Fasciolosis in the Mediterranean island of Corsica (France): Insights from epidemiological and malacological investigations.

Fasciolosis is a re-emergent parasitic disease of worldwide significance with a major global impact on livestock health and production. In the French Mediterranean island of Corsica, fasciolosis has been recognized for a long time but little is known about its dynamic as the main investigations are outdated. Three compartments - definitive domestic hosts, intermediate hosts and environment - involved in fasciolosis transmission were studied by applying an integrative and extensive approach: (1) farm and abattoir surveys, (2) snail sampling, identification and infection prospection, and (3) snail habitat analysis; and (4) a questionnaire-based survey to inquire about husbandry practices and environmental risks. Our results indicate a significant circulation of the liver flukes in Corsican livestock, with 90% (252/279) of the sampled farms testing positive for anti-F. hepatica antibodies. At the abattoir, 46% (67/149) of cattle were positive for F. hepatica antibodies and eggs were present in the bile of 19% (26/139) bovines. In addition, high prevalence of Dicrocoelium dendriticum (69%) was observed in slaughtered cattle. Malacological surveys registered the occurrence of several lymnaeid species in a variety of habitats throughout the island. In particular, we report for the first time the presence of the invasive lymnaeid snail Pseudosuccinea columella in Corsica, a potential intermediate host for F. hepatica. We also found that the presence of Galba truncatula and, to a lesser extent, that of Peregriana peregra, is associated with altitude. Fasciola hepatica DNA was detected in the latter species occurring at two different sites. Finally, a questionnaire-based study revealed risky management practices among Corsican farmers, low perception of transmission and a suboptimal use of flukicide treatments as main control strategy. Our results show that animal fasciolosis in Corsica is characterised by a significant circulation and a favourable epidemiological scenario for transmission to occur.

Ultrastructural study of spermiogenesis and the spermatozoon of Acanthocephaloides incrassatus (Molin, 1858) (Acanthocephala, Paleacanthocephala, Arhythmacanthidae) from Anguilla anguilla (Pisces, Teleostei) in Urbino ponds (Corsica Island).

This study deals with first ultrastructure features of Acanthocephaloides incrassatus (Paleacanthocephala, Arhythmacanthidae), a parasite of the fish Anguilla anguilla, reported for the first time in a Mediterranean pond. The spermiogenesis of A. incrassatus shows original specificities which have never been pointed out to this day in ultrastructural studies on spermiogenesis: the centriolar derivative is divided into two parts of different densities: an electron-dense, and the other, electron-lucent; a ring form has been observed on each side of the axoneme; a centriole with one central element. After the elaboration of a flagellum of 9+2 pattern, the centriole migrates in a nuclear groove. Rapidly, the centriole disappears. Then, the flagellum migration occurs by a series of processes and gives rise to a spermatozoon. The spermatozoon of A. incrassatus presents its own specificities: it exhibits an evolution of the centriolar derivative characterized by only nine peripheral elements deprived of a central element in the anterior part, then nine peripheral and one central element, and finally, nine peripheral elements with two central elements. An assumption is emitted on a probable correspondence of the evolution of the derivative centriolar during the spermiogenesis and the evolution that occurs in the spermatozoon. Protein granules also show different sizes and forms, full or emptied of their contents compared with data on other Acanthocephala.

The influence of altitude, hydrographic network and season on brown trout parasites in Corsica using indicator species analysis.

The parasites of 484 brown trout, Salmo trutta, were studied between 2004 and 2007. An indicator value (IndVal) method was used for analysis, which combines measures of fidelity and specificity. Because of its resilience to detect changes in abundance, IndVal is an effective ecological bio-indicator. The IndVal method demonstrated that altitude, hydrographic network and season could influence the occurrence of parasite species in brown trout. A randomization test identified three parasite species as having a significant indicator value for altitude (the trematode Nicolla wisniewskii, and the nematodes Spinitectus gordoni and Rhabdochona gnedini); five parasite species for hydrographic network (the trematodes Nicolla testiobliquum, N. wisniewskii, Plagioporus stefanskii, and the nematodes S. gordoni and R. gnedini) and two parasite species for season (the nematodes S. gordoni, and R. gnedini). Data for species composition and infection levels should help to improve the monitoring and management of parasitism in salmonid populations.

Sperm ultrastructure of the digenean Siphoderina elongata (Platyhelminthes, Cryptogonimidae) intestinal parasite of Nemipterus furcosus (Pisces, Teleostei).

The ultrastructure of the spermatozoon of Siphoderina elongata was studied by transmission electron microscopy. A description and drawings of the mature spermatozoon are presented in this paper. Several ultrastructural elements of this male gamete have been observed: a nucleus, two mitochondria, two axonemes of 9 + "1" pattern, external ornamentation of the plasma membrane, spine-like bodies and cortical microtubules. The presence, the location or the number of these elements have been compared with other digenean spermatozoa. Moreover, a close attention was paid to the organization of the external ornamentation region. This zone presents a single row of cortical microtubules disposed in a semi-circle around a mitochondrion and associated with external ornamentation and spine-like bodies. The aim of this study is to highlight criteria which can be interesting in Platyhelminthes phylogeny.

Comparison of arsenic and antimony contents in tissues and organs of brown trout caught from the river Presa polluted by ancient mining practices and from the river Bravona in Corsica (France): a survey study.

The present study evaluates the concentrations of arsenic (As) and antimony (Sb) in the intestine, liver, muscle, gonads, gills, and kidney of Salmo trutta subsp. from the Presa River in Corsica (France; n = 10), which crosses an abandoned arsenic mine, and from the Bravona River (reference site; n = 10). Both metalloids were analyzed by means of ICP-MS. The relationships between fish size (length and weight) and metalloid concentrations in their tissues were investigated by linear regression analysis. In all fish samples concentrations of As and Sb (expressed as micrograms per gram fresh weight) were highest in the kidney. Lowest Sb concentrations were found in the muscle, whereas lowest As concentrations were found in the gonads of S. trutta. Two organotropisms were revealed: one for As-kidney (21.4656) > intestine (3.9535) > gills (3.0404) > liver (1.1743) > muscle (0.9976) > gonads (0.8081); and the other for Sb-kidney (0.70067) > gills (0.6181) > intestine (0.2576) > gonads (0.1673) > liver (0.9625) > muscle (0.0753). Results of linear regression analysis in most cases showed a significant negative correlation between metalloid concentration and fish size. Highly significant (p < 0.05) negative correlations were found between fish length and As concentration in the gonads, as well as between fish length and Sb concentrations in the gills. Arsenic concentrations in female fish were significantly higher than those in males in the kidney, gonads, gills, and liver. The same results were found for Sb, except in the liver, where the tendency was reversed.

Parasitofauna study of the brown trout, Salmo trutta (Pisces, Teleostei) from Corsica (Mediterranean island) rivers.

Corsica is a Mediterranean island characterised by a great number of rivers. Salmonides are the main fishes which populate these rivers. Very appreciated by fishermen, Salmonides are represented by three species in the insular hydrographical network, among which an autochthonous species, the brown trout (Salmo trutta). In the present work, we have analysed the parasitofauna of this species. According to our knowledge, this research has never been carried out in Corsica. In a first step, we drew up an inventory of the parasites found in this freshwater fish. In a second step, we studied the differences which appeared in the composition of parasite communities of this species.

Sperm ultrastructure of the digenean Aphallus tubarium (Rudolphi, 1819) Poche, 1926 (Platyhelminthes, Cryptogonimidae) intestinal parasite of Dentex dentex (Pisces, Teleostei).

The ultrastructural organization of the spermatozoon of a cryptogonimid digenean, Aphallus tubarium, a parasite of Dentex dentex, is described. The spermatozoon possesses the elements found in other digeneans: two axonemes with 9+"1" pattern, a mitochondrion, a nucleus, cortical microtubules, external ornamentation and spine-like bodies. However, the mitochondrion appears as a cord with a bulge; this characteristic has never been described in other studied cryptogonimid and in other digeneans except in one lepocreadiid, Holorchis micracanthum. Likewise, the presence of a thin cytoplasm termination in the anterior part of the spermatozoon has never been pointed out in the cryptogonimids.

Ultrastructural study of spermiogenesis and the spermatozoon of Cavisoma magnum (Southwell, 1927) (Acanthocephala, Palaeacanthocephala, Cavisomidae), from Siganus lineatus (Pisces, Teleostei, Siganidae) (Valenciennes, 1835) in New Caledonia.

This paper presents an ultrastructural study of Cavisoma magnum (Acanthocephala, Cavisomatidae) with a Transmission Electron Microscopy tool. This parasite of the fish Siganus lineatus is here reported for the first time from off New Caledonia, South Pacific. It is the first study describing the ultrastructure, spermiogenesis and spermatozoon of a species of the family Cavisomatidae. The young spermatid of C. magnum possesses a centriole constituted of doublets without a central element. After the elaboration of a flagellum of 9+2 pattern, the centriole migrates in a nuclear groove. Then the flagellum migration occurs and gives rise to a spermatozoon. The distribution and the size of the protein granules are reported and the posterior extremity appears like a chromatin lamina wave. Comparative ultrastructural data are presented on sperm and spermiogenesis of the Acanthocephala and Rotifers examined to date and the phylogenetic implications are discussed.

Sperm ultrastructure of Helicometra epinepheli (Platyhelminthes, Digenea, Opecoelidae), parasite of Epinephelus fasciatus (Pisces, Teleostei).

This paper describes the ultrastructure of the mature spermatozoon of the digenean Helicometra epinepheli. The ultrastructural elements observed are: two axonemes with a 9+"1" pattern of Trepaxonemata, four attachment zones, a nucleus, two mitochondria, external ornamentation of the plasma membrane, spine-like bodies and cortical microtubules. A particularity of this spermatozoon is the presence of an apical cone. However, the spermatozoon presents the general pattern of the Opecoelidae and thus differs from Helicometra fasciata (which appears as an exception in this family) by several ultrastructural features: the presence of external ornamentation and spine-like bodies and the arrangement of cortical microtubules around the first mitochondrion in the region of the ornamentation. Each ultrastructural feature is discussed and compared with the literature to highlight characters which could be useful for phylogeny.

Spermatozoon ultrastructure of Gyliauchen sp. (Digenea: Gyliauchenidae), an intestinal parasite of Siganus fuscescens (Pisces: Teleostei).

The ultrastructure of the mature spermatozoon of Gyliauchen sp., a parasite of the dusky rabbitfish Siganus fuscescens, was studied by transmission electron microscopy. The spermatozoon possesses two axonemes of the 9+"1" pattern of Trepaxonemata, four attachment zones, one mitochondrion, a nucleus, cortical microtubules, external ornamentation of the plasma membrane, and spine-like bodies. The main characteristics of this spermatozoon are the presence of one mitochondrion, spine-like bodies not associated with the external ornamentation, and a posterior extremity of type 3 that is characterized by the following sequence: posterior extremity of the nucleus then posterior extremity of the second axoneme. Numerous other ultrastructural features are also discussed and compared to the digenean spermatology literature. This is the first study of a member of the Gyliauchenidae and the fourth within the Lepocreadioidea. The results show that many ultrastructural characters are variable within this superfamily and could be useful for phylogeny.

Spermatozoon ultrastructure of Aponurus laguncula (Digenea: Lecithasteridae), a parasite of Aluterus monoceros (Pisces: Teleostei).

The mature spermatozoon of Aponurus laguncula, a parasite of the unicorn leatherjacket Aluterus monoceros, was studied by transmission electron microscopy. The spermatozoon possesses 2 axonemes of the 9+"1" trepaxonematan pattern, attachment zones, a nucleus, a mitochondrion, external ornamentation of the plasma membrane and cortical microtubules. The major features are the presence of: 1) external ornamentation in the anterior part of the spermatozoon not associated with cortical microtubules; 2) one mitochondrion; and 3) cortical microtubules arranged as a single field in the ventral side. The maximum number of microtubules is in the nuclear region. The extremities of the axonemes are characterized by the disappearance of the central core and the presence of microtubule doublets or singlets. This study is the first undertaken with a member of the Lecithasteridae and exemplifies the sperm ultrastructure for the superfamily Hemiuroidea.

Ultrastructural study of the spermatozoon of Heterolebes maculosus (Digenea, Opistholebetidae), a parasite of the porcupinefish Diodon hystrix (Pisces, Teleostei).

This paper describes the ultrastructure of the mature spermatozoon of Heterolebes maculosus. It is the first study of this kind concerning the Opistholebetidae (Platyhelminthes, Digenea). The ultrastructural elements observed in the spermatozoon are: two axonemes with 9+"1" pattern of Trepaxonemata and their attachment zones, two mitochondria, a nucleus, cortical microtubules, external ornamentation of the plasma membrane and spine-like bodies. The number and the disposition of cortical microtubules, the organisation of 11 cortical microtubules disposed in semi-circle around the first mitochondrion in the external ornamentation region and the organisation of the posterior part of the spermatozoon are discussed. Three principal types of posterior part of digenean spermatozoa are proposed. The similarity between the spermatozoon of the Opistholebetidae H. maculosus and Opecoelidae enables us to confirm that these two families are closely related.

Influence of season and host age on wild boar parasites in Corsica using indicator species analysis.

The indicator value (Ind Val) method which combines measures of fidelity and specificity has been used in a study on wild boar parasites in Corsica during 2001-2003. Because of its resilience to changes in abundance, IndVal is a particularly effective tool for ecological bioindication. The Ind Val method showed how season can influence the occurrence of parasite species in the wild boar, and also identified parasites as bioindicators relative to host age. The randomization test identified five parasite species having a significant indicator value for the season (the ticks, Hyalomma aegyptium and Rhipicephalus sanguineus, the louse, Haematopinus suis and the nematodes Globocephalus urosubulatus and Ascaris suum and two indicator species of an age class (the nematodes G. urosubulatus and Metastrongylus sp.). Data on species composition and infection levels would help improve the monitoring and management of parasitism in Suidae populations.

[Factors favouring necrosis after curietherapy for oral cavity epitheliomas (author's transl)]. / Facteurs favorisant la survenue des nécroses après curiethérapie des épithéliomas de la cavité buccale.

The authors studied the factors which favour necrosis after curietherapy, in a series of 82 patients with epithelioma of the oral cavity and a previous series of 280 cases. The principal factor is the size of the tumor. The other factors (macroscopic appearance, dose, quantity of radioactive material, degree of inhomogeneity, distance between the lines, association with external irradiation), are or only moderate importance, as shown by the variations observed, though they are difficult to evaluate in an exact manner, partly for methodological reasons. The frequency of necrosis of bone tissue is directly relaxed to the number of radioactive lines in contact with the maxilla. Alcohol and tabacco abuse have a definite influence but this cannot be calculated. In conclusion, therefore, it would appear possible to reduce the frequency of necrotic lesions by reducing the tumoral size by curietherapy, by applying no more than 2 lines in contact with the mandible for bony necrotic lesions, and by stopping the abuse of alcohol and tobacco.