Search results for "Parasite"
showing 10 items of 827 documents
Interactions related to non-host snails in the host-finding process of Euparyphium albuferensis and Echinostoma friedi (Trematoda: Echinostomatidae) …
2003
In order to determine whether the miracidia of Euparyphium albuferensis and Echinostoma friedi are sensitive to their host snail (HS) and capable of discriminating between HS and non-host snails (NHS), or whether these NHS can interfere and thus reduce the infection rates (decoy effect), a total of three experiments were conducted with HS, NHS and snail-conditioned water (SCW). Gyraulus chinensis is the HS for E. albuferensis miracidia, while Physa acuta, Radix peregra and Lymnaea fuscus are considered NHS. For E. friedi miracidia R. peregra, G. chinensis and L. fuscus are the HS, while P. acuta is the NHS. The NHS R. peregra produces the greatest decoy effect on Euparyphium albuferensis mi…
Miracidial infectivity of Hypoderaeum conoideum (Trematoda: Echinostomatidae): differential susceptibility of two lymnaeid species.
1999
A study was made of the infectivity of Hypoderaeum conoideum miracidia to a range of laboratory-reared specimens of freshwater snail species (Lymnaea peregra, L. corvus, Physella acuta, and Gyraulus chinensis) that coexist with the parasite in the same natural habitat. L. peregra and L. corvus were found to be equally susceptible to the parasite when specimens of each snail species were singly exposed to miracidia. However, when miracidia could choose either lymnaeid species, they showed a high degree of specificity toward L. peregra. The results obtained suggest that H. conoideum miracidia are capable of distinguishing among these lymnaeids in their orientation to the host. This indicates …
The life cycle ofBrachylaima ruminae n. sp. (Trematoda: Brachylaimidae), a parasite of rodents
1986
The life cycle of Brachylaima ruminae n.sp. (Trematoda: Brachylaimidae), a duodenal parasite of rodents on the Mediterranean island of Formentera (Spain) is elucidated. The new species follows a terrestrial triheteroxenous life cycle. Eggs passed in the faeces of the definitive host must be ingested by a specific first intermediate host, the land snail Rumina decollata. Branched cercariogenous sporocysts develop in the digestive gland. Microcercous cercariae come out through the terminal birth pores of the branches. Cercariae shed by the snail are terrestrial, crawling on humid substratum. They contact the second intermediate host, another land snail, principally the species R. decollata an…
Being successful in the world of narrow opportunities: transmission patterns of the trematode Ichthyocotylurus pileatus.
2009
SUMMARYParasites with complex life cycles face 2 major challenges for transmission in northern latitudes. They have to cope with the general unpredictability associated with the series of transmission events required for completion of the cycle, and transmission has to be completed within a narrow temporal window because of strong seasonality. Despite this, some parasites show high transmission success, suggesting the operation of effective transmission mechanisms. We explored the transmission of Ichthyocotylurus pileatus (Trematoda) from its snail (Valvata macrostoma) to fish (Perca fluviatilis) hosts by examining some key characteristics in the dynamics of the cercarial emergence from sna…
Halfway up the trophic chain: development of parasite communities in the sparid fish Boops boops
2007
SUMMARYWe examined the patterns of composition and structure of parasite communities in the Mediterranean sparid fish Boops boops along a gradient of fish sizes, using a large sample from a single population. We tested the hypothesis that species forming the core of the bogue parasite fauna (i.e. species which have a wide geographical range and are responsible for recognizable community structure) appear early in the fish ontogeny. The sequential community development observed supported the prediction that core species appear in the fish population earlier than rare and stochastic species. There was also a strong correlation between the order of ‘arrival’ of the species and their overall pr…
Morphology of Bertiella studeri (Blanchard, 1891) sensu Stunkard (1940) (Cestoda: Anoplocephalidae) of human origin and a proposal of criteria for th…
2000
Human material of an African specimen of Bertiella studeri (Blanchard, 1891), a typical intestinal cestode of monkeys, is described. Mature, postmature and gravid proglottides, and eggs, previously inadequately figured, are illustrated and photographed. The description of the species agrees with that provided by Stunkard (1940). A comparative study with other descriptions of the species is made in an attempt to clarify previous findings. The morphological differences reported in various earlier descriptions of the species suggest that B. studeri should be regarded as a "B. studeri species complex". Improvements are required in the descriptions of new future findings in order to clarify the …
Observations on a new species of Unicapsula (Myxosporida) in the fish Maena smaris (L.) by conventional and electronmicroscopy
1975
A myxosporidian parasite believed to be congeneric with Unicapsula muscularis Davis (1924), type (and only) species of this genus, was found in the dorsal muscles of the fish Maena smaris (L.) at Banyuls-sur-Mer, France. The spores were tripartite, with corresponding components of the three parts differentially developed. One part consisted of a small shell valve overlying no more than a trace of sporoplasm but covering a polar apparatus with well-developed polar capsule. Each of the other two parts consisted of a long shell valve covering a large sporoplasm and a polar apparatus with only the rudiment of a polar capsule. Electron microscope pictures of the trophozoite showed evidence of pi…
Consistent isotopic differences between Schistocephalus spp. parasites and their stickleback hosts
2015
Published version available at http://dx.doi.org/10.3354/dao02893 Parasite−host systems show markedly variable patterns in isotopic fractionation: parasites can be either depleted or enriched in 15N and 13C as compared to their hosts. However, it remains unknown whether isotopic fractionation patterns are similar in comparable parasite−host systems from markedly different ecosystems. Results of this study show that large-sized Schistocephalus spp. endoparasites are consistently depleted in 15N (by on average −2.13 to −2.20‰) as compared to their nine-spined stickleback Pungitius pungitius and three-spined stickleback Gasterosteus aculeatus hosts. The differences between parasites and host f…
Prevalence of bacteria and absence of anisakid parasites in raw and prepared fish and seafood dishes in Spanish restaurants
2015
This study evaluated the presence of bacteria and anisakid parasites in 45 samples of raw anchovies in vinegar, a dish widely eaten in Spain, and in 227 samples of cooked fish and cephalopods served in Spanish food service establishments. Our analysis showed that, according to European and Spanish regulation, 14 to 30% of the prepared fish and cephalopod dishes exceeded the maximum allowable level for mesophilic aerobic counts, and 10 to 40% of these samples exceeded the allowable levels for Enterobacteriaceae. None of the studied samples showed evidence of anisakid parasites, Escherichia coli, Staphylococcus aureus, Salmonella, or Listeria monocyto genes. These results indicate that applic…
Parasite infracommunities as predictors of harvest location of bogue (Boops boops L.): a pilot study using statistical classifiers
2005
The accuracy of classifying bogue (Boops boops) according to the fishery from which it was harvested was evaluated by applying several statistical classification techniques to fish parasite abundances. Bogue captured in 2001 in two fisheries off the Atlantic coast of Spain were compared with one off the Spanish Mediterranean coast. One hundred bogue were classified to each harvest location (fishery) using different numbers of parasite species chosen as predictors by a best subset method. Two parametric methods of classification (linear and quadratic discriminant analysis) were compared with two non-parametric approaches (k-nearest neighbour classification and feed-forward neural network) an…