Effect of intermediate host size (Cerastoderma edule) on infectivity of cercariae of Himasthla quissetensis (Echinostomatidae: Trematoda)

2005 ◽  
Vol 85 (4) ◽  
pp. 809-812 ◽  
Author(s):  
Xavier de Montaudouin ◽  
K. Thomas Jensen ◽  
Céline Desclaux ◽  
Anne M. Wegeberg ◽  
Marie C. Sajus
Keyword(s):  
Shell Length ◽  
Parasite Species ◽  
Host Size ◽  
Marine Bivalve ◽  
Free Living ◽  
Experimental Procedure ◽  
Cerastoderma Edule ◽  
Infection Pattern ◽  
South West ◽  
Fourth Species

The edible cockle (Cerastoderma edule), a common marine bivalve in semi-sheltered sandflats, is a natural host for many parasite species of the genus Himasthla (Echinostomatidae: Trematoda). In a previous paper, Wegeberg et al. (1999) showed segregation of cockle infection by three Himasthla species (H. interrupta, H. continua, H. elongata) in relation to host tissue (foot, mantle, siphon) and host size (1·5 to 14 mm shell length). Following the same experimental procedure, a fourth species, H. quissetensis, an introduced dominant parasite of cockles in Arcachon Bay (south-west France) was investigated. The infection pattern was very similar to the patterns shown by H. elongata and H. continua. Cercariae (the free-living stage shed from prosobranch snails and encysting as metacercariae in bivalves) were most successful in the shell-length range of 6–14 mm, where 74% of the added cercariae were recovered as metacercariae. The comparison with the other Himasthla species supports the previous conclusion that the efficiency of cercariae to infect cockles depends on host size.

Prospective enzymes for omega-3 PUFA biosynthesis found in endoparasitic classes within the phylum Platyhelminthes

2020 ◽  
Vol 94 ◽  
Author(s):  
D. Babaran ◽  
M.T. Arts ◽  
R.J. Botelho ◽  
S.A. Locke ◽  
J. Koprivnikar
Keyword(s):  
Parasite Species ◽  
De Novo ◽  
Genomic Data ◽  
Wide Distribution ◽  
Omega 3 ◽  
Free Living ◽  
Chain Pufa ◽  
Pufa Biosynthesis ◽  
Aquatic Food ◽  
Long Chain

Abstract The free-living infectious stages of macroparasites, specifically, the cercariae of trematodes (flatworms), are likely to be significant (albeit underappreciated) vectors of nutritionally important polyunsaturated fatty acids (PUFA) to consumers within aquatic food webs, and other macroparasites could serve similar roles. In the context of de novo omega-3 (n-3) PUFA biosynthesis, it was thought that most animals lack the fatty acid (FA) desaturase enzymes that convert stearic acid (18:0) into ɑ-linolenic acid (ALA; 18:3n-3), the main FA precursor for n-3 long-chain PUFA. Recently, novel sequences of these enzymes were recovered from 80 species from six invertebrate phyla, with experimental confirmation of gene function in five phyla. Given this wide distribution, and the unusual attributes of flatworm genomes, we conducted an additional search for genes for de novo n-3 PUFA in the phylum Platyhelminthes. Searches with experimentally confirmed sequences from Rotifera recovered nine relevant FA desaturase sequences from eight species in four genera in the two exclusively endoparasite classes (Trematoda and Cestoda). These results could indicate adaptations of these particular parasite species, or may reflect the uneven taxonomic coverage of sequence databases. Although additional genomic data and, particularly, experimental study of gene functionality are important future validation steps, our results indicate endoparasitic platyhelminths may have enzymes for de novo n-3 PUFA biosynthesis, thereby contributing to global PUFA production, but also representing a potential target for clinical antihelmintic applications.

scholarly journals Filtering out parasites: sand crabs (Lepidopa benedicti) are infected by more parasites than sympatric mole crabs (Emerita benedicti)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3852
Author(s):  
Zen Faulkes
Keyword(s):  
Parasite Species ◽  
Neural Tissue ◽  
Fine Sand ◽  
Swash Zone ◽  
Crab Species ◽  
Decapod Crustaceans ◽  
Primary Host ◽  
Litopenaeus Setiferus ◽  
Infection Pattern ◽  
Behavioural Tests

Two digging decapod crustaceans, the sand crab speciesLepidopa benedictiand the mole crab speciesEmerita benedicti, both live in the swash zone of fine sand beaches. They were examined for two parasites that infect decapod crustaceans in the region, an unidentified nematode previously shown to infectL. benedicti, and cestode tapeworm larvae,Polypocephalussp., previously shown to infect shrimp (Litopenaeus setiferus).Lepidopa benedictiwere almost always infected with both parasite species, whileE. benedictiwere rarely infected with either parasite species. This difference in infection pattern suggests that tapeworms are ingested during sediment feeding inL. benedicti, whichE. benedictiavoid by filter feeding. LargerL. benedictihad morePolypocephalussp. larvae. The thoracic ganglia, which make up the largest proportion of neural tissue, contained the largest numbers ofPolypocephalussp. larvae. Intensity ofPolypocephalussp. infection was not correlated with how longL. benedictiremained above sand in behavioural tests, suggesting thatPolypocephalussp. do not manipulate the sand crabs in a way that facilitates trophic transmission of the parasite.Litopenaeus setiferusmay be a primary host forPolypocephalussp., andL. benedictmay be a secondary, auxiliary host.

scholarly journals What factors explain the geographical range of mammalian parasites?

2019 ◽  
Vol 286 (1903) ◽  
pp. 20190673 ◽  
Author(s):  
James E. Byers ◽  
J. P. Schmidt ◽  
Paula Pappalardo ◽  
Sarah E. Haas ◽  
Patrick R. Stephens
Keyword(s):  
Host Species ◽  
Parasite Species ◽  
Geographical Area ◽  
Complete Information ◽  
Sampling Effort ◽  
Free Living ◽  
Living Species ◽  
Habitat Breadth ◽  
Taxonomic Groups ◽  
Host Characteristics

Free-living species vary substantially in the extent of their spatial distributions. However, distributions of parasitic species have not been comprehensively compared in this context. We investigated which factors most influence the geographical extent of mammal parasites. Using the Global Mammal Parasite Database we analysed 17 818 individual geospatial records on 1806 parasite species (encompassing viruses, bacteria, protozoa, arthropods and helminths) that infect 396 carnivore, ungulate and primate host species. As a measure of the geographical extent of each parasite species we quantified the number and area of world ecoregions occupied by each. To evaluate the importance of variables influencing the summed area of ecoregions occupied by a parasite species, we used Bayesian network analysis of a subset ( n = 866) of the parasites in our database that had at least two host species and complete information on parasite traits. We found that parasites that covered more geographical area had a greater number of host species, higher average phylogenetic relatedness between host species and more sampling effort. Host and parasite taxonomic groups had weak and indirect effects on parasite ecoregion area; parasite transmission mode had virtually no effect. Mechanistically, a greater number of host species probably increases both the collective abundance and habitat breadth of hosts, providing more opportunities for a parasite to have an expansive range. Furthermore, even though mammals are one of the best-studied animal classes, the ecoregion area occupied by their parasites is strongly sensitive to sampling effort, implying mammal parasites are undersampled. Overall, our results support that parasite geographical extent is largely controlled by host characteristics, many of which are subsumed within host taxonomic identity.

scholarly journals Microsporidian Infection in a Free-Living Marine Nematode

2012 ◽  
Vol 11 (12) ◽  
pp. 1544-1551 ◽  
Author(s):  
A. M. Ardila-Garcia ◽  
N. M. Fast
Keyword(s):  
Marine Nematode ◽  
Free Living ◽  
Content Type ◽  
Infection Pattern ◽  
Transmission Electron ◽  
Muscle Tissues ◽  
Natural Hosts ◽  
In The Wild ◽  
Microsporidian Infection

ABSTRACT Microsporidia are unicellular fungi that are obligate endoparasites. Although nematodes are one of the most abundant and diverse animal groups, the only confirmed report of microsporidian infection was that of the “nematode killer” ( Nematocida parisii ). N. parisii was isolated from a wild Caenorhabditis sp. and causes an acute and lethal intestinal infection in a lab strain of Caenorhabditis elegans . We set out to characterize a microsporidian infection in a wild nematode to determine whether the infection pattern of N. parisii in the lab is typical of microsporidian infections in nematodes. We describe a novel microsporidian species named Sporanauta perivermis (marine spore of roundworms) and characterize its infection in its natural host, the free-living marine nematode Odontophora rectangula. S. perivermis is not closely related to N. parisii and differs strikingly in all aspects of infection. Examination by transmission electron microscopy (TEM) revealed that the infection was localized in the hypodermal and muscle tissues only and did not involve the intestines. Fluorescent in situ hybridization (FISH) confirmed infection in the muscle and hypodermis, and surprisingly, it also revealed that the parasite infects O. rectangula eggs, suggesting a vertical mode of transmission. Our observations highlight the importance of studying parasites in their natural hosts and indicate that not all nematode-infecting microsporidia are “nematode killers”; instead, microsporidiosis can be more versatile and chronic in the wild.

A review of the infectious agents, parasites, pathogens and commensals of European cockles (Cerastoderma eduleandC. glaucum)

2012 ◽  
Vol 93 (1) ◽  
pp. 227-247 ◽  
Author(s):  
Matt Longshaw ◽  
Shelagh K. Malham
Keyword(s):  
Systematic Review ◽  
Life Cycle ◽  
Parasite Species ◽  
Future Research ◽  
Infectious Agents ◽  
Cerastoderma Edule ◽  
Cerastoderma Glaucum ◽  
Burrowing Behaviour ◽  
The Individual ◽  
Population Effects

A systematic review of the parasites, pathogens and commensals of the edible cockle (Cerastoderma edule) and of the lagoon cockle (Cerastoderma glaucum) has been completed. A total of 59 different conditions have been reported throughout the range of both of these hosts; of these 50 have been reported in edible cockles, and 28 in lagoon cockles. Cockles are hosts to viruses, bacteria, fungi (including Microsporidia), Apicomplexa, Amoeba, Ciliophora, Perkinsozoa, Haplosporidia, Cercozoa, Turbellaria, Digenea, Cestoda, Nematoda, Crustacea and Nemertea. A number of these have been reported sporadically although they may be associated with mortalities. In particular, mortalities have been associated predominately with digeneans and some protistan infections. In many cases pathology is marked in affected animals and parasites have been shown to reduce fecundity, alter burrowing behaviour and limit growth. This review provides information on the individual and population effects of these conditions as well as providing suggestions for future research. In particular, there has been a lack of taxonomic rigour applied to many studies and as a result there are a number of erroneous host records. There is a need to re-describe a number of parasite species and to determine the life cycle of those considered to be important mortality drivers.

Abbreviata (Nematoda: Physalopteroidea) in Lizards of the Varanus Gouldii Complex (Varanidae) in Western Australia.

1983 ◽  
Vol 31 (2) ◽  
pp. 285 ◽  
Author(s):  
HI Jones
Keyword(s):  
Immune Response ◽  
Western Australia ◽  
Host Immune Response ◽  
The State ◽  
Stomach Wall ◽  
Host Size ◽  
The South ◽  
Positive Correlation ◽  
South West

Six species of nematode in the genus Abbreviata were recovered from the stomachs of 58 Varanus gouldii, s.l., in Western Australia: A. hastaspicula, A. barrowi, A, antarctica, A. levicauda, sp. nov., A. tumidocapitis, sp. nov., and an unnamed species. A. occidentalis Jones, 1978 is reduced to synonomy with A. antarctica (Linstow, 1899). A, hastaspicula was recovered from all hosts examined except those from the south-west of the State, where it was replaced by A. antarctica. A. levicauda and A. tumidocapitis occurred concurrently with one or both of the above species. Th'e increase in A. hastaspicula numbers with host size in V. gouldii, s.s., (P<0,05) and in V. panoptes (P<0,05) indicates that there is no effective host immune response. A. hastaspicula numbers were unaffected by concurrent A. levicauda infection. There was a positive correlation between numbers of Abbreviata sp. larvae and A. hastaspicula (P<0.01), and between Abbreviata sp. larvae and A. antarctica (P<0.01), in V. gouldii, s.s. No larvae were seen in the stomach wall of these Varanus, and it is concluded that those which occur commonly in this situation in elapid snakes are probably larvae of A. hastaspicula or A. levicauda, which appear to be unable to mature in these hosts.

scholarly journals Detection and quantification of house mouse Eimeria at the species level – challenges and solutions for the assessment of Coccidia in wildlife

2019 ◽  
Author(s):  
Víctor Hugo Jarquín-Díaz ◽  
Alice Balard ◽  
Jenny Jost ◽  
Julia Kraft ◽  
Mert Naci Dikmen ◽  
...  
Keyword(s):  
House Mouse ◽  
Parasite Species ◽  
Host Population ◽  
Species Level ◽  
Free Living ◽  
Additional Indication ◽  
Tissue Samples ◽  
Species Specific ◽  
Apicoplast Genome ◽  
Detection And Quantification

AbstractDetection and quantification of coccidia in studies of wildlife can be challenging. Therefore, the prevalence of coccidia is often not assessed at the parasite species level in non-livestock animals. Parasite species-specific prevalences are especially important when studying evolutionary questions in wild populations. We tested whether increased host population density increases the prevalence of individual Eimeria species at the farm level, as predicted by epidemiological theory. We studied free-living commensal populations of the house mouse (Mus musculus) in Germany and established a strategy to detect and quantify Eimeria infections. We show that a novel diagnostic primer targeting the apicoplast genome (Ap5) and coprological assessment after flotation provide complementary detection results increasing sensitivity. Genotyping PCRs confirm detection in a subset of samples and cross-validation of different PCR markers does not indicate a bias towards a particular parasite species in genotyping. We were able to detect double infections and to determine the preferred niche of each parasite species along the distal-proximal axis of the intestine. Parasite genotyping from tissue samples provides an additional indication for the absence of species bias in genotyping amplifications. Three Eimeria species were found infecting house mice at different prevalences: Eimeria ferrisi (16.7%; 95% CI 13.2 – 20.7), E. falciformis (4.2%; 95% CI 2.6 – 6.8) and E. vermiformis (1.9%; 95% CI 0.9 – 3.8). We also find that mice in dense populations are more likely to be infected with E. falciformis and E. ferrisi.We provide methods for the assessment of prevalences of coccidia at the species level in rodent systems. We show and discuss how such data can help to test hypotheses in ecology, evolution and epidemiology on a species level.

The population dynamics of competition between parasites

Parasitology ◽  
1985 ◽  
Vol 91 (2) ◽  
pp. 317-347 ◽  
Author(s):  
A. P. Dobson
Keyword(s):  
Population Dynamics ◽  
Parasite Species ◽  
Interference Competition ◽  
Population Level ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Control Agent ◽  
Host Population ◽  
Free Living ◽  
The Impact

A number of published studies of competition between parasite species are examined and compared. It is suggested that two general levels of interaction are discernible: these correspond to the two levels of competition recognized by workers studying free-living animals and plants: ‘exploitation’ and ‘interference’ competition. The former may be defined as the joint utilization of a host species by two or more parasite species, while the latter occurs when antagonistic mechanisms are utilized by one species either to reduce the survival or fecundity of a second species or to displace it from a preferred site of attachment. Data illustrating both levels of interaction are collated from a survey of the published literature and these suggest that interference competition invariably operates asymmetrically. The data are also used to estimate a number of population parameters which are important in determining the impact of competition at the population level. Theoretical models of host-parasite associations for both classes of competition are used to examine the expected patterns of population dynamics that will be exhibited by simple two-species communities of parasites that utilize the same host population. The analysis suggests that the most important factor allowing competing species of parasites to coexist is the statistical distribution of the parasites within the host population. A joint stable equilibrium should be possible if both species are aggregated in their distribution. The size of the parasite burdens at equilibrium is then determined by other life-history parameters such as pathogenicity, rates of resource utilization and antagonistic ability. Comparison of these theoretical expectations with a variety of sets of empirical data forms the basis for a discussion about the importance of competition in natural parasite populations. The models are used to assess quantitatively the potential for using competing parasite species as biological control agents for pathogens of economic or medical importance. The most important criterion for identifying a successful control agent is an ability to infect a high proportion of the host population. If such a parasite species also exhibits an intermediate level of pathology or an efficient ability to utilize shared common resources, antagonistic interactions between the parasite species contribute only secondarily to the success of the control. Competition in parasites is compared with competition in free-living animals and plants. The comparison suggests further experimental tests which may help to assess the importance of competition in determining the structure of more complex parasite-host communities.

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