Showing papers in "Journal of Parasitology in 2016"
TL;DR: Results showed that chronic T. gondii infection communication among immune cells promotes neuroinflammation through cytokine networks and induces pathological progression of AD in the mice brain, whereas the presence of neuroanatomical Toxoplasma tissue cysts in the brain could also affect the behavioral functions in T. Gondii–infected mice.
Abstract: This study tests the hypothesis that in chronic Toxoplasma gondii infection communication among immune cells promotes neuroinflammation through cytokine networks and potentiate cognitive impairments in BALB/c mice with Alzheimer's disease (AD). The animal model of Toxoplasma infection was established by the intraperitoneal inoculation of 20–25 tissue cysts from the Tehran strain of T. gondii. We injected amyloid-beta 1–42 peptide (Aβ1–42, 1 and 2 μl) into the hippocampus of BALB/c mice to establish an animal model of AD. The behavioral experiments such as spatial learning and memory were performed using the Morris water maze test. The mRNA levels of TNF-α, IL-1β, IFN-γ, and inducible nitric oxide synthase (iNOS) were examined by real-time PCR. We found that T. gondii infection caused AD-like symptoms and impaired learning and memory functions of the infected BALB/c mice. We also found that in Toxoplasma infection + Aβ1–42 (1 μl) group, T. gondii infection could potentiate AD in infected mice rece...
42 citations
TL;DR: Molecularly link the cercaria, metacercari, and adult stage of the life cycle of A. ostrowskiae from the brain and eyes of several freshwater fish to identify the snail host for this parasite.
Abstract: Ocular diplostomiasis is caused by trematode species in the family Diplostomidae, specifically those in the genera Austrodiplostomum, Diplostomum, and Tylodelphys. Diplostomid trematodes are globally distributed parasites of fish. Heavy infections of diplostomids that parasitize the eyes of fish can result in acute mortality while chronic infections are often characterized by impaired vision or blindness. In the southeastern United States, commercial catfish production is threatened by piscivorous birds and the many trematode species that parasitize them. The life cycles typically involve a piscivorous avian definitive host, a mollusk first intermediate host, and a fish second intermediate host. A survey of parasites infecting the snail host Biomphalaria havanensis (= B. obstructa ) in catfish production ponds was undertaken. Snails were collected from 2 separate ponds during the summer of 2014 and observed for the release of trematode cercariae. A total of 1,740 snails were collected. Three distinct longifurcate pharyngeate cercariae were observed and these cercariae were characterized morphologically and molecularly. Sequencing of ∼4,200 base pairs (bp) of the nuclear ribosomal genes and ∼450 bp of the mitochondrial cytochrome c oxidase gene revealed 3 genetically distinct species. One morphotype shared 99-100% sequence identity with metacercariae from the aqueous and vitreous humors of gizzard shad Dorosoma cepedianum and channel catfish Ictalurus punctatus as well as an adult trematode, Austrodiplostomum ostrowskiae, a parasite of the double-crested cormorant Nannopterum auritus. The remaining 2 cercariae morphotypes shared 99-100% sequence identity with an unidentified Tylodelphys sp. and Austrodiplostomum sp. metacercaria from the brain and eyes of several freshwater fish. Herein we molecularly link the cercaria, metacercaria, and adult stage of the life cycle of A. ostrowskiae, identifying the snail host for this parasite, in addition to providing notes on 2 cercariae representing 2 other diplostomids.
35 citations
TL;DR: An overview of all published 18S rRNA sequence data for haemogregarines suggests that any taxonomic changes now would be premature, and type species need to be assessed, sampling across hosts improved, and multiple genes employed prior to taxonomic alterations.
Abstract: Haemogregarines are a group of apicomplexan parasites composed of 3 families that infect a wide range of hosts. Many species within these families have been subjected to reclassifications and reassignments, especially because the use of molecular tools to estimate their phylogenetic relationships became more widespread. The 18S rRNA gene has been the only widely used gene for studying the diversity of haemogregarines and recent phylogenetic analyses of this gene have indicated incongruences with the current taxonomy, such that a new genus Bartazoon has recently been proposed. To investigate the current taxonomic situation further, we conducted an overview of all published 18S rRNA sequence data for haemogregarines. We highlight that our understanding of the real diversity and phylogenetic relationships of haemogregarines is still limited, which undermines the proposed systematic revision. Notably all the molecular evidence comes from a single gene, and many studies have shown that single-gene trees often do not reflect species trees. Combined with doubts over the relationships of Hemolivia, the recent identification of a new lineage that could also warrant creation of a new genus, and issues with the type species for Hepatozoon, we suggest that any taxonomic changes now would be premature. In our opinion, type species need to be assessed, sampling across hosts improved, and multiple genes employed prior to taxonomic alterations. Otherwise taxonomic instability will be likely.
35 citations
TL;DR: Results show that an ortholog of the archetypal, single-copy, anticoagulant hirudin is present in at least 2 of 3 species examined, corroborating the notion of a single origin of blood feeding in the ancestral leech.
Abstract: One of the recalcitrant questions regarding the evolutionary history of clitellate annelids involves the feeding preference of the common ancestor of extant rhynchobdellid (proboscis bearing) and arhynchobdellid (jaw bearing) leeches. Whereas early evidence, based on morphological data, pointed towards independent acquisitions of blood feeding in the 2 orders, molecular-based phylogenetic data suggest that the ancestor of modern leeches was a sanguivore. Here, we use a comparative transcriptomic approach in order to increase our understanding of the diversity of anticoagulation factors for 3 species of the genus Placobdella, for which comparative data have been lacking, and inspect these in light of archetypal anticoagulant data for both arhynchobdellid and other rhynchobdellid species. Notwithstanding the varying levels of host specificity displayed by the 3 different species of Placobdella, transcriptomic profiles with respect to anticoagulation factors were largely similar —this despite the ...
32 citations
TL;DR: The isolates of Euclinostomum obtained in this study form a single, monophyletic group separate from recently published data from Euclinstomum sp.
Abstract: Metacercariae of species of Euclinostomum have been found encysted in kidney, liver, and muscles of several fish species, while adults occur in the mouth, pharynx, larynx, trachea, and upper esophagus of fish-eating birds. The aim of this work was to gather molecular and morphological data from the type species, Euclinostomum heterostomum, as a starting point for needed revisions of the genus. Metacercariae were collected from cichlids in Lake Kinneret, Israel, and all were identified as E. heterostomum based on morphology. This identification was further confirmed by principal components analyses that revealed no partitions in morphometric resemblance, indicating that the material represents a single species, and that the specimens were morphometrically similar to other descriptions of E. heterostomum. In phylogenetic analysis of concatenated partial internal transcribed spacer 1 and 2, 5.8S rDNA, and partial cytochrome c oxidase I barcode sequences, the isolates of Euclinostomum obtained in thi...
28 citations
TL;DR: The phylogenetic analysis indicates 2 distinct clades of Cytauxzoon in felids, with all of the sequences clustering with sequences of Cynaxzoon sp./CytauxZoon manul from Palaearctic felids.
Abstract: Parasitic protists of the genus Cytauxzoon are detected in a wide range of wild and domestic felids. Bobcats are a confirmed reservoir of Cytauxzoon felis in North America while domestic cats are susceptible hosts suffering from severe or fatal illness. Cytauxzoon infections are mainly reported from American felids and, recently, several sub-clinical and clinical findings were reported from European, Asian, and African felids. In 2014, the collection of organs of 4 Eurasian lynx and 12 wild cats from 11 Romanian localities was carried out to determine the prevalence and genetic diversity of Cytauxzoon spp. We detected an overall high prevalence of 62.5% in both species of wild felids; 50% in wild cats and 100% in Eurasian lynx. The phylogenetic analysis indicates 2 distinct clades of Cytauxzoon in felids, with all of our sequences clustering with sequences of Cytauxzoon sp./Cytauxzoon manul from Palaearctic felids. Further studies, development of new genetic markers, and experimental transmission studies are required for clarifying the taxonomy and life cycle of feline Cytauxzoon in the Old World.
28 citations
TL;DR: Phylogenetic analysis of the D1–D3 domains of the nuclear large subunit ribosomal DNA revealed that Baracktrema and Unicaecum share a recent common ancestor and form a clade sister to the freshwater turtle blood fluke of Spirorchis, paraphyletic Spirhapalum, and Vasotrema and that, collectively, these flukes were sister to all other tetrapod blood flukes.
Abstract: Baracktrema obamai n. gen., n. sp. infects the lung of geoemydid turtles (black marsh turtle, Siebenrockiella crassicollis [type host] and southeast Asian box turtle, Cuora amboinensis) in the Malaysian states of Perak, Perlis, and Selangor. Baracktrema and Unicaecum Stunkard, 1925 are the only accepted turtle blood fluke genera having the combination of a single cecum, single testis, oviducal seminal receptacle, and uterine pouch. Baracktrema differs from Unicaecum by having a thread-like body approximately 30−50× longer than wide and post-cecal terminal genitalia. Unicaecum has a body approximately 8−12× longer than wide and terminal genitalia that are anterior to the distal end of the cecum. The new genus further differs from all other accepted turtle blood fluke genera by having a cecum that is highly convoluted for its entire length, a spindle-shaped ovary between the cirrus sac and testis, a uterine pouch that loops around the primary vitelline collecting duct, a Laurer's canal, and a dorsa...
24 citations
TL;DR: Although both Giardia assemblages A and B were identified in children and adults,assemblage A infected younger children more frequently and was more closely related to severe clinical manifestations than assemblage B.
Abstract: Giardia duodenalis is considered the most common intestinal parasite in humans worldwide. Children are especially affected, with more severe consequences than adults. The present study was designed to determine the distribution of assemblages A and B Giardia infection in children and adults, with the use of light microscopy and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) as diagnostic procedures, and to investigate its associations with clinical and epidemiological data collected from children and adult groups. This cross-sectional study was conducted from October 2012 to October 2013 by collecting fecal samples from 200 children and 200 adults complaining of diarrhea. Samples were subjected to parasitological examination by direct wet smear and formol-ether methods. Genotyping of G. doudenalis samples was conducted by PCR-RFLP analysis. Giardia duodenalis infection caused by assemblages A and B was identified in 60 samples, 34 from children and 26 from adults. Assemblage B was detected in 38 patients (63.34%), and assemblage A was detected in 22 patients (36.66%). Assemblage A was significantly more frequent in children with age range 2-8 yr, and assemblage B was higher in children with age range 6-16 yr old. Diarrhea frequency/day and recurrences per month affected patients infected with assemblage A (P value < 0.001) more frequently. Children infected with assemblage A presented significantly more severe diarrhea and dehydration than those infected with assemblage B (P value < 0.001). Although both Giardia assemblages A and B were identified in children and adults, assemblage A infected younger children more frequently and was more closely related to severe clinical manifestations than assemblage B.
24 citations
TL;DR: The phylogenetic relationships of Cucullanidae were explored using near-complete sequences of the 18S rDNA (rRNA gene) and showed that all aspects of the conventional classification of Seuratoidea and its taxa should be scrutinized by even more extensive sampling across hosts and habitats.
Abstract: The phylogenetic relationships of Cucullanidae were explored using near-complete sequences of the 18S rDNA (rRNA gene). Sequences (1,750–1,760 bp) were obtained from 7 species of Cucullanidae belonging to 3 genera, Cucullanus (2 spp.), Dichelyne (2 spp.), Truttaedacnitis (3 spp.), and 1 species of Quimperiidae (Paraseuratum sp.). These sequences were aligned with those of 128 other nematode species available in GenBank, including 3 other cucullanids (Dichelyne mexicanus, Cucullanus robustus, and Cucullanus baylisi) and 2 non-cucullanid seuratoids (Paraquimperia africana, and Linstowinema sp.). Bayesian (BPP) and maximum likelihood (ML) analyses of 2 different datasets strongly supported a monophyletic Cucullanidae. Bayesian analysis placed this family as the sister group to a clade containing species of Diplogasterida, Strongylida, Rhabditida, and Tylenchida with very strong support. Neither BPP nor ML analyses recovered a close relationship of Cucullanidae to Ascaridida. None of the 3 non-cucu...
24 citations
TL;DR: Genotyping of T. gondii was performed by multiplex nested polymerase chain reaction restriction fragment length polymorphism (Mn-PCR-RFLP) in DNA obtained from the lungs of experimentally infected mice, the hearts of naturally infected free-range chickens, and human blood samples of newborns with congenital toxoplasmosis.
Abstract: Genotyping of Toxoplasma gondii is traditionally performed using DNA obtained from tachyzoites after isolation by bioassay in mice. In this study, genotyping of T. gondii was performed by multiplex nested polymerase chain reaction restriction fragment length polymorphism (Mn-PCR-RFLP) in DNA obtained from the lungs of experimentally infected mice, the hearts of naturally infected free-range chickens, and human blood samples of newborns with congenital toxoplasmosis. The efficiency of Mn-PCR varied according to the marker. We obtained complete genotypes of all of the mice lung samples. In chickens, total or partial genotyping was performed on all of the 15 samples. Two complete genotypes were obtained, including one identified for the first time, and another previously described in different hosts including dogs, cats, and humans. In blood from infants, partial genotypes were obtained in 8 of the 12 samples. Mouse bioassay is the most efficient method to obtain DNA from T. gondii, but direct tissu...
23 citations
TL;DR: The results show that geckos of Tarentola spp.
Abstract: Hemogregarines are the most-commonly reported hemoparasites in reptiles. In this work we analyzed samples from 572 individuals of 6 species of the wall gecko genus Tarentola from European and African countries adjacent to the Mediterranean Sea as well as from the Macaronesian islands. Screening was done using hemogregarine-specific primers for the 18S rRNA gene. Positive amplifications were sequenced so that the diversity of the hemogregarines from these hosts could be assessed within a phylogenetic framework. The results from the phylogenetic analysis showed that within Tarentola, the detected parasites are comprised of at least 4 distinct main lineages of Hepatozoon spp. In clades A and B, the new sequences clustered closely together with the ones previously known from individuals of the genus Tarentola and other species of geckos but also with those from other vertebrate host groups including skinks, snakes, iguanids, and rodents. Clade C included a sample from Tarentola angustimentalis of ...
TL;DR: Results demonstrate that L. infantum is able to penetrate into the brain parenchyma, either alone or in association to other zoonotic pathogens.
Abstract: The aims of this study were to investigate the presence of Leishmania infantum and possible co-infection with Anaplasma platys, Babesia vogeli, Ehrlichia canis, and Toxoplasma gondii in the brain of 24 dogs naturally infected by L. infantum. A total of 24 mongrel adult dogs (22 clinically affected, 2 with neurological signs, and 2 subclinically infected) aged between 2 and 5 yr, naturally infected by visceral leishmaniasis, were selected. Fragments from meninges, frontal cortex, thalamus, cerebellum, and choroid plexus of the lateral ventricles and fourth ventricle were collected, mixed, and tested by real-time polymerase chain reaction (qPCR). Leishmania infantum DNA was detected in 95.8% (23/24) of the infected dogs, including the subclinically infected. A total of 14/24 (58.3%) dogs were co-infected by E. canis and L. infantum, 4/24 (16.7%) were co-infected by E. canis, B. vogeli, and L. infantum, 2/24 (8.3%) were co-infected by B. vogeli and L. infantum, and 1/24 (4.2%) dog was co-infected by...
TL;DR: It is found that S. solidus eggs, derived from the in vitro culture of 3 different plerocercoids, developed normally in salinities of up to 12.5‰, but above this egg viability dropped rapidly, and no egg hatching was observed at salinITIES above 20‰.
Abstract: Schistocephalus solidus plerocercoids commonly infect three-spined stickleback Gasterosteus aculeatus populations in brackish and freshwaters, but infections are typically absent from marine populations. Here we provide an experimental test of the salinity tolerance of S. solidus eggs, to determine the role of salinity in limiting the distribution of infection in coastal zones. We find that S. solidus eggs, derived from the in vitro culture of 3 different plerocercoids, developed normally in salinities of up to 12.5‰, but above this egg viability dropped rapidly, and no egg hatching was observed at salinities above 20‰. Our results are consistent with the distribution of infections in natural stickleback populations and add resolution to previous descriptive observations on salinity tolerance in S. solidus. They also demonstrate that S. solidus presents a novel disease challenge to marine populations of three-spined sticklebacks entering brackish and freshwater environments.
TL;DR: The study demonstrates the value of an integrative taxonomy approach to address the apparently complicated systematics of the allocreadiids and erected two new taxa to reflect these results.
Abstract: This study investigates the systematics of Paracreptotrema Choudhury, Perez-Ponce de Leon, Brooks and Daverdin, 2006 using morphological data (stained whole mounts and scanning electron microscopy) and partial sequences of the 28S ribosomal rRNA gene, obtained from freshly collected material. In total, 484 specimens representing 4 species, i.e., Paracreptotrema blancoi (157), Paracreptotrema profundulusi (12), Paracreptotrema rosenthali (8), and Paracreptotrema blancoi sensu Salgado-Maldonado et al. (2011) (307) were collected. Existing museum depositions were also studied. The 28S rRNA gene sequences of these Paracreptotrema spp. were aligned, along with sequences from 22 other allocreadiids and 4 other non-allocreadiid xiphidiatan species. Bayesian inference and maximum likelihood analyses indicated a paraphyletic Paracreptotrema split into 3 clades: 1 comprising P. blancoi and P. rosenthali that was sister to a clade formed by 3 other species of allocreadiids (species of Wallinia, Creptotrematina, and Auriculostoma) typically found in characid fishes, a second clade formed solely by Paracreptotrema heterandriae as the sister taxon of the aforementioned species, and a third by P. profundulusi and specimens erroneously identified as P. blancoi. Two new taxa were erected to reflect these results: Paracreptotrematoides for Paracreptotrema heterandriae, and Pseudoparacreptotrema for Paracreptotrema profundulusi and P. macroacetabulata (the species erroneously identified as P. blancoi from profundulids across Middle America). Closer consideration of the morphology corroborates these findings. The revised systematics also indicated that Paracreptotrema spp. are found in poeciliids, whereas Pseudoparacreptotrema spp. parasitize profundulids. The study demonstrates the value of an integrative taxonomy approach to address the apparently complicated systematics of the allocreadiids.
TL;DR: It is suggested that fish parasite species composition and richness in the Richelieu River are influenced by environmental parameters which in turn ultimately are driven by a combination of climatic conditions and anthropogenic activities in the watershed.
Abstract: The Richelieu River, Quebec, is a highly-regulated waterway subject to numerous anthropogenic influences from municipal effluents and agricultural activities. Parasite communities in 234 spottail shiners (Notropis hudsonius) were examined from 4 localities in late spring 2003 and 2004. Component species richness varied between 15 and 18 species in 2003 but declined to 9 to 13 in 2004, while total parasite abundance was consistently lower in 2003. Parasite component community similarity among localities could not be directly linked to available upstream water quality measurements or anthropogenic activity and was best explained by precipitation. Total precipitation in May 2003 was approximately 40% more than in May 2004, presumably altering patterns of runoff, river flow rates, and water quality. This study suggests that fish parasite species composition and richness in the Richelieu River are influenced by environmental parameters which in turn ultimately are driven by a combination of climatic conditions and anthropogenic activities in the watershed.
TL;DR: The results confirm reservations expressed earlier about the affinities of P. hobergi, but substantially challenge inferences drawn previously about the biogeographical history of potamotrygonid stingrays based on parasitological data.
Abstract: The genus Pararhinebothroides was established for a species of cestode (Parahinebothroides hobergi) found parasitizing the Tumbes round stingray, Urobatis tumbesensis (McEachran & Chirichigno), in the inshore Pacific waters in the Gulf of Guayaquil, Ecuador. Its apparent affinities with the freshwater endemic genus Rhinebothroides were considered evidence to support the long-standing, yet controversial, biogeographical hypothesis that freshwater stingrays of the family Potamotrygonidae derived from a Pacific marine ancestor during the Cretaceous Period before the uplifting of the Andes. Here, we re-evaluate the phylogenetic and taxonomic status of P. hobergi based on examination of the available type material and newly collected material from the type host near the type locality. The new material allowed the description of tegumental structures using scanning electron microscopy and the generation of a hypothesis for the phylogenetic position of the species based on molecular data for the first t...
TL;DR: The successful recovery of C. parvum coproantigens from prehistoric coprolites demonstrates the existence of C-parvum in Mesoamerica before European contact in the 1400s.
Abstract: In the present study, 90 coprolites from La Cueva de los Muertos Chiquitos (CMC) were subjected to enzyme-linked immunosorbent assay (ELISA) tests for 3 diarrhea-inducing protozoan parasites, Entamoeba histolytica, Giardia duodenalis, and Cryptosporidium parvum, to determine whether these parasites were present among the people who utilized this cave 1,200–1,400 yr ago. These people, the Loma San Gabriel, developed as a culture out of the Archaic Los Caracoles population and lived throughout much of present-day Durango and Zacatecas in Mexico. The Loma San Gabriel persisted through a mixed subsistence strategy of hunting-gathering and agricultural production. The results of ELISA testing were negative for both E. histolytica and G. duodenalis across all coprolites. A total of 66/90 (∼73% prevalence) coprolites tested positive or likely positive for C. parvum. The high prevalence of C. parvum among CMC coprolites contributes to our growing knowledge of the pathoecology among the Loma San Gabriel w...
TL;DR: In this article, the probability of detecting avian haemosporidia (Plasmodium and Haemoproteus) using molecular techniques differs among blood, liver, heart, and pectoral muscle tissues.
Abstract: We tested whether the probability of detecting avian haemosporidia (Plasmodium and Haemoproteus) using molecular techniques differs among blood, liver, heart, and pectoral muscle tissues. We used a paired design, sampling the 4 tissue types in 55 individuals of a wild South American suboscine antbird, the white-shouldered fire-eye (Pyriglena leucoptera). We also identified parasites to cytochrome b lineage. Detection probability was significantly lower in blood compared to the other 3 tissue types combined. Eight of 22 infections were not detected in blood samples; 4–7 infections were not detected in the other individual tissues. The same parasite lineage was recovered from different tissues.
TL;DR: The effects of clutch size and diet are consistent with previous studies and have been linked to immune function and parasite exposure, respectively, whereas the effect of migration supports the hypothesis of ”migratory exposure” rather than that of “m migratory escape.”
Abstract: The life history characteristics of hosts often influence patterns of parasite infection either by affecting the likelihood of parasite exposure or the probability of infection after exposure. In birds, migratory behavior has been suggested to affect both the composition and abundance of parasites within a host, although whether migratory birds have more or fewer parasites is unclear. To help address these knowledge gaps, we collaborated with airports, animal rescue/rehabilitation centers, and hunter check stations in the San Francisco Bay Area of California to collect 57 raptors, egrets, herons, ducks, and other waterfowl for parasitological analysis. After dissections of the gastrointestinal tract of each host, we identified 64 taxa of parasites: 5 acanthocephalans, 24 nematodes, 8 cestodes, and 27 trematodes. We then used a generalized linear mixed model to determine how life history traits influenced parasite richness among bird hosts, while controlling for host phylogeny. Parasite richness was greater in birds that were migratory with larger clutch sizes and lower in birds that were herbivorous. The effects of clutch size and diet are consistent with previous studies and have been linked to immune function and parasite exposure, respectively, whereas the effect of migration supports the hypothesis of "migratory exposure" rather than that of "migratory escape."
TL;DR: Phylogenetic analysis using the 18S rRNA gene and mitochondrial cox1 gene indicated S. heydorni shared the closest affinity with species of Sarcocystis, which employ ruminants as intermediate hosts and canids as definitive hosts.
Abstract: Cattle are intermediate hosts for 2 zoonotic species of Sarcocystis, Sarcocystis hominis and Sarcocystis heydorni. Here we report S. heydorni from cattle for the first time in China. Sarcocysts of S. heydorni were found in muscle from 173 of 1,630 (10.6%) cattle in abattoirs (9.7% in skeletal muscles, 3.4% esophagus, 2.5% diaphragm, and 0.1% tongue; heart muscle was negative). By means of light microscopy, S. heydorni sarcocysts were thin-walled (<1 μm). Using transmission electron microscopy, the sarcocyst wall had short (0.3–0.5 × 0.5–0.9 μm) stubby protrusions, the tips of which contained electron-dense, disk-shaped plaques, similar to the sarcocyst wall type 29b. In preliminary transmission attempts, a human volunteer did not excrete sporocysts in feces after ingesting 579 sarcocysts S. heydorni isolated from cattle. Phylogenetic analysis using the 2 molecular markers (18S rRNA gene and mitochondrial cox1 gene) indicated S. heydorni shared the closest affinity with species of Sarcocystis, whi...
TL;DR: Questions regarding the spatial dependence of the host diversity–parasite diversity relationship may be most-effectively addressed within a single multi-host–multi-parasites system.
Abstract: Host species richness and parasite species richness are often positively correlated, but the strength of this relationship varies from study to study. What accounts for this variability? Here, we explore the role of spatial scale in mediating the commonly reported positive relationship between host and parasite diversity. Building from ecological theory, we lay out a series of hypotheses for how spatial grain size might influence both the strength and slope of this relationship. Most significantly, we consider how variability in spatial grain size may result in differences in sampling effort that affect estimates of host and parasite richness differently, and we explore the potential for spatial grain to have divergent effects on strength versus slope of the relationship between host and parasite richness. Finally, we examine what empirical data exist to test the outlined hypotheses and conduct a meta-regression of published studies. Our analyses-which detected no significant associations-highlight several factors that compromise our ability to robustly compare the host-parasite richness relationship across contexts, including mismatches between absolute spatial scale and spatial scale of ecological processes as well as variability across and within studies with respect to spatial grain size, taxonomic resolution, definitions of "hosts" and "parasites," and sampling effort. This work suggests that questions regarding the spatial dependence of the host diversity-parasite diversity relationship may be most-effectively addressed within a single multi-host-multi-parasite system.
TL;DR: Both neighbor-joining (NJ) and maximum likelihood (ML) trees showed 2 clear separate clusters grouping together the species from the Palearctic region and those from the Nearctic/Neotropical regions.
Abstract: A complete morphological description, supported by molecular data, of Clinostomum detruncatum metacercariae is reported in this study. The metacercariae were found infecting Synbranchus marmoratus from the Parana River, municipality of Guaira, Parana State, Brazil. The taenioidean uterus is the main morphological characteristic of this species. Both neighbor-joining (NJ) and maximum likelihood (ML) trees showed 2 clear separate clusters grouping together the species from the Palearctic region (Clinostomum complanatum, Clinostomum cutaneum, Clinostomum phalacrocoracis, Clinostomum philippinense) and those from the Nearctic/Neotropical regions (Clinostomum marginatum, Clinostomum tataxumui, C. detruncatum, Clinostomum sp. 7). The latter clade is divided into 2 subclades grouping species from North America and Mexico (C. marginatum and C. tataxumui), and those from Brazil (C. detruncatum and Clinostomum sp. 7).
TL;DR: Survey of cattle and pastures for ticks and for each pathogen found few Ehrlichia infections in cattle-associated ticks and current A. marginale rates in Tennessee beef cattle nearing 11%, additional research is needed to establish baseline tick, Anaplasma, and EHRlichia data for future management studies.
Abstract: Anaplasma marginale is the causative agent for bovine anaplasmosis (BA) and Ehrlichia ruminantium is the causative agent for heartwater, 2 devastating diseases of cattle. BA is common in the United States and frequently reported in western Tennessee cattle; however, cases of heartwater are not yet established in the continental United States. Because both pathogens are transmitted via the bites of infected ticks, the objective of this study was to survey cattle and pastures for ticks and for each pathogen. University of Tennessee AgResearch has 7 research and education centers (REC) located throughout the state at which they manage cattle. Ticks were collected from selected cattle (every fourth to sixth animal) and pastures (via dragging) associated with the herd from each REC during the summer of 2013. A total of 512 ticks were collected from cattle (n = 386) and pastures (n = 126) and were PCR-screened for Anaplasma and Ehrlichia using genus-specific primers. Collections consisted of 398 (77.7%) Amblyomma americanum, 84 (16.4%) Amblyomma maculatum, and 30 (5.9%) Dermacentor variabilis. Ticks were not recovered from pastures or cattle east of the Tennessee Plateau. The North American vectors for An. marginale and E. ruminantium were identified (D. variabilis and A. maculatum, respectively), but neither pathogen was recovered. A large proportion of ticks were collected from cattle and, of these, a majority were attached to their host (compared to questing on their host or engorged on the host). Four A. americanum were positive for Ehrlichia spp. (Ehrlichia ewingii, Ehrlichia chaffeensis, and Panola Mountain Ehrlichia), all in western Tennessee. With the identification of a few Ehrlichia infections in cattle-associated ticks and current A. marginale rates in Tennessee beef cattle nearing 11%, additional research is needed to establish baseline tick, Anaplasma, and Ehrlichia data for future management studies.
TL;DR: This article examined colony structure for an additional 5 echinostomoid species, 4 of which infect the marine snail Cerithidea californica and 1 (Echinostoma liei) that infects the freshwater snail Biomphalaria glabrata.
Abstract: Complex societies where individuals exhibit division of labor with physical polymorphism, behavioral specialization, and caste formation have evolved several times throughout the animal kingdom. Recently, such complex sociality has been recognized in digenean trematodes; evidence is limited to 6 marine species. Hence, the extent to which a soldier caste is present throughout the Trematoda is sparsely documented, and there are no studies detailing the structure of a species lacking such a social structure. Here we examine colony structure for an additional 5 echinostomoid species, 4 of which infect the marine snail Cerithidea californica and 1 (Echinostoma liei) that infects the freshwater snail Biomphalaria glabrata. For all species, we present redia morphology (pharynx and body size) and the distribution of individuals of different castes throughout the snail body. When morphological evidence indicated the presence of a soldier caste, we assessed behavior by measuring attack rates of the differe...
TL;DR: This is the first study providing molecular identification for the presence of zoonotic species S. suihominis in pork in India and warrants intervention policies to stop the practice of rearing pigs under unhygienic conditions.
Abstract: Three species of Sarcocystis-S. miescheriana, S. suihominis, and S. porcifelis-have been recorded from pigs ( Sus scrofa ). Among these 3 species, the zoonotic species S. suihominis is of paramount importance and an important food safety issue. Previous studies indicate prevalence of porcine Sarcocystis species in India, but molecular evidence, among other evidence, is required for proper species differentiation. Myocardium from 250 stray and farm pigs destined for slaughter for human consumption were collected from slaughter shops located in urban slums in Punjab, northern India. Tissues were examined for Sarcocystis by using an intact cyst isolation method, pepsin acid digestion, Sarcocystis 18S ribosomal RNA polymerase chain reaction (PCR), and real-time quantitative PCR with melting curve analysis (qPCR-MCA). The combination of primers was used for 18S rRNA PCR amplification followed by sequencing. Ten representative samples were sequenced in both the directions from which 7 readable sequences were obtained for phylogenetic analysis. Sarcocystis cysts/zoites were recorded in 146 (58.4%), 169 (67.6%), 182 (72.8%), and 191 (76.4%) of samples by using intact cyst isolation, pepsin HCl digestion, conventional PCR, and qPCR-MCA, respectively. Molecularly, 1 S. miescheriana isolate and 6 isolates of the zoonotic species S. suihominis were recorded. This is the first study providing molecular identification for the presence of zoonotic species S. suihomonis in India. The prevalence of zoonotic S. suihominis in pork in India is worrisome and warrants intervention policies to stop the practice of rearing pigs under unhygienic conditions.
TL;DR: Estragole and thymol display important anti-Toxoplasma activity and are effective against T. gondii ME49 strain, and orally administered estragole in infected pregnant mice improved the weight of offspring compared with untreated controls.
Abstract: Toxoplasmosis is caused by Toxoplasma gondii , an obligatory intracellular protozoan. Normally benign, T. gondii infections can cause devastating disease in immunosuppressed patients and through congenital infection of newborn babies. Few prophylactic and therapeutic drugs are available to treat these infections. The goal of the present study was to assess the anti-Toxoplasma effects in a congenital and noncongenital model of toxoplasmosis (using ME49 strain), besides assessing immunological changes, in vitro cytotoxicity, and in vivo acute toxicity of commercial estragole and thymol. The congenital experimental model was used with intermediate stages of maternal infection. The serum levels of immunoglobulin (Ig)M, IgG, interleukin (IL)-10, IL-12, and interferon-gamma (IFN-γ) were quantified from infected and treated C57Bl/6 mice. Estragole and thymol respectively exhibited low to moderate in vivo toxicity and cytotoxicity. Animals treated with estragole showed high IFN-γ and strong type 1 helper T cell response. Both compounds were active against T. gondii ME49 strain. Furthermore, orally administered estragole in infected pregnant mice improved the weight of offspring compared with untreated controls. Subcutaneous administration of both compounds also increased the weight of mouse offspring born to infected mothers, compared with untreated controls. Estragole and thymol display important anti-Toxoplasma activity. Further studies are needed to elucidate the mechanism of action of these compounds.
TL;DR: High parasite egg outputs from hosts in this California raccoon population increase human exposure risk, and this risk could be reduced by management strategies that target heavily infected juvenile raccoons.
Abstract: California has more reported human raccoon roundworm cases than any other state due to large and overlapping human and raccoon populations. Infection by this parasite, Baylisascaris procyonis, is relatively benign in raccoons but can cause severe pathology in other species. Disease risk is driven by environmental egg contamination which increases with raccoon density, worm intensity, and worm prevalence. To improve knowledge about risk to humans and other species, 189 raccoons from southern California were examined to investigate how host age and season affect worm abundance, demography, and fecundity. Adult worms were present in animals as young as 10 wk and 100% of 4-mo-old raccoons were infected. Although 80% of sampled raccoons hosted adult B. procyonis, prevalence and abundance were lower in older animals. There were more worms in juvenile than in adult raccoons, resulting in a convex age-intensity profile. Coupled with raccoon demography, this drove fall peaks in parasite abundance and egg ...
TL;DR: It was found that low temperature significantly stimulated and maintained tetany in infected ants while light, humidity, ant size, and infection intensity had no influence on this behavior.
Abstract: The lancet fluke, Dicrocoelium dendriticum, is perhaps the best-known example of parasite manipulation of host behavior, which is manifested by a radically changed behavior that leaves infected ants attached to vegetation at times when transmission to an herbivore host is optimal. Despite the publicity surrounding this parasite, curiously little is known about factors inducing and maintaining behavioral changes in its ant intermediate host. This study examined the importance of 3 environmental factors on the clinging behavior of red wood ants, Formica polyctena , infected with D. dendriticum . This behavior, hypothesized to involve cramping of the mandibular muscles in a state of tetany, was observed in naturally infected F. polyctena under controlled temperature, light, and humidity conditions. We found that low temperature significantly stimulated and maintained tetany in infected ants while light, humidity, ant size, and infection intensity had no influence on this behavior. Under none of the experimental conditions did uninfected ants attach to vegetation, demonstrating that tetany was induced by D. dendriticum . Temperature likely has a direct impact on the initiation of clinging behavior, but it may also serve as a simple but reliable indicator of the encounter rate between infected ants and ruminant definitive hosts. In addition, temperature-sensitive behavior manipulation may protect infected ants from exposure to temperatures in the upper thermal range of the host.
TL;DR: This is the first report of the introduction of Australian temnocephalans, C. pedum and Didymorchis sp.
Abstract: The redclaw crayfish, Cherax quadricarinatus (Decapoda: Parastacidae), is native to Australia but has been introduced to South Africa as a warm-water aquaculture species. In a South African natural waterbody, examined crayfish had high-intensity infections of 3 temnocephalan species on their body surfaces and within the branchial chambers. Temnocephalans were characterized using light and scanning electron microscopy and identified as Craspedella pedum, Diceratocephala boschmai, and Didymorchis sp. This is the first report of the introduction of Australian temnocephalans, C. pedum and Didymorchis sp., to Africa and expands the known distribution of these species beyond their presumptive native range. The present study also documents a naturalized population of C. quadricarinatus from a natural water body in South Africa, comprising a new geographical locality record.
TL;DR: It was concluded that household clustering, house construction, and conventional behavioral practices (living with cattle) greatly impact the epidemiology of CL in the region and have significant implications for prospective control programs.
Abstract: Pakistan faces critical challenges pertaining to cutaneous leishmaniasis (CL), where it's distribution is more or less patchy. The goal of this study was to assess the incidence of CL as well as to identify potential risk factors in Peshawar region, Khyber Pakhtunkhwa, Pakistan. The study was conducted in the dermatology outpatient unit at Kuwait Teaching Hospital, Peshawar, Khyber Pakhtunkhwa, Pakistan. Longitudinal out-patient department visit data for 9,631 CL patients spanning a 42-mo (April 2011-October 2014) period was analyzed using autoregressive integrated moving average (ARIMA) time series models ARIMA(1,0,0)(0,1,0)12 and ARIMA(0,0,0)(0,1,0)12. The ARIMA concluded that the number of patients was increasing over time. Over the duration, frequency of male patients (58.2%) was higher. The mean age of CL patients was 16.4 (confidence interval = 16.14-16.70) yr and the majority of the patients were aged 5-20 yr (52.6%). Inflow of CL patients peaked close to February and March, followed by a decline until its lowest point in the months of August and September (P 20 yr) to derive 63 matched pairs. Using univariate conditional logistic regression analyses of the matched pairs, we found that living in congested rooms (>6 persons), having family members with lesions (active/scars), keeping cattle inside dwellings at night, and having in-door vegetation were established as factors that significantly increased the risk of CL. On the other hand, living in houses constructed with bricked walls or wooden roofs (thatched/beam), ownership of treated bed nets, and having meshed windows were proven to be protective against CL. It was evident that the disease incidence has been on a gradual rise over the past few years. It was concluded that household clustering, house construction, and conventional behavioral practices (living with cattle) greatly impact the epidemiology of CL in the region. Conclusions from this study have significant implications for prospective control programs.