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Biomedical subjects

J A Rioux

Publications and source records attributed to J A Rioux.

At least 73 records · Page 4Linked to original sources
PubMed1984

[Ecology of leishmaniasis in Southern France. 18. Enzymatic identification of Leishmania infantum Nicolle, 1908, isolated from Phlebotomus ariasi Tonnoir, 1921, spontaneously infected in the Cévennes].

Out of 187 female Phlebotomus ariasi caught in the Cévennes focus of leishmaniasis 3 were found naturally infected with Leishmania. The infection in one of the three had spread from the midgut to the pharynx and proboscis. Stocks of Leishmania were isolated from two of the flies and 8 isoenzymes were examined. The newly isolated parasites were found to be indistinguishable from zymodeme 1 of Leishmania infantum s. st.

Animals↗
PubMed1984

[A new Phlebotomus for Spain. Phlebotomus (Adlerius) mascittii Grassi, 1908].

The authors have made the first discovery of Phlebotomus mascittii in Spain. The species was caught in Catalonia in the provinces of Gerona and Barcelona. Altogether 7 individual sandflies (4 male, 3 female) were collected (using oiled paper traps) in four separate sub-mediterranean sites (between 650 and 780 m).

Animals↗
PubMed1984

Ecology of leishmaniasis in the south of France. 19. Determination of the hosts of Phlebotomus ariasi Tonnoir, 1921 in the Cévennes by bloodmeal analyses.

Engorged sandflies were collected using 58 CDC light traps set up nightly for 5 weeks at 12 stations in the commune of Roquedur, Gard, France, in the Cévennes focus of leishmaniasis. Of 782 engorged females, 593 were Phlebotomus ariasi, 3 were P. mascittii and 186 were not identified. Using the precipitin ring test and counter-current immuno-electrophoresis, the bloodmeals were tested with antisera to man, leporids, rodents, canids, mustelids, equids, suids, bovids, birds, lizards and amphibia. Of 530 identified bloodmeals, 2 were avian blood, 26 were mixed meals of mammalian blood and 25 were meals taken from unidentified mammals. Of the 477 other sandflies, 211 (44.2%) had fed on canids, 107 (22.4%) on man, 70 (14.7%) on bovids (presumed to be cattle at one station and goats elsewhere), 33 (6.9%) on leporids (probably mostly domesticated rabbits), 26 (5.5%) on mustelids (probably badgers), 17 (3.6%) on horses and 13 (2.7%) on rodents (probably brown rat). The proportions of feeds on different mammals varied according to their availability at each station. When both man and dog were equally available, the dog was preferred. The finding that, away from human habitation, P. ariasi commonly feeds on mustelids suggests the need for a reappraisal of animals of this family as possible reservoirs of leishmaniasis in the Cévennes.

Animals↗
PubMed1984

Ecology of leishmaniasis in the south of France. 20. Dispersal of Phlebotomus ariasi Tonnoir, 1921 as a factor in the spread of visceral leishmaniasis in the Cévennes.

The dispersal of Phlebotomus ariasi was studied in mark-release-recapture experiments in the summer of 1980 in a valley on the north-eastern slopes of the Oiselette range in the Cévennes mountains, in the commune of Roquedur, Gard, 50 km north of Montpellier, France. More than 5,000 specimens of P. ariasi were marked with fluorescent powders and released in 9 batches at 3 different places. Seven batches were engorged females and two were unengorged females and males. From 1-29 days after release, 497 marked sandflies (approximately 9%) were recaptured by active searches with UV lamps or in 58 CDC light traps set up in groups of 4 or 5 at 12 recapture stations. Females released engorged generally remained within 250 m of the release point for the first eight days while the bloodmeal was being digested after which there was a tendency to disperse to distances greater than 350 m presumably in a search for oviposition sites or another bloodmeal. The furthest distance to which a female released engorged was shown to move was 925 m; it was caught 12 days after release. Some of the females released unfed quickly moved away from release points, sometimes to distances of 1,000 m or more. One of these was caught 68.5 hrs after release at a station 2,200 m from the release point. Male sandflies tended to stay near the point of release and were not recaptured at distances greater than 600 m. There was no evidence that the movement of the sandflies was assisted by wind. Observations on the dispersal of female sandflies confirm that leishmaniasis can be more widely spread than generally assumed by the movements of the vector.

Animals↗
PubMed1982

[Meriones shawi (Duvernoy, 1842) [Rodentia, Gerbillidae] a reservoir of Leishmania major, Yakimoff and Schokhor, 1914 [Kinetoplastida, Trypanosomatidae] in South Morocco (author's transl)].

For the first time a report is made of Meriones shawi (Duvernoy, 1842) infected by Leishmania major Yakimoff and Shokhor, 1914. The parasite was observed in two of 28 Meriones captured in the immediate vicinity of the Tata administrative center (South Morocco). M. shawi, because it is sub-commercial with man and abundant, is very likely one of the reservoirs of human cutaneous leishmaniasis in this area.

Animals↗
PubMed1982

[Enzymatic typing of 11 strains of Leishmania isolated in mainland Italy from the visceral murine, canine and vulpine forms. Demonstration of an enzymatic variant in the fox (Vulpes vulpes) and the dog].

Enzyme typing by starch gel electrophoretic techniques was carried out on 11 Leishmania isolates from Italy in laboratories in Montpellier and London. The enzymes studied in the former were ME, G-6-PD, 6-PGD, PGM, PGI, GOT (= ASAT), MDH and IDH. In London slightly different procedures were used to examine ME, 6-PGD, PGM, PGI and ASAT. In addition, SOD, ALAT, NH, and MPI were studied. The combined data revealed that four Rattus rattus and four dogs were infected with classical L. infantum (zymodème 1). In addition, two other dogs and a fox were infected with an enzyme variant (zymodème 18) which differed in four of the 12 enzymes examined. These findings raise the question of the heterogeneity of the parasites causing visceral leishmaniasis.

Animals↗
PubMed1982

[Ecology of leishmaniasis in south France. 17. Sampling of Phlebotomus by the method of adhesive traps. Comparison with the technic of capture on human bait].

In the analysis of the ecology of foci of leishmaniasis in the South of France, a comparison was made of two methods of sampling the vector: the technique of oiled paper traps and of hand-catching off human bait. The techniques, used in parallel in a rural site (Cévennes) and in an urban site (built up areas in Marseilles) gave comparable results. In the Cévennes focus of visceral leishmaniasis, Phlebotomus ariasi Tonnoir, 1921 is the dominant sandfly; in the urban focus, it is replaced by Phlebotomus perniciosus Newstead, 1911. The analysis of captures shows that, in the South of France, in general, the method of sampling by oiled papers can be used instead of man-biting catches. The former method is easier and permits work over a wide area at many places simultaneously.

Animals↗
PubMed1981

[Significance of enzymatic polymorphism in Leishmaniae--On three heterozygous stocks of Leishmania infantum Nicolle, 1908, Leishmania cf. tarentolae Wenyon, 1921 and Leishmania aethiopica Bray, Ashford and Bray, 1973 (author's transl)].

The analysis of 8 isoenzymes (PGM, PGI, G-6-PDH, 6-PGDH, IDH, MDH, ME, GOT)of 49 stocks of leishmaniae [35 of Leishmania infantum Nicolle, 1908, 10 of Leishmania cf. tarentolae Wenyon, 1921, 2 of Leishmania tropica (Wright, 1903) and 2 of Leishmania aethiopica Bray, Ashford and Bray, 1973] revealed heterozygous structures in three stocks. These structures were expressed by two (PGM) or three (PGI, 6-PGDH) spots on the electrophoretic gels. Two stocks were heterozygous for PGI alone [one of L. infantum from a dog in the Cévennes, France; one of presumed Leishmania tarentolae from Sergentomyia minuta (Rondani, 1843) from P. O., France] and one was heterozygous for PGI, PGM and 6-PGDH (L. aethiopica from man in Ethiopia). The results are comparable to those seen in eukaryotic organism with sexual reproduction and suggest that leishmaniae have diploid structures and a process of genetic exchange.

Animals↗
PubMed1981

[The application of a numerical method to the taxonomy of the genus Leishmania Ross, 1903,--The recognition of 146 original lines in the Old World. Use of allozymic characters. Epidemiological and phyletic significance (author's transl)].

Using enzyme characters determined by starch gel electrophoresis, the authors have applied the method of Numerical Taxonomy to the genus Leishmania Ross, 1903. Eight isoenzymes (PGI, ME, PGM, GOT, G-6-PDH, 6-PGDH, MDH and IDH) of 146 Old World strains are examined. 35 electromorphs, corresponding to equivalent number of isoenzymes, are identified by this method, and then grouped into 14 zymodemes. These zymodemes were used as Operational Taxonomy Units (OTU) and pairs were compared, using Jaccard's index of similarity. A matrix of association was constructed using these indices and it forms the basis for the taxonomic scheme elaborated. The final relationships are exhibited in the agglomerative dendrogram, constructed using complete linkage. The separation into phylons is confirmed by correspondence analysis. It is concluded that the original lines fall into five groups corresponding to the complexes Leishmania donovani, Leishmania tropica, Leishmania major, Leishmania aethiopica and cf. Leishmania tarentolae. The phylons as recognised by Numerical Taxonomy, can be equated with the taxa of traditional systematics. The phyletic significance of the individualized phylons is then provided by a genetic approach. Thus, it is possible to compute the genetic distances of Nei with allozyme frequency values of 0,0.5 and 1. The new dendrogram is similar to the previous one: Leishmania major constitutes an homogeneous taxon, long isolated from the others. Leishmania donovani and Leishmania tropica have retained a nonnegligible amount of genetic similarity, attesting both a common origin and a more recent evolutionary divergence.

Animals↗
PubMed1980

[Leishmania infantum Nicolle, 1908, the agent of the autochthonous oriental sore. Apropos of the biochemical identification of 2 strains isolated in the eastern Pyrenees].

Two strains of parasites isolated from cases of oriental sore in the Pyrénées-Orientales were identified by electrophoretic analysis of eight isoenzymes (PGM, PGI, G-6-PDH, 6-PGDH, IDH, MDH, ME and GOT). Both strains were identical with Leishmania infantum Nicolle, 1908, which normally causes visceral leishmaniasis. It is probable that, in the Mediterranean region, some cutaneous lesions observed within the area of visceral leishmaniasis are caused by this species rather than by Leishmania tropica (Wright, 1903) or Leishmania major (Yakimoff and Schokor, 1914) traditionally believed to be agents of cutaneous leishmaniasis in the Old World.

Aged↗
PubMed1980

Fructose in wild-caught Phlebotomus ariasi and the possible relevance of sugars taken by sandflies to the transmission of leishmaniasis.

Cold, acidified anthrone was used to test 200 wild-caught sandflies (Phlebotomus ariasi females) for the presence of fructose. This sugar, or others with a fructose moiety, were demonstrable in 157 (79%) of the flies; proportions of flies positive in different tests ranged from 44 to 91%. Higher proportions of flies gave positive results when tested less than one hour after capture than when kept in the laboratory for more than 12 hours before testing. Similarly high percentages of flies were positive in samples collected coming to engorge on dogs and in those caught in CDC miniature light traps. These results, together with published reports of the demonstration of sugars in 25 individually tested sandflies of other species confirm that, like other biting flies, sugar is an important part of the diet of sandflies. Natural sugars may influence the development of leishmaniae in sandflies and their subsequent transmission. The anthrone test was found to be simple, rapid and suitable for field use; it is a valuable addition to indirect techniques for the study of the behaviour of sandflies.

Animals↗
PubMed1978

[Ecology of intestinal schistosomiasis in Guadeloupe. Epidemiological analysis and data for a model study (author's transl)].

In Guadeloupe, during a general survey on intestinal schistosomiasis, the authors made a structural analysis of a limited focus of infection. The focus is formed by a river basin on the Carribean coast of Basse-Terre island. Sampling of the various elements of the parasitic cycle was done in spatial units defined by ecological and epidemiological criteria. The study of corresponding populations shows that: -- inside the twelve delimited sectors, only two include both hosts and parasites. They are zones with ditches and small temporary streams; -- the vector (Biomphalaria glabrata) density is always high in inhabited sectors; -- the rat, although present over the whole river basin, is only parasitized near inhabited places; -- fluorescent antibody level is an excellent indicator of the level of infection of human populations. Its variation can be detected in a time interval of less than one year; -- distance from contaminated water is one of the principal risk factors. A mathematical expression for this is given.

Adolescent↗
PubMed1976

[Autogenesis and cerebral neurosecretion in Aedes detritus (Haliday, 1833) (Diptera - Culicidae].

In anautogenous females of the Dipteran Culicidae Aedes detritus (Haliday, 1833), the neurosecretory products synthesized by the A cells of the pars intercerebralis are stored in the pericarya in absence of blood meal; on the contrary, in the autogenous females they are steadily released from emergency till the stages 3-4 of vitellogenesis; a slight storage occurs by the end of vitellogenesis. These facts suggest the important meaning of these cells in the regulation processes of vitellogenesis in Mosquitoes.

Aedes↗