Artificially prepared cow pats containing Ostertagia ostertagi eggs were deposited on two comparable grazing plots at weekly intervals during June and July 1987. Before deposition the cow pats, on the one plot, were inoculated with 0·250 g mycelial fragments per kg of faeces of the predacious fungus Arthrobotrys oligospora. On the other control plot comparable numbers of non-inoculated cow pats were placed at the same time. Subsequently, in July, two equal groups of calves were turned out one on each plot to graze for two months after which they were necropsied. The number of infective O. ostertagi larvae in inoculated cow pats was reduced by 42% and herbage larval infectivity around them by 50–71% as compared with the corresponding parameters in control pats and surrounding herbage. After a grazing period of two months the calves on the plot with inoculated cow pats had acquired worm burdens that were on average 37% lower than those of calves on the control plot. The lower degree of parasitism in these calves was also reflected in lower egg counts, lower serum pepsinogen levels and higher body weight.

Hamsters experimentally infected with Opisthorchis viverrini had significant depression of the antibody response to sheep red blood cells. The depression was more severe with prolonged infections. Lymphoproliferative response to phytohaemagglutinin stimulation was also depressed when compared with uninfected controls. The immunodepression in these animals was abolished by anthelmintic treatment, suggesting that the immunodepressive effect is reversible and is associated with active infection.

The present study examined sequence variation in four mitochondrial (mt) genes, namely cytochrome c oxidase subunits 1 (cox1) and 2 (cox2), and NADH dehydrogenase subunits 1 and 2 (nad1 and nad2) among Clonorchis sinensis isolates from different endemic regions in China, and their phylogenetic relationships with other zoonotic trematodes were reconstructed. A portion of the cox1 and cox2 genes (pcox1 and pcox2), and nad1 and nad2 genes (pnad1 and pnad2) were amplified separately from individual liver flukes by polymerase chain reaction (PCR) and the amplicons were subjected to sequencing from both directions. The intra-specific sequence variations within C. sinensis were 0–1.6% for pcox1, 0–1.4% for pcox2, 0–0.9% for pnad1 and 0–1.0% for pnad2. Phylogenetic analyses based on the combined sequences of pcox1, pcox2, pnad1 and pnad2 revealed that all the C. sinensis isolates grouped together and were closely related to Opisthorchis felineus. These findings revealed the existence of intra-specific variation in mitochondrial DNA (mtDNA) sequences among C. sinensis isolates from different geographic regions, and demonstrated that mtDNA sequences provide reliable genetic markers for phylogenetic studies of zoonotic trematodes.

The parasite fauna of stray cat populations, comprising mainly helminth parasites, is described for the first time from the arid environment of the Qatar peninsula. During the winter and summer months of 2005, 824 faecal samples were examined from six sites in Qatar. Up to seven species of parasites were identified, six of which were nematodes – Strongyloides stercoralis as the most prevalent (18.4%), followed by Aelurostrongylus abstrusus (7.5%), Toxocara cati (6.1%), Ancylostoma tubaeforme (5.9%) and Physaloptera sp. (4.8%) and Toxascaris leonina (0.7%) – and one sporozoan species, Isospora felis (0.5%). Unidentified cestode eggs were also recovered from 10.7% of samples examined. The parasite species were found to be highly overdispersed in faecal samples from all sites, whereas the prevalence and intensity of infections were influenced by site and season. Infection levels tended to be higher during the winter season, especially in the case of A. abstrusus and A. tubaeforme, when conditions of temperature and humidity were more favourable for the development of egg and/or larval stages of parasites compared with the extremely hot and dry summer months. The results are discussed in relation to the distribution of the cat population in the vicinity of Doha and its outskirts and the potential threat of parasite transmission to human communities in Qatar.

A preliminary study to detect human worm carriers of Taenia solium in Papua (Irian Jaya), Indonesia was carried out using stool examinations for the detection of copro-antigens and adult proglottids after chemotherapy, and confirmation by mitochondrial DNA analysis using expelled proglottids and metacestodes developed in NOD/Shi-scid mice from eggs of expelled proglottids. Approximately 8.6% of the local population in Kama (5/58), 1 km from the local capital city centre, Wamena, were confirmed to harbour adult T. solium using these techniques.

Entomopathogenic nematodes (Heterorhabditidae and Steinernematidae) were isolated from Sri Lankan soils using the Galleria baiting technique. Samples collected from different agro-ecological regions and different habitat types revealed that the presence of nematodes was restricted to sandy coastal soils. Two heterorhabditid and three steinernematid RFLP types were discovered within 5–100 m of the sea. Members of both families were equally prevalent. However, no parasitized insects were found although insect species were encountered which are potentially natural hosts. These nematodes were present at high temperatures (some above 30°C) and neither the monsoon rain nor the drought had any effect on their prevalence.

Among eyeflukes, Tylodelphys Diesing, 1850 includes diverse species able to infect the eyes, but also the brain, pericardial sac and body cavity of their second intermediate host. While the genus shows a cosmopolitan distribution with 29 nominal species in Africa, Asia, Europe and America, a likely lower research effort has produced two records only for all of Australasia. This study provides the first description of a species of Tylodelphys and the first record for a member of the Diplostomidae in New Zealand. Tylodephys sp. metacercaria from the eyes of Gobiomorphus cotidianus McDowall, 1975 is distinguished from its congeners as being larger in all, or nearly all, metrics than Tylodelphys clavata (von Nordmann, 1832), T. conifera (Mehlis, 1846) and T. scheuringi (Hughes, 1929); whereas T. podicipina Kozicka & Niewiadomska, 1960 is larger in body size, ventral sucker and holdfast sizes and T. ophthalmi (Pandey, 1970) has comparatively a very small pharynx and body spination. Tylodelphys sp. exhibits consistent genetic variation for the 28S rDNA, internal transcribed spacer (ITS) and Cox1 genes, and phylogenetic analyses confirm that it represents an independent lineage, closely related to North American species. Morphological and molecular results together support the distinct species status of Tylodephys sp. metacercaria, the formal description and naming of which await discovery of the adult. Furthermore, the validity of T. strigicola Odening, 1962 is restored, T. cerebralis Chakrabarti, 1968 is proposed as major synonym of T. ophthalmi, and species described solely on the basis of metacercariae are considered incertae sedis, except those for which molecular data already exist.

In recent years there have been major socio-economic changes within Afghanistan such that the present public health burden of soil-transmitted helminths (STH), especially that within school-aged children, remains to be determined. A baseline parasitological survey was therefore carried out in four defined areas of Afghanistan to better assess the distribution, prevalence and intensity of STH infections prior to a nationwide de-worming campaign beginning within World Food Programme assisted schools. A cross-sectional examination of 1001 children aged between 8 and 15 years old revealed that approximately half (47.2%) were infected with at least one STH. Infections with Ascaris lumbricoides were most widespread (40.9%) and elevated prevalences were detected in urban environments; for example, schoolchildren in Kabul were more likely to be infected (OR=2.2, 95% CI 1.6–3.0) than elsewhere and these infections were often of higher intensity (OR=7.6, 95% CI 4.9–11.8). Trichuris trichiura (9.9%) and hookworms (0.7%), previously unknown from Afghanistan, were encountered. The blood haemoglobin concentration of surveyed children was also assessed: 4% resulted to be anaemic (Hb<11 g dl−1), and 0.4% to be severely anaemic (Hb<7 g dl−1).

Mice were infected percutaneously with cercariae of Schistosoma japonicum or S. mansoni and parasites recovered by tissue-mincing from the skin or lungs or by perfusion of the mesenteric veins. S. japonicum had a narrow peak of recovery (up to 30%) from the lungs 3 days after infection, whereas lung recovery of S. mansoni peaked only on day 6 and levelled off during the following week. Infection with S. japonicum induced lung petechiae, but only after most of the parasites had left the lungs. The axillary lymph nodes draining the infection site increased in weight after infection and this effect was much greater and longer with S. mansoni than with S. japonicum. S. japonicum was perfusable from the mesenteric veins earlier (from day 3 onwards) and in higher number (40–60% from days 6 to 10) than S. mansoni (20% on day 20). The percentage of cercariae developing to adult worms was 57% for S. japonicum and 33% for S. mansoni. The data demonstrate that S. japonicum might escape from local tissue reactions in the skin and lungs and, due to its rapid migration, might induce only poor lymphocyte proliferation. As a possible consequence, S. japonicum may establish more efficiently in mice than S. mansoni.

Self insemination appears to be the normal process of sperm transfer in Echinococus granulosus and has been observed in both terminal and subterminal proglottids of worms from dogs.

Cross fertilization between adjacent proglottids or between proglottids of different strobila was not observed.

In some instances, the genital pore was found occluded by a ‘plug’ of material which may represent an antige–antibody precipitate.

The implications of self-insemination in relation to in vitro studies and to the genetics of ‘strain’ production in the genus Echinococcus are discussed.

A survey for parasites has been undertaken in 20 mountain gorillas (Gorilla gorilla beringei) from the Eastern Congo Kivu province.

Six full-grown (two males and four females), three adolescents (one male and two females), and eleven young gorillas were examined, some of them during several consecutive months. Nine autopsies were performed.

No protozoa were discovered in the blood. Plasmodium parasites which are common in gorillas and chimpanzees from West Africa were never found in the Eastern Congo primates, including ten other gorillas examined previously and some fifty chimpanzees. Severe diarrhoea with a balantidiasis picture developed in two young gorillas. Autopsy revealed however an intensive infection with Oesophagostomum stephanostomum and resulting fatty degeneration of the liver. Oligotrichida belonging to the genus Troglodytella were commonly found in the intestinal tract. Oesophagostomum stephanostomum eggs were consistently present in the stools of the gorillas and autoinfection caused the death of several young gorillas 4 to 6 weeks after their capture.

The production of cercariae from their snail host is a fundamental component of transmission success in trematodes. The emergence of Echinoparyphium recurvatum (Trematoda: Echinostomatidae) cercariae from Lymnaea peregra was studied under natural sunlight conditions, using naturally infected snails of different sizes (10–17 mm) within a temperature range of 10–29°C. There was a single photoperiodic circadian cycle of emergence with one peak, which correlated with the maximum diffuse sunlight irradiation. At 21°C the daily number of emerging cercariae increased with increasing host snail size, but variations in cercarial emergence did occur between both individual snails and different days. There was only limited evidence of cyclic emergence patterns over a 3-week period, probably due to extensive snail mortality, particularly those in the larger size classes. Very few cercariae emerged in all snail size classes at the lowest temperature studied (10°C), but at increasingly higher temperatures elevated numbers of cercariae emerged, reaching an optimum between 17 and 25°C. Above this range emergence was reduced. At all temperatures more cercariae emerged from larger snails. Analysis of emergence using the Q10 value, a measure of physiological processes over temperature ranges, showed that between 10 and 21°C ( ≈ 15°C) Q10 values exceeded 100 for all snail size classes, indicating a substantially greater emergence than would be expected for normal physiological rates. From 14 to 25°C ( ≈ 20°C) cercarial emergence in most snail size classes showed little change in Q10, although in the smallest size class emergence was still substantially greater than the typical Q10 increase expected over this temperature range. At the highest range of 21–29°C ( ≈ 25°C), Q10 was much reduced. The importance of these results for cercarial emergence under global climate change is discussed.

The effect of pollutants on the intensity of infection of metazoan parasites in the Mayan catfish, Ariopsis assimilis was investigated. Data were collected on pollutants and metazoan parasites from 76 catfish from five localities in Chetumal Bay in October, 1996. Nineteen pollutants (pesticides, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)) were found in the catfish livers. Heavy metal content was not determined. Nineteen metazoan parasite species were recovered. After controlling for fish length and sampling station, there was a significant negative linear relationship between the intensity of the larval digenean Mesostephanus appendiculatoides and 1,1,1,-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) concentrations. This negative relationship may be explained either by the effect of the pesticide on the mortality of (i) free-living larval forms, (ii) metacercariae in the fish, (iii) infected fish or (iv) intermediate host snails. There were significant differences between fish parasitized and not parasitized with M. appendiculatoides with respect to their DDT concentrations. There were also significant differences between the variances of the mean Clark's coefficient of condition values between catfish parasitized and not parasitized by M. appendiculatoides, with the variance of non-parasitized catfish being significantly larger. The results provided statistical evidence that DDT has a detrimental effect on M. appendiculatoides infection intensity. Furthermore, the significantly larger variance value of Clark's coefficient for non-parasitized fish suggested that DDT affects both the parasite and general host condition.

The first human infection with Gongylonema in Iran is reported in a 35-year-old Iranian woman with complaints of one year duration and treated as a psychotic patient. Two worms, a male, and a female, were retrieved, described, and identified as G. pulchrum based on their morphological characteristics.

Human infection by Dirofilaria repens in Serbia has been increasing steadily. The first case was reported in 1971, presented in the form of a single subcutaneous nodule on the back of a young boy. As established by a literature search, eight additional cases were reported until mid-2001. The most frequent site of infection was subcutaneous tissue, with the exception of two cases, in which parasites were found in subconjunctiva and epididymis. Our study, conducted from 2001 to 2008, encompasses 19 new cases. Most of them (63.1%) presented as ocular or periocular infections, in which the parasite was typically found under the conjunctiva. In other cases a parasitic nodule was localized in the temporal region of the head, epididymis, testicle, abdomen, breast or arm. The diagnosis was made by morphological and histological analysis of the extracted intact worms and parasite sections from the tissue. Morphology of the filarial worms was well preserved in more than half of the cases (12/19) and there was never more than one parasite found inside the lesions. Adult worms and immature nematodes were observed in nine and seven cases, respectively. Furthermore, in two cases microfilariae were discovered inside the pseudocoelom, sections of the female reproductive tubes filled with clearly visible larval stages. Dirofilaria repens infection was diagnosed by its morphological features (17/19) or by performing polymerase chain reactions (PCR) using paraffin-embedded tissues (2/19) in the cases where the morphology was insufficient for identification and the parasites had been determined initially as Dirofilaria spp. The amplified 246 bp PCR product showed that the worms were D. repens.

Laboratory investigations were designed to study the influence of temperature, pH and oxygen tension on the growth of Arthrobotrys oligospora, a nematode-trapping microfungus. Experiments were performed to evaluate the potential role of A. oligospora in destroying third-stage larvae of Cooperia spp. on agar plates and in cattle faeces. The fungus had a growth rate optimum at 23°ree;C and pII 6. Anaerobic cultivation for 23 hours at 23°ree;C and 39°ree;C inhibited fungal growth, but it did not destroy the fungus, which regained growth upon a subsequent shift to aerobic conditions at 23°ree;C. Under experimental conditions in petri-dishes containing agar, the nematode-trapping efficiency of the fungus was striking in that 100% of a population of third-stage larvae of Cooperia spp. was captured within three days of the experiment. The trapping efficiency in faeces was shown to depend upon the inoculation level. At a concentration of approximately 2500 conidia per g faeces, 99% of the larvae were destroyed. The possibilities of using nematode-trapping fungi in controlling animal-parasitic nematodes arc discussed.

A study has been carried out to determine the morphological changes to the adult liver fluke, Fasciola hepatica after treatment in vivo with artemether. Rats were infected with the triclabendazole-resistant Sligo isolate of F. hepatica, dosed orally with artemether at a concentration of 200 mg/kg and flukes recovered at 24, 48 and 72 h post-treatment (p.t.). Surface changes were monitored by scanning electron microscopy and fine structural changes to the tegument and gut by transmission electron microscopy. Twenty-four hours p.t., the external surface showed minor disruption, in the form of mild swelling of the tegument. The tegumental syncytium and sub-tegumental tissues appeared relatively normal. Forty-eight and seventy-two hours p.t., disruption to the tegumental system increased, with isolated patches of surface blebbing and reduced production of secretory bodies by the tegumental cells being the main changes seen. The gastrodermal cells showed a relatively normal morphology 24 h p.t. By 48 h, large numbers of autophagic vacuoles and lipid droplets were present. Autophagy increased in magnitude by 72 h p.t. and substantial disruption to the granular endoplasmic reticulum was observed. Results from this study show that flukes treated in vivo with artemether display progressive and time-dependent alterations to the tegument and gut. Disruption to the gut was consistently and substantially more severe than that to the tegument, suggesting that an oral route of uptake for this compound predominates. This is the first study providing ultrastructural information on the effect of an artemisinin compound against liver fluke.

Suspensions of embryonated (L2) Toxocara canis and T. cati eggs were maintained under freezing conditions in order to study the impact on their long term viability The eggs had been removed from the uteri of adult Toxocara spp. worms and the suspended in a 0.4% formalin solution before being frozen in 20 ml plastic tubes in the freezer compartment of a domestic refrigerator. Assessment of embryonated egg viability over a period of 34 days was conducted by microscopic examination under a high light intensity Embryonated T. cati eggs were found to exhibit a greater resistance to freezing than those of T. canis. A difference in the size, design of the egg shell or the metabolism of the larval form may have accounted for the observed differences in the percentage viabilities over time between the two species of Toxocara.

A polymerase chain reaction (PCR) technique has been used for the differentiation of T. canis and T. cati eggs isolated from soil and previously identified from microscopical observations. The method, using specific primers for the identification of the two Toxocara species, was assessed in both the field and laboratory. Successful results were obtained when only a single or large numbers of eggs were recovered from 40 g soil samples. The method is sensitive, allows analysis of material independent of the stage of egg development and can be adapted for the recovery of other species of parasites from soil.

The present study investigated the suitability and importance of buffaloes, camels, sheep, goats and pigs in maintaining the life-cycle of Echinococcus granulosus in Aligarh, India. A total of 565 (36%) of 1556 buffaloes, 20 (2%) of 1208 goats, 5 (1%) of 559 pigs, 6 (6%) of 109 sheep and two of three camels were found to harbour hydatid cysts. The frequency distribution of the hydatid cysts in each intermediate host species was over-dispersed and in buffaloes cyst fertility increased with increasing cyst size. Of 2171, 95 and four buffalo, goat, and camel cysts examined 327 (15%), two (2%) and three cysts respectively were fertile. No pig or sheep cysts were found to contain protoscoleces. The unfenced buffalo abattoir and the large number of dogs allowed access to the abattoir coupled to the number of buffaloes slaughtered in comparison to the other potential hosts, indicates that the buffalo is the most significant host for maintaining the life-cycle of the parasite in this area of India. Applicable control measures for the region are suggested.