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A G Chabaud

Publications and source records attributed to A G Chabaud.

At least 55 records · Page 3Linked to original sources
PubMed1988

[Redescription of Dictyocaulus noerneri Ralliet et Henry, 1907, parasite of Capreolus capreolus in Europe. Comparison with D. viviparus (Bloch, 1782), a parasite of cattle].

Both species are easily distinguished by the shape and the thickness of the buccal ring. In D. noerneri, the buccal ring is 12-14 microns high, kidney like shape in optical section and thick in en face view. In D. viviparus, the buccal ring is 22-25 microns high, triangular shape in optical section and thin in en face view. The taxon Dictyocaulus eckerti Skrjabin, 1931, described from Rangifer larandus in Western Siberia, has been misused to call the Dictyocaulids of european Cervidae. If those are identical to the species of the reindeer, D. eckerti must be synonymysed with D. noerneri, if the two species are different, in any case the Dictyocaulids of european Cervidae must be called D. noerneri.

Animals↗
PubMed1988

Experimental modifications of the circadian rythm of Plasmodium vinckei petteri following cryopreservation; probable resistance of the merozoïte to thawing.

Plasmodium vinckei petteri, in white mice, is a particularly useful strain for studies on the circadian rythm of Plasmodium. An experimental model was set up: it showed that the rythm of asexual schizogony in the blood varies with the time and the mode of inoculation (cryopreserved blood or syringe passage). When frozen blood is injected, the time of schizogony depends on the time of injection; on the contrary, when the passage is by syringe from mouse to mouse, the rythm of schizogony is the same in the donor and the receptor mouse, regardless of the time of injection. The only possible explanation is that all intracellular parasites are destroyed by the thawing of blood and the free merozoïte is the only resistant stage.

Animals↗
PubMed1988

Forest and savanna onchocerciasis: comparative morphometric histopathology of skin lesions.

A comparative study was made of skin biopsies from onchocerciasis patients living in the forest and in the savanna of West Africa. The lesions and their pathogenesis were similar in the two series of patients. An inflammatory reaction around the extra-lymphatic microfilariae was observed. But the localization of the microfilariae was slightly different: the mean distances between the microfilariae and the border of the basement membrane of the epidermis was approximately 115 microns in the forest and 138 microns in the savanna. Statistical analysis showed that the forest microfilariae were in the superficial parts of the dermis when the densities were low and in deep parts of the dermis when the densities were high. In the savanna, the phenomenon, although less clearly defined was reverse. The two situations were inverted when the density of microfilariae reached approximately 51 microfilariae per calibrated snip, which was seldom the case. Therefore, the most cases, microfilariae appeared to have been more superficial in the forest than the savanna.

Adolescent↗
PubMed1987

Relationships between cercarial indices of Schistosoma haematobium, S. bovis and S. curassoni from Senegal and the isoenzyme genotypes of the adult worms.

S. haematobium and S. curassoni appear to consist of three and two G6PDH genotypes respectively whereas only a single genotype has been observed in S. bovis. This genotype corresponds to one of those exhibited by S. curassoni, but the two species may be distinguished using the AcP enzyme system. The antero-dorsal cercarial indices for S. haematobium gave a mean of 0.78 ranging from 0.67 +/- 0.03 to 0.90 +/- 0.11; S. curassoni gave a mean of 1.11, ranging from 1.00 +/- 0.05 to 1.23 +/- 0.14 and S. bovis a mean of 1.30 within the range 1.01 +/- 0.25 to 1.67 +/- 0.18. From these data it is apparent that there is some correlation between antero-dorsal Cl and enzyme genotype: nevertheless the variation in Cl is somewhat greater than that observed in enzyme genotypes. Generally, Cl values lower than 0.90 can be considered to be due to S. haematobium, those above 1.15 to be S. bovis and intermediate values of 0.90-1.15 indicate S. curassoni.

Animals↗
PubMed1987

[Morphology of the teguments of Schistosoma haematobium; comparison with S. curassoni, S. bovis and S. intercalatum].

Study by SEM of the anterior dorsal teguments of male Schistosoma haematobium from infected rodents. Only paired males, at least hundred days post infection, display a typical morphology. Differentiation from other closely related species obtained experimentally from rodents is possible: bovis: no spines on the tubercles; haematobium: tubercles 10 to 15 microns wide with closely packed spines; curassoni: tubercles over 15 microns wide, with large, closely packed spines; intercalatum: tubercles under 10 microns wide, with scattered spines. It is suggested that the three haematobium genotypes A, B and D are slightly different: A: pointed spines, numerous small additional spines between the tubercles; B: pointed spines, no small additional spines between the tubercles; D: blunt spines. Moreover, the lengths of the prepatent periods in the molluscs of the three S. haematobium genotypes are possibly different: A 72-86 days, B 38-46 days, D 55-58 days. The differentiation of A, B and D is supported by limited data and conclusions on this particular aspect are presented only as a working hypothesis.

Animals↗
PubMed1987

[Morphology of the teguments of Schistosoma bovis; variations linked to the vertebrate host; comparison with S. curassoni].

S. E. M. study of the dorsal anterior one third of male Schistosoma bovis and of the anterior ventral border of the gynaecophoric duct. S. bovis was previously described as possessing spineless tubercles. This is so in specimens obtained from experimentally infected rodents, but in cattle, on the contrary, when conditions are favourable, teguments have spiny tubercles. Two morphological types have been observed: the first in Bos taurus from Sardinia, the second in domestic (Bos indicus) and wild (Hippotragus equinus and Damaliscus korrigum) bovids from Senegal, Tchad and Centrafrican Republic.

Animals↗
PubMed1987

[New filaria of the Cercopithifilaria genus, parasite of an African carnivore].

Description of Cercopithifilaria corneti sp. n., a parasite of the subcutaneous tissues of Nandinia binotata, is given. With its 16 species parasitizing a variety of mammals from all over the world, the genus Cercopithifilaria has a homogeneous morphology and a uniform biology (dermal microfilariae, ixodid vectors). It is suggested that the unexpected host range is the consequence of particular speciation phenomena in relation to the biology of Ixodidae.

Africa↗
PubMed1986

[Anatomo-pathologic study of skin and ocular lesions in rodents infested by Monanema spp.: significance for the study of human onchocerciasis].

Skin and ocular lesions were studied in murids Lemniscomys striatus L. infested by 2 isolates of Monanema spp, a rodent filaria with skin-dwelling microfilariae. Histologic examination disclosed microfilariae in lymphatic vessels. Penetration of microfilariae in extra-vascular tissues caused vascular changes, subacute inflammatory cells infiltration, granulomatous nodules and scarring lesions. These alterations corresponded to the successive stages of an inflammatory process. No correlation noted between tissular lesions, delay of filarial infestations and number of microfilariae in the "snip". The presence of lesions in one or several tissular areas demonstrated that extravascular escaping of microfilariae was not synchronous. Symptomatology of filariasis depended on the localization of the lesions. Similarities between the lesions noted in murids Lemniscomys striatus L. and those observed in man showed that the 2 isolates of Monanema spp. used in this study were very close to O. volvulus in the pathological domain. They might be considered as a valuable and reproducible experimental model.

Animals↗
PubMed1986

[Atlas of infective larvae of filariae].

The family Onchocercidae contains 78 genera, all of which are filarial parasites transmitted by blood-sucking vectors. The infective larval stages of 34 genera are described, including representatives of all those genera with large numbers of species and with the highest pathogenicity for man. A dichotomous key for the identification of infective larvae is presented, which may prove useful for epidemiological studies. Only the most easily recognized morphological characteristics have been taken into account. They appear to be of phylogenetic significance, for the correlation between these characters and the various genera currently recognized in the family Onchocercidae is good.

Animals↗
PubMed1985

[Survey on Schistosomes of man and livestock in Senegal using specific identification given by chetotaxy of cercaria. I. New arguments for the validation of S. curassoni Brumpt, 1931, parasite of man and domestic Bovidae].

Study of Senegal cercariae emitted by naturally infected snails or by snails experimentally infected using eggs from human urine or from sheep liver, and study of the corresponding eggs. The relative position of the dorsal sensillae of cercariae is described by an "AD index" and the ratio length/width of eggs by an "L/l index." At the present time, we have not finished the epidemiological studies, certain experiments are imperfect and the isoenzyme analysis of the corresponding adults is incomplete. Nevertheless information given by the indices AD and L/l agree and lead us to admit the existence of a Schistosome different to mattheei, haematobium and bovis and which, following Brumpt and Gretillat we refer to as Schistosoma curassoni. If one relies on the indices, the study indicates that: a) S. mattheei has not been found in Senegal, b) S. bovis is quite rare, c) S. haematobium apparently exists in pure infections in Casamance and in mixed infections with S. curassoni in man in the north and in the east, d) S. curassoni is apparently the dominant species in domestic ruminants and in man in the north and in the east, e) Bulinus umbilicatus is the principal vector of S. curassoni and S. haematobium.

Animals↗
PubMed1984

[New Haemoproteidae parasites of Chiroptera in Thailand].

Hipposideros larvatus of Thailand are parasitized by two new Haemosporidia : a) Nycteria brucechwatti n. sp. can be differentiated from all other Nycteria species by the schizonts which are the largest in the genus and by the absence of accessory chromatin dots in the gametocytes; Biguetiella minuta n. g. n. sp. has very small intra-hepatocytic schizonts (less than 15 micron) and gametocytes of the "falciparum" type. These two species are considered as vicariant forms of parasites of Miniopterus, namely Polychromophilus and Bioccala. The subgenus Bioccala is raised to genus status and problems related to the study of polyparasitic infections of the same host are discussed.

Animals↗
PubMed1982

[New data on the Dipetalonema lineage (Filarioidea, Nematoda)].

The evolutionary line of Dipetalonema can apparently be divided into four groups: I: Australian species; II: paleoendemic South American species; III: the Tetrapetalonema group; IV: the Acanthocheilonema group. Loxodontofilaria at present insufficiently known to be classified and several species belonging to the Acanthocheilonema group are the object of the present study. Descriptions are given of Loxodontofilaria asiatica n. sp., parasite of Elephas indicus in Burma, Cercopithifilaria degraaffi n. sp., parasites of Papio ursinus in South Africa, C. cephalophi n. sp., parasite of Cephalophus dorsalis and C. gabonensis n. sp., parasite of Atherurus africanus in Gabon. Additional morphological data are given on Cercopithifilaria didelphis, C. rugosicauda, Acanthocheilonema pachycephalum, A. viteae, Molinema dessetae, Dipetalonema gracile, Orihelia sp., Skrjabinofilaria skrjabini, Breinlia (B.) spratti, Litomosa sp., Loxodontofilaria hippopotami. Yatesia n. gen. with type species Yatesia hydrochoerus (Yates, 1980), is proposed, distinguished by specialized characters of the posterior extremity. The genus Cercopithifilaria is used to accomodate species considered as specialized Acanthocheilonema. Chenofilaria is placed in synonymy with Acanthocheilonema. Loxodontofilaria includes the three filarid species from elephants, L. loxodontis, L. gossi, L. asiatica n. sp. and the species from the Hippopotamus, L. hippopotami; D. okapiae is considered a species inquirenda. The interpretation given for the neotropical fauna is the following: --Skrjabinofilaria, Orihelia, Dasypafilaria and Dipetalonema may be true paleoendemics in South America. --Molinema and Ackertia on the one hand and Yatesia on the other may be forms of African origin introduced at the end of the Eocene during the migration of African rodents into South America. The cpature in American reptiles (the genus Macdonaldius) could have occurred during this period. --Surprisingly, the two species of Dipetalonema in Didelphis may be late captures of neartic origin: A. pricei from Acanthocheilonema in carnivores and C. didelphis from a Cercopithifilaria in eutherian mammals.

Africa↗
PubMed1981

[Quentius kozeki n. g., n. sp., rictularid nematode parasite in an American marsupial (author's transl)].

Description of the female of Quentius kozeki n. g., n. sp., parasitic in Marmose at Cali (Columbia). Because of its cephalic structure, the species is considered to be the most primitive Rictulariidae actually known. In addition, however, it has aberrant and specialized characters. The existence of this species seems to indicate that the rictularioids were established as early as the Cretaceous in American marsupials. They could have been maintained in these animals at least until the Oligocene before invading Northern rodents of the Nearctic region. From these hosts, as Quentin (1971) demonstrated, there was a North-South evolution throughtout the world.

Animals↗
PubMed1981

[Description of Spirobakerus weitzeli n. g., n. sp., and remarks on the Nematodes Spirocercidae (author's transl)].

Description of Spirobakerus weitzeli n. g., n. sp., parasitic in a Cricetidae of Columbia and revision of the Neotropical Spirocercidae. The taxa Leiuris vazipereirai (Lopez-Neyra, 1951) n. comb. and Texicospirura cesticellus (Molin, 1860) n. comb. are proposed. The endemic neotropical Spirocercidae include: --Four paleoendemic genera: Didelphonema in marsupials, Leiuris in the Bradypodidae, Tejeraia in Caviomorphs and tapirs, and Spirobakerus in the Cricetidae (which in interpreted as an example of the capture phenomenon). Given the conspicuous development and anterior location of the median cephalic formations, these four genera are considered as the most primitive Spirocercidae in the world fauna. --Two recently endemic forms: Texicospirura in peccarries and Physocephalus lassancei in cervids. Their more evolved morphological characters seem to indicate a much later introduction into the Netropical zone.

Animals↗
PubMed1981

[On the Filariae of the genus Aproctella (Splendidofilariinae) (author's transl)].

Aproctella alessandroi n. sp., parasitic in various Passeriformes in Colombia and Guadeloupe, and A. golvani n. sp., a similar species with smaller microfilariae parasitic in sparrows in Guadeloupe, are described. The life cycle of A. alessandroi was studied in Aedes togoi (development in 13 days in the flight muscles; first-stage larva cylindrical; third-stage larva 1 330-1 600 microns long; oesophago-intestinal junction distinct). The larval biology of Aproctella is very similar to that of Cardiofilaria, confirming the close relationship of these two genera. The biology differs from that of two other genera of Splendidofilariinae of birds, Splendidofilaria and Chandlerella (vectors: Culicoides and Simuliids; development in flight muscles and haemocoel; first stage larva almond-shaped; third stage larva 400-600 microns de long; oesophago-intestinal junction indistinct). In these latter genera, the larval biology is remarkably similar to that of Lemdaninae of reptiles and birds (Saurositus, Eufilaria). It seems there is not a distinct separation between the Splendidofilariinae and the Lemdaninae.

Animals↗