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Biomedical subjects

C Boulard

Publications and source records attributed to C Boulard.

At least 37 records · Page 2Linked to original sources
PubMed1997

The prevalence of goat hypodermosis in Greece.

Goat hypodermosis caused by Przhevalskiana silenus is common in Greece causing quite serious losses on animal production and breeding, but no data regarding the prevalence of this parasitic disease were available within the last 17 years. Towards this end, at the slaughter house of the area of Thessaloniki, the number of affected hides due to skin penetration by P. silenus larvae was recorded and the prevalence was assessed to be 54.2%. The mean number of holes found per hide was 27.07 (ranged from 0 to 162 holes per hide). Moreover, a total of 4900 goat blood serum samples were collected from different parts of the country and tested for hypodermosis using the ELISA method. Based on the results of this test, the prevalence of the infection was found to be 49.2%, varying from place to place between 4.6 and 85.1%. The range of the infection per flock was from 0 up to 100%.

Animal Husbandry↗
PubMed1997

The prevalence of bovine hypodermosis in Greece.

Hypodermosis is a common parasitic disease of great importance on cattle production and breeding worldwide. In Greece, no reliable data are available regarding the extent of this infection and therefore, as expected, no national or regional control programme is being applied. In order to cover this lack of information, a total of 4200 cattle blood sera were collected from different parts of the country and tested for hypodermosis using the ELISA method. The prevalence of the infection was found to be 37.4%, varying from place to place between 0.7 and 78.8%. The range of the infection per flock was from 0 up to 100%.

Animals↗
PubMed1996

Sero-surveillance of hypodermosis in a herd under therapeutic control. Effect of a low level of infestation.

A cattle herd from the experimental farm of INRA in Nouzilly has been treated for hypodermosis since October 1990. Additionally, a regional eradication scheme has been implemented in this area since autumn 1992. Bi-monthly warble counts were performed between March and July each year on an average of 200 animals. No warble was recorded in this herd from 1991 to 1994 with the exception of two dairy cows in 1993. In autumn 1994, therapeutic control measures were stopped. Serological surveys were performed in the autumn of each year from 1991 until 1995. Anti-Hypoderma antibodies were found in 25%, 27.2%, 4.3%, 3.2% and 0% of the animals respectively. An experimental low infestation was conducted in the summer of 1994. During the spring 1994, third instars of Hypoderma bovis were collected from naturally infested animals. From a total of 13 pupae, six adults (four males and two females) emerged and were released in the herd of Nouzilly on 24 June and 4 July. In October 1994 serological investigations revealed two animals seropositive for hypodermosis. This number increased to six in January 1995. The antibody kinetics of these six animals remained parallel throughout the next 6 months: the titres increased up to April and started to fall in May to return to negative values in August. Manual examinations of the animals at weekly intervals between April and July revealed the presence of four warbled animals with one, one, two and three warbles respectively. The two other seropositive animals remained warble free. One other animal showed antibody titre fluctuations between negative and low positive values, but was warble free in the spring. In October 1995 all the animals of the herd were seronegative. The interpretation and the value of a sensitive immunodiagnosis in a large eradication programme are discussed and compared with warble counts, especially in the case of a low level of infestation.

Animals↗
PubMed1996

Local immune response to experimental Fasciola hepatica infection in sheep.

Macrophages, eosinophils, neutrophils and lymphocyte subpopulations (OvCD5+, OvCD4+, OvCD8+, OvWC1+ and lg+) were identified in sections of hepatic tissue and hepatic lymph nodes from sheep experimentally infected with F. hepatica and necropsied 14, 28, 42 or 56 days post infection. The migratory tunnels produced by juvenile flukes appeared as local areas of necrosis surrounded by infiltrating inflammatory cells, particularly numerous macrophages, eosinophils and OvCD4+ lymphocytes n addition, B lymphocyte proliferation was observed in hepatic lymph nodes and in hepatic portal tracts. Only three juvenile flukes were identified in the sections. They where partially in contact with healthy tissue and partially with neutrophils, macrophages and eosinophils; they were covered by IgM Host-parasite interactions resulting from immune response regulation by helper T lymphocytes and from immune evasion by the parasite are discussed.

Animals↗
PubMed1996

Cross-reactive, stage-specific antigens in the Oestridae family.

The larval stages of different economically important Oestridae species were studied for their antigenicity and cross reactivity, using ELISA and immunoblotting. The immune sera of cattle from Algeria, Belgium, France and Switzerland were compared for their capacity to recognize the stage-specific antigens of their specific parasites Hypoderma bovis and H lineatum, originating from different populations. This comparison was extended to other Hypoderminae species responsible for economic losses in European animal production: H diana in roe deer and H tarandi in reindeer. The specific host for each of these parasites recognized common epitopes of hypodermin C, a collagenolytic enzyme previously well characterized in the first instar of H bovis and H lineatum. No cross reactivity was found with other Oestridae, such as Oestrus ovis or Gasterophilus intestinalis. The specificity of hypodermin C was evaluated using sera from animals harbouring other arthropods such as ticks, helminths, including Fasciola hepatica and Haemonchus contortus, or protozoa such as Anaplasma sp, and no reaction was observed. The use of hypodermin C is therefore suggested as an antigen in the immuno-survey of economically-important Hypoderminae.

Abattoirs↗
PubMed1996

[Transcultural spatial dispositions and the early parent-child interactions: joint hospitalization facilities].

Joint hospitalizations of father/mother and baby now routinely practiced in the United Kingdom and United States is generally founded on analytical or systemic theories. In France, the thirty or so existing joint parent/child hospitalization facilities should adopt a qualitative approach suited to the cultural context. A few socio-architectural examples could inspire psychiatric teams specialized in joint parent/baby care to transpose specific cultural relationships: the crib of the main house in Provence, the "cow camp" of the peul people in Niger, the "haouche" in Little Kabylia, the "rain hut" in the Casamance area of Senegal. This rediscovery would obviously draw its effectiveness from intercultural traditions buried not too deeply in our ethnocentrism.

Africa↗
PubMed1995

Comparison of hepatic and extrahepatic drug-metabolizing enzyme activities in rats given single or multiple challenge infections with Fasciola hepatica.

The activity of drug-metabolizing enzymes was compared in liver, kidneys and lungs of rats given single or repetitive fluke infections. Fascioliasis was induced by oral administration of 20 metacercariae of F. hepatica to rats, either 6, or 12 and 6, or 12, 9 and 6 weeks before sacrifice. In the liver of mono-infected rats, significant reductions (24-67%) were observed in microsomal content of cytochrome P450 and all P450-dependent monooxygenases investigated. Conjugations to glutathione or acetate were lowered by 34-50% in these animals. In multiply infected animals, a majority of specific enzymatic activities were unchanged, while some monooxygenase activities such as aminopyrine demethylation or benzo(a)pyrene hydroxylation were increased by 26-76% in the liver of tri-infected rats. A renal compensatory process occurred in all infected groups, since cytochrome P450, benzphetamine demethylation and glutathione conjugation were significantly increased. By contrast, dealkylation of benzphetamine and pentoxyresorufin were decreased in the lungs of monoinfected rats. The development of parasite resistance would account for the recovery of liver drug metabolizing capabilities in multi-infected animals.

Animals↗
PubMed1995

Humoral and cellular immune responses to Fasciola hepatica experimental primary and secondary infection in sheep.

Blood leukocyte changes, serum hepatic enzyme levels, lymphocyte proliferation in response to Concanavalin A (ConA) and to parasitic excretory-secretory products (FhESP), and antibody (IgG and IgM) responses (ELISA and Western blot) were studied in sheep, the natural susceptible host of F. hepatica, during the first 3 months of an experimental primary or secondary infection. The proportion of flukes established was similar in once- and twice-infected groups, but the flukes originating from the secondary infection migrated more rapidly to the bile ducts. Primary infection induced a marked peripheral eosinophilia from 3 to 13 weeks post-primary infection (PPIW). FhESP-specific IgM were produced from PPIW 2 with peaks in PPIW 3 and 9-10; FhESP-specific IgG increased from PPIW 2 to 6 and became stable afterwards. Western blotting revealed 12 major antigenic fractions in FhESP from 12, 15, 20, 24, 27, 28.5, 30, 41, 51, 56, 69 and 156 kDa; some non-specific ones have been characterized. A sequential recognition of higher then lower molecular weight antigens was observed. FhESP-specific lymphocyte proliferation was marked from PPIW 2 to 5. In contrast, ConA stimulation of lymphocytes was decreased. After secondary infection in PPIW 6, immune responses were modified. The ConA-induced lymphocyte proliferation was transitorily increased. In contrast, the humoral response, in particular against the early recognized antigens, and the level and the duration of the FhESP-specific lymphocyte proliferative response, were reduced.

Animals↗
PubMed1995

Evaluation of nitroxynil and closantel activity using ELISA and egg counts against Fasciola hepatica in experimentally and naturally infected cattle.

The responses of cattle infected with Fasciola hepatica to treatment with nitroxynil or closantel were monitored by faecal egg counts and by ELISA assay of anti-fluke antibodies. A first trial with experimentally infected heifers showed an increase in anti-fluke antibody titre as early as 2 weeks post-infection. Eggs were first detected in the faeces 10 weeks after infection. Egg output increased steadily over the next 8 weeks and then rapidly decreased. Treatment of a 20-week infection with nitroxynil was followed by a slow decrease in antibody titre 4 weeks later. This decrease continued over the next 40 weeks, but returned to pre-infection levels in only 2 out of 4 animals. The faecal egg count fell to zero 2 weeks after treatment and remained so for the following 30 weeks, although 1 animal produced a few eggs 32 and 34 weeks post-treatment. Within this period, neither diagnostic technique discriminated between this persistently infected animal and the others. In a second trial, 45 cattle from a naturally infected herd were treated with nitroxynil or closantel. The faecal egg counts of the treated cattle were zero within the following 2 months, whereas there were eggs in the faeces of the control (untreated) group. Nevertheless, the treated cattle showed a small, non-significant drop in anti-fluke antibody titre. These results demonstrate the need for new tools to monitor and evaluate accurately the efficacy of anthelmintic treatment.

Animals↗
PubMed1995

Effect of the parasite enzyme, hypodermin A, on bovine lymphocyte proliferation and interleukin-2 production via the prostaglandin pathway.

The immune function of cattle infected with a primary infestation of Hypoderma lineatum is impaired during the first instar migration of the larvae. Hypodermin A (HA) is an enzyme secreted by the larvae that is implicated in immunosuppression. The response of bovine peripheral blood mononuclear cells (PBMC) to HA was examined in this study. HA blocked their proliferation in response to phytohaemagglutinin (PHA) and its effect was enhanced when cells were preincubated with HA before activation. This suggests that HA affects the lymphocyte commitment to blastogenesis during the early stages of their activation. HA also markly reduced the production of interleukin-2 (IL-2) in PHA-stimulated bovine PBMC cultures. Furthermore, indomethacin, which inhibits prostaglandin (PG) synthesis, blocked the immunosuppressive effect of HA on the PBMC proliferative response. The concentration of PGE2 in medium of PBMC or PMA-stimulated monocyte cultures was increased by incubation with HA. Thus, the HA appeared to act by reducing IL-2 production via a prostaglandin-dependent pathway.

Animals↗
PubMed1995

[Epidemiology of bovine hypodermyiasis in canton Vaud: comparison of two methods of mapping the infestation with a view to strategic treatment].

The geographic distribution of bovine hypodermyiasis in the canton Vaud/Switzerland has been investigated in two ways: By direct examination of the animals by the livestock officers at the 1993 annual census and by ELISA on bulk milk sampled in January 1994. The efficacy of the two methods is compared and the distribution of hypodermyiasis presented on a map. The serological analyses have revealed a highly satisfactory degree of sensitivity and specificity (92.1% and 98.1%, resp.). The epidemiological interpretation however, is rather difficult, partly because quite often the animals are not infested on their farms but rather while being on alpine pastures. A monitoring of the herds with a view to an efficient control of hypodermyiasis could thus in a first instance be based on the indications provided by the livestock officers, whereas a serological monitoring in a second place would allow to detect the last and remaining foci of infestation.

Animals↗
PubMed1994

Influence of anti-inflammatory treatments on experimental infection of rats with Fasciola hepatica: changes in serum levels of inflammatory markers during the early stages of fasciolosis.

Anti-inflammatory treatments with dexamethasone, indomethacin or aspirin shortly before or immediately after the experimental infection of rats with Fasciola hepatica resulted in an increase in the rats' burden of adult flukes, suggesting that the inflammatory system played an active part in the rats' immune defense against invasive F hepatica. An anti-parasitic effect of cyclosporin A on F hepatica infection in rats was also demonstrated. A weekly study of various inflammatory markers (acute phase proteins, leucocytes and platelets) demonstrated that no inflammatory reaction had occurred after the first two weeks of infection, but that there was a significant increase in acute phase proteins after three and four weeks. These increases indicated that a chronic inflammatory reaction, associated with liver damage and an increasing eosinophilia, had occurred.

Acute-Phase Proteins↗
PubMed1994

Influence of pro-inflammatory treatments on experimental infection of rats with Fasciola hepatica: changes in serum levels of inflammatory markers during the early stages of fasciolosis.

The effect of stimulating an inflammatory reaction by injecting rats with either Freund's complete adjuvant or turpentine oil shortly before or after they were infected experimentally with Fasciola hepatica on the establishment of the parasite was studied. Freund's complete adjuvant, given either four hours before or four hours after infection with F hepatica and turpentine oil given four hours before infection resulted in a 40 to 50 per cent decrease in the rats' fluke burden. The study of markers of inflammation (acute phase proteins, leucocytes and platelets) demonstrated that the fluke had a modulating effect on the rat's inflammatory response. During the first few days after infection, F hepatica stimulated a transitory inflammatory reaction, as suggested by changes in the level of acute phase proteins (APP) in the serum. No further change in the APP titre occurred until three weeks after infection, when, together with an increase in the extent of the liver lesions, the change in the titre of APP indicated that a systemic and chronic inflammatory process had taken place.

Acute-Phase Proteins↗
PubMed1994

Sequencing and gene expression of hypodermins A, B, C in larval stages of Hypoderma lineatum.

The cDNAs of hypodermins, enzymes secreted by the larvae of the parasitic fly Hypoderma lineatum, were sequenced. Four cDNA clones were isolated, one encoding hypodermin A (HA), one encoding hypodermin C (HC), and the two others encoding proteins related to hypodermin B (HB). The amino acid sequences deduced from the nucleotide sequences confirmed that these enzymes are serine proteases. HA and one of the HB proteins had potential N-linked glycosylation sites. Analysis of hypodermin protein, RNA and DNA at different larval stages indicated that protein overexpression is regulated transcriptionally for HA and HB, and by transcriptional and DNA amplification for HC.

Amino Acid Sequence↗
PubMed1994

Complement depletion in rats infected with Fasciola hepatica: in vivo and in vitro studies.

The action of Fasciola hepatica on rat complement was evaluated by measuring the haemolytic activity. Extracts from metacercariae and eggs and the excretory and secretory products of adult flukes reduced the classical pathway of complement-mediated lysis by normal rat sera in a protein dose-dependent manner. Whole metacercariae produced the same effect. In vitro incubation of newly excysted juveniles and intact eggs with normal rat serum had no detectable effect on serum complement activity by either the alternative or classical pathway. During the course of rat fasciolosis a depletion in the classical pathway of complement-mediated lysis was demonstrated particularly 6-9 weeks post-infection; the alternative pathway of complement-mediated lysis was not affected.

Animals↗
PubMed1993

Analysis of the results obtained using a technic of experimental primary infestation with Fasciola hepatica in the rat.

In this work, we analyzed the results obtained using a technic of infestation with Fasciola hepatica in the rat. The infestations were carried out with 30 metacercariae in a gelatin capsule. The humoral immune response, measured by ELISA, and the liver necroses, spleen size, number and length of the flukes recovered at necropsy were followed during the course of four experimental primary infestations. The results showed that the magnitude of the parasitic burden did not correlate with the humoral immune response of the rat. The study of the liver necroses, spleen size, fluke length and antibody titres showed that the use of 30 metacercariae in a capsule as a technic of infestation in the rat ensured the homogeneity of the parasite development and the humoral immune response of the host.

Animals↗
PubMed1993

In vitro effects of Fasciola hepatica on the main functions of polymorphonuclear leukocytes: chemotaxis and free radical generation induced by phagocytosis.

The effects of adult fluke excretions-secretions (ES) on two major functions of circulating bovine polymorphonuclear (PMN) cells were investigated. Under agarose, PMN chemotaxis was not affected by the ES. ES preincubated with PMN for 15, 30 or 60 min at 37 degrees C, before a chemoluminescence assay, inhibited phagocytosis and/or free radical generation in a dose and time dependent manner.

Animals↗