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J P Dedet

Publications and source records attributed to J P Dedet.

At least 19 recordsLinked to original sources
PubMed2006

Leishmaniasis in Portugal: enzyme polymorphism of Leishmania infantum based on the identification of 213 strains.

This study reports isoenzyme polymorphism of Leishmania strains isolated in different regions of Portugal between 1982 and 2005. A total of 213 strains were obtained from cases of visceral and cutaneous leishmaniasis isolated from immunocompetent patients (adults and children) and immunocompromised adults, as well as from dogs and sandflies. Four zymodemes were identified: MON-1, MON-24, MON-29 and MON-80. Zymodeme MON-1 was identified in 96.7% of the strains, predominating in both immunocompetent and immunocompromised human patients, and it was the only zymodeme isolated from dogs. Isoenzyme diversity in HIV-infected patients was higher than in the immunocompetent group, in which all the strains from visceral leishmaniasis were MON-1. The domestic dog was confirmed as the reservoir host of zoonotic leishmaniasis in Portugal and Phlebotomus perniciosus and Phlebotomus ariasi as vectors. The overall low enzyme polymorphism observed in the Portuguese foci contrasts with the neighbouring foci in Spain.

Adult↗
PubMed2005

Cutaneous leishmaniasis in Tunisia: results of the iso-enzymatic characterization of 71 strains.

Three clinico-epidemiological forms of cutaneous leishmaniasis (CL) exist in Tunisia: zoonotic cutaneous leishmaniasis (ZCL; epidemic in the centre and the south-west); sporadic cutaneous leishmaniasis (SCL; found in the north); and chronic cutaneous leishmaniasis (CCL; originally described from Tataouine, in the south-east). As few isolates of Leishmania from Tunisian cases of CL have been typed, isolates were collected, using NNN medium, from 71 such cases. Most (59) of the cases investigated came from the north of the country, including 16 from Sidi Bourouis, where there was an epidemic outbreak of SCL in early 2001; the other 12 cases were natives of the centre or south of the country. The 71 strains were then characterized, at the Centre National de Référence des Leishmania, in Montpellier, France, by iso-enzyme analysis. This revealed four zymodemes: two of L. infantum and one each of L. major and L. killicki. The MON-1 zymodeme of L. infantum, which is more usually associated with visceral leishmaniasis, was recovered from seven of the cases, including six natives of Sidi Bourouis. The MON-24 zymodeme of this species, which appears to be responsible for the SCL, was isolated from 48 cases, all of whom lived in the north of the country. Another 15 cases (nine from the centre, four from the north, and two from the south-east of the country) were found to be harbouring L. major MON-25, the zymodeme usually causing ZCL. Only a single isolate of L. killicki was made; this was of the MON-8 zymodeme responsible for the CCL, and came from a native of Gafsa, in the south-west. Six of the cases investigated (five infected with L. infantum MON-24 and one with L. major MON-25) showed involvement of their nasal and labial mucosae. These results increase the number of strains typed from Tunisian cases of CL more than four-fold, and should help to elucidate the geographical distribution and epidemiology of the various forms of the disease.

Adolescent↗
PubMed2005

Stages in the identification of phlebotomine sandflies as vectors of leishmaniases and other tropical diseases.

The first time the term phlebotomine sandfly was used, was by an Italian naturalist, Philippo Bonanni, in 1691. The first description though was made by another Italian naturalist, Scopoli, under the name Bibio papatasi. The name of the genus, Phlebotomus, was not given until 1840 by Rondani and Berté. The first description of an American phlebotomine sandfly was made by Coquillett, in 1907. The discovery of the three first sandflies in Brazil is the work of Lutz and Neiva, in 1912. From this date till 1921, 11 new species were described in this country and since then their number is still increasing and has reached 229 at this time. The history of the identification of phlebotomine sandflies as vectors, in Brazil like elsewhere in South America, is as complex as the one of the leishmaniases themselves, to which it is closely linked. The knowledge of cutaneous leishmaniasis in Brazil goes back to 1909, when Gaspar Vianna proposed to name the parasites that were found Leishmania braziliensis (1911). Following the observation of the Sergent brothers on the role of Phlebotomus papatasi in the transmission of cutaneous leishmaniasis in Algeria (1921), it became obvious that phlebotomine sandflies should be incriminated as vectors of cutaneous leishmaniasis in the Americas and that proof should be sought of their role. This is what various Brazilian scientists have done, like Aragão in 1922, Pessôa and Pestana in 1940. In the 1950s evidence was produced that the different forms of leishmaniasis that infest the American continent were caused by distinct species of the parasite. Subsequently, successful searches for the specific vectors were carried out. A by-product of the epidemiological studies of leishmaniases has been the discovery of the transmission of other parasites of the Trypanosomatid families (Crithidia, Endotrypanum, Trypanosoma). More recently, since the 1960s, a large number of viruses amongst which Rhabdoviridae, Bunyaviridae and Reoviridae, have been isolated from phlebotomine sandflies. Between 1961 and 1995, 69 serotypes of different arboviruses were obtained from different zones of Brazilian Amazonia.

Animals↗
PubMed2004

Leishmaniasis due to Leishmania tropica MON-102 in a new Moroccan focus.

In Morocco, between March and April 2002, large numbers of human leihsmaniasis cases were detected during a survey at Zouagha My Yacoub province in Fès State. Among 95 cases, 76 were positive by direct observation of Giemsa-stained smears. Sixteen stocks were isolated in NNN medium and identified as Leishmania tropica MON-102, using isoenzyme techniques on starch gel electrophoresis.

Animals↗
PubMed2004

Comparative study of cutaneous leishmaniasis in human immunodeficiency virus (HIV)-infected patients and non-HIV-infected patients in French Guiana.

BACKGROUND: Few data are available on cutaneous leishmaniasis caused by dermotropic species in human immunodeficiency virus (HIV)-infected patients. OBJECTIVES: To describe nine cases of cutaneous leishmaniasis in HIV+ patients and to compare their clinical features and their response to treatment with those of HIV- patients with the forms of leishmaniasis commonly found in French Guiana. METHODS: A case-control study was carried out between July 1994 and December 2000 in French Guiana. We compared the following variables in nine HIV-infected patients with leishmaniasis and 27 matched controls: clinical type of leishmaniasis, number of lesions, presence of lymphangitis and adenopathy, the rate of recovery after treatment, and recurrence or reinfection. RESULTS: Eight of the HIV-infected patients had localized cutaneous leishmaniasis and one had mucocutaneous leishmaniasis. All of the controls had localized cutaneous leishmaniasis. Leishmania guyanensis was the only species isolated from HIV-infected subjects. HIV-Leishmania coinfected patients had a higher rate of recurrence or reinfection (P < 0.02) and a lower rate of recovery after one treatment cycle with pentamidine (P < 0.02) than did HIV- subjects. The CD4+ lymphocyte counts exceeded 200 mm(-3) in all HIV+ patients at the time of the diagnosis with leishmaniasis. CONCLUSIONS: In French Guiana, cutaneous leishmaniasis in moderately immunosuppressed HIV-infected subjects (> 200 CD4+ T cells mm(-3)) is characterized by a higher rate of recurrence or reinfection and is more difficult to treat than that in HIV- subjects.

AIDS-Related Opportunistic Infections↗
PubMed2004

Identification of Leishmania strains from Jordan.

The enzymatic profiles of 22 Jordanian Leishmania isolates obtained from humans, Psammomys obesus and Phlebotomus papatasi were determined using starch-gel electrophoresis and a 15-enzyme system. Thirteen of the isolates were typed as L. major and the other nine, all from Mediterranean or sub-Mediterranean regions, as L. tropica. The two zymodemes of L. major encountered, MON-26 and MON-103, differed in terms of purine nucleoside phosphorylase 2. The MON-26 isolates came from the Jordanian plateau whereas those of MON-103 were only collected from the Jordan valley. The four zymodemes of L. tropica observed (MON-7, MON-137, MON-200 and MON-265) were identical for only two of the 15 enzymes studied (i.e. isocitrate dehydrogenase and glucose phosphate isomerase), confirming the high level of enzymatic polymorphism of L. tropica. So far, MON-200 and MON-265 have only been found in Jordan.

Animals↗
PubMed2004

Short report: Treatment failure due to mixed infection by different strains of the parasite Leishmania infantum.

Therapeutic failure in a human immunodeficiency virus-negative patient with visceral leishmaniasis was due to mixed infection by two different Leishmania infantum zymodemes: L. infantum zymodeme MON-98, which is a rare zymodeme and is reported for the first time in Greece, and zymodeme MON-1, which is common in the Mediterranean region. The two strains were isolated from two samples of bone marrow from the patient obtained before the administration of treatment and 20 days later, since there was no improvement in the clinical signs. The zymodemes MON-98 and MON-1 exhibited different behaviors in vitro and showed different sensitivities to meglumine antimoniate in vitro and in vivo, as shown by clinical findings. Mixed infections with different Leishmania strains may explain the differences in the clinical course of leishmaniasis in many patients and may be the reason for treatment failures.

Animals↗
PubMed2004

Disseminated cutaneous leishmaniasis due to Leishmania guyanensis: case of a patient with 425 lesions.

Disseminated cutaneous leishmaniasis is characterized by the presence of a large (> or =10) number of lesions at several anatomic sites (head, limbs, and trunk). Most of the lesions are small, papular, and appear simultaneously with or secondarily to one or several ulcerated lesions of localized cutaneous leishmaniasis. We report the first case of disseminated cutaneous leishmaniasis in French Guiana. It concerns a 24-year-old woman who tested negative for human immunodeficiency virus (HIV). The disease began with three lesions that became ulcerated. One week later, multiple papulo-nodular lesions appeared. We counted a total of 425 lesions. Leishmania were observed in the lesions. The species involved was L. guyanensis, which has never been described in a case of disseminated cutaneous leishmaniasis. The patient was rapidly cured by a single course of pentamidine. Disseminated cutaneous leishmaniasis should be distinguished from other types of leishmaniasis with multiple lesions. These include anergic diffuse cutaneous leishmaniasis, post-kala-azar leishmaniasis, and leishmaniasis associated with HIV infection.

Adult↗
PubMed2003

Human cutaneous leishmaniasis due to Leishmania infantum in the Sidi Bourouis focus (Northern Tunisia): epidemiological study and isoenzymatic characterization of the parasites.

The authors report an increase of the number of case of cutaneous leishmaniasis in the Sidi Bourouis region community of Siliana Governorate (Tunisia), with 38 cases diagnosed in 6 months (1st November 2000-30th April 2001), contrary to its usual sporadic character. The isoenzymatic identification of 15 isolated strains emphasizes the role of the Leishmania infantum zymodeme MON-1 as an important factor in the genesis of the sporadic cutaneous leishmaniasis of Northern Tunisia. In fact it was isolated in 6 cases while L. infantum MON-24, the usual agent was isolated in 9 cases.

Aged↗
PubMed2003

Visceral leishmaniasis. Persistence of parasites in lymph nodes after clinical cure.

Visceral leishmaniasis (VL) is generally associated with severe immunodeficiency (AIDS; renal, liver, and heart transplantations; haemopoietic malignancies). More rarely it can be related to an immunotolerence status such as pregnancy. Various observations report the development of leishmaniasis several months or even years after exposure to the parasite. Relapses occur rarely in patients not known to be immunocompromised, but are common after incomplete treatment. They are frequent in patients with Leishmania/HIV co-infection. Asymptomatic phases and relapses suggest that parasite can exist in the tissues for a long time before and/or after clinical onset of the disease. The mechanisms of onset of clinical leishmaniasis following exposure and infestation are highly relevant to understanding the pathology of the disease. The survival of Leishmania parasite between infection and disease or after cure is a very important issue for clinicians and epidemiologists. We describe two cases of VL occurring in a patient with lymphoma and in a pregnant woman. In both cases, parasites remained present in the lymph nodes after clinical cure.

Adult↗
PubMed2002

A previously unclassified trypanosomatid responsible for human cutaneous lesions in Martinique (French West Indies) is the most divergent member of the genus Leishmania ss.

Two cases of skin lesions similar to those caused by Leishmania parasites have been reported from Martinique. Parasites isolated from these lesions were unlike Leishmania reference strains by isoenzyme analysis and electron microscopy and were assumed to be monoxenous trypanosomatids which normally only infect invertebrates. Both strains have now been retyped by isoenzyme analysis and found to be identical to each other and distantly related to all other Leishmania species. The sequence of the 18S ribosomal RNA gene and partial sequences of the DNA polymerase alpha and RNA polymerase II largest subunit genes were obtained. These sequences indicated that the Martinique parasites clustered with L. enriettii and were basal to all other euleishmania. However, support for both the position basal to all euleishmania and the clustering with L. enriettii was low. The Martinique parasites may cluster with L. (Leishmania) or L. (Viannia) or form a novel clade within the euleishmania either with or without L. enriettii.

Animals↗
PubMed2002

Value of two PCR methods for the diagnosis of canine visceral leishmaniasis and the detection of asymptomatic carriers.

The value of 2 PCR methods, targeting genomic and kinetoplast minicircle DNA respectively, was investigated for both diagnosis and prevalence studies of canine visceral leishmaniasis (CVL). The first method (R) was 5000-fold less sensitive than the second (method KRV). Both were tested for diagnosis of CVL in 44 sick dogs with confirmed disease using different biological samples. Method R was highly efficient when using invasive samples, but the use of method KRV proved necessary for a 100% sensitive diagnosis using peripheral blood. This method was applied to peripheral blood and skin samples in 263 dogs during a mass survey in the Cévennes focus. PCR was compared to serology and all results were analysed according to clinical status. The 'CVL-infection' prevalence was found to be 79.8% by PCR compared with 29.6% by serology: 89.4% of symptomatic and 65.2% of asymptomatic dogs harboured parasites in peripheral blood. This study confirms the high prevalence of asymptomatic carriers of Leishmania. In total, for the diagnosis of CVL in sick dogs, method R is recommended in view of its 100% positive predictive value (compared with 30% for method KRV). A strategy best adapted for prevalence surveys might combine serology and highly sensitive PCR on peripheral blood.

Animals↗
PubMed2002

Human cutaneous leishmaniasis caused by Leishmania naiffi is wide-spread in South America.

Four human cases of localized cutaneous leishmaniasis caused by Leishmania naiffi are reported. Two of the cases were infected in French Guiana, one in French Guiana or Martinique, and the other in Ecuador or Peru. The geographical distribution of L. naiffi is clearly larger than that initially reported. Three zymodemes were represented by the four isolates, confirming that there is intraspecific polymorphism in L. naiffi.

Adult↗
PubMed2002

[Epidemiologic surveillance of cutaneous leishmaniasis in Guiana. Summary of military data collected over 10 years].

This report describes the results of epidemiological surveillance of cutaneous leishmaniasis in French military personnel in French Guiana. Data was collected regarding microscopic diagnosis, clinical manifestations, and lesion location as well as compliance with vector control measures. Year-to-year variations in the incidence in the general population have been attributed to changes in climatic conditions. Monitoring incidence and density curves, correlation of findings with local epidemiological data, and analysis of the most recent epidemic in 1998/99 (326 cases, attack rate 3.2% men years) highlight the importance of behavioral factors. The proportion of total cases involving military personnel varied widely from 20 to 85%. Investigation consistently showed that failure to apply elementary protective measures against sandfly bites was the most determinant factor in this proportion. Strict compliance with these measures appears to reduce the risk of infection considerably.

Animals↗
PubMed2001

Sudan: the possible original focus of visceral leishmaniasis.

Fifty-two Leishmania strains, obtained from human patients and dogs in a visceral leishmaniasis focus in Sudan, were characterized by isoenzyme electrophoresis (15 enzymes). The phylogenetic analysis showed that the 7 Leishmania zymodemes obtained hold ancestral positions on the phylogenetic tree, supporting the hypothesis of an East African origin of visceral leishmaniasis.

Animals↗
PubMed2001

Virulence of Leishmania infantum is expressed as a clonal and dominant phenotype in experimental infections.

Human Leishmania infantum infection results in a spectrum of clinical expressions ranging from cutaneous to either asymptomatic or fatal visceral disease. In this context, characterization of parasite virulence appears to be relevant as a biological marker of intrinsic parasitic factors that can affect the pathology of leishmaniasis. Since parasite populations in naturally infected hosts are likely to be composed of multiclonal associations, we first explored the biodiversity of parasite virulence at the intrastrain level in vitro and in vivo by using 11 clones isolated from three strains previously known to express different virulence phenotypes in mice. Subsequently, we studied the course of infection in mice inoculated simultaneously or successively with strains or clones showing various virulence phenotypes. Analysis of in vitro growth characteristics showed no differences among clones from the different parental strains. By contrast, in vivo experiments evidenced a marked intrastrain heterogeneity of virulence to mice. One out of five clones obtained from a virulent strain showed a typical virulence phenotype, while the remaining four clones had low-virulence profiles, as did the six clones isolated from two low-virulence strains. In mixed multiclonal infections, the virulence phenotype was expressed as a dominant character over the associated low-virulence clones. After a challenge with either a homologous or a heterologous strain or clone, virulence phenotypes were conserved and expressed as in naive mice independently from the preexisting population. These results strongly suggest that parasite virulence in L. infantum visceral leishmaniasis is clonal and dominant in nature.

Animals↗