Biomedical subjects

J Cabaret

Publications and source records attributed to J Cabaret.

At least 109 records · Page 6Linked to original sources

PubMed1992

A method for studying interbreeding of nematodes of the subfamily Ostertagiinae in sheep with abomasal fistulae.

Interbreeding in two nematode species, Teladorsagia circumcincta and Ostertagia leptospicularis, was studied in lambs using small populations. Offspring from a single mated female were investigated for T. circumcincta. The following protocol was found to be satisfactory for small populations: virgin females and adult males were obtained from donor lambs infected artificially and transferred into the abomasa of fistulated sheep or lambs being treated with a long-acting corticosteroid. Infective larvae obtained from cultures of faeces of fistulated sheep were given to a recipient lamb and when this animal was slaughtered it was possible to examine the adult nematodes resulting from the interbreeding. Interbreeding between one male and one female was not successful while there was limited recovery of infective larvae from the implantation of a single mated female.

Abomasum↗

PubMed1992

Interspecific interactions in naturally acquired nematode communities from sheep abomasum in relation to age of host and season in four areas of León (Spain).

The abomasa of naturally infected ewes (407) and lambs (190) from four areas of León were collected weekly over 2 years in the abattoir of León (north-west Spain). The major species and morphs found were Teladorsagia circumcincta and Trichostrongylus axei and to a lesser extent Marshallagia marshalli and Teladorsagia trifurcata. The putative interactions between species were assessed by Euclidian distances based on the results of multivariate analyses. The estimation of interaction was either based on mean intensities of worm burdens or on frequencies of nematode species within individual hosts. The areas, years, seasons and categories of sheep (ewes or lambs) did not influence the interaction estimates. These were not dependent upon the size of worm burden. The majority of interactions were positive. Slight negative interactions were found only with T. circumcincta-T. axei, T. circumcincta-M. marshalli and M. marshalli-T. axei. Positive interactions were recorded between the less frequent species.

Abomasum↗

PubMed1992

Effect of concurrent infection with Muellerius capillaris on the development of redial generations of Fasciola hepatica in Lymnaea truncatula.

The rediae of Fasciola hepatica were counted according to generation in adult and juvenile Lymnaea truncatula following single infection with Fasciola hepatica, double infection with F. hepatica and then Muellerius capillaris, or double infection with M. capillaris and F. hepatica. The rediae found in double infections were essentially first generation and an early cohort from the second generation. The following differences were observed in adult snails which underwent double infection when compared to corresponding single infections: i) dependent rediae were almost completely absent; ii) degenerating independent rediae were found in identical or decreased numbers; iii) living independent rediae of the first generation were decreased in number, while those of the second generation had variable decreased numbers. The results were similar in juvenile snails with double infections, except that the numbers of degenerating independent rediae were higher than those found in corresponding single infections and the numbers of rediae of the second generation were increased. The order of exposure in double infections had no influence on the number and maturation of fasciolid rediae.

Animals↗

PubMed1992

Influence of desiccation of faeces on survival and infectivity of first-stage larvae of Muellerius capillaris and Neostrongylus linearis.

First-stage larvae of pure strains of M. capillaris and N. linearis (Nematoda: Protostrongylidae) from goats were used to assess the influence of rapid desiccation on survival. M. capillaris survived desiccation of faeces better than N. linearis. The latter species was particularly susceptible to duration of storage after desiccation (0 to 10 days). Surviving larvae of desiccated batches of M. capillaris were less able to infect the land-snail Candidula intersecta. Resistance of first-stage larvae to desiccation is a key factor in infectivity and may partly account for the geographical distribution of the two species of protostrongylids.

Animals↗

PubMed1992

Identification of Schistosoma mansoni, S. rodhaini, S. bovis, S. haematobium, and S. intercalatum cercariae using segmentation analysis.

Cercariae of five species of schistosomes identified with certainty were fixed in boiled alcohol and mounted in glycerol-alcohol mixture. The cercarian body (Cbl) and tail-furcae lengths (Ctl) were measured, the values of which were treated using a computer. Even mean values allowed partly identification of the present species, the segmentation analysis gave better informations for separating any cercaria taken at random, with a given probability (p). Thus, five classes (A, B, C, D, E) have been established: class A: Cbl > 139 microns and Ctl, > 236 microns, p = 0.59 to be considered as S. bovis; class B: Cbl > 139 and Ctl < 236, p = 0.86 to be considered as S. haematobium; class C; Cbl < 114 microns, p = 0.75 to be considered as S. intercalatum; class D: 114 < Cbl < 125 microns, p = 0.57 to be considered as S. mansoni; class E: 125 < Cbl < 139 microns, p = 0.57 to be considered as S. rodhaini. Two groups of schistosome have been established on basis of cercarian morphometry with S. intercalatum, S. mansoni and S. rodhaini from one side, S. haematobium and S. bovis to the other side.

Animals↗

PubMed1992

Interbreeding in the subfamily Ostertagiinae (Nematoda: Trichostrongylidae) of ruminants.

The interbreeding of 6 species of ostertagiines was studied in a sheep model. Virgin young females of selected nonpolymorphic strains of Ostertagia ostertagi, Ostertagia leptospicularis, and Teladorsagia circumcincta were mated with various male ostertagiines. Interbreeding was successful between O. ostertagi and Ostertagia lyrata, O. leptospicularis and Ostertagia kolchida, and T. circumcincta and Teladorsagia trifurcata, respectively. Their offspring were fertile and resembled one parent or the other without intermediate forms: each pair is a polymorphic species. Infertile hybrids, intermediate in form, were obtained from interbreeding between O. ostertagi and O. leptospicularis and they remain valid species.

Animals↗

PubMed1991

Survival of snails and characteristic lesions of Fasciola hepatica infection in four European species of Lymnaea.

The survival of snails and characteristic organ lesions were investigated in four different age categories (new-born, 1 and 2 mm shell height, adults) and in four species of Lymnaea (L. glabra, L. palustris, L. peregra ovata, L. truncatula) infected by Fasciola hepatica. Mortalities were higher in infected groups on Days 30 and 45 post-infection (+42% and +45%, respectively) than in controls. Lesions depended on the species and age of the Lymnaea. Epithelial necrosis of the kidney was recorded in L. glabra, L. palustris and L. p. ovata, whereas intralamellar deposits were found in the same organ of L. truncatula. All categories of L. truncatula had evolutive infections (snails with living parthenitae); the young snails of other species became infected, but the adults did not, as estimated at Day 45 post-infection. The lesions were related to the intensity of evolutive infections: necrosis of the digestive gland was found in moderate to low infections and, conversely, gonadal atrophy with epithelial necrosis was found in highly infected snails.

Animals↗

PubMed1991

Survival of sheep and goat first stage protostrongylid larvae in experimental conditions: influence of humidity and temperature.

The survival of first-stage larvae of a laboratory strain of Muellerius capillaris and of a natural multispecific infection (Neostrongylus linearis, Cystocaulus nigrescens, Protostrongylus rufescens) was studied for 10 to 12 day periods. The survival was estimated either on larvae in faeces or kept in tap water. Temperature (-18 degrees C to 37 degrees C) and desiccation were the ecological factors investigated. M. capillaris was the most tolerant to these factors but showed better survival at 4 degrees C (and at -18 degrees C on one occasion). N. linearis survived better at 25 degrees C or -18 degrees C and C. nigrescens at 4 degrees C and -18 degrees C. Humidification of faeces was unfavourable to the latter species. All the species could stand desiccation of faeces up to 67% of dry-matter for M. capillaris or 82% for other species. Larval survival estimated for L1 in tap water was different from that estimated for larvae in faeces. The variation in resistance to unfavourable temperatures or moisture conditions may account partly for the geographical distribution of the species.

Animals↗

PubMed1991

Polymorphism of helminths: from morphology to genetics.

Morphological polymorphism is a common phenomenon among several groups of nematodes. Morphs are readily distinguished from species as they differ only by few minor morphological features and are associated in a characteristic manner in their distribution within hosts. Morphological polymorphism has not been recorded in cestodes; strains of Echinococcus are not morphs. The study of eco-ethological polymorphism is still in its infancy but may prove of interest, in particular in trematodes.

Adaptation, Biological↗

PubMed1991

Efficacy of netobimin against Muellerius capillaris and resistant strain of digestive tract strongyles in dairy goats.

The efficacy of netobimin against digestive tract strongyles and the small lungworm Muellerius capillaris was tested in a dairy goat herd. The drenches were given orally at the rate of 20 mg/kg of body weight once, 10 mg/kg on 2 successive days, or 7.5 mg/kg on 3 successive days. Fecal egg counts and larval counts were done 8 days before and on the day of drenching; further counts were performed on postdrenching days 8 and 18. Two goats were necropsied, 1 on postdrenching day 5 and 1 on day 10 in the group treated on 3 successive days. The fecal egg counts were reduced by 44 to 79% depending on dosage on postdrenching day 18; the remaining worms were Trichostrongylus colubriformis. The larval counts of M capillaris were reduced by 72 to 92%, depending on dose. The reduction was significant in all the treated groups, compared with that in the control group. The use of netobimin at the dosage of 10 mg/kg given on 2 successive days or 7.5 mg/kg given on 3 successive days might be recommended to treat goats infected with Muellerius spp and digestive tract strongyles.

Analysis of Variance↗

PubMed1990

Genetic and environmental factors associated with nematode infection of dairy goats in northwestern France.

The helminth parasitism (strongyles and Muellerius) of dairy goats was investigated in commercial farms of northwestern France. The study was undertaken in spring (n = 263 goats) and autumn (n = 165); the breed, age, polledness, absence or presence of wattles, and reproductive status were recorded for each goat. The faecal output of strongyle eggs was significantly related to breed, polledness, presence of wattles and age. The faecal output of first stage larvae of Muellerius was correlated with breed, age and pregnancy.

Age Factors↗

PubMed1990

Land snails and periods at high risk for protostrongylid infection on a sheep-grazed pasture of northeast Tunisia.

The population density and level of infection of terrestrial molluscs, and the output by sheep of first stage protostrongylid larvae, were assessed monthly during a 1-year study. Muellerius capillaris was the predominant protostrongylid (approximately 80% of the larval output); Neostrongylus was also found. Eobania vermiculata, Cernuella virgata and Trochoidea elegans were the most common molluscs. Juveniles were less infected than adults. Banded E. vermiculata had a lower intensity of infection than unbanded ones. Nearly 75% of protostrongylid larvae harboured by molluscs on the studied pasture were found in E. vermiculata. The infectivity of pasture was at its lowest in the dry and hot period (June-September). Infection of snails was primarily related to temperature and the importance and frequency of rains, and secondarily to larval excretion in sheep faeces.

Animals↗

PubMed1990

A technique for identification of cercariae of Schistosoma haematobium, S. curassoni, S. bovis and S. intercalatum.

The chaetotaxy of 84 samples or isolates of Schistosoma spp. from western or central Africa has been studied. Three indices were calculated for cercariae of each sample; their average value, the skewness and kurtosis of each indice was established. Each species (S. haematobium, S. curassoni, S. bovis and S. intercalatum) was discriminated with nine variables. The present work gives information to assess, specific diagnosis with simple calculations easily achieved on a small computer.

Animals↗

PubMed1990

The fate of the filaria Monanema martini in two rodent hosts: recovery rate, migration, and localization.

In Meriones unguiculatus, the recovery rate of 80 inoculated larvae was low (about 20%) and irregular. In the natural host Lemniscomys striatus, the recovery rate was about 50% with inoculated doses of 30, 80 or 400 L3, but slightly higher for 400 L3. This rate was constant from day 2 to month 8 post infection (p.i.). When 7-9 reinoculations were performed in one year, the recovery rate of the late inoculation was of only 14%. After subcutaneous inoculations, larvae penetrated into the peripheric lymphatic vessels from hour 6 p.i. and migrated to the lumbar and mesenteric lymph nodes; this first migratory phase was achieved 5 days p.i. Later, the larvae migrated into the digestive tract lymphatic system. Filarial localization did not depend upon the L3 dose: half were found in the caecum and anterior colon (3 cm) wall, and half were distributed in the posterior colon, mesentery and small intestine. A small number (3-5%) of the filariae were found in the pulmonary blood vessels, as a result of accidental migration by the thoracic canal. A similar phenomenon is known in the lymphatic filariae Brugia spp. in rodents and Conispiculum flavescens in a lizard. Several arguments suggest that the genus Monanema is fundamentally lymphatic. Migrations and life of filariae in the lymphatic system seems to be more usual than it is generally admitted. In onchocerciasis, this may at least partially explain the lymphopathology of the inguinal region.

Analysis of Variance↗

PubMed1990

The filaria Litomosoides galizai in mites; microfilarial distribution in the host and regulation of the transmission.

The mites, Bdellonyssus bacoti, are engorged on rodents having 800 to 60,000 microfilarie/10 mm3 blood. Quantitation of L. galizai larval development shows that an additional blood meal improves development and that high microfilaremiae do not result in a proportional increase in the number of infective larvae. The first important stage of transmission regulation occurs during ingestion of microfilariae: the numbers of ingested microfilariae are lower than expected in cases of high microfilaremia. This phenomenon cannot be ascribed to the mite vector that engorges a constant blood meal whatever the level of microfilaremia. Contrarily, one finds that microfilarial density in the small peripheral blood vessels (blood drawn from incision of the dorsal skin) increases less than in large blood vessels (retro-orbital sinus). A similar observation was reported by Dickerson et al. (1989) working with Wuchereria bancrofti. We assume that in both cases, the high microfilaremiae cause the small blood vessles accessible to the vector to become saturated with parasites. Although regulation during engorging is not the sole factor to monitor the infection in B. bacoti (another one operates during larval development of L. galizai), demonstrating its existence seems to us fundamental: it points out the concept that sub-ingestion, as well as over-ingestion, shows the inequalities of microfilarial densities in the host which seem to be dependent on mechanical factors such as the diameter of blood vessles and the size of microfilariae.

Animals↗

PubMed1990

Epidemiology of gastrointestinal helminths of sheep in the Rabat area of Morocco.

The epidemiology of gastrointestinal helminths of sheep on permanent pastures in Morocco was studied by monthly examination of faeces of ewes for helminth eggs and by use of batches of 3 tracer lambs each month from December 1979 to November 1980. The main helminth genera encountered were Teladorsagia, Haemonchus, Trichostrongylus and Moniezia, with Nematodirus, Cooperia, Oesophagostomum and Trichuris occasionally recorded. The faecal egg counts of ewes showed 2 peaks; the first in March due to the acquisition of larvae during the rainy season and periparturient rise, the second in October probably due to maturation of inhibited larvae. The worm burdens of tracer lambs showed that there was a gradual accumulation of nematodes from December, reaching a peak in May; an absence of infection in July and August during the dry period, and a second peak in November. Infection by Moniezia was higher during the dry season.

Animals↗

PubMed1990

Dual or single infection of the terrestrial snail Solatopupa similis (Bruguière, 1792) with two protostrongylid nematodes, Muellerius capillaris (Mueller, 1889) and Neostrongylus linearis (Marotel, 1913).

The land snails Solatopupa similis were experimentally infected with two protostrongylidae, Muellerius capillaris and Neostrongylus linearis. Although the apparent rate of penetration was always high (64-91%), infection remained low (less than 3 larvae/snail); most of the larvae that penetrated the snails did not develop into second stage larvae. Rates of snail mortality recorded in infected groups were higher than those observed in non infected snails.

Animals↗

PubMed1990

Single and dual infections of the land snail Helix aspersa with Muellerius capillaris and Alloionema appendiculatum (Nematoda).

Helix aspersa, a land snail, has been experimentally infected with 2 species of nematodes Muellerius capillaris and Alloionema appendiculatum. A significant reduction of infection with M. capillaris was recorded in snails preinfected with A. appendiculatum, whereas snails preinfected with M. capillaris were as susceptible to A. appendiculatum.

Analysis of Variance↗