Over the past few years, the cercarial dermatitis has become a new problem of public health, obviously linked to the prolonged stay of migrant birds on our territory. This is a skin affection ...characterized by pruriginous and papulous eruptions caused by penetration of avian bilharzian larvae under the skin. These larvae are emitted by molluscs, mostly limneids. In aquatic birds, especially in migrating Anatidae, these larvae reach the visceral vessels, become adults in a few weeks, lay eggs, then degenerate. Corresponding miracidia contaminate new limneids. Since 1993, the total number of annual cases of cercarial dermatitis has increased from only ten to thousands in France and the affection rages in pools where limneids, migrating water birds and swimmers gather together. Fever, respiratory and/or digestive allergic symptoms appear in some cases. This clinical pattern has encouraged to undertake research on the future of these bilharzian larvae in mammals organism. A preliminary investigation on a rodent model showed that, once the skin barrier had been crossed, the schistosomulae migrated into the lungs of the host; there they survived a week and induced lesions. The goal of this study is to carry on the research, over a longer period, after exposure to cercariae, simultaneously in mammals and birds, with two species of bilharziae present in France. The selected models are the gerbil Meriones unguiculatus for mammals, and the ducks Anas platyrhynchos and Cairina moschata, for birds. 5 M. unguiculatus and 2 A. platyrhynchos were exposed to cercariae emitted by Radix auricularia; 2 gerbils and 5 A. platyryhnchos to larvae of R. peregra, 3 C. moschata to larvae emitted by two species of molluscs: 70-230 from R. auricularia and 330-585 from R. peregra. 5 gerbils died between 2 and 5 weeks after exposure, 2 gerbils sacrificed early, served as control animals for skin manifestations. Eight ducks were sacrificed between 2 and 4 weeks after; the 2 last ones, exposed several times, were sacrificed respectively 7 and 13 weeks after the first exposure. Visceral and skin samples were submitted to histological study. The control gerbils developed skin dermatitis. In ducks, R. auricularia was the vector of Trichobilharzia franki, whose selective dwelling site was the mesentery; R. peregra was the vector of an indeterminate species found in the lungs and nose. This species is called Bilharzia sp. in this study. The ducks, exposed to two kinds of larvae, displayed worms in these two main locations. In gerbils, T. franki induced lesions in the mesenteric veins and the peritoneum. Bilharzia sp. gave rise to lesions in lung arteries, pleura and liver veins. Vascular changes encompassed endothelitis and lymphocytic vasculitis, while serosa displayed mesothelial hyperplasia. The types of lesions observed in gerbils were noticed in ducks, and, according to the species of bilharzia, in the homologous viscera. Additional foreign body granulomas centred on worm's debris or their eggs, and vascular thromboses were present, too. In addition, ducks displayed lesions involving several other viscera including the intestine, the kidneys and the peripheral nerves. These changes were multiple and diffuse in C. moschata exposed to two species of bilharziae. They were observed mainly in mesenteric and intestinal vessels, pulmonary arteries and hepatic veins. In gerbils, the lesions persisted 2 to 5 weeks after exposure, but worms were not identified in the neighbouring tissues near the damaged vessels. In ducks, lesions were important between 2 and 7 weeks after exposure; they co-existed with live or dead worms, sometimes paired, with or without eggs. The hepatic lesions regressed 13 weeks, after exposure. In mammals and birds, young worms could migrate into the same visceral vessels, and stimulating formation of persistent lesions. In individuals exposed to the same cercariae, development of similar lesions would be probable.
Summary
The authors present marsh rat Holochilus brasiliensis, jirds Meriones shawi and M. unguiculatus as new models of Schistosoma haematobium infection. Histological findings were compared with ...those of classic models mouse Mus and hamster Mesocricetus. In new models, embryonated eggs were seen in the stool from 90 days post infestation (DPI) and active disease developed from 117 to 175 DPI. Seven out of 10 rodents presented granulomatous and/or chronic cystitis, fibrosis, polyps and urothelial changes: squamous metaplasia, precancerous dysplasia and squamous cell carcinoma of the urinary bladder. In the digestive tract of all new models, granulomas eroded the mucosa, formed inflammatory polyps, infiltrated the wall and accumulated into bilharziomas. In the liver, granulomatous hepatitis surrounded by bilharzial pigment deposit was apparent. Pipe‐stem fibrosis involved 4 rodents with precirrhotic changes in 1 and portal hypertension in 2. One female Meriones suffered from granulomatous endometritis and salpingitis. All new models developed pulmonary granulomatosis with associated vascular lesions: giant cell arteritis in 1 rodent, thromboses in 3 and pulmonary hypertension in 4 others. In classic models, 1 Mus presented a squamous cell carcinoma of the urinary bladder while Mesocricetus displayed diverse lesions in digestive and genital tracts, liver and lungs. All tissue lesions, resembling those seen in humans in all points, were far more frequent and severe in new models than in classic ones. Those involving the urinary bladder have never been reported in other models such as monkeys: Pan troglodytes, Cercopithecus aethiops and Cebus apella. A comparison was carried out between different models on the basis of experimental conditions: definitive hosts, number of cercariae used, type and duration of infection. This study clearly demonstrated that Holochilus brasiliensis, Meriones shawi and M. unguiculatus are perfectly adequate models in terms of laboratory facilities. They are helpful in investigating the pathogenic mechanism of some disorders in S. haematobium infection, particularly tumours of the urinary bladder, and this may enhance therapeutic assays.
Euparyphium albuferensis Esteban et al., 1997 (Trematoda: Echinostomatidae) is a parasite of the mollusc Gyraulus chinensis (D.) (Gastropoda: Planorbidae) and the mammals Rattus spp. in a nature park ...near Valencia, Spain. In the present work, the cercarial chaetotaxy is fully determined for specimens emitted by naturally infected G. chinensis. Of particular importance are the following sensillary arrangements: 5 CIV DL, 3 CIV CIV D at the dorso-cephalic level and 0 UV and 22-26 UD in the tail. Evidence is presented to the effect that these sensillary clusters are characteristic of the genus Euparyphium and allow an easy diagnosis, unlike in the case of the adult worms where there are sometimes few or no differences between Echinoparyphium and Echinostoma. A table synthesises the main data on the cercarial sensilla of Euparyphium spp. and the closely related genera Echinoparyphium, Echinostoma, Hypoderaeum, Moliniella, Neoacanthoparyphium, Paryphostomum and Isthmiophora. This shows clear variations in their respective numbers, from 3-5 in CIV DL, 2-4 in CIV D, 0-15 in UV and 19 to 57 in UD, according to the genus. These clusters appear adequate to identify, at the cercarial stage, the principal genera of the Echinostomatinae.PUBLICATION ABSTRACT
Des ressemblances chétotaxiques rapprochent Deropristis sp. (Acanthocolpidae) Lepocreadium album (Lepocreadiidae) Cainocreadium labracis (Opecoelidae) et Diphterostomum brusinae (Zoogonidae) que nous ...décrivons. Les mêmes traits se retrouvent chez onze autres cercaires précédemment décrites, c’est-à-dire chez Allocreadium ictaluri décrite par Seitner en 1951, chez huit cercaires d’Allocreadiidae, Opecoelidae et Zoogonidae décrites par J. Richard en 1971, chez Cercaria micrura décrite par M. Lambert en 1972 et chez Cercaria doricha pigmentata (cercaire rhodométope) décrite par Ch. Bayssade-Dufour en 1973. La comparaison de ces quinze cercaires permet donc de les attribuer à une même superfamille : les Allocreadioidea et de définir les caractères chétotaxiques de cette superfamille ; ce sont CID = une papille ; AID médiodorsal = 0 ou 1 papille ; S = 3 ou 4 cycles ; CIIO présent ; et chez les cercaires modèles, U = 6 ou plus de 6 papilles, réparties selon 4 axes chez les Allocreadiidae, Acanthocolpidae et les cercaires rhodométopes, selon 2 axes chez les Lepocreadiidae et en cercle sur le moignon caudal chez les Opecoelidae. A ces traits communs se superposent des traits différentiels ; quelques familles ont une chétotaxie de type primitif à symétrie dorso-ventrale très nette, d’autres ont une chétotaxie de type évolué sans symétrie dorso-ventrale. La corrélation qui existe entre le type de chétotaxie (primitif ou évolué), le mode de formation des cercaires (dans des sporocystes ou dans des rédies) et l’existence ou l’absence, parmi les caractères allocreadioides, d’un petit reliquat de caractères chétotaxiques plagiorchioides, permet de formuler une hypothèse sur l’origine et l’évolution des Allocreadioidea. Ceux dont la chétotaxie est de type primitif présentent un reliquat de caractères plagiorchioides (S = 2 cycles par exemple) et naissent dans des sporocystes ; ils seraient peu éloignés du branchement plagiorchioide-allocreadioide : ce sont les Zoogonidae et les cercaires rhodométopes. Des familles à symétrie chétotaxique dorso-ventrale moins accusée, naissent soit dans des sporocystes, soit dans des rédies et ont une chétotaxie strictement allocreadioide. Elles sont plus éloignées du branchement plagiorchioide-allocreadioide. Ce sont les Opecoelidae et les Allocreadiidae. Des familles sans symétrie chétotaxique dorso-ventrale, possédant une chétotaxie strictement allocreadioide (S = 3 ou 4 cycles) et naissant dans des rédies, n’ont plus aucun point commun avec les Plagiorchioidea. Ce sont les Allocreadioidea les plus évolués. Ils sont représentés ici par les Acanthocolpidae et les Lepocreadiidae.
The species hereby described : Deropristis sp. (Acanthocolpidae), Lepocreadium album (Lepocreadiidae), Cainocreadium labracis (Opecoelidae) and Diphterostomum brusinae (Zoogonidae) are related by their chaetotaxic similarities. The same features are found among eleven previously described cercariae i.e. in Allocreadium ictaluri described by Seitner in 1951, in eight cercariae from Allocreadiidae, Opecoelidae and Zoogonidae described by J. Richard in 1971, in Cercaria micrura described by M. Lambert, 1972, and in Cercaria doricha pigmentala (rhodometopa cercaria) described by Ch. Bayssade-Dufour in 1973 A comparison established between these fifteen cercariae enabled the authors to include them in one superfamily : Alloereadioidea and to state its chaetotaxic characters which are the following ones : CID = I papilla, mediodorsal AID = O or I papilla, S = 3 or 4 circles ; presence of CIIO, U ⩾ 6 papillae in urodel cercariae distributed along four axis in Allocreadiidae Acanthocolpidae and rhodometopa cercariae, along two axis in Lepocreadiidae and on one circle on the reduced tail of Opecoelidae. Some differentiating features are added to the common ones ; some families have a primitive-type chaetotaxy with conspicuous dorso-ventral symmetry, while other families display a highly-evoluted type of chaetotaxy without a dorso-ventral symmetry. The correlation found between the type of chaetotaxy (primitive or evoluted), the pattern of cercariae formation (arising from sporocysts or rediae), the presence of lack among the allocreadioid characters of a small residuary lot of plagiorchioid chaetotaxic characters have enabled the authors to put forward an hypothesis of the origin and the evolution of the Alloereadioidea. Those which retain a primitive type of chaetotaxy, display some residuary plagiorchioid characters (S = 2 circles for instance) and arise from sporocysts ; they might not be so far removed from the branching of Plagiorchioidea from the Alloereadioidea : they include the Zoogonidae and the rhodometopa cercariae. Some families showing a less pronounced dorso-ventral chaetotaxic symmetry arise either from sporocysts or from rediae and have a strictly allocreadioid chaetotaxy. They are more distant from the plagiorchioid-allocreadioid branching. They include the Opecoelidae and Allocreadiidae. The other families which have no dorso-ventral chaetotaxic symmetry, but showing a strictly allocreadioid chaetotaxy (S = 3 or 4 circles) and arising from rediae, have not any more common features with the Plagiorchioidea. They include the most highly evoluted Alloereadioidea. They are recorded here as the Acanthocolpidae and the Lepocreadiidae.
The disposition of cercarial papillae of 68 pre-identified Schistosoma species was established. All the cercariae originated from Africa and Madagascar and were either obtained from natural or ...experimental infections, and belonged to three species Schistosoma haematobium, S. bovis and S. curassoni. Discriminant analysis was based on nine characters: average values, skewness and kurtosis of three cercarial indices (AD, AL and U) for each sample or isolate. AD, AL correspond respectively to the relative distance between dorsal and lateral papillae. U corresponds to the total number of tail stem papillae. With the exception of two cases of the 68 (one of them corresponding to cercariae shed by a non-African experimentally infected snail), the method enabled discrimination of S. haematobium, S. bovis and S. curassoni.
La bilharziose intestinale humaine provoquée par Schistosoma mansoni est une maladie africaine introduite depuis trois siècles environ en Amérique du Sud et aux Caraïbes. Les soies antéacétabulaires ...latérales et les soies caudales préfurcales de la cercaire permettent de différencier les souches africaines des souches américaines. L’établissement d’un indice portant sur les distances relatives entre certaines soies antéacétabulaires est susceptible de fournir des données objectives sur le difficile problème posé par l’adaptation des souches humaines aux Rats. L’adaptation d’un souche humaine aux Muridés ne s’effectue pas par une sélection brutale au cours du premier passage, comme il est habituel pour la plupart des parasites, mais par un phénomène complexe ne commençant à se manifester de façon décisive qu’au cours du quatrième passage environ ; expérimentalement, l’indice cercarien humain (n = 1,0) ne change pas lors des premier et deuxième passage, puis commence à se modifier au troisième passage (n = 1,3) et atteint 1,5 au quatrième passage. Cette notion d’adaptation tardive se retrouve dans l’étude de différents phénomènes observés par nous-mêmes ou nos collègues (soies du miracidium, réussite des passages expérimentaux, durée de la prépatence, traversée de la peau, etc...). L’indice des parasites adaptés au Rat (1,7), très différent de l’indice des parasites adaptés à l’Homme (1,0) nous paraît avoir une très grande importance pratique pour deux problèmes essentiels dans la bilharziose intestinale. a. Gravité des formes cliniques. On peut supposer que les souches murines seraient à l’origine des formes très graves de la maladie (cirrhose portale), car elles seraient mal adaptées à l’Homme. Il devient possible, par la simple détermination de l’indice cercarien des parasites émis par chaque malade, de voir s’il y a une corrélation entre la gravité clinique et l’indice plus ou moins élevé des cercaires, et d’infirmer ou de confirmer cette hypothèse. b. Existence de foyers murins. Une seconde question, très importante, qui se pose à propos de cette maladie, est de savoir si elle peut se maintenir spontanément chez l’animal, en-dehors de toute contamination humaine. En Guadeloupe, les nombreuses souches des différentes régions de l’île, provenant soit du Mollusque, soit du Rat, soit de l’Homme, ont un indice d’environ 1,3, différent de l’indice 1,0 d’Afrique. Cet indice pourrait provenir de l’adaptation à un Mollusque différent (B. glabrata au lieu de B. pfeifferi), mais nous pensons plutôt qu’il s’agit d’un morphe indiquant l’existence de souches passant alternativement chez le Rat et chez l’Homme. A ces données s’opposent celles d’un gîte bien particulier (celui de Grand-Etang), où l’indice cerca- rien, égal à 1,6, est comparable à celui des souches de laboratoire entretenues depuis de nombreuses années chez les Muridés. Nous croyons donc pouvoir confirmer les données épidémiologiques de Combes, Léger et Golvan, 1975, qui concluaient à l’existence d’une maladie purement murine dans ce biotope particulier.
It is generally accepted that human intestinal bilharziasis due to Schistosoma mansoni originated in Africa and was introduced into South America and the West-Indies about three centuries ago. A study of the chaetotaxy of the cercariae as well as experimental breeding showed that there are small differences between the African and American strains which can be considered infraspecific : lateral preacetabular setae are in a triangular pattern in the African strains and along a line in the American strains and there are four or five prefurcal caudal dorsal and ventral setae in the African, and six or more in the American strains. This enables the African and the American strains to be distinguished. Chaetotaxy can also throw some light on the processes leading to adaptation of Schistosoma mansoni to murine-rodents. The cercarial index (c.i.) differs between the pure human and pure murine strains. The cercarial index is the ratio of a distance between the first and second lateral preacetabular setae to the distance between the first and second dorsal preacetabular setae. The cercarial index of the human African strains (c.i. = 1.00) differs from the c.i. of the human American strains (1.10 to 1.40) and from the murine well- adapted parasites (1.69 to 2.34). Experimental infection showed that the morphological adaptation of the human strain to murine rodents is a gradual process that begins only after the third passage in murines. This observation of a slow adaptation was also noted in a change of number of miracidial setae, snail susceptibility to infection, the production of cercariae, the length of the prepatent period, as well as the ability of the different cercariae to penetrate murine of human skin. The cercarial index may be of practical importance in the understanding of clinical and epidemiological problems of bilharziasis : a. Severity of disease. One could speculate that cases of severe bilharziasis could perhaps be caused by murine strains poorly adapted to Man. It is now possible by a single determination of the cercarial index to establish the origin of the infestation. b. Epidemiological significance of chaetotaxy. An important problem raised by this disease is to know if the parasite population can persist in animals without any human contamination.
La chétotaxie cercarienne permet de différencier quatre groupes de Schistosomatinae :—Schistosomatium douthitti, parasite de Stagnicola et Lymnaea (Lymnaeidae) ;—Schistosoma japonicum, parasite ...d’Oncomelania (Melaniidae) ;—Schistosoma mansoni et S. rodhaini, parasites de Biomphalaria (Planorbiinae, Bulinidae) ;—Schistosoma haematobium, S. bovis, S. margrebowiei, S. mattheei, S. leiperi et S. intercalatum, parasites d’Isidora, Physopsis et Bulinus (Bulininae, Bulinidae). Dans le troisième groupe, elle permet l’identification de chacune des deux espèces : S. mansoni et S. rodhaini. Dans le quatrième groupe, elle montre de petites différences statistiques dans la topographie des sensilles de chacune des six espèces considérées.
The cercarial chaetotaxy permits the differenciation of four groups of Schistosomatinae.—Schistosomatium douthitti, parasite of Stagnicola and Lymnaea (Lymnaeidae);—Schistosoma japonicum, parasite of Oncomelania (Melaniidae);—Schistosoma mansoni and S. rodhaini, parasites of Biomphalaria (Planorbiinae, Bulinidae);—Schistosoma haematobium, S. bovis, S. margrebowiei, S. mattheei, S. leiperi and S. intercalatum, parasites of Isidora, Physopsis and Bulinus (Bulininae, Bulinidae). For the third group, cercaria of Schistosoma mansoni and S. rodhaini may be distinguished. In the fourth group, small statistical differences in the topography of the sensillae can be shown between the various species.
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