Schistosome parasites commonly show specificity to their intermediate mollusc hosts and the degree of specificity can vary between parasite strains and geographical location. Here the role of miracidial behaviour in host specificity of Schistosoma haematobium on the islands of Zanzibar is investigated. In choice-chamber experiments, S. haematobium miracidia moved towards Bulinus globosus snail hosts in preference to empty chambers. In addition, miracidia preferred uninfected over patent B. globosus. This preference should benefit the parasite as patent snails are likely to have mounted an immune response to S. haematobium as well as providing poorer resources than uninfected snails. Miracidia also discriminated between the host B. globosus and the sympatric, non-host species Cleopatra ferruginea. In contrast, S. haematobium did not discriminate against the allopatric Bulinus nasutus. Penetration of the host by miracidia was investigated by screening snails 24 h after exposure using polymerase chain reaction (PCR) with S. haematobium specific DraI repeat primers. There was no difference in the frequency of penetration of B. globosus versus B. nasutus. These responses to different snail species may reflect selection pressure to avoid sympatric non-hosts which represent a transmission dead end. The distribution of B. nasutus on Unguja is outside the endemic zone and so there is less chance of exposure to S. haematobium, hence there will be little selection pressure to avoid this non-host snail.

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.

Forty-three specimens of Leptodactylus podicipinus (Anura: Leptodactylidae) were collected in the south-eastern Pantanal, municipality of Corumbá, State of Mato Grosso do Sul, Brazil in February and July 2007, and examined for endoparasites. Forty (93%) specimens were infected with at least one helminth species. The predominant parasites were nematodes (Aplectana sp., Cosmocerca podicipinus, Oswaldocruzia lopesi, Physalopteroides venancioi, Rhabdias sp.), but the trematode Catadiscus propinquus also showed high prevalence. The trematodes Infidum infidum and Travtrema stenocotyle were also found, but in only one specimen. Adult frogs showed higher parasite diversity than subadults. Leptodactylus podicipinus was preferentially infected by direct life-cycle parasites and was reported as a new host record for seven helminth species.

The activities of trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) were observed in muscles, individual parts of the reproductive system and haemolymph of Ascaris suum. The highest activity of TPS was detected in the upper uterus, while the lowest activity of TPS was detected in the ovary and oviduct of the nematode. Relatively high activity was detected in muscles, haemolymph and two remaining parts of the uterus. The TPP activity was the highest in lower length of the uterus, following muscles, ovary, central and upper uterus. The lowest activity of TPP was detected in the haemolymph and oviduct of A. suum. Besides TPS and TPP, trehalose was also detected in the studied tissues except the cuticle and the intestine. Glucose was present in all organs, but the highest concentration was found in the cuticle and intestine.

Every month during the year 2006–2007, the 24, 48, 72 and 96 h LC50 values of a molluscicide, cypermethrin, were determined for a snail Lymnaea acuminata, with concomitant estimation of levels of temperature, pH, dissolved oxygen and carbon dioxide and electrical conductivity, both in control and test water. On the basis of a 24 h toxicity assay, it was noted that LC50 values of 10.39, 10.90 and 11.19 mg l− 1 during the months of May, June and July, respectively, were most effective in killing the snails, while the molluscicide was least effective in the month of January, when its 24 h LC50 was 65.84 mg l− 1.There was a significant positive correlation between LC50 of cypermethrin and levels of dissolved O2/pH of water in corresponding months. On the contrary, a negative correlation was observed between LC50 and dissolved CO2/temperature of test water in the same months. In order to ascertain that such a relationship between toxicity and abiotic factors is not coincidental, the nervous tissue of the snail was assayed for the activity of acetylcholinesterase (AChE), acid phosphatase (ACP) and alkaline phosphatase (ALP) to sublethal concentrations (40% and 80%) of 24 h LC50 during each of the 12 months of the same year. The findings confirmed that abiotic factors indeed influence toxicity of cypermethrin in the snail. A significant positive rank correlation between AChE, ACP and ALP activity did exist following exposure to the corresponding sublethal concentrations. Moreover, there was a maximum inhibition of 61.29 and 76.16% of AChE and ACP, respectively, in snails exposed to 80% of the 24 h LC50 in the month of May. A similar treatment caused a maximum inhibition of 70.53% of ALP activity in the month of June. This work shows conclusively that the best time to control the snail population with cypermethrin is during the months of May and June.

Triclabendazole (TCBZ) remains the drug of choice for treating infections of the liver fluke, Fasciola hepatica in livestock and has become the main drug used to treat human cases of the disease as well. Cases of resistance in livestock continue to be reported, suggesting that the problem is increasing. In order to address the problem, there is a need for better understanding of drug action. A ‘state-of-play’ review on different aspects of TCBZ activity was published by the present author in 2005. The main purpose of the current review is to assess what progress has been made in the past four years towards understanding the main aspects of drug activity, including drug pharmacokinetics and pharmacodynamics and an understanding of the mechanism(s) of resistance. Also, what advances have been made in identifying alternative compounds and using drug combinations to enhance TCBZ activity. Stemming from a number of in vivo studies, it has become evident that fluke isolates of differing sensitivity to TCBZ differ in some of their biological parameters, and information on this interesting phenomenon will be presented. An update on the use of TCBZ for human fascioliasis is also given. The review will indicate what progress has been made, but will also highlight areas that remain inadequately understood and require greater research focus.

An update on the redial generations of Fasciola hepatica was carried out to highlight the different developmental patterns of rediae, the effects of some factors on these generations, and the consequences of such developmental patterns on cercarial productivity. The development of generations is dependent on the behaviour of the first mother redia of the first generation. If this redia remains alive throughout snail infection, it produces most second-generation rediae. In contrast, if it dies during the first weeks, daughter redia formation is ensured by a substitute redia (the second mother redia of the first generation, or the first redia of the second generation). Environmental and biotic factors do not modify the succession of redial generations, but most act by limiting the numbers of rediae, either in all generations, or in the second and/or third generations. An abnormal development of rediae reduces the number of cercariae and most are formed by the second cohort of the first generation. By contrast, most cercariae are produced by the first cohort of the second generation when redial development is normal. The mother rediae described by previous authors might correspond to the first generation and the second cohort of the second generation, while daughter rediae would be the second cohort of the second generation and the first cohort of the third generation. Under certain circumstances, daughter redia formation is ensured by the first two mother rediae or all first-generation rediae, thus demonstrating that the first mother redia is not the only larva to ensure daughter redia formation.

The prevalence of Brugia malayi was surveyed in three highly endemic provinces in southern Thailand as part of an ongoing evaluation of the effectiveness of two rounds of mass drug administration (MDA). Prior to MDA IV, and thereafter every 6 months up to 18 months, including MDA V at 12 months, nocturnal blood sampling was assayed for microfilaria (mf) and IgG4 antibodies in 200 subjects from Nakorn Srithammarat and Surathani provinces. From an additional 300 subjects from Narathiwatt province, daytime blood was also examined for IgG4 antibodies for 1 year. Subjects who tested positive, with reciprocal IgG4 titres above 100, were dichotomized in the ‘good compliant’ or ‘uncertain compliant’ groups. Stool samples were examined for intestinal parasites from all 500 subjects simultaneously. Only two subjects (1%) tested positive for mf, while 98 subjects (19.6% of 500) tested positive for IgG4. In general, the good drug-compliant subjects were less likely to exhibit the IgG4 response than subjects in the uncertain compliant group. Only six subjects (1.2%) exhibited lymphoedema while 68 subjects (13.6%) had a total of 105 parasitic infections, with female instances of protozoan infections exceeding male instances of helminth infections. It was concluded that the two MDA rounds were highly successful in not only in reducing mf to negligible levels but also in lowering antifilarial IgG4 titres in the good compliant subjects. The IgG4 assay is a sensitive and cost-effective surveillance tool for the early detection of brugian infections that is not contingent on nocturnal blood collections.

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.

The present study was conducted to determine the prevalence of canine dirofilariosis in Hatay province, south of Turkey. A total of 269 blood samples were collected from owned dogs in this multi-centre survey between March and July 2006. Blood samples were examined by modified Knott and enzyme-linked immunosorbent assay (ELISA) techniques to detect circulating microfilariae and antigens of Dirofilaria immitis, respectively. Seventy out of 269 dogs (26.0%) were positive for D. immitis. However, 61.4% of positive dogs had occult infection. The prevalence of canine dirofilariosis was heterogeneous in Hatay province, with higher values in shoreline (33.0%) and riverside (30.9%) areas followed by the lowland (25.5%) or mountainous (15.2%) areas. No statistically significant differences were observed in relation to sex (females, 33.3%; males, 24.4%, P>0.05). When evaluating the prevalence of D. immitis by age, the highest prevalence was observed in dogs older than 4 years of age. Large breeds (29.6%) and the dogs living outdoors (30.2%) showed a higher prevalence in comparison to small breeds (21.4%) and the dogs living indoors (10.5%), respectively. In conclusion, according to the results of this study canine dirofilariosis had a high prevalence in Hatay province. Therefore, prophylaxis against heartworm is advisable to decrease the incidence of canine dirofilariosis.

Exposure of encysted metacercariae of Clinostomum complanatum to UV light (254 nm) for 60 min reduced their development into adult worms in buff-backed herons (95.7% reduction in worm burden). Metacercariae that succeeded in developing into adult worms, showed low fecundity levels. Furthermore, 30% of eggs laid showed abnormal shape; however, all normal and abnormal eggs failed to hatch into miracidia. The effectiveness of UV-irradiated metacercariae as a vaccine was investigated. Compared to control unvaccinated herons, the vaccinated group showed a significantly high protection rate (73.8%) against challenge. In vitro, worm development after challenge showed decreased fecundity and increased egg abnormalities, where only 1.5% of all eggs produced hatched into miracidia. A passive haemagglutination test revealed increased antibody titres against soluble adult worm antigen in both vaccinated and vaccinated-challenged birds. It was concluded that vaccination of herons using encysted metacercariae UV-irradiated for 60 min can protect them against challenge infection.

A water-insoluble, detergent-soluble, surface-associated glycoprotein, designated as Dssd1, was found to induce microfilaria clearance in Mastomys coucha implanted with Setaria digitata. Intraperitoneal implantation of adult female worms of S. digitata in M. coucha could induce microfilaraemia lasting about 165 days in circulation. Immunization of M. coucha with Dssd1 antigen either before or after implantation of worms resulted in a significant reduction in microfilaria density. Complete clearance of circulating microfilaria was achieved by immunization (before and after implantation) in animals by 95 and 105 days post-implantation, respectively, indicating the efficacy of Dssd1 antigen in the clearance of microfilaraemia in infected M. coucha.

In the past decade, swimmer's itch (SI) has repeatedly occurred in people who have been wading or bathing in ponds or lakes in Iceland where water birds and snails are abundant. Some of the affected sites were warmed by geothermal activity, and others were not. A search for the causative agent of SI, ocellate furcocercariae that have been found in Iceland only in Radix peregra snails, revealed an average infection prevalence of 1.4% (n = 12,432). Locally, infection rates commonly exceeded 6%, the highest value observed being 24.5%. A search for adult schistosomes in visceral organs and the nasal cavities of 110 water birds belonging to the orders Gaviiformes, Podicipediformes and Anseriformes revealed eggs, miracidia or adult stages of at least seven previously identifiable schistosome species in four anseriform bird species. A previously unknown species of schistosome, Allobilharzia visceralis, was detected in whooper swans (Cygnus cygnus), and classified in a new genus. In mallards (Anas platyrhynchos) a nasal Trichobilharzia sp. and the visceral schistosome T. franki were identified. In red-breasted merganser (Mergus serrator), distinct egg types belonging to two species of the genus Trichobilharzia have been found. In grey-lag goose (Anser anser) two different egg types were also found – a large Trichobilharzia sp. and small eggs of a Dendritobilharzia sp. Additionally, unidentified cercariae, probably belonging to a previously undescribed genus were detected in R. peregra in Oslandsstjörn. Taken together, the data obtained by morphological examination of eggs and recent DNA sequencing results, indicate that at least eight species of bird schistosomes occur in Iceland.

Fish larvae of ‘corvinas’ (Pachyurus bonariensis and Plagioscion ternetzi) from Sinhá Mariana Lagoon, Mato Grosso State, were collected from March 2000 to March 2004, in order to determine the parasitic fauna of fishes. Larvae from the two species were parasitized by the same endoparasites: Contracaecum sp. Type 2 (larvae) (Nematoda: Anisakidae) in the mesentery and Neoechinorhynchus (Neoechinorhynchus) paraguayensis (Acanthocephala: Neoechinorhynchidae) in the stomach and the terminal portion of the intestine. Statistical analysis showed that there was a significant positive correlation between the standard length of hosts and the abundance of acanthocephalans and nematodes, and that the prevalence of nematodes presented a significant positive correlation with the standard length of the two species of hosts, indicating the presence of a cumulative process of infection. The present study constitutes the first record of nematodes and acanthocephalans parasitizing larval fish, as well as the first record of endoparasites in fish larvae in Brazil. In addition, it lists a new locality and two species of hosts for Contracaecum sp. Type 2 (larva) and N. (N.) paraguayensis.

The objective of this cross-sectional study was to determine the prevalence and intensity of soil-transmitted helminths (STHs) in children aged 0–25 months and to identify the associated risk factors for Ascaris lumbricoides infections. The study was conducted in three villages outside Ile-Ife, Osun state, Nigeria in May/June 2005. Stool samples (369) were processed by formol-ether concentration. Ascaris lumbricoides (12.2%) was the dominant infection. Age, father's occupation and dog ownership were identified as the significant risk factors in the minimal adequate model for A. lumbricoides. The odds of being infected with A. lumbricoides increased as the children got older. Children aged 12–17 months and 18–25 months were 8.8 and 12.4 times, respectively, more likely to harbour Ascaris than those aged 7–11 months. The odds of harbouring Ascaris for children whose families owned a dog were 3.5 times that of children whose families did not own a dog. Children whose fathers were businessmen were 0.4 times less likely to be infected with Ascaris than those whose fathers were farmers. The findings from this study suggest that many of these young children, who are at a critical stage of development, are infected with Ascaris and that the prevalence of infection with this parasite increases with age. This study has highlighted the need to incorporate preschool children into deworming programmes in endemic regions and to investigate innovative ways of delivering cost-effective deworming treatment to this high-risk age group.

A total of 142 serum specimens from Croatian children aged 3–18 years, with peripheral eosinophilia and without any clinical symptoms, were tested for the presence of Toxocara canis IgG antibodies using an enzyme-linked immunosorbent assay (ELISA) and Western blot method. The overall T. canis seropositivity rate in the samples tested was 31%. There was no statistical difference in the seroprevalence rate between boys (32.1%) and girls (29.7%, χ2 = 0.092, P = 0.761). The T. canis seropositivity varied significantly between age groups both in boys (Fisher's test P < 0.001) and girls (Fisher's test P = 0.007). The highest seroprevalence rate was found in boys aged 11–14 (42.9%) and girls aged 7–10 (44.2%). Our results showed a high seroprevalence rate of T. canis infection among children with eosinophilia. It is important that testing for toxocariasis should be included in a differential diagnosis of eosinophilia, especially in children.

Alveolar echinococcosis (AE) is endemic to Hokkaido, Japan. For the past 20 years, detection of AE among inhabitants has involved serological screening using an enzyme-linked immunosorbent assay (ELISA) followed by Western blotting (WB). Between the years 1987 and 2000, antigens targeted on 66, 55 and 30–35 kDa bands were routinely used in the WB step of AE diagnosis. However, since 2001 diagnosis has been dependent on three smaller molecular weight antigens (26–28, 18 and 7–8 kDa). Due to its higher sensitivity, this improved WB approach has been used as a confirmation step in the screening process and also for the testing of suspected AE cases in hospital outpatients. Using the improved WB technique, a total of 1745 serum samples were examined in 2001–2006 with 81 patients detected and registered with AE. Interestingly, sera from 76 of the 81 diagnosed AE patients (93.8%) demonstrated reactivity with all three antigens. However, sera from the remaining five patients (6.2%) demonstrated no reactivity with the 18 kDa antigen, even though they exhibited clearly detectable levels of reactivity with the 26–28 and 7–8 kDa bands. These results suggest that medical practitioners need to pay particular attention to the specific reactions to some different diagnostic antigens to minimize the risk of misdiagnosing AE patients. In turn, these results may also provide important diagnostic information for cystic echinococcosis (CE).

During the years 2002–2007, Icelandic freshwater snails and birds from different orders were examined for bird schistosomes. Only the snail Radix peregra and anatid birds proved to be infected. In total, 32 samples of bird schistosome cercariae from seven localities and four samples of adults of Anas platyrhynchos and Mergus serrator from two localities were used for sequencing of the internal transcibed spacer (ITS) region of rDNA. Based on the sequence and position in the phylogenetic tree, five species/genotypes of bird schistosomes were identified. Three of them correspond to the sequences in GenBank for Trichobilharzia franki, Trichobilharzia sp. JR-2007 from Anas penelope (isolates Pl7 and Pl10) and schistosomatid sp. JR-2004 from Physa fontinalis. The other two species/genotypes belong to the genus Trichobilharzia, but their further determination was not possible due to lack of data. All of these species/genotypes develop in R. peregra, probably the only suitable intermediate host species in Iceland. As T. franki and schistosomatid sp. JR-2004 were previously reported from other snail species, the findings from Iceland proved that, under some circumstances, bird schistosomes are able to adapt to a different snail species; some of them can even adapt to a snail belonging to a different gastropod family. High diversity of bird schistosomes in Iceland is probably linked with migratory flyways of birds, as several bird species from Iceland overwinter in western Europe as well as in North America.

Despite being conspicuous members of neotropical lizard communities, aspects of the life history of many teiid lizard species are poorly known, especially endoparasites infecting the genus Kentropyx. We studied seven specimens of K. calcarata collected at an Amazonian site in Mato Grosso state, Central Brazil in 2007. Four species of helminth were recovered: Oswaldocruzia sp., Piratuba digiticauda, Physaloptera retusa and Physalopteroides venancioi. Piratuba digiticauda, a body-cavity, parasite had the highest prevalence (42.9%), whereas the stomach parasites P. venancioi and P. retusa presented the highest intensity of infection and abundance, respectively. Moreover, this is the first report of Oswaldocruzia sp., P. digiticauda and P. venancioi in K. calcarata and new locality records for all nematodes were assigned.

The structure and composition of parasite communities of Mullus argentinae were analysed under two alternative hypotheses in a sample of 75 specimens caught off Mar del Plata, Argentina (38°27′S, 57°90′W). The first, based on the dominance of trophically transmitted larval parasites of low host-specificity among fish species in the region, predicts that infracommunities will be random subsets of regionally available species. The second, based on previous studies on other mullids, predicts that infracommunities will be dominated by adult digeneans. The parasite fauna of goatfishes was mainly composed of endoparasites, with metacercariae of Prosorhynchus australis accounting for most individual parasites and greatly affecting infracommunity descriptors. Its importance was reinforced by the low number of trophically transmitted larval parasites. Both hypotheses were refuted; parasite communities were not dominated either by trophically transmitted larval parasites of low host-specificity or by adult digeneans. Prosorhynchus australis was the only species displaying any degree of phylogenetic specificity. Therefore, the influence of phylogenetic factors seems to exceed that of ecological ones in determining the observed structure of infracommunities. However, it is precisely host ecology that allows P. australis to become the determinant of infracommunity structure by constraining the acquisition of other parasites. Studies aiming to determine the relative importance of evolutionary and ecological processes as structuring forces of parasite communities should take into account not only the identity and specificity of their component parasites, but also their availability in the compound community.