Biomedical subjects

R Piarroux

Publications and source records attributed to R Piarroux.

At least 19 recordsLinked to original sources

PubMed2006

Diagnostic value of serum precipitins to mould antigens in active hypersensitivity pneumonitis.

Serum precipitins have a controversial diagnostic value in hypersensitivity pneumonitis (HP). The present authors' objective was to assess their diagnostic value by developing scores from a panel of specific antigens tested by two techniques (electrosyneresis and double diffusion) to discriminate active HP from other interstitial lung diseases. Consecutive patients presenting with a condition for which HP was considered in the differential diagnosis were included in the study. All patients underwent the same standardised diagnostic procedure, including precipitin tests performed in routine conditions. Clinical manifestations, bronchoalveolar lavage and high-resolution computed tomography defined the presence or absence of HP. Receiver-operating characteristic curves and logistic regression were used to develop the serological scores. A total of 122 patients (including 31 cases of HP) were included in the study. Five antigens from the panel were selected for the serological scores (Absidia corymbifera, Eurotium amstelodami, Wallemia sebi, Saccharopolyspora rectivirgula and mesophilic Streptomyces sp.). Electrosyneresis was more discriminative than the double-diffusion technique. Predictive negative values varied 81-88% and predictive positive values varied 71-75% for prevalence of HP 20-35%. In conclusion, serological scores using a panel of relevant antigens may guide both biological and clinical practice in areas of high prevalence of hypersensitivity pneumonitis.

Adult↗

PubMed2006

Taxonomic position and geographical distribution of the common sheep G1 and camel G6 strains of Echinococcus granulosus in three African countries.

The taxonomic and phylogenetic status of Echinococcus granulosus strains are still controversial and under discussion. In the present study, we investigated the genetic polymorphism of E. granulosus isolates originating from three countries of Africa, including a region of Algeria, where the common G1 sheep and the camel G6 strains coexist sympatrically. Seventy-one hydatid cysts were collected from sheep, cattle, camels, and humans. Two mitochondrial markers (cox1 and nad1) were used for strain identification. Two nuclear markers (actII and hbx2) were used to study the possible occurrence of cross-fertilization. Despite the heterogeneity observed among the G1 isolates, they were all localized within one robust cluster. A second strong cluster was also observed containing all of the G6 isolates. Both strains appeared as two distinct groups, and no cases of interbreeding were found. Thus, the attribution of a species rank can be suggested. We also found the Tasmanian sheep G2 strain for the first time in Africa. Because of the slight variations observed between the common sheep and the Tasmanian sheep strains, further studies should be carried out to elucidate the epidemiological relevance of this genetic discrimination.

Algeria↗

PubMed2006

Genotyping of human cystic echinococcosis in Xinjiang, PR China.

The Xinjiang Uygur Autonomous Region, multi-ethnic province in northwestern China, is one of the most important foci of human cystic echinococcosis (CE) in the world. Two Echinococcus granulosus genotypes (G1 and G6) are known to infect the intermediate hosts in this area but, to date, the source of the human infection remains unclear. The current study aimed to genetically analyse 67 hydatid cysts removed from 47 CE patients for which epidemiological, clinical and serological data were also recorded. Mitochondrial cox 1 gene sequencing suggested that the E. granulosus G1 genotype is the major source of infection (45/47 CE patients). Nevertheless, for the first time in China, 2 patients were found with hydatid cysts of the G6 genotype. In addition, 45 E. granulosus gravid tapeworms, isolated from 13 dogs, were genotyped. The majority of adult worms (42/45) exhibited the G1 genotype, whereas 3 adult tapeworms with the G6 genotype were found in one dog, that also harboured E. granulosus tapeworms of the G1 genotype. This sympatric occurrence of G1 and G6 genotypes of E. granulosus, not only in the same area but also in the same definitive host, raises the interesting question of putative genetic recombination between these E. granulosus genotypes.

Adolescent↗

PubMed2006

EmsB, a tandem repeated multi-loci microsatellite, new tool to investigate the genetic diversity of Echinococcus multilocularis.

In order to explore the genetic diversity within Echinococcus multilocularis (E. multilocularis), the cestode responsible for the alveolar echinococcosis (AE) in humans, a microsatellite, composed of (CA) and (GA) repeats and designated EmsB, was isolated and characterized in view of its nature and potential field application. PCR-amplification with specific primers exhibited a high degree of size polymorphism between E. multilocularis and Echinococcus granulosus sheep (G1) and camel (G6) strains. Fluorescent-PCR was subsequently performed on a panel of E. multilocularis isolates to assess intra-species polymorphism level. EmsB provided a multi-peak profile, characterized by tandemly repeated microsatellite sequences in the E. multilocularis genome. This "repetition of repeats" feature provided to EmsB a high discriminatory power in that eight clusters, supported by bootstrap p-values larger than 95%, could be defined among the tested E. multilocularis samples. We were able to differentiate not only the Alaskan from the European samples, but also to detect different European isolate clusters. In total, 25 genotypes were defined within 37 E. multilocularis samples. Despite its complexity, this tandem repeated multi-loci microsatellite possesses the three important features for a molecular marker, i.e. sensitivity, repetitiveness and discriminatory power. It will permit assessing the genetic polymorphism of E. multilocularis and to investigate its spatial distribution in detail.

Animals↗

PubMed2005

Genetic typing of Echinococcus granulosus in Romania.

In Romania, cystic echinococcosis is endemic and affects, besides humans, various animal species including sheep, cattle, and swine. As yet, no molecular-genetic typing has been carried out to clearly identify the putative strains being transmitted there. Parasite samples (protoscoleces or germinal layers) were collected from infected intermediate hosts and subsequently analyzed by comparing the PCR-amplified DNA sequences of three targets: one nuclear (BG1/3) and two mitochondrial (cox1 and nadI). Three strains were identified with the mitochondrial sequences: (i) the common sheep strain (G1) which circulates between sheep and cattle and is infective for humans, (ii) the Tasmanian sheep strain (G2) infecting sheep and cattle, and (iii) the pig strain (G7) predominantly found in swine. To our knowledge, this is the first report which demonstrates the occurrence of the Tasmanian sheep strain in cattle and the sympatric occurrence of these three strains (G1, G2, and G7) in Europe.

Animals↗

PubMed2005

Detection of Echinococcus multilocularis in wild boars in France using PCR techniques against larval form.

Recently, new data have been collected on the distribution and ecology of Echinococcus multilocularis in European countries. Different ungulates species such as pig, goat, sheep, cattle and horse are known to host incomplete development of larval E. multilocularis. We report a case of E. multilocularis portage in two wild boars from a high endemic area in France (Department of Jura). Histological examination was performed and the DNA was isolated from hepatic lesions then amplified by using three PCR methods in two distinct institutes. Molecular characterisation of PCR products revealed 99% nucleotide sequence homology with the specific sequence of the U1 sn RNA gene of E. multilocularis, 99 and 99.9% nucleotide sequence homology with the specific sequence of the cytochrome oxydase gene of Echinococcus genus and 99.9% nucleotide sequence homology with a genomic DNA sequence of Echinococcus genus for the first and the second wild boar, respectively.

Animals↗

PubMed2004

Echinococcus granulosus strain typing in North Africa: comparison of eight nuclear and mitochondrial DNA fragments.

Recent studies of Echinococcus granulosus molecular strain typing have enabled a better understanding of the transmission cycle of cystic echinococcosis. There have been many publications in this area but there is a need for the evaluation of these tools. We have attempted to respond to this need in our study, which assessed 8 DNA fragments of 40 E. granulosus cysts from North Africa. Parasitological material was collected from 5 types of intermediate hosts, in 5 different countries. The primers chosen to amplify DNA targets were defined either in nuclear DNA, or in mitochondrial DNA. After amplification, PCR products were sequenced. The sequences obtained were aligned and comparisons were made within the group and with GenBank sequences. Whether the target was nuclear or mitochondrial, the same 2 main groups of genotypes were found. The first one, the 'sheep' strain, was found in the human, sheep and cattle samples collected in North Africa. The second one, the 'camel' strain, was found in the camel cysts and cattle and human cysts from Mauritania. These findings further confirm the congruence of the data given by the nuclear and the mitochondrial genome.

Africa, Northern↗

PubMed2004

Epidemiology of alveolar echinococcosis in southern Cantal, Auvergne region, France.

Alveolar echinococcosis (AE) is a helminth zoonosis which is encountered only in the northern hemisphere. In central France, the Auvergne region represents the most western and southern extension of this helminthiasis. In 1999, a human case of AE was diagnosed in the southern part of the Cantal department, where AE was supposed absent, and an epidemiological survey was subsequently carried out. The transmission of the zoonosis in the sylvatic and peridomestic definitive hosts was studied, as well as that in the rodent and human intermediate hosts. Eleven red foxes (Vulpes vulpes) were shot, and 50 fox faecal deposits were collected. Twelve farm dogs had their faeces taken by rectal touch, and four were checked after arecoline purgation. Optical detection of Echinococcus multilocularis worms was achieved on fox intestines after scraping, and also on dog stools after arecoline therapy. Coproantigen ELISA assay was performed for the 11 scraping products, for the 50 fox faeces, and for the 12 dog faecal samples. No adult AE agent was observed by microscopy, and the ELISA assay yielded positive results in one of 11 fox intestines, one of 50 fox faeces, and 2 of 12 dog faecal samples. Twenty-five small mammals were trapped, of which 19 were Arvicola terrestris water voles. One rodent liver exhibited a hepatic lesion consistent with AE. An epidemiological questionnaire was completed in 85 human volunteers, who were also serologically tested for AE. Only one (the case's husband) exhibited a Western-blotting pattern indicative of a low-grade AE infection. The results of this preliminary study suggested a slow AE extension to the south of Cantal department from the northern focus.

Aged↗

PubMed2004

Cutaneous Alternaria infection in renal transplant recipients: a report of two cases with an unusual mode of transmission.

We report two cases of cutaneous alternariosis in renal transplant recipients. The diagnosis was made by mycologic and histologic examination. The patients were treated with itraconazole. In one patient who had undergone surgical resection of the cutaneous lesion along with antifungal treatment, the follow-up period was uneventful with no signs of recurrence. In the other patient, surgical excision of the lesion was not performed prior to antifungal therapy. The lesion disappeared following treatment but local recurrence was observed 1.5 years later with an unfavorable evolution despite administration of the second course of therapy. Resection of the lesion and prolongation of the treatment resulted in a satisfactory course with no signs of local recurrence over a follow-up period of 4.5 years. Interestingly, both of the patients had a previous history of a mild traumatic event with a stretcher in our outpatient clinic where the follow-up visits were made. A vast mycologic survey was then made in our department, which disclosed that some of the stretchers were contaminated by the fungi and could have potentially served as the reservoirs and vectors for the transmission of the fungus.

Adult↗

PubMed2004

Microbiological evolution of hay and relapse in patients with farmer's lung.

BACKGROUND: Recent studies in France have shown that Absidia corymbifera and, to a lesser degree Eurotium amstelodami and Wallemia sebi, play a role in farmer's lung disease (FLD), but that Saccharopolyspora rectivirgula, classically incriminated, does not. Little is known about farmers' reactions to these fungi or the circumstances which lead to exposure. AIMS: To investigate the conditions which favour the development of these microorganisms in hay and to analyse the relation between their concentration and the risk of occurrence of FLD. METHODS: Sequential microbiological analyses of each batch of hay stored in 10 farms at risk for FLD and a serological survey of 10 farmers (five with a past history of FLD). RESULTS: Exposure to microorganisms varied widely according to farms and periods. These microorganisms usually reached a peak in January and proliferated when harvesting conditions favoured excessive humidity in hay (rain during harvest, soil in the hay). Three of the five FLD patients presented with FLD respiratory recurrence and positive serology for A corymbifera during the winter (2000-01), after exposure to a significantly higher amount of A corymbifera than other farmers. Similar, but less significant, results were found for E amstelodami exposure, but not with W sebi. CONCLUSIONS: Results contribute to confirming A corymbifera as a major aetiological agent of FLD in Doubs, and encourage further studies with a view to implementing preventive measures.

Absidia↗

PubMed2003

Cystic echinococcosis in Algeria: cattle act as reservoirs of a sheep strain and may contribute to human contamination.

In Algeria, cystic echinococcosis (CE) is a serious economic and public health problem. The common sheep/dog cycle is usually considered as the major source of human contamination. But to date the main strain of Echinococcus granulosus involved in the human contamination and the role of other hosts are still unknown. This paper reports an original work performed in northern Algeria combining field observations and molecular analysis. In a first step, examination of 6237 carcasses in slaughterhouses showed high infection and fertility rates in cattle and dromedaries. Then, in a second step, we used a molecular biology approach to identify the E. granulosus strain(s) involved. Forty-six samples from various origins were collected. They were analysed using comparison of PCR-amplified DNA sequences with one genomic (BG 1/3) and two mitochondrial (COI and NDI) targets. Results show the presence of a "sheep" strain of E. granulosus in North Algeria circulating between cattle and ovines and infectious to humans, whereas in South Algeria, a "camel" strain and a "sheep" strain were found to circulate in camels and in sheep, respectively. This study also reports an ambiguous genotype which resembled the "sheep" strain genotype (Gl) on the basis of the partial COI gene sequence, whereas on the basis of the partial NDI gene sequence, it was similar either to the "sheep" strain (Gl) or to the "camel" strain (G6). Besides its basic interest, our study confirms the role of other hosts (mainly cattle) in leading to transmission to humans and suggests that control measures should not only target sheep.

Algeria↗

PubMed2002

Influence of buffered propionic acid on the development of micro-organisms in hay.

We tested the benefit of using buffered propionic acid (BPA) as a means of preventing farmer's lung disease (FLD). BPA, a new formulation of propionic acid, a hay preservative with no deleterious effect on farm machinery or cattle, reduces the development of micro-organisms in hay. Twenty pairs of round bales were analysed for concentration of micro-organisms measured in the winter following hay treatment. Each pair included one untreated bale and one bale treated with BPA during haymaking. Our results showed the following decreases in concentration in treated bales: total fungal species, 40% (P < 0.05); Eurotium amstelodami (the main species found), 65% (P < 0.01); and thermophilic actinomycetes, 60% (not significant), respectively. We conclude that BPA could be used to prevent FLD.

Actinomycetales↗

PubMed2002

Evaluation of internal transcribed spacer region of ribosomal DNA sequence analysis for molecular characterization of Candida albicans and Candida dubliniensis isolates from HIV-infected patients.

Molecular typing systems have been needed to study Candida colonization in HIV-infected patients, particularly for investigating virulence and fluconazole resistance. Three methods--electrophoretic karyotyping (EK), detection of restriction fragment length polymorphisms (RFLP) and randomly amplified polymorphic DNA analysis (RAPD)--have been most frequently used. In this study, comparative sequence analysis of the internal transcribed spacer (ITS) region of rDNA was evaluated for delineation of Candida isolates from 14 HIV-infected patients. EK, ITS sequence analysis, RFLP and RAPD resulted in 11, 10, 9 and 8 DNA genotypes, respectively, from 39 Candida albicans isolates. The 10 genotypes observed using ITS sequence analysis were defined by six variation sites in the sequence. Molecular typing of sequential oral isolates showed the persistence of the same genotype of C. albicans in nine patients, and genotype variation in one patient. EK and RAPD showed that another patient was co-infected by two distinct genotypes and ITS analysis identified one of the two genotypes as Candida dubliniensis. Comparative ITS sequence analysis is a quick and reproducible method that provides clear and objective results, and it also identifies C. dubliniensis. The discriminatory power of this new typing approach could be improved by concomitant analysis of other DNA polymorphic sequences.

AIDS-Related Opportunistic Infections↗

PubMed2002

[Fungal contamination detection in cornea preservation media].

PURPOSE: Fungi can cause major complications following corneal grafting. In this study we aimed to verify the efficiency of a fungal contamination detection protocol for human corneas in preservation before clinical use. MATERIALS AND METHODS: The 12 most frequently found species of fungi responsible for keratitis and endophthalmitis were inoculated to preservation medium used by most French eye banks. A protocol used by several centers, including a daily visual control, was followed in order to check that it showed the presence of all microorganisms, particularly slow-growing filamentous fungi. RESULTS: Every species was detected in a time from 2 to 4 days. CONCLUSION: This microbiological contamination detection protocol of detection for human corneas in organ culture at +31 degrees C, seems to effectively detect the main agents responsible for fungal contamination.

Candida↗

PubMed2002

[Management of a cholera epidemic by a humanitarian organization].

Far from disappearing with modern progress, cholera outbreaks have never been more common than in the last decade. Because of its close relationship with poverty, malnutrition, poor access to health care, warfare, and sometimes natural disaster, cholera is a major priority for action by doctors from humanitarian organization. In this article a brief overview about cholera is followed by an account of one non-governmental organization's approach to management of a cholera outbreak. The author describe the circumstances surrounding the alert and the fact-finding mission focused on documenting the presence of an epidemic, measuring its magnitude, and predicting its outcome. The next phase of management involved response planning with development of a control strategy and raising money for intervention, which is often difficult for epidemics not reported in the media. The control modalities were then deployed in the field including assisting patient management, preventing transmission, training personnel, supervising activities, coordinating tasks performed by different actors, and finally program evaluation. This experience shows that successful cholera management programs can be conducted in a professional manner by teams composed essentially of volunteers under the supervision of a knowledgeable staff able to adapt general control techniques to the specific conditions encountered in the field.

Altruism↗

PubMed2002

[Cholera: epidemiology and transmission. Experience from several humanitarian interventions in Africa, Indian Ocean and Central America].

With more than 50 countries affected and 200,000 notified cases per year (which is a gross underestimation), cholera, after having almost disappeared 50 years ago, has again become the calamity it was in the 19th century. To understand how this plague could have suddenly reappeared and spread all over the world and then taken root in the world's poorest countries, we give a brief outline here of the epidemiology of cholera, divided into three parts. The first part examines the origin and spread of the cholera pandemics, and particularly that of the seventh pandemic which, more than forty years after it began, is still, raging, in successive epidemic waves. The second part describes the modes of transmission of the cholera vibrio as they are seen in the field, examining the case of the cholera epidemic in the Comoro Islands in 1998. The third part shows the links between cholera and humanitarian disasters, through the use of concrete examples (refugee settlements, cyclones and volcanic eruptions). In conclusion, all the arguments presented here highlight not only the role of water and the lack of hygiene, but also the role of technical progress, especially in international transports, in the spread of the present pandemic.

Africa↗

PubMed2001

[Visceral leishmaniases].

Leishmanioses are a group of infections caused by the protozoa Leishmania. Humans are infected by female sandfly bites. Leishmaniosis is found in Mediterranean Europe, America, Africa and Asia. Various clinical expressions are possible: visceral (kala-azar) or cutaneous (Old world cutaneous leishmaniosis). In Mediterranean Europe, visceral leishmaniosis with the classical triad, splenomegaly, pallor, fever, was traditionally a childhood disease whereas today the disease with atypical clinical expressions strikes immunocompromised patients. In these atypical forms of visceral leishmaniosis, diagnosis and treatment are particularly difficult. Leishmania-DNA research using polymerase chain reaction is often necessary to perform the diagnosis, and lipid-associated formulations of amphotericin B, rapidly effective and well-tolerated in patients without immunodeficiency, do not prevent recurrences in immunocompromised patients.

Amphotericin B↗

PubMed2001

Longitudinal study of anti-Candida albicans mucosal immunity against aspartic proteinases in HIV-infected patients.

Oropharyngeal candidiasis (OPC), mainly caused by Candida albicans, is commonly observed in HIV-infected patients. Secreted aspartic proteinases (Saps) are virulent agents involved in adherence to the mucosal surface and in tissue invasion. The immune secretory response to these agents was investigated in 15 HIV-infected patients, during oral yeast colonization and episodes of oropharyngeal candidiasis (OPC), in a 1-year longitudinal study. We developed an avidin-biotin-amplified immunofluorometric assay for the detection of specific immunoglobulins G, A, and M against somatic, Sap2 and Sap6 antigens. We report increases in anti-somatic, anti-Sap2, and anti-Sap6 salivary antibodies in patients with OPC. Over the 1-year period, not only OPC episodes but also variations in yeast colonization levels were correlated with variations in salivary anti-Sap6 antibody levels. Our results show the ability of HIV-infected patients to produce high levels of salivary antibodies; however, these antibodies were not efficient in limiting candidal infection, probably because of cellular cooperation deficiency and the enhanced virulence of the infecting strain.

AIDS-Related Opportunistic Infections↗