Search

Blastocystis sp. is a common parasite in the intestinal tract of humans and animals. The clinical diagnosis of Blastocystis sp. mainly depends on the microscopic observation of parasite, which can lead to false-negative results. An accurate and convenient diagnostic approach for Blastocystis sp. infection is crucial for effectively preventing and controlling blastocystosis. Herein, we developed a recombinase polymerase amplification (RPA) method for detecting Blastocystis sp. The results showed that the DNA amplification by RPA established in this study could be performed within 5 min at 37°C, with maximum band intensity observed at 30 min. The minimum detection limit of RPA was 100 fg μ L−1, consistent with conventional polymerase chain reaction (cPCR). Furthermore, the RPA method exhibited no cross-reactivity with 7 other non-target pathogens in the intestinal tract. Next, the newly established RPA method was used to analyse 40 fecal samples collected clinically, and the detection results were consistent with cPCR. These results corroborate that the newly developed RPA method has good sensitivity and specificity and offers the advantage of short detection times, which can be harnessed for differential diagnosis and rapid detection of Blastocystis sp. [ABSTRACT FROM AUTHOR]

Avian endoparasites play important roles in conservation, biodiversity and host evolution. Currently, little is known about the epidemiology of intestinal helminths and protozoans infecting wild birds of Britain and Ireland. This study aimed to determine the rates of parasite prevalence, abundance and infection intensity in wild passerines. Fecal samples (n = 755) from 18 bird families were collected from 13 sites across England, Wales and Ireland from March 2020 to June 2021. A conventional sodium nitrate flotation method allowed morphological identification and abundance estimation of eggs/oocysts. Associations with host family and age were examined alongside spatiotemporal and ecological factors using Bayesian phylogenetically controlled models. Parasites were detected in 20.0% of samples, with corvids and finches having the highest prevalences and intensities, respectively. Syngamus (33%) and Isospora (32%) were the most prevalent genera observed. Parasite prevalence and abundance differed amongst avian families and seasons, while infection intensity varied between families and regions. Prevalence was affected by diet diversity, while abundance differed by host age and habitat diversity. Infection intensity was higher in birds using a wider range of habitats, and doubled in areas with feeders present. The elucidation of these patterns will increase the understanding of parasite fauna in British and Irish birds. [ABSTRACT FROM AUTHOR]

Most individual fish in wild and farmed populations can be infected with parasites. Fish intestines can harbour protozoans, myxozoans and helminths, which include several species of digeneans, cestodes, nematodes and acanthocephalans. Enteric parasites often induce inflammation of the intestine; the pathogen provokes changes in the host physiology, which will be genetically selected for if they benefit the parasite. The host response to intestinal parasites involves neural, endocrine and immune systems and interaction among these systems is coordinated by hormones, chemokines, cytokines and neurotransmitters including peptides. Intestinal fish parasites have effects on the components of the enteric nervous and endocrine systems; mechanical/chemical changes impair the activity of these systems, including gut motility and digestion. Investigations on the role of the neuroendocrine system in response to fish intestinal parasites are very few. This paper provides immunohistochemical and ultrastructural data on effects of parasites on the enteric nervous system and the enteric endocrine system in several fish–parasite systems. Emphasis is on the occurrence of 21 molecules including cholecystokinin-8, neuropeptide Y, enkephalins, galanin, vasoactive intestinal peptide and serotonin in infected tissues. [ABSTRACT FROM AUTHOR]

Caryophyllideans are intestinal parasites of freshwater fishes, occupying a basal position among the 'true' tapeworms. We performed detailed cytogenetic analyses of the well-known caryophyllidean species Caryophyllaeus laticeps. For comparison, we also examined for the first time the chromosomes of Paracaryophyllaeus gotoi, a specific parasite of loaches in China. Both species showed a diploid chromosome number of 2n = 20, n = 10m. Chromomycin A3 (CMA3)/diamidino-2-phenylindole (DAPI) staining performed for the first time in the class Cestoda revealed CMA3+/DAPI− bands in the pericentromeric regions of the short arms of chromosome pair no. 7 in the karyotype of C. laticeps. Fluorescence in situ hybridization with the 18S rDNA probe confirmed the presence of a single cluster of major rDNA near the centromere on a pair of small chromosomes in both species. These findings support the hypothesis that the ancestral state in the family Caryophyllaeidae is a single interstitial cluster of major rDNA genes and thus one nucleolar organizer region per haploid genome. Our results, which we presented together with literature data plotted on a phylogenetic tree, show stability of caryophyllidean karyotypes at the genus level, but showed differences between genera without a clear phylogenetic signal. The data allowed us to at least formulate a hypothesis about the ancestral haploid chromosome number of n = 10 for the family Caryophyllaeidae and possibly for the sister family Capingentidae. In addition, we compared two populations of C. laticeps from water bodies with different levels of polychlorinated biphenyl contamination, showing a slightly increased incidence of chromosomal abnormalities at the contaminated site. [ABSTRACT FROM AUTHOR]

Durrington Walls was a large Neolithic settlement in Britain dating around 2500 BCE, located very close to Stonehenge and likely to be the campsite where its builders lived during its main stage of construction. Nineteen coprolites recovered from a midden and associated pits at Durrington Walls were analysed for intestinal parasite eggs using digital light microscopy. Five (26%) contained helminth eggs, 1 with those of fish tapeworm (likely Dibothriocephalus dendriticus) and 4 with those of capillariid nematodes. Analyses of bile acid and sterol from these 5 coprolites show 1 to be of likely human origin and the other 4 to likely derive from dogs. The presence of fish tapeworm reveals that the Neolithic people who gathered to feast at Durrington Walls were at risk of infection from eating raw or undercooked freshwater fish. When the eggs of capillariids are found in the feces of humans or dogs it normally indicates that the internal organs (liver, lung or intestines) of animals with capillariasis have been eaten, and eggs passed through the gut without causing disease. Their presence in multiple coprolites provides new evidence that internal organs of animals were consumed. These novel findings improve our understanding of both parasitic infection and dietary habits associated with this key Neolithic ceremonial site. [ABSTRACT FROM AUTHOR]

Ascaris lumbricoides, the roundworm, and Trichuris trichiura, the whipworm, are human intestinal nematode parasites; both are soil-transmitted helminths, are often placed together in an epidemiological context and both remain neglected despite high prevalence. Our understanding of parasitic disease continues to be enhanced through animal models. Despite the similarities between whipworm and roundworm, there are key differences between the two species and these have influenced the application of their respective animal models. In the case of T. trichiura, the fact that a murine equivalent, T. muris completes its life cycle in a mouse model has greatly enhanced our knowledge of whipworm biology, pathogenicity and immunology. In contrast, A. lumbricoides and its porcine equivalent, Ascaris suum, lack a rodent model in which the life cycle is completed. However, evidence continues to accumulate demonstrating that mice represent useful models of early Ascaris infection, a key stage of the life cycle. The use of mouse models for both Ascaris and Trichuris has a long history with early pioneers discovering fundamental aspects of each parasite's biology. Novel technologies and perspectives, as outlined in this special issue, demonstrate how through the prism of mouse models, we can continue to explore the similarities and differences between roundworms and whipworms. [ABSTRACT FROM AUTHOR]

Post-mortem examination of a fin whale Balaenoptera physalus stranded in the Mediterranean Sea led to the finding of Bolbosoma balaenae for the first time in this basin. In this work, we describe new structural characteristics of this parasite using light microscopy and scanning electron microscopy approaches. Moreover, the molecular and phylogenetic data as inferred from both ribosomal RNA 18S-28S and the mitochondrial DNA cytochrome oxidase c subunit 1 (cox1) for adult specimens of B. balaenae are also reported for the first time. Details of the surface topography such as proboscis's hooks, trunked trunk spines of the prebulbar foretrunk, ultrastructure of proboscis's hooks and micropores of the tegument are shown. The 18S + 28S rRNA Bayesian tree (BI) as inferred from the phylogenetic analysis showed poorly resolved relationships among the species of Bolbosoma. In contrast, the combined 18S + 28S + mtDNA cox1 BI tree topology showed that the present sequences clustered with the species of Bolbosoma in a well-supported clade. The comparison of cox1 and 18S sequences revealed that the present specimens are conspecific with the cystacanths of B. balaenae previously collected in the euphausiid Nyctiphanes couchii from the North Eastern Atlantic Ocean. This study provided taxonomic, molecular and phylogenetic data that allow for a better characterization of this poor known parasite. [ABSTRACT FROM AUTHOR]

This epidemiological study assesses the occurrence of enteric parasites in 4303 patients attended at two public hospitals in Ankara (Turkey) during 2018–2019. Microscopy was used as a screening test. Giardia duodenalis was also identified using a commercial ELISA for the detection of parasite-specific coproantigens. Giardia-positive samples by microscopy/ ELISA were confirmed by real-time PCR and characterized using a multilocus genotyping scheme. Blastocystis sp. was genotyped in a sample subset. Blastocystis sp. (11.1%, 95% CI 11.4‒14.8%) and G. duodenalis (1.56%, 95% CI 1.22‒1.96) were the most prevalent pathogens found. Cryptosporidium spp., Entamoeba histolytica and intestinal helminths were only sporadically (<0.5%) found. For G. duodenalis, sequence (n = 30) analyses revealed the presence of sub-assemblages AII (23.3%), discordant AII/AIII (23.3%) and mixed AII + AIII (6.7%) within assemblage A, and BIII (10.0%), BIV (3.3%) and discordant BIII/BIV (23.3%) within assemblage B. Two additional sequences (6.7%) were assigned to the latter assemblage but sub-assemblage information was unknown. No associations between G. duodenalis assemblages/ sub-assemblages and sociodemographic and clinical variables could be demonstrated. For Blastocystis sp., sequence (n = 6) analyses identified subtypes ST1, ST2 and ST3 at equal proportions. This is the first molecular characterization of G. duodenalis based on MLG conducted in Turkey to date. [ABSTRACT FROM AUTHOR]

Due to the efforts to control schistosomiasis transmission in tropical countries, a large proportion of individuals from endemic areas present low parasite loads, which hinders diagnosis of intestinal schistosomiasis by the Kato-Katz (KK) method. Therefore, the development of more sensitive diagnostic methods is essential for efficient control measures. The aim was to evaluate the accuracy of a real-time polymerase chain reaction (RT-PCR) to detect Schistosoma mansoni DNA in fecal samples of individuals with low parasite loads. A cross-sectional population-based study was conducted in a rural community (n = 257) in Brazil. POC-CCA® was performed in urine and feces were used for RT-PCR. In addition, fecal exams were completed by 18 KK slides, saline gradient and Helmintex techniques. The combined results of the three parasitological tests detected schistosome eggs in 118 participants (45.9%) and composed the consolidated reference standard (CRS). By RT-PCR, 117 out of 215 tested samples were positive, showing 91.4% sensitivity, 80.2% specificity and good concordance with the CRS (kappa = 0.71). RT-PCR identified 86.9% of the individuals eliminating less than 12 eggs/g of feces, demonstrating much better performance than POC-CCA® (50.8%). Our results showed that RT-PCR is a valuable alternative for the diagnosis of intestinal schistosomiasis in individuals with very low parasite loads. [ABSTRACT FROM AUTHOR]

Gastrointestinal helminth infection likely affects the gut microbiome, in turn affecting host health. To investigate the effect of intestinal parasite status on the gut microbiome, parasitic infection surveys were conducted in communities in Nan Province, Thailand. In total, 1047 participants submitted stool samples for intestinal parasite examination, and 391 parasite-positive cases were identified, equating to an infection prevalence of 37.3%. Intestinal protozoan species were less prevalent (4.6%) than helminth species. The most prevalent parasite was the minute intestinal fluke Haplorchis taichui (35.9%). Amplicon sequencing of 16S rRNA was conducted to investigate the gut microbiome profiles of H. taichui-infected participants compared with those of parasite-free participants. Prevotella copri was the dominant bacterial operational taxonomic unit (OTU) in the study population. The relative abundance of three bacterial taxa, Ruminococcus, Roseburia faecis and Veillonella parvula, was significantly increased in the H. taichui-infected group. Parasite-negative group had higher bacterial diversity (α diversity) than the H. taichui-positive group. In addition, a significant difference in bacterial community composition (β diversity) was found between the two groups. The results suggest that H. taichui infection impacts the gut microbiome profile by reducing bacterial diversity and altering bacterial community structure in the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

Alveolar echinococcosis is a neglected parasitic zoonosis caused by the metacestode Echinococcus multilocularis , which grows as a malignant tumour-like infection in the liver of humans. Albendazole (ABZ) is the antiparasitic drug of choice for the treatment of the disease. However, its effectiveness is low, due to its poor absorption from the gastro-intestinal tract. It is also parasitostatic and in some cases produces side-effects. Therefore, an alternative to the treatment of this severe human disease is necessary. In this context, the repositioning of drugs combined with nanotechnology to improve the bioavailability of drugs emerges as a useful, fast and inexpensive tool for the treatment of neglected diseases. The in vitro and in vivo efficacy of dichlorophen (DCP), an antiparasitic agent for intestinal parasites, and silica nanoparticles modified with DCP (NP-DCP) was evaluated against E. multilocularis larval stage. Both formulations showed a time and dose-dependent in vitro effect against protoscoleces. The NP-DCP had a greater in vitro efficacy than the drug alone or ABZ. In vivo studies demonstrated that the NP-DCP (4 mg kg−1) had similar efficacy to ABZ (25 mg kg−1) and greater activity than the free DCP. Therefore, the repurposing of DCP combined with silica nanoparticles could be an alternative for the treatment of echinococcosis. [ABSTRACT FROM AUTHOR]

Little is known about the types of intestinal parasites that infected people living in prehistoric Britain. The Late Bronze Age archaeological site of Must Farm was a pile-dwelling settlement located in a wetland, consisting of stilted timber structures constructed over a slow-moving freshwater channel. At excavation, sediment samples were collected from occupation deposits around the timber structures. Fifteen coprolites were also hand-recovered from the occupation deposits; four were identified as human and seven as canine, using fecal lipid biomarkers. Digital light microscopy was used to identify preserved helminth eggs in the sediment and coprolites. Eggs of fish tapeworm (Diphyllobothrium latum and Diphyllobothrium dendriticum), Echinostoma sp., giant kidney worm (Dioctophyma renale), probable pig whipworm (Trichuris suis) and Capillaria sp. were found. This is the earliest evidence for fish tapeworm, Echinostoma worm, Capillaria worm and the giant kidney worm so far identified in Britain. It appears that the wetland environment of the settlement contributed to establishing parasite diversity and put the inhabitants at risk of infection by helminth species spread by eating raw fish, frogs or molluscs that flourish in freshwater aquatic environments, conversely the wetland may also have protected them from infection by certain geohelminths. [ABSTRACT FROM AUTHOR]

Giardia duodenalis is a common intestinal parasite in humans and other mammals, and it causes major public and veterinary health problems worldwide. China is a major pig-raising country, and studies on Giardia in pigs have important public health significance. The present study was conducted to investigate the prevalence of Giardia and assess its genetic characterization. A total of 93 samples were collected from two farms in Shanghai. The presence of Giardia was determined using PCR and sequence analysis of glutamate dehydrogenase, beta-giardin and triose phosphate isomerase genes. The average prevalence of G. duodenalis infection was 26.88% (25/93) in the pigs, with 28.13% (18/64) in farm 1 vs 24.14% (7/29) in farm 2. All the PCR-positive products were successfully sequenced, and assemblage E was more prevalent. Zoonotic assemblages A and B and canine-specific assemblage C were identified in farm 1, whereas, only assemblage E was detected in farm 2. Interestingly, two pig isolates showed 100% homology with human-derived isolates from Australia and China at the bg and tpi loci respectively. Pigs infected with Giardia infect humans by polluting the environment; whether pigs are a potential environmental source of the human pathogen in China requires more epidemiological data. [ABSTRACT FROM AUTHOR]

Dientamoeba fragilis (D. fragilis) is an intestinal parasite frequently detected in humans with abdominal pain and diarrhoea, but it is also commonly found in asymptomatic subjects. Hence its clinical relevance is often disputed. The introduction of polymerase chain reaction (PCR) is a versatile and sensitive diagnostic technique for the detection of intestinal parasites, and in some Western world countries PCR has almost completely replaced microscopic diagnostics. PCR has however resulted in an increase in the number of D. fragilis -positive patients. The disputed pathogenic nature of this intestinal parasite and an apparent increase in the incidence of patients with positive PCR results have renewed the discussions between clinicians and microbiologists on how to deal with an infected patient. Moreover, treatment guidelines differ throughout the world which makes it difficult for clinicians to choose an optimal therapeutic regimen. Aim: To summarize and discuss the current knowledge on the pathogenicity, best diagnostic approach, treatment and follow-up of children and adults infected with D. fragilis. [ABSTRACT FROM AUTHOR]

Within-host interactions among coinfecting parasites are common and have important consequences for host health and disease dynamics. However, these within-host interactions have traditionally been studied in laboratory mouse models, which often exclude important variation and use unnatural host–parasite combinations. Conversely, the few wild studies of within-host interactions often lack knowledge of parasite exposure and infection history. Here we exposed laboratory-reared wood mice (Apodemus sylvaticus) that were derived from wild-caught animals to two naturally-occurring parasites (nematode: Heligmosomoides polygyrus , coccidia: Eimeria hungaryensis) to investigate the impact of coinfection on parasite infection dynamics, and to determine if the host immune response mediates this interaction. Coinfection led to delayed worm expulsion and prolonged egg shedding in H. polygyrus infections and lower peak E. hungaryensis oocyst burdens. By comparing antibody levels between wild and colony-housed mice, we also found that wild mice had elevated H. polygyrus -IgG1 titres even if currently uninfected with H. polygyrus. Using this unique wild-laboratory system, we demonstrate, for the first time, clear evidence for a reciprocal interaction between these intestinal parasites, and that there is a great discrepancy between antibody levels measured in the wild vs those measured under controlled laboratory conditions in relation to parasite infection and coinfection. [ABSTRACT FROM AUTHOR]

While some single-celled intestinal parasites are direct causes of diarrhoea and other types of intestinal pathology, the impact of other gut micro-eukaryotes on human health remains elusive. The fact that some common luminal intestinal parasitic protists (CLIPPs) have lately been found more often in healthy than in diseased individuals has fuelled the hypothesis that some parasites might in fact be protective against disease. To this end, the use of new DNA technologies has helped us investigate trans-kingdom relationships in the gut. However, research into these relationships is currently hampered by the limited data available on the genetic diversity within the CLIPPs genera, which results in limited efficacy of publicly available DNA sequence databases for taxonomic annotation of sequences belonging to the eukaryotic component of the gut microbiota. In this paper, I give a brief overview of the status on CLIPPs in human health and disease and challenges related to the mapping of intestinal eukaryotic diversity of the human gut. [ABSTRACT FROM AUTHOR]

Camelids (llama, alpaca, vicunãs, guanacos) are important for the economy of South America and Eimeria infections are an important cause of mortality in camelids. Of the six species of Eimeria in camelids, Eimeria macusaniensis , considered the most pathogenic, is distinctive; its oocysts are the largest among all Eimeria species in animals, its prepatent period is more than 1 month, and its oocysts have been found in mummies from prehistoric times. Although, E. macusaniensis gametogonic stages are found associated with enteritis in naturally infected camelids, the schizogonic stages are unknown and clinical disease has been reported in some camelids with no oocysts in feces. Described herein are morphological details of gametogonic development and oocyst formation of E. macusaniensis in a naturally infected llama (Lama lama), solely infected with this parasite. Microgamonts, macrogamonts and oocysts were located in large (up to 300 µ m diameter) parasitophorous vacuoles of enterocytes in the ileum. Schizonts were not found. Review of previous reports suggests that multinucleated microgamonts have been mistaken for schizonts. Gametogonic development described in the present study can serve as a guide for differential diagnosis of Eimeria species in the histological sections of intestines. [ABSTRACT FROM AUTHOR]

For the majority of intestinal parasites, real-time PCR-based diagnosis outperforms microscopy. However, the data for Trichuris trichiura have been less convincing and most comparative studies have been performed in populations with low prevalence. This study aims to improve detection of T. trichuria DNA in human stool by evaluating four sample preparation methods. Faecal samples (n = 60) were collected at Flores island, Indonesia and examined by microscopy. Aliquots were taken and a bead-beating procedure was used both on directly frozen stool and on material preserved with 96% ethanol. PCR on frozen samples showed 40% to be positive for T. trichiura, compared with 45% positive by microscopy. The percentage positive increased when using ethanol preservation (45·0%), bead-beating (51·7%) and a combination (55·0%) and all three methods showed significantly higher DNA loads. The various procedures had a less pronounced effect on the PCR results of nine other parasite targets tested. Most prevalent were Ascaris lumbricoides (≈60%), Necator americanus (≈60%), Dientamoeba fragilis (≈50%) and Giardia lamblia (≈12%). To validate the practicality of the procedure, bead-beating was applied in a population-based survey testing 910 stool samples. Findings confirmed bead-beating before DNA extraction to be a highly efficient procedure for the detection of T. trichiura DNA in stool. [ABSTRACT FROM AUTHOR]

While it is known that intestinal parasite communities vary in their composition over time, there is a lack of studies addressing how variation in component communities (between-hosts) manifests in infracommunities (within-host) during the host lifespan. In this study, we investigate the changes in the intestinal parasite infracommunities in wild-living rufous mouse lemurs (Microcebus rufus) from Ranomafana National Park in southeastern Madagascar from 2010 to 2012. We used high-throughput barcoding of the 18S rRNA gene to interrogate parasite community structure. Our results show that in these nematode communities, there were two frequently occurring putative species and four rarer putative species. All putative species were randomly distributed over host individuals and they did not occur in clear temporal patterns. For the individuals caught in at least two different years, there was high turnover of putative species and high variation in fecal egg counts. Our study shows that while there was remarkable variation in infracommunities over time, the component community was relatively stable. Nevertheless, the patterns of prevalence varied substantially between years in each component community. [ABSTRACT FROM AUTHOR]

For many years PCR- and other DNA-based methods of pathogen detection have been available in most clinical microbiology laboratories; however, until recently these tools were not routinely exploited for the diagnosis of parasitic infections. Laboratories were initially reluctant to implement PCR as incorporation of such assays within the algorithm of tools available for the most accurate diagnosis of a large variety of parasites was unclear. With regard to diagnosis of intestinal parasitic infections, the diversity of parasites that one can expect in most settings is far less than the parasitological textbooks would have you believe, hence developing a simplified diagnostic triage is feasible. Therefore the classical algorithm based on population, patient groups, use of immuno-suppressive drugs, travel history etc. is also applicable to decide when to perform and which additional techniques are to be used, if a multiplex PCR panel is used as a first-line screening diagnostic. [ABSTRACT FROM PUBLISHER]

The cellular mucosal and systemic effectors of gilthead sea bream (GSB) (Sparus aurata) involved in the acute immune response to the intestinal parasite Enteromyxum leei were studied in fish experimentally infected by the anal route. In the intestinal inflammatory infiltrates and in lymphohaematopoietic organs (head kidney and spleen) of parasitized fish, the number of plasma cells, B cells (IgM immunoreactive) and mast cells (histamine immunoreactive) were significantly higher, whereas the number of acidophilic granulocytes (G7 immunoreactive) decreased, compared with non-parasitized and unexposed fish. These differences were stronger at the posterior intestine, the main target of the parasite, and no differences were found in the thymus. In non-parasitized GSB, the percentage of splenic surface occupied by melanomacrophage centres was significantly higher. These results suggest that the cellular response of GSB to E. leei includes proliferation of leukocytes in lymphohaematopoietic organs and recruitment into intestines via blood circulation involving elements of innate and adaptive immunity. Acidophilic granulocytes and mast cells presented opposite patterns of response to the parasite infection, with an overall depletion of the former and an increased amount of the latter. Some differences between both cell types were also detected in regard to their granule density and cell morphology. [ABSTRACT FROM AUTHOR]

Two new microsporidia, Anostracospora rigaudi n. g., n. sp., and Enterocytospora artemiae n. g., n. sp. infecting the intestinal epithelium of Artemia parthenogenetica Bowen and Sterling, 1978 and Artemia franciscana Kellogg, 1906 in southern France are described. Molecular analyses revealed the two species belong to a clade of microsporidian parasites that preferentially infect the intestinal epithelium of insect and crustacean hosts. These parasites are morphologically distinguishable from other gut microsporidia infecting Artemia. All life cycle stages have isolated nuclei. Fixed spores measure 1·3×0·7 μm with 5–6 polar tube coils for A. rigaudi and 1·2×0·9 μm with 4 polar tube coils for E. artemiae. Transmission of both species is horizontal, most likely through the ingestion of spores released with the faeces of infected hosts. The minute size of these species, together with their intestinal localization, makes their detection and identification difficult. We developed two species-specific molecular markers allowing each type of infection to be detected within 3–6 days post-inoculation. Using these markers, we show that the prevalence of these microsporidia ranges from 20% to 75% in natural populations. Hence, this study illustrates the usefulness of molecular approaches to study prevalent, but cryptic, infections involving microsporidian parasites of gut tissues. [ABSTRACT FROM PUBLISHER]

The population dynamics of Ascaridia galli was studied in 70 ISA Brown layer pullets, 42 of them were each experimentally infected with 500 embryonated A. galli eggs and 28 chickens were kept as uninfected controls. Six chickens from the infected group and 4 from the control group were necropsied at 3, 7, 10, 14, 21, 28 and 42 days post-infection (d.p.i.). The mean worm recovery varied from 11–20% of the infection dose with the highest recovery at 3 d.p.i. and the lowest at 21 and 42 d.p.i. (P < 0·05). More larvae were recovered from the intestinal wall than from the content (P < 0·0001) and intestinal content larvae were longer than those from the wall (mean length 1·6 and 1 mm, respectively, P < 0·0001). Although larvae were growing over time, a population of small-sized larvae (length < 1 mm) was recovered at all d.p.i. During the first week of infection most of the larvae were located in the anterior half of the jejunoileum but they moved posteriorly with the age of infection. Thus, a subpopulation of larvae mainly in the lumen grew with time while another subpopulation remained small and associated with the mucosa. During the infection both subpopulations moved to a more posterior localization in the gastrointestinal (GI) tract. [ABSTRACT FROM PUBLISHER]

Mucosal mast cells (MMC) play a crucial role in the expulsion of Strongyloides ratti adults from the small intestine of mice. We reported the large intestinal parasitism of S. ratti in rats, and there has been no report on MMC in the large intestine of the natural host. We studied kinetics of MMC, together with eosinophils, in the upper and lower small intestines, caecum and colon of infected rats. Two distinct phases of mastocytosis were revealed: one in the upper small intestine triggered by stimulation of ‘ordinary’ adults, and the other in the colon stimulated by ‘immune-resistant’ adults that started parasitizing the colon around 19 days post-infection. In all 4 intestinal sites, the MMC peaks were observed 5–7 days after the number of adult worms became the maximum and the height of MMC peaks appeared to be dependent on the number of parasitic adults, suggesting an important role played by worms themselves in the MMC buildup. [ABSTRACT FROM AUTHOR]

Cyathostomins are the most prevalent equine intestinal parasites and resistance has been reported in these nematodes against all 3 licensed anthelmintic classes. Strategies need to be developed that are less dependent upon drugs and more reliant on management-based control. To develop these we need to understand natural transmission patterns better. Here, we analysed longitudinal fecal egg count (FEC) data from 5 pony populations used for conservation purposes. We tested how egg excretion varied amongst populations and individuals, and how this was affected by age and climate. There was evidence for consistency in FECs over time at the individual level; this was generally weak and accounted for <10% of the total variance. Animals <5 years old had higher FECs and there was profound seasonal variation in FECs, with highest levels recorded in spring/summer. Effects of monthly temperature and rainfall explained most, but not all, of the observed seasonal variation and associations between climate measures and FECs were stronger in younger versus adult animals. One population was occasionally treated with anthelmintics and analysis of this population suggested that treatment substantially altered the seasonal dynamics. This paper highlights the variability in strongyle egg excretion amongst individuals and the factors involved in this variation. [ABSTRACT FROM PUBLISHER]

Strongyloides ratti (Nagoya strain) is unique in that a portion of adults parasitizing the small intestine withstands ‘worm expulsion’, which starts at around day 8 post-infection (p.i.) by host immunity, and establishes in the large intestine after day 19 p.i. To investigate the mechanism, adults obtained from the small intestine at day 7 or 19 p.i. were transplanted into the colon of infection-primed immune rats. Adults obtained at day 7 p.i. were rejected quickly, whereas those obtained at day 19 p.i. could establish infection. Moreover, the body length and the number of intrauterine eggs increased in the large intestine. In a separate experiment, large intestinal parasitism was abolished by the treatment of host rats with an anti-oxidant, butylated hydroxyanisole. These results indicate that small intestinal adults between days 7 and 19 p.i. acquired the ability to parasitize the large intestine of immune rats, and that free radicals produced by the host may have played a significant role in the process. [ABSTRACT FROM PUBLISHER]

Objective: Numerous studies have revealed the presence of oxidative stress in parasitic infections. However, such studies were lacking in the Malaysian population. Previously, we have provided evidence that oxidative stress is elevated in Malaysians infected with intestinal parasites. Stool examinations revealed that about 47·5% of them were infected with the polymorphic protozoa, Blastocystis hominis. However, they were found to have mixed infection with other intestinal parasites. Methodology: Therefore, in order to investigate the role of B. hominis alone in affecting oxidative stress status, here we compared the levels of oxidative stress biomarkers in urine and blood samples between uninfected and B. hominis-infected rats. Results: Infected rats exhibited elevated levels of oxidative indices namely advanced oxidative protein products (AOPP), hydrogen peroxide (H2O2) and lipid hydroperoxide (LHP) indicating that their overall oxidative damage level was higher. Ferric reducing antioxidant power (FRAP) was elevated at the initial stage of infection but decreased significantly during the last week of study duration suggesting that the antioxidant status of the host may be overwhelmed by oxidative damage. Conclusion: To date, this is the first comprehensive in vivo study to provide evidence for Blastocystis infection to correlate with significant oxidative burst leading to oxidative stress. [ABSTRACT FROM AUTHOR]

Faecal samples from 163 captive and semi-captive individuals, 61 samples from wild individuals and 38 samples from captive groups of Bornean orangutans (Pongo pygmaeus) in Kalimantan, Indonesia, were collected during one rainy season (November 2005-May 2006) and screened for intestinal parasites using sodium acetate-acetic acid-formalin-concentration (SAFC), sedimentation, flotation, McMaster- and Baermann techniques. We aimed to identify factors influencing infection risk for specific intestinal parasites in wild orangutans and individuals living in captivity. Various genera of Protozoa (including Entamoeba, Endolimax, Iodamoeba, Balantidium, Giardia and Blastocystis), nematodes (such as Strongyloides, Trichuris, Ascaris, Enterobius, Trichostrongylus and hookworms) and one trematode (a dicrocoeliid) were identified. For the first time, the cestode Hymenolepis was detected in orangutans. Highest prevalences were found for Strongyloides (individuals 37%; groups 58%), hookworms (41%; 58%), Balantidium (40%; 61%), Entamoeba coli (29%; 53%) and a trichostrongylid (13%; 32%). In re-introduction centres, infants were at higher risk of infection with Strongyloides than adults. Infection risk for hookworms was significantly higher in wild males compared with females. In groups, the centres themselves had a significant influence on the infection risk for Balantidium. Ranging patterns of wild orangutans, overcrowding in captivity and a shift of age composition in favour of immatures seemed to be the most likely factors leading to these results. [ABSTRACT FROM AUTHOR]

The intestinal parasite community of Arctic foxes (Vulpes lagopus) on the Svalbard archipelago in the High Arctic was investigated in relation to the abundance and distribution of intermediate hosts. Five species of cestodes (Echinococcus multilocularis, Taenia crassiceps, Taenia polyacantha, Taenia krabbei and Diphyllobothrium sp.), ascaridoid nematodes and one unidentified acanthocephalan species were found. The cestodes E. multilocularis, T. crassiceps and T. polyacantha all showed a decreasing prevalence in the fox population with increasing distance from their spatially restricted intermediate host population of sibling voles (Microtus levis). In addition, the prevalence of E. multilocularis in a sample from the vole population was directly related to the local vole abundance. The cestode T. krabbei uses reindeer as intermediate host, and its prevalence in female foxes was positively related to the density of reindeer (Rangifer tarandus platyrhyncus). Finally, the prevalence of the ascaridoid nematodes also decreased with increasing distance from the vole population, a finding that is consistent with the idea that voles are involved in transmission, most likely as paratenic hosts. The prevalence of the remaining species (Diphyllobothrium sp. and an unidentified acanthocephalan) was very low. We conclude that the distribution and abundance of intermediate host structure the gastrointestinal parasite community of the Arctic fox on the Svalbard archipelago. [ABSTRACT FROM AUTHOR]

SUMMARYOxidative stress has been implicated as an important pathogenic factor in the pathophysiology of various life-threatening diseases such as cancer, cardiovascular diseases and diabetes. It occurs when the production of free radicals (generated during aerobic metabolism, inflammation, and infections) overcome the antioxidant defences in the body. Although previous studies have implied that oxidative stress is present in serum of patients with parasitic infection there have been no studies confirming oxidative stress levels in the Malaysian population infected with intestinal parasites. Three biochemical assays namely hydrogen peroxide (H2O2), lipid peroxidation (LP) and advanced oxidative protein product (AOPP) assays were carried out to measure oxidative stress levels in the urine of human subjects whose stools were infected with parasites such as Blastocystis hominis, Ascaris, Trichuris, hookworm and microsporidia. The levels of H2O2, AOPP and LP were significantly higher (P<0?001, P<0?05 and P<0?05 respectively) in the parasite-infected subjects (n=75) compared to the controls (n=95). In conclusion, the study provides evidence that oxidative stress is elevated in humans infected by intestinal parasites. This study may influence future researchers to consider free radical-related pathways to be a target in the interventions of new drugs against parasitic infection and related diseases. [ABSTRACT FROM AUTHOR]