Showing papers in "Journal of Helminthology in 2010"

Rapid diagnostic multiplex PCR (RD-PCR) to discriminate Schistosoma haematobium and S. bovis.

Abstract: Schistosoma haematobium and S. bovis are widespread schistosome species causing human and cattle schistosomiasis, respectively, in Africa. The sympatric occurrence of these two species and their ability to infect the same Bulinus intermediate snail hosts necessitates precise methods of identification of the larval stages. A rapid diagnostic 'mulitplex' one-step polymerase chain reaction protocol (RD-PCR) was developed using cytochrome oxidase subunit 1 (COX1) mitochondrial DNA (mtDNA) to discriminate between S. haematobium and S. bovis. A single forward primer and two species-specific reverse primers were used to produce a polymerase chain reaction (PCR) fragment of 306 bp and 543 bp for S. bovis and S. haematobium, respectively. Serial dilutions were carried out on various lifecycle stages and species combinations to test the sensitivity and specificity of the primers. This RD-PCR proved highly sensitive, detecting a single larval stage and as little as 0.78 ng of genomic DNA (gDNA) from an adult schistosome, providing a cost-effective, rapid and robust molecular tool for high-throughput screening of S. haematobium and S. bovis populations. In areas where human and cattle schistosomiasis overlap and are transmitted in close proximity, this mitochondrial assay will be a valuable identification tool for epidemiological studies, especially when used in conjunction with other nuclear diagnostic markers.

Genetic variability of Haemonchus contortus (Nematoda: Trichostrongyloidea) in alpine ruminant host species.

Abstract: Genetic variability of the ovine parasite Haemonchus contortus from the Alpine area was investigated using mitochondrial DNA (nd4 gene), internal transcribed spacers 1 and 2 and microsatellites, in order to assess whether cross-transmission between domestic and wild ruminants occurs. The dataset was composed of 78 individual adult male H. contortus collected from chamois (Rupicapra r. rupicapra), roe deer (Capreolus capreolus), alpine ibex (Capra ibex ibex), domestic goat (Capra hircus) and sheep (Ovis aries) from different alpine areas. The data obtained show low host specificity and high genetic variation within H. contortus populations. The analyses indicate the presence of two mitochondrial haplotype clusters among host species and the absence of cryptic parasite species, confirming H. contortus as a generalist nematode and suggesting that parasite transmission between populations of domestic and wild ruminants normally occurs.

Diversity of metazoan parasites of the African catfish Clarias gariepinus (Burchell, 1822) as indicators of pollution in a subtropical African river system.

Abstract: The relationship between parasite species diversity and organic pollution in the upper Manyame catchment, Zimbabwe, was investigated between October 2006 and January 2007. The parasite assemblage comprised 13 species in total. Species richness in the unpolluted sites was high; in the moderately polluted sites, it was low, while in the polluted sites, only one parasite species was encountered. Component community diversity, as measured by the Shannon index (H'), decreased with increase in organic pollution. The distribution and occurrence of ectoparasites (Dolops ranarum, Lamproglena clariae, Chonopeltis sp. and Macrogyrodactylus sp.) and one endoparasite (Lytocestus sp.) were limited to the unpolluted sites, demonstrating their sensitivity to organic pollution. The prevalence of the nematodes Paracamallanus cyathopharynx, Procamallanus laevionchus and Contracaecum spp. larvae decreased along the pollution gradient, showing their high sensitivity to organic pollution. The platyhelminths Diplostomum sp. and Polyonchobothrium clarias were the most tolerant and occurred at both polluted and unpolluted sites. Proteocephalus sp. and Caryophyllaeus sp. were limited to the polluted sites, probably as a result of high abundance of oligochaetes and copepods, their intermediate hosts that thrive in sewage-enriched sediments, at the downstream sites. The observed results assume that the decrease in parasite diversity can be related to increased organic pollution. Some parasites requiring complex life histories were absent along with pollution-related disappearance of their vector hosts. Further studies should address the identification of parasite life stages that are more sensitive to pollutants.

Gastro-intestinal nematode infections in goats relative to season, host sex and age from the Kashmir valley, India

Abstract: The present study aimed to investigate the seasonal epidemiological prevalence of gastro-intestinal nematodes (GINs) of goats with respect to sex and age of the host in the Kashmir valley from 1 February 2005 to 31 January 2007. A total of 1267 goats were examined [faecal examination: 938 (year 1: 470; year 2: 468); gastro-intestinal (GIT) examination: 329 (year 1: 175; year 2: 154)]. The overall prevalence of GIN infection in these animals was 54.3% (year 1: 54.8%; year 2: 53.8%; P = 0.842). The different parasites reported with their respective prevalences (%) were: Haemonchus contortus (48.3); Bunostomum trigonocephalum (30.1); Chabertia. ovina (29.8); Ostertagia circumcincta (29.8); Nematodirus spathiger (25.2); Trichostrongylus spp. (25.1); Oesophagostomum columbianum (23.5); Trichuris ovis (19.0); and Marshallagia marshalli (16.6). The mean maximum prevalence of GIN infection (faecal examination: 75.6 +/- 0.20; GIT examination: 85.3 +/- 0.95), faecal egg counts (2552 +/- 85.7) and average worm burden (333.25 +/- 2.25) were found in the summer and they were lowest in winter (prevalence: faecal examination, 23.2 +/- 0.95; GIT examination, 12.7 +/- 0.20; faecal egg counts: 134.15 +/- 9.15; and average worm burden: 79.8 +/- 52.2), with significant differences between the seasons (P or = 0.05). Thus seasonal dynamics and age of the host animals significantly influenced the prevalence of GIN infection. The above findings will be helpful in devising the appropriate control strategies for GINs of goats reared under the traditional husbandry system in temperate agro-climatic conditions in the Kashmir valley as well as in similar climatic zones of other parts of the world.

Dirofilaria infections in working dogs in Slovakia.

Abstract: A monitoring programme aimed at the diagnosis of subcutaneous dirofilariasis and heartworm disease in working (police and military) dogs in Slovakia has been performed during the period of September 2007 to February 2008. In cooperation with the Ministry of the Interior and the Ministry of Defence, in total, 710 dogs (591 police dogs and 119 military dogs) were investigated for the presence of microfilariae in blood. All police and military dogs in active service held on the territory of Slovakia were included. Microfilariae were detected in 118 (20.0%) police dogs and 10 (8.4%) military dogs. The most infected individuals originated from southern parts of Slovakia (Trnava region 53.6% and Nitra region

Health research based on geospatial tools: a timely approach in a changing environment.

Abstract: The possibilities of disease prediction based on the environmental characteristics of geographical areas and specific requirements of the causative infectious agents are reviewed and, in the case of parasites whose life cycles involve more than one host, the needs of the intermediate hosts are also referred to. The geographical information systems framework includes epidemiological data, visualization (in the form of maps), modelling and exploratory analysis using spatial statistics. Examples include climate-based forecast systems, based on the concept of growing degree days, which now exist for several parasitic helminths such as fasciolosis, schistosomiasis, dirofilariasis and also for malaria. The paper discusses the limits of data collection by remote sensing in terms of resolution capabilities (spatial, temporal and spectral) of sensors on-board satellites. Although the data gained from the observation of oceans, land, elevations, land cover, land use, surface temperatures, rainfall, etc. are primarily for weather forecasting, military and commercial use, some of this information, particularly that from the climate research satellites, is of direct epidemiological utility. Disease surveillance systems and early-warning systems (EWS) are prime examples of academic approaches of practical importance. However, even commercial activities such as the construction of virtual globes, i.e. computer-based models of the Earth, have been used in this respect. Compared to conventional world maps, they do not only show geographical and man-made features, but can also be spatially annotated with data on disease distribution, demography, economy and other measures of particular interest.

Pig-farming systems and porcine cysticercosis in the north of Cameroon

Abstract: A survey was conducted in 150 households owning 1756 pigs in the rural areas of Mayo-Danay division in the north of Cameroon. A questionnaire survey was carried out to collect information on the pig-farming system and to identify potential risk factors for Taenia solium cysticercosis infection in pigs. Blood samples were collected from 398 pigs with the aim of estimating the seroprevalence of T. solium cysticercosis. The results showed that 90.7% of the pigs are free roaming during the dry season and that 42.7% of households keeping pigs in the rural areas have no latrine facility. Seventy-six per cent of the interviewed pig owners confirmed that members of the household used open-field defecation. Enzyme-linked immunosorbent assay (ELISA) for antigen and antibody detection showed an apparent prevalence of cysticercosis of 24.6% and 32.2%, respectively. A Bayesian approach, using the conditional dependence between the two diagnostic tests, indicated that the true seroprevalence of cysticercosis in Mayo-Danay was 26.6%. Binary logistic regression analysis indicated that a lack of knowledge of the taeniasis-cysticercosis complex and the absence of a pig pen in the household were associated with pig cysticercosis.

Methodical approaches in the identification of areas with a potential risk of infection by bird schistosomes causing cercarial dermatitis.

Abstract: Larval stages (cercariae) of schistosomatid flukes represent the causative agents of swimmer's itch (cercarial dermatitis), a waterborne allergic disease. Cercariae of bird schistosomes are the most frequently reported agent. Recent studies on parasite behaviour in mammals showed that infections by cercariae can be linked to more than skin syndromes. Despite the failure of complete development in mammals, bird schistosomes can escape from the skin and migrate transitorily in the hosts. These findings brought novel insights into the fate and potential pathogenic effect of the parasites in non-compatible hosts, including humans. Cercarial dermatitis occurs globally and recently is considered to be re-emerging; however, there are no data on the number of afflicted persons per year. This might be explained by a relatively low interest in human skin infections arising after bathing in fresh water. In addition, the real occurrence of bird schistosomes in the field is known only for a few areas. The paucity of epidemiological/biogeographical data is probably caused by difficulties associated with detection of the parasites in intermediate and definitive hosts. Therefore, based on personal experience and data available in the literature, we have summarized methodological approaches enabling the detection of bird schistosomes in various hosts and environments.

Susceptibility to praziquantel of male and female cercariae of praziquantel-resistant and susceptible isolates of Schistosoma mansoni.

Abstract: Praziquantel (PZQ) is now widely used for the treatment of human schistosomiasis. However, in recent years, there has been a growing concern about the resistance of Schistosoma to PZQ. The mechanisms of PZQ action against Schistosoma and resistance of Schistosoma to PZQ are poorly understood. Here, we report differential susceptibilities to PZQ between male and female cercariae in the PZQ-susceptible and PZQ-resistant isolates of Schistosoma mansoni, using tail loss as a measurement of PZQ action. The miracidia were collected by hatching eggs collected from faeces of infected mice. Single-sex cercaria lines were made by infecting a single Biomphalaria glabrata snail with a single miracidium. The sex of each single-sex cercaria line was identified by a direct W1-specific polymerase chain reaction (PCR) technique. Single-sex cercariae of two isolates were exposed to four different concentrations of PZQ, respectively. The tail shedding of cercariae was observed under a dissecting microscope for five time points up to 100 min after adding PZQ. The results showed that male cercariae have higher tail-shedding rates than that of female cercariae when PZQ-susceptible isolates of S. mansoni are exposed to the same concentration of PZQ. But this phenomenon was not observed in the PZQ-resistant isolates. This sexual differential resistance phenomenon of S. mansoni suggests that resistance to PZQ is induced by decreasing the PZQ susceptibility of male worms. The experiment described here may also be useful for developing tests to detect PZQ resistance in the field.

Seroprevalence of Cysticercus cellulosae and associated risk factors in free-range pigs in Kenya

Abstract: Porcine cysticercosis is an emerging zoonosis with public health and economic importance. A cross-sectional study was undertaken to investigate the disease in free-range pigs on 182 smallholder farms in Busia District, Kenya. The survey households were selected using a snowballing technique. Serum samples were obtained from 284 pigs of all ages at farm level and 37 pigs from slaughter slabs in the study area. The samples were analysed for the presence of cysticercus antigen using an antigen enzyme-linked immunosorbent assay (ELISA). A structured questionnaire was administered to determine the risk factors for porcine cysticercosis on the study farms. At pig level, the total number of pigs testing positive were 11, resulting in a seroprevalence of 4% (95% confidence interval (CI): 1.9-6.2%), while the farms with a positive pig were 9% (95% CI: 3.9-14.1%). All pigs examined in the slaughter slab survey were seronegative. The distribution of possible risk factors for porcine cysticercosis that were observed at farm level was as follows: free-range pig keeping (100%), history of human taeniosis infection in a family (51%), slaughtering of pigs at home (20%), lack of meat inspection (15%) and absence of latrines (15%). The only significant (χ 2 = 4.4, P = 0.034, odds ratio (OR) = 3.8) risk factor associated with the occurrence of cysticercosis was lack of latrines at household level. The study shows that porcine cysticercosis is prevalent in free-range pigs in Busia District, Kenya and thus control measures need to be instituted.

The effects of host size and temperature on the emergence of Echinoparyphium recurvatum cercariae from Lymnaea peregra under natural light conditions.

Abstract: 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.

Molecular and immunohistochemical studies on epidermal responses in Atlantic salmon Salmo salar L. induced by Gyrodactylus salaris Malmberg, 1957

Abstract: Various strains of Atlantic salmon exhibit different levels of susceptibility to infections with the ectoparasitic monogenean Gyrodactylus salaris. The basic mechanisms involved in this differential ability to respond to this monogenean were elucidated using controlled and duplicated challenge experiments. Highly susceptible East Atlantic salmon allowed parasite populations to reach up to 3000 parasites per host within 6 weeks, whereas less susceptible Baltic salmon never reached larger parasite burdens than 122 parasites per host during the same period. The present study, comprising immunohistochemistry and gene expression analyses, showed that highly susceptible salmon erected a response mainly associated with an increased expression of interleukin-1β (IL-1β), interferon-γ (IFN-γ), IL-10 and infiltration of CD3-positive cells in the epidermis of infected fins. Less susceptible salmon showed no initial response in fins but 3–6 weeks post-infection a number of other genes (encoding the immune-regulating cytokine IL-10, cell marker MHC II and the pathogen-binding protein serum amyloid A) were found to be up-regulated. No proliferation of epithelial cells was seen in the skin of less susceptible salmon, and IL-10 may play a role in this regard. It can be hypothesized that resistant salmon regulate the parasite population by restricting nutrients (sloughed epithelial cells and associated material) and thereby starve the parasites. In association with this ‘scorched-earth strategy’, the production of pathogen-binding effector molecules such as serum amyloid A (SAA) (or others still not detected) may contribute to the resistance status of the fish during the later infection phases.

FMRFamide-like peptides in root knot nematodes and their potential role in nematode physiology.

Abstract: FMRFamide-like peptides (FLPs) are a diverse group of neuropeptides that are expressed abundantly in nematodes They exert potent physiological effects on locomotory, feeding and reproductive musculature and also act as neuromodulators However, little is known about the specific expression patterns and functions of individual peptides The current study employed rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR) to characterize flp genes from infective juveniles of the root knot nematodes, Meloidogyne incognita and Meloidogyne minor The peptides identified from these transcripts are sequelogs of FLPs from the free-living nematode, Caenorhabditis elegans; the genes have therefore been designated as Mi-flp-1, Mi-flp-7, Mi-flp-12, Mm-flp-12 and Mi-flp-14 Mi-flp-1 encodes five FLPs with the common C-terminal moiety, NFLRFamide Mi-flp-7 encodes two copies of APLDRSALVRFamide and APLDRAAMVRFamide and one copy of APFDRSSMVRFamide Mi-fip-12 and Mm-flp-12 encode the novel peptide KNNKFEFIRFamide (a longer version of RNKFEFIRFamide found in C elegans) Mi-flp-14 encodes a single copy of KHEYLRFamide (commonly known as AF2 and regarded as the most abundant nematode FLP), and a single copy of the novel peptide KHEFVRFamide These FLPs share a high degree of conservation between Meloidogyne species and nematodes from other clades, including those of humans and animals, perhaps suggesting a common neurophysiological role which may be exploited by novel drugs FLP immunoreactivity was observed for the first time in Meloidogyne, in the circumpharyngeal nerve ring, pharyngeal nerves and ventral nerve cord Additionally, in situ hybridization revealed Mi-flp-12 expression in an RIR-like neuron and Mi-flp-14 expression in SMB-like neurons ‡ , respectively These localizations imply physiological roles for FLP-12 and FLP-14 peptides, including locomotion and sensory perception

Variation in the morphometrics of diplostomid metacercariae (Digenea: Trematoda) infecting the catfish, Clarias gariepinus in Tanzania.

Abstract: Diplostomum species are economically important worldwide due to their metacercariae which parasitize the eyes of fish, in both natural and aquaculture systems. However, their striking morphological similarity, especially at the metacercarial stage, makes species separation difficult. Three closely related diplostomid metacercariae, namely Diplostomum mashonense (type 3), Tylodelphys sp. 1 and 2 (type 1 and 2, respectively), coexist in the cranial cavity of the catfish, Clarias gariepinus from Mindu dam, Lake Victoria, Msimbazi, Ruvu and Kilombero rivers. The morphometrics of these three species were analysed by discriminant function analysis to investigate the degree of variation among the populations from the five localities sampled. The first canonical functions for all visual examination plots accounted for over 50% of the between-group variability. The observed differences were mainly from measurements associated with length, indicating that these measurements are important in the description of population characteristics. Visual examination of the samples along the canonical functions showed a clear between-population differentiation. The overall random assignment of individuals into their original groups was high (97%). These extensive morphometric variations introduce doubt about the reliability of measurements in the determination of species in these trematodes, as they may lead to misidentifications.

In vitro nematicidal activity of extracts of Canthium mannii (Rubiaceae), on different life-cycle stages of Heligmosomoides polygyrus (Nematoda, Heligmosomatidae).

Abstract: The increasing prevalence of anthelmintic-resistant strains of helminths, drug residues in animal products and high cost of conventional anthelmintics has created an interest in studying medicinal plants as an alternative source of anthelmintic. The potential nematicidal activities of four extracts from the bark of Canthium mannii (Rubiaceae) stem were investigated in vitro. Extracts were diluted in distilled water (DW) to obtain five different concentrations (1.5, 2.0, 2.5, 3.0 and 3.5 mg/ml) and put in contact with eggs and larvae of Heligmosomoides polygyrus. The different stages of the life cycle were also put in contact with the same concentration of mebendazole (MBZ, positive control). One millilitre of each extract at different concentrations and control were added to 1 ml solution containing 30–40 eggs or 10–15 larvae (L1, L2 and L3) and distributed in different Petri dishes. The eggs and larvae were incubated at 24°C and exposure times were: 48 h for un-embryonated eggs, 6 h for embryonated eggs; 2, 4, 6 and 24 h for L1 and L2 larvae, 24–48 h for infective larvae (L3), and 5 days for the larval development test (from L1 to L3). DW and 1% dimethyl sulphoxide (DMSO) were used as placebo and DMSO control, respectively. Significant effects were obtained with three of the four extracts, and differences were observed depending on the parasite stage. Cold water extract (CWE), hot water extract (HWE) and ethanol extract (ETE) inhibited embryonic development (40, 45 and 10%) and hatching of embryonated eggs (40, 85 and 80%), respectively, at 3.5 mg/ml. Only ETE killed L1 (97.18%) and L2 (92.68%) larvae of H. polygyrus after 24 h at 3.5 mg/ml and drastically reduced the production rate (6% at 3.0 and 3.5 mg/ml) of infective larvae (L3) after 5 days of incubation compared to other extracts (P < 0.05). However, the infective larvae of H. polygyrus were resistant to the effect of each of the tested products (extracts and mebendazole). These in vitro results suggested that extracts of C. mannii, used by traditional healers in Dschang, Western Region of Cameroon (Central Africa) to cure intestinal helminthiasis and abdominal pains of their patients, possess nematicidal properties. The active principles responsible for the activity could be secondary metabolites such as alkaloids and saponins present in the extracts. It is suggested that further experiments incorporating in vivo purification of extracts and toxicological investigations should be carried out.

Variation in the helminth community structure of Thrichomys pachyurus (Rodentia: Echimyidae) in two sub-regions of the Brazilian Pantanal: the effects of land use and seasonality.

Abstract: The Pantanal is a large ecosystem located in South America. This preserved area is seasonally flooded due to abundant rainfall during the summer and the subsequent overflow of the Paraguai River. In this paper, we examine the helminth community structure in the wild rodent Thrichomys pachyurus during the wet and dry seasons in two locations of the preserved and cattle ranching areas in the Southern Pantanal. We identified 12 species of helminth, and, although we did not find any differences in species richness between locations within the Pantanal, we found that richness was higher during the wet season. Helminth species were largely aggregated in both farm locations and during seasons. The most common helminth species were more abundant during the dry season than during the wet season, which may have been due to the increased habitat availability and rodent population increase. The intensity of the infection also followed the same pattern for most helminths. The trichostrongylids (Heligmostrongylus crucifer, H. almeidai and Pudica cercomysi) were dominant at both farm locations. The land use of each area was not correlated with helminth diversity. However, species composition of the helminth community of T. pachyurus differed between locations and may be correlated with environmental differences between the habitats. The seasonality of the Pantanal was highly correlated with helminth parasitism in T. pachyurus.

Parasitic castration of Buccinanops cochlidium (Gastropoda: Nassariidae) caused by a lepocreadiid digenean in San José Gulf, Argentina.

Abstract: Parasitic castration of Buccinanops cochlidium from San Jose Gulf, Argentina, caused by a lepocreadiid digenean, is reported for the first time. Rediae and ophtalmotrichocercous cercariae probably belonging to Opechona sp. were identified in the gonad and digestive gland. Opechona sp. has been reported previously parasitizing B. monilifer from a northern locality in the Argentine Sea. Overall prevalence of infection was 15.5%; it varied seasonally, rising during the warm months after the host oviposition period. Cercariae were expelled at the same time as the hatching of snail embryos (during the higher water temperature period). Rediae affected male and female snails equally, but prevalence increases along with host size. The parasite causes the complete castration of the host. Parasitized adult snails showed a reduction of penis size in comparison with healthy males. It remains to be confirmed whether the peak of cercariae emission coincides with the presence of jellyfishes and scombrid or other fishes in the area, which could act as second intermediate and definitive hosts, respectively.

Consequences of an outbreak of columnaris disease (Flavobacterium columnare) to the helminth fauna of perch (Perca fluviatilis) in the Queen Mary reservoir, south-east England.

Abstract: Parasitism of fish in fully bunded storage reservoirs has rarely been studied, while the impact of a rapid decline in a fish population on its parasite fauna is poorly understood. The present paper investigates the helminth fauna of perch (Perca fluviatilis) over a 5-year period in the Queen Mary reservoir, a large (290 ha) completely artificial water storage impoundment, which forms a unique and challenging habitat for its resident fish population. After 3 years of study, the perch population suffered a significant reduction due to a disease outbreak caused by the pathogenic bacterium Flavobacterium columnare, 'columnaris disease', and the subsequent effects on the helminth fauna over the next 2 years are evaluated. Conditions in the reservoir favour the development of large populations of zooplankton, which act as intermediate hosts for the majority of helminths in the dominant perch community. The prevalence and intensity of helminth infections showed much variation over the period prior to the perch mortality. These were likely to be due to changes in the zooplankton biomass, which was exposed to biotoxins released from periodic algal blooms and the application of copper to control them. The outbreak of F. columnare resulted in a significant decrease in the size and condition coefficient of the perch population. Changes also occurred in the composition of helminth parasites, with many species demonstrating either an increase or decrease in infection levels. These changes may be partly associated with an increase in the zooplankton biomass and altered population structure, probably caused by a decrease in fish predation pressure, which would influence the parasite population dynamics, although other factors directly associated with changes in the perch population are also likely to be influential. The long-term affects on the levels of helminth infections in the fish and associated intermediate hosts in the Queen Mary reservoir are discussed.

Anthelmintic effects of Prosopis laevigata n-hexanic extract against Haemonchus contortus in artificially infected gerbils ( Meriones unguiculatus).

Abstract: The anthelmintic effect of Prosopis laevigata (mezquite) n-hexanic extract was evaluated against Haemonchus contortus endoparasitic stages in artificially infected gerbils (Meriones unguiculatus). Prosopis laevigata leaves were collected from the Sierra de Huautla, Ecological Reserve of the Biosphere, in Morelos State, Mexico; dehydrated under shade and macerated with n-hexane for 3 days, followed by distillation for 8 h. This procedure was repeated three times and the final extract was kept at 4°C. The in vivo effect of the plant extract was evaluated in gerbils artificially infected with H. contortus. Plant extract concentration was 40 mg/ml. Three groups of gerbils were as follows: group 1 (n = 7), P. laevigata extract at 100 μl intraperitoneally (IP); group 2 (n = 6), control – Tween 20 in water at a single dose of 100 μ l IP; group 3 (n = 8) also served as a control, receiving water only, to determine the mortality due to causes other than the plant extract. An additional group of seven gerbils (group 4) was administered fenbendazole, as a positive control. Five days later the animals were euthanized and stomach and mucosa removed to quantify the nematodes. Data were analysed using the Student's t-test to compare the mean of nematodes obtained in groups 1, 2 and 3. The parasite population in the plant extract treated group 1 was reduced by 42.5% (P < 0.05) with respect to the control group 2; and when control group 3 was used for comparison the parasitic reduction was estimated as 53.11%. This study shows the in vivo anthelmintic effect of P. laevigatan-hexane extract for the first time, using gerbils as an in vivo model, with potential use in sheep.

A faecal analysis of helminth infections in wild and captive wolves, Canis lupus L., in Poland.

Abstract: One hundred and three samples of faeces of reared grey wolves from four locations (Stobnica Park and Zoological Gardens in Bydgoszcz, Wroclaw and Cracow) and twenty-six samples of faeces from two free-roaming packs of grey wolf (Canis lupus L.) in Pila (Forest Divisions: Borne Sulinowo, Czarnobor, Jastrowo) and Zielona Gora (Forest Divisions: Torzym, Krosno Odrzanskie) were collected between 2005 and 2007. Helminth eggs were detected in 78.6% of faecal samples of reared grey wolves and in 88.4% of those of free-roaming wolves. The trematode Alaria alata (80.1%) and nematodes Eucoleus aerophilus (23.1%) and Spirocerca lupi (11.5%) were only detected from wild packs of wolves and the nematodes Ancylostoma caninum (35.9%), Trichuris vulpis (15.5%) and Toxocara canis (3.9%) were only detected from reared wolves. Differences were observed in the prevalence and composition of helminth fauna between reared and wild grey wolves and our results are compared with those from studies within Poland and elsewhere in Europe.

Schistosoma mansoni infection as a predictor of severe anaemia in schoolchildren in eastern Sudan.

Abstract: A cross-sectional study was carried out to investigate the prevalence and risk factors for severe anaemia among schoolchildren in New Halfa, eastern Sudan. After taking age and gender, haemoglobin (Hb) levels were measured and all children were screened for malaria and intestinal parasitic infections, including schistosomiasis. Six hundred and forty (230 boys, 410 girls) schoolchildren aged 8-18 years were enrolled. The mean (SD) of the haemoglobin was 9.6 (1.7) mg/dl. One hundred and eleven (17.3%) and 33 (5.2%) children had Schistosoma mansoni infection and Hymenolepis nana infection, respectively. Five hundred and eighty (90.6%) of these children had anaemia (Hb < 12 g/dl), and 103 (16.0%) of them had severe anaemia (Hb < 8 g/dl). Girls (OR = 2.5, 95% CI = 1.1-5.3; P = 0.01) were at higher risk for severe anaemia in univariate and multivariate analyses. Schistosoma mansoni infections were associated with severe anaemia in univariate analyses only. Thus, there was a high prevalence of severe anaemia among these children. This needs to be investigated in more depth in the future, and more attention should be paid to the health of adolescent girls.

Philometra floridensis sp. n. (Nematoda: Philometridae) from the ovary of red drum Sciaenops ocellatus (Osteichthyes: Sciaenidae) off the coast of Florida, USA.

Abstract: A new nematode species, Philometra floridensis sp. n. (Philometridae), is described from male and female specimens found in the ovary of red drum, Sciaenops ocellatus (Linnaeus) (Sciaenidae, Perciformes), from the Gulf of Mexico off Treasure Island, Florida, USA. Based on light and scanning electron microscopy examination, the new species differs from most other gonad-infecting Philometra spp. in having a smooth gubernaculum with a distinct dorsal tooth on the distal tip. The new species is most similar to P. carolinensis Moravec, de Buron & Roumillat, 2006, but differs in length and shape of spicules. It can be distinguished from P. carolinensis and other species with unknown males, by the markedly greater body length of gravid females (up to about 100 cm). Philometra floridensis is the third valid gonad-infecting species of Philometra reported from sciaenids.

Fungus-benzimidazole interactions: a prerequisite to deploying egg-parasitic fungi Paecilomyces lilacinus and Verticillium chlamydosporium as biocontrol agents against fascioliasis and amphistomiasis in ruminant livestock.

Abstract: In vitro trials investigating the effects of albendazole and triclabendazole anthelmintics on the growth profiles of the egg-parasitic fungi Paecilomyces lilacinus and Verticillium chlamydosporium were undertaken. In addition, in vivo trials were conducted in goats fed on millet grain cultures of each fungus and administered albendazole and triclabendazole anthelmintics. In vitro growth revealed V. chlamydosporium to be more sensitive to albendazole compared to P. lilacinus. In contrast, triclabendazole had the least inhibitory effect on in vitro growth of both P. lilacinus and V. chlamydosporium. Similar to albendazole, growth of P. lilacinus was more vigorous at 0.5 ppm concentration of triclabendazole. Efforts to re-isolate these egg-parasitic fungi from faeces of goats fed on fungal millet grain cultures before and following single intraruminal administration of albendazole and triclabendazole showed that P. lilacinus was not able to be re-isolated from the faeces at any sampling period. In contrast, V. chlamydosporium was able to be re-isolated from the faeces at all of the sampling periods except for the samples taken at 8-18 h and 18-24 h after administration of albendazole and triclabendazole, respectively. Lack of fungal activity at these times coincided with peak plasma availability of anthelmintics and suggests faecal levels of drugs were also high at these times and impacted negatively on fungal viability.

Temporal variation of Meiogymnophallus minutus infections in the first and second intermediate host.

Abstract: In order to study seasonal patterns of Meiogymnophallus minutus infections in its intermediate hosts, bivalve samples were collected monthly between April 2008 and March 2009 from a high intertidal flat at Courtmacsherry Bay, Ireland. Infection rates in the first intermediate host Scrobicularia plana did not fluctuate significantly with season. Completely developed M. minutus cercariae appeared in daughter sporocysts from June and prevailed from July to October, indicating that transmission of M. minutus from its first to its second intermediate host is confined to this period of the year. All analysed individuals of the second intermediate host Cerastoderma edule were found to be infected with metacercariae. Infection levels significantly increased in September, suggesting recent cercarial invasions. Throughout the year, the majority of metacercariae were hyperinfected by the pathogenic microsporidian Unikaryon legeri. Spreading of hyperinfections was confined to spring and summer. Newly settled metacercariae were not affected by hyperparasitism and presumably retained their infectivity for half a year. Our findings suggest that the spreading of hyperinfections is correlated with higher water temperatures and that the entire metacercarial population has to rebuild every year as a consequence of hyperparasite-induced mortality.

Molecular evidence confirms that Proctoeces humboldti and Proctoeces chilensis (Digenea: Fellodistomidae) are the same species.

Abstract: Two species of Proctoeces Odhner, 1911 have been described in marine organisms from Chile: P. humboldti George-Nascimento & Quiroga (1983), parasitizing the gonads of keyhole limpets (Fissurella spp.), and P. chilensis Oliva (1984), an intestinal parasite of Sicyases sanguineus (Teleostei); both species were subsequently considered as P. lintoni Siddiqi & Cable (1960). To assist in the resolution of the taxonomic identification of Proctoeces species in marine organisms from Chile, phylogenetic studies using DNA sequences from the V4 region of the SSU rRNA gene were performed. Several specimens of P. lintoni were isolated from keyhole limpets (Fissurella spp.) and clingfish (S. sanguineus) from Bahia San Jorge (23°40'S) and Bahia Concepcion (36°50'S). Phylogenetic analyses were conducted using three different approaches: a neighbour-joining (NJ), a maximum likelihood (ML) and Bayesian inference (BI). The phylogenetic analysis confirms that specimens of Proctoeces obtained from keyhole limpets and those specimens from the clingfish are in fact the same species. We prefer to consider our specimens as Proctoeces cf. lintoni, as the morphology of Proctoeces appears to be of doubtful value and genetic information about P. lintoni Siddiqi & Cable (1960) is not available. In addition, our results strongly suggest that there are at least three species in this genus.

Parasites of Apollonia melanostoma (Pallas 1814) and Neogobius kessleri (Guenther 1861) (Osteichthyes, Gobiidae) from the Danube River in Austria.

Abstract: Two invasive fish species, the round goby Apollonia melanostoma syn. Neogobius melanostomus (Pallas 1814) and the bighead goby Neogobius kessleri (Gunther, 1861), have established a firm population in Austrian waters during the past 15 years. As there have been no records of the parasite fauna from these populations, a total of 79 specimens of A. melanostoma and 12 specimens of N. kessleri were examined for parasites between May and October 2007 from three different sampling sites from the Danube River in Austria. In total 12 parasite taxa were recovered. The protozoans Trichodina sp. and Ichthyophthirius multifiliis from the gills and skin; two crustacean species, Paraergasilus brevidigitus and Ergasilus sieboldi, from the gills; and the two monogeneans Gyrodactylus sp. and Dactylogyrus sp., from the skin and gills respectively, all occurred at low prevalence and intensities. Furthermore, cystacanths of the acanthocephalan Acanthocephalus lucii were found in the body cavity. Metacercariae of the digeneans Diplostomum sp. and Tylodelphys clavata were found in the lens of the eye and the vitreous humour, respectively. Adults of two digeneans, Nicolla skrjabini and Bunodera nodulosa, were found in the intestine. In addition, during this survey metacercariae of the Holarctic digenean Bucephalus polymorphus, encysted in the skin and fins, with prevalence up to 78%, were recorded for the first time in Austria.

Trichinella zimbabwensis in a naturally infected mammal.

Abstract: Trichinella zimbabwensis has been detected in wild and farmed Nile crocodiles (Crocodylus niloticus) and in wild monitor lizards (Varanus niloticus) of several African countries, but it has never been detected in mammals in nature, in spite of its infectivity to rodents, pigs, foxes and monkeys under laboratory conditions. The aim of this work was to describe the first detection of T. zimbabwensis in a naturally infected lion (Panthera leo) of the Kruger National Park (KNP) of South Africa. The sequence of the expansion segment V, a highly variable non-coding sequence of the large subunit ribosomal RNA of the genus Trichinella, of larvae from the lion was identical to that of larvae of T. zimbabwensis collected from a Nile crocodile originating from the same locality as the lion, suggesting a possible transmission of this parasite between mammals and reptiles. The KNP proves to be a very interesting area for parasites of the genus Trichinella since three taxa (Trichinella nelsoni, Trichinella T8 and T. zimbabwensis) circulate among the wildlife of this protected area.

Infection levels of Austrodiplostomum compactum (Digenea, Diplostomidae) metacercariae in Plagioscion squamosissimus (Teleostei, Sciaenidae) from the Nova Avanhandava reservoir, São Paulo State, Brazil

Abstract: This study was aimed at evaluating the infection levels of Austrodiplostomum compactum metacercariae in 378 specimens of Plagioscion squamosissimus ('corvina' or 'pescada branca') from the Nova Avanhandava reservoir, low Tiete River, Sao Paulo State, Brazil. High prevalence, mean intensity of infection and abundance were observed in P. squamosissimus during most of the study, with the exception of March 2004. The relative condition factor (Kn) did not differ between parasitized and non-parasitized fish. A statistically significant positive correlation was observed between host standard length and intensity of infection. The analysis of biotic and abiotic variables showed that no abiotic variable correlated with parasitic infection levels. Moreover, P. squamosissimus status was demonstrated to be unaffected by A. compactum metacercariae infection.

Tegumental surface changes in adult Paramphistomum microbothrium (Fischoeder 1901) following in vitro administration of artemether.

Abstract: The treatment of paramphistomiasis, a neglected tropical disease, has been carried out with different fasciolicidal compounds, all showing weak efficacy. Therefore, the search for alternative paramphistomicidal drugs is warranted. In the present study, the in vitro effects of artemether on adult Paramphistomum microbothrium were evaluated, for the first time, using scanning electron microscopy. After 24 h of incubation with 10 microg ml(-1) artemether, tegumental damage of both anterior and posterior ends of the fluke had occurred in the majority of the specimens examined. Sensory papillae surrounding the oral aperture were ruptured, while those at the acetabular region appeared to be sunken due to tegumental swelling. The tegumental disruption became more pronounced and both oral sucker and acetabulum were severely distorted, on increasing the concentration to 20 microg ml(-1). With higher concentration of 30 microg ml(-1), gross swellings of the body of the fluke, clearly visible to the naked eye, were observed, and damage to both oral sucker and acetabulum was so extreme that little recognizable structure remained.

Duddingtonia flagrans , Monacrosporium thaumasium and Pochonia chlamydosporia as possible biological control agents of Oxyuris equi and Austroxyuris finlaysoni

Abstract: The action of four fungal isolates of the species Duddingtonia flagrans (AC001), Monacrosporium thaumasium (NF34a) and Pochonia chlamydosporia (VC1 and VC4) on eggs of Oxyuris equi and Austroxyuris finlaysoni was evaluated in two assays (A and B). Eggs of O. equi (Test A) and A. finlaysoni (Test B) were plated on Petri dishes with 2% water-agar with grown fungal isolates and control without fungus. After 5, 10 and 15 days, 100 eggs were collected and classified according to the following parameters: type 1 effect, physiological and biochemical effect without morphological damage to the eggshell; type 2 effect, lytic effect with morphological alteration of the eggshell and embryo; and type 3 effect, lytic effect with morphological alteration of the eggshell and embryo, hyphal penetration and internal egg colonization. Pochonia chlamydosporia isolates VC1 and VC4 showed ovicidal activity for type 1, 2 and 3 effects on eggs of O. equi and eggs of A. finlaysoni. In vitro assays A and B showed that P. chlamydosporia had a negative influence on eggs of O. equi and A. finlaysoni and can be considered as a potential biological control agent of nematodes.