum. The overall percentage of dogs with microfilaraemia in the episodic weakness group was 44 and that of the clinically normal group 16, with a statistically significant difference (P<0.01). The prevalence of microfilaraemia due to the nonpathogenic filarial species (Dirofilaria repens, Acanthocheilonema reconditum) was 34% and 16% for the episodic weakness group and the clinically normal dogs, respectively, with no significant difference.

In a previous hybridisation study it was found that six African schistosome species could be distinguished by their egg morphology and snail infectivity, and that their hybrids were also distinct. The present paper describes complementary studies on the behaviour of the same parasites in rodents.

Statistically significant differences were found between the behaviour of each pair of sibling species with regard to some of the following characters: percentage of worm recovery; rate of egg production; percentage distribution of eggs in the liver, small and large intestines. This is further evidence that these forms are distinct species.

There were also significant differences between the hybrids and their “parental” species, and between the behaviour of the parasites in mice and hamsters. The distinct behaviour of the hybrids raises the possibility of genetically modifying these parasites in order to attenuate their pathogenicity with a view to using hybrids as heterologous immunising agents.

A mitochondria-rich fraction isolated from the cuticle-hypodermis-muscie system of Setaria cervi, a bovine filarial parasite, possessed substrate-coupled cytochrome c reductases and cytochrome c oxidase in appreciable activities. All these activities were located predominantly in the membranes. NADH-coupled cytochrome c reductase was more prominent than NADPH- and succinate-coupled reductases. All the three reductases exhibited marked sensitivity to rotenone and antimycin A. Salicylhydroxamic acid strongly inhibited succinate requiring reductase and cytochrome c oxidase, but the other two reductases only mildly. Sodium azide activated the reductases but substantially inhibited the oxidase activity. Potassium cyanide activated the succinate requiring reductase but did not cause any noticeable change in the activities of pyridine nucleotide linked reductases. Anthelmintics also influenced these activities but no definite correlation could be drawn regarding their mode of action.

To understand the characteristic features of the Mongolian gerbil, Meriones unguiculatus, as an animal model of ascarid infections, the migration behaviour and pathogenesis of larvae were investigated in experimentally infected gerbils. Embryonated eggs from each of Toxocara canis,Baylisascaris procyonis, B. transfuga, Ascaris suum, and A. lumbricoides were orally inoculated into gerbils and larvae were recovered from various organs at designated periods. In T. canis-infected gerbils, larvae were present in the liver 3 days after infection and in the skeletal muscle and brain via the heart and lungs at a similar rate. In B. procyonis- and B. transfuga-infected gerbils, larvae were present in the lungs within 24 h after infection, with some having reached the brain by that time. After 24 h, larvae of B. procyonis tended to accumulate in the brain, while those of B. transfuga accumulated in skeletal muscles. In A. suum- and A. lumbricoides-infected gerbils, larvae remained in the liver on day 5 post-infection and elicited pulmonary haemorrhagic lesions, which disappeared 7 days after initial infection. Thereafter, no larvae of any type were recovered. Ocular manifestations were frequently observed in T. canis- and B. procyonis infected gerbils, but were rare in B. transfuga-infected gerbils. In the cases of A. suum and A. lumbricoides, migration to the central nervous system and eyes was extremely rare, and larvae had disappeared by 2 weeks post-infection. Fatal neurological disturbances were observed in B. procyonis-infected gerbils, whereas irreversible non-fatal neurological symptoms were observed in the case of B. transfuga.

The water rat Nectomys squamipes is endemic in Brazil and found naturally infected with Schistosoma mansoni. Helminth communities, their prevalences, intensity of infection and abundance in N. squamipes in an endemic area of schistosomiasis in the state of Rio de Janeiro, Brazil were studied. Four species of nematodes (Physaloptera bispiculata, Syphacia venteli, Hassalstrongylus epsilon and Litomosoides chagasfilhoi) were recovered in 85.3%, two trematodes (Schistosoma mansoni and Echinostoma paraensei) in 38.8% and one cestode species (Raillietina sp.) in 1.7% of rats examined. Rats were infected with up to five helminth species each, and these were highly aggregated in distribution. For H. epsilon and S. venteli, intensities and abundances were higher in adult male and subadult female hosts, respectively. Hassaltrongylus epsilon, P. bispiculata, S. venteli and S. mansoni were classified as dominant species, L. chagasfilhoi and E. paraensei as co-dominant and Raillietina sp. as subordinated. No significant correlation was found in the intensity of infecton between each pair of helminth species. Schistosoma mansoni was not related to any other helminth species according to their infection rates, althougth S. mansoni was well established in the natural helminth comunity of the water rat.

The pink shrimp Farfantepenaeus duorarum may acquire pollutants, helminths and symbionts from their environment. Statistical associations were studied between the symbionts and helminths of F. duorarum and pollutants in sediments, water and shrimps in Campeche Sound, Mexico. The study area spatially overlapped between offshore oil platforms and natural shrimp mating grounds. Spatial autocorrelation of data was controlled with spatial analysis using distance indices (SADIE) which identifies parasite or pollutant patches (high levels) and gaps (low levels), expressing them as clustering indices compared at each point to produce a measure of spatial association. Symbionts included the peritrich ciliates Epistylis sp. and Zoothamnium penaei and all symbionts were pooled. Helminths included Hysterothylacium sp., Opecoeloides fimbriatus, Prochristianella penaei and an unidentified cestode. Thirty-five pollutants were identified, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides and heavy metals. The PAHs (2–3 ring) in water, unresolved complex mixture (UCM), Ni and V in sediments, and Zn, Cr and heptachlor in shrimps were significantly clustered. The remaining pollutants were randomly distributed in the study area. Juvenile shrimps acquired pesticides, PAHs (2–3 rings) and Zn, while adults acquired PAHs (4–5 rings), Cu and V. Results suggest natural PAH spillovers, and continental runoff of dichlorodiphenyltrichloroethane (DDT), PCBs and PAHs (2–3 ring). There were no significant associations between pollutants and helminths. However, there were significant negative associations of pesticides, UCM and PCBs with symbiont numbers after controlling shrimp size and spatial autocorrelation. Shrimps and their symbionts appear to be promising bioindicators of organic chemical pollution in Campeche Sound.

Two new species of Paramphtstomum from cattle are described, namely, P. hiberniae n.sp. and P. scotiae n.sp., first collected from Irish and Scottish cattle respectively.

A brief account of gametogenesis and early cleavage division is given.

The chromosome number for P. scotiae is n=8, 2n=16, for P. hiberniae no definite number is given but it is believed to be n = 8 (6–8), 2n=16 (12–16). Notes are made on some specimens received from the Netherlands and France.

P. hiberniae and P. scotiae are compared with P. cervi and P. leydeni.

A study has been made of the early larval stages of the nematode Trichuris muris. It was found that the capacity of larvae to infect mice developed some time after the apparent completion of growth in the egg; no moult was observed to occur within the egg. Hatching took place in the small intestine of the mouse between 30 and 60 minutes after infection and the larvae were carried down into the caecum. Penetration was first observed one hour after infection and by 4 hours almost all the larvae had entered the caecal mucosa. Larvae appeared to penetrate into the epithelial cells of the mucosal glands after first entering through the gland opening. During the first 4 to 5 days the larvae remained within the glands, coiled around the gland lumen, but as growth occurred, the larvae occupied a more superficial position and eventually came to lie with the anterior region of the body within the mucosa and the posterior region lying free in the caecal lumen. Moulting larvae were recovered on the 9th 10th and 11th day after infection.

The objectives of this study were to evaluate the contamination by eggs of Toxocara in sandy areas or grass lawns of outdoor recreation areas that are used by children, and the frequency of seroprevalence in children, from three cities of fewer than 45,000 inhabitants in Paraná, Brazil. From May 2005 to December 2007, five samples were taken from each of 13 sandy sites and 18 grass lawns, all from plazas and public schools. Blood samples from children aged 0–12 years were analysed by immunoassay for anti-Toxocara IgG. The soil samples were processed by floatation and sedimentation. Eggs of Toxocara spp. were present in 44.7% (38/85) of the samples from grassed areas and in 21.4% (15/70) of the sand samples. The lawns were 2.16 times more contaminated than the sand (P = 0.0009). However, the epidemiological variables showed no statistically significant difference between seropositive (36.8%; 130/353), and seronegative children. The rate of seropositivity was higher in children aged 0–5 years (P = 0.03), who were 1.94 times more likely to develop persistent wheezing (P = 0.02).

A survey of the occurrence of Dirofilaria immitis, Borrelia burgdorferi, Ehrlichia canis and Anaplasma phagocytophium in dogs was undertaken in the People's Republic of China between October 2008 and October 2009. A total of 600 blood samples were taken from dogs in four cities in China: 300 in Beijing, 150 in Shenzhen, 30 in Shanghai and 120 in Zhengzhou. All samples were tested for the heartworm antigen and antibodies of canine B. burgdorferi, E. canis and A. phagocytophium by using the canine SNAP® 4Dx® test kit. The occurrence of D. immitis, B. burgdorferi, E. canis and A. phagocytophium was 1.17% (7/600), 0.17% (1/600), 2.17% (13/600) and 0.5% (3/600), respectively. In Shenzhen city 2% (3/150), 8.67% (13/150) and 2% (3/150) of samples were positive for D. immitis, E. canis and A. phagocytophium, respectively. The occurrence of heartworm antigen was 0.33% (1/300) in Beijing, 2.00% (3/150) in Shenzhen, 3.33% (1/30) in Shanghai and 1.67% (2/120) in Zhengzhou. We found E. canis and A. phagocytophium only at one site, Shenzhen, while the only occurrence of B. burgdorferi was at Beijing. In conclusion, the dog population in China is at potential risk for D. immitis, B. burgdorferi, E. canis and A. phagocytophium infection, the risk being especially high in southern China.

The possibility was examined of using a haemoglobinase released during in vitro incubation of adult Fasciola hepatica for immunodiagnosis of fascioliasis. By SDS gel electrophoresis the enzyme appeared as two closely migrating bands with a molecular weight of approximately 27 000 daltons. After Western blotting the bands reacted with serum from rats infected with F. hepatica and mice infected with Schistosoma mansoni. The enzyme was therefore not a good antigen for immunodiagnosis.

It was found that with high level infections of Trichinella spiralis self-cure in immune mice occurs only slightly earlier than in normal mice. With low level infections self-cure is much earlier. In the host parasite combination studied the majority of the adult worms were found in the posterior part of the small intestine and no migration along the intestine was found. It is postulated that as migration is of such a variable occurrence it is not a necessary accompaniment to self-cure in T. spiralis infections. Where an early self-cure occurs it is obviously an important component of the immunity complex but other components such as reduced fecundity are equally important in limiting larval invasion of the muscles of immune mice.