Browsing by Autor "Mireille Hontebeyrie"

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Autonomic neuropathy and immunological abnormalities in Chagas' disease
(Springer Science+Business Media, 1992) Adrián Fernández; Mireille Hontebeyrie; G. Saïd
Integrate Study of a Bolivian Population Infected by Trypanosoma cruzi, the Agent of Chagas Disease
(Instituto Oswaldo Cruz, Ministério da Saúde, 2002) Simone Frédérique Brénière; Marie France Bosseno; François Noireau; Nina Yacsik; Pascale Liegeard; Christine Aznar; Mireille Hontebeyrie
A cross section of a human population (501 individuals) selected at random, and living in a Bolivian community, highly endemic for Chagas disease, was investigated combining together clinical, parasitological and molecular approaches. Conventional serology and polymerase chain reaction (PCR) indicated an active transmission of the infection, a high seroprevalence (43.3%) ranging from around 12% in < 5 years to 94.7% in > 45 years, and a high sensitivity (83.8%) and specificity of PCR. Abnormal ECG tracing was predominant in chagasic patients and was already present among individuals younger than 13 years. SAPA (shed acute phase antigen) recombinant protein and the synthetic peptide R-13 were used as antigens in ELISA tests. The reactivity of SAPA was strongly associated to Trypanosoma cruzi infection and independent of the age of the patients but was not suitable neither for universal serodiagnosis nor for discrimination of specific phases of Chagas infection. Anti-R-13 response was observed in 27.5% only in chagasic patients. Moreover, anti-R13 reactivity was associated with early infection and not to cardiac pathology. This result questioned previous studies, which considered the anti-R-13 response as a marker of chronic Chagas heart disease. The major clonets 20 and 39 (belonging to Trypanosoma cruzi I and T. cruzi II respectively) which circulate in equal proportions in vectors of the studied area, were identified in patients' blood by PCR. Clonet 39 was selected over clonet 20 in the circulation whatever the age of the patient. The only factor related to strain detected in patients' blood, was the anti-R-13 reactivity: 37% of the patients infected by clonet 39 (94 cases) had anti-R13 antibodies contrasting with only 6% of the patients without clonet 39 (16 cases).
PCR-based diagnosis for Chagas' disease in Bolivian children living in an active transmission area: comparison with conventional serological and parasitological diagnosis
(Cambridge University Press, 1997) Patrick Wincker; Jenny Telleria; M. F. Bosseno; Micaela Cardoso; Patrícia Marques; Nina Yaksic; Christine Aznar; P. LIEGEARD; Mireille Hontebeyrie; François Noireau
A large field study has been performed in the Cochabamba region of Bolivia with the aim of comparing the polymerase chain reaction (PCR) with other diagnostic methods for Chagas' disease. The amplification of Trypanosoma cruzi-specific kinetoplast DNA sequences in blood samples was compared with classical serological methods, specific IgM detection and direct parasite visualization for 268 school children in a single village where Chagas' disease transmission is active. Of 113 children positive by classical serology or buffy coat examination, 106 were detected by PCR (sensitivity: 93.8%). We did not observe any significant difference of PCR sensitivity between initial (IgM and/or buffy coat positive) and indeterminate stage (only IgG positive) patients. Among the remaining 155 children unconfirmed as chagasic (who were either only IgM positive, IgG-, IgM-, and buffy coat-negative) only 1 case was PCR positive. This case may be due to DNA contamination, or to a very recent infection not detected otherwise, or to specific immune depression. These results show that PCR is a very sensitive parasitological test for Chagas' disease in active transmission regions. The future follow-up of the possibly infected patients who were only IgM-positive should clarify the interest of PCR and IgM tests in the detection of starting infections.
POLYMERASE CHAIN REACTION DETECTION AND SEROLOGIC FOLLOW-UP AFTER TREATMENT WITH BENZNIDAZOLE IN BOLIVIAN CHILDREN INFECTED WITH A NATURAL MIXTURE OF TRYPANOSOMA CRUZI I AND II
(American Society of Tropical Medicine and Hygiene, 2006) María Flóres-Chávez; Marie-France Bosseno; Brigitte Bastrenta; JOSE-LOUIS ALCAZAR DALENZ; Mireille Hontebeyrie; Susana Revollo; Simone Frédérique Brénière
Thirty-five Bolivian children (5-10 years of age) seropositive for infection with T. cruzi underwent specific chemotherapy with benznidazole. Before treatment, 57.1% had a positive parasitologic diagnosis. Some patients presented an early conversion by polymerase chain reaction of blood samples, while others were still positive four and seven months after the end of the treatment, which indicated an absence of parasite clearance. Strain typing showed that most patients were infected by a mixture of clones I and II of T. cruzi. Serologic conversion in conventional tests and antibodies to shed acute-phase antigen were observed in two and four patients, respectively. For the other patients, the average rate of antibody decay was half the initial rate. The parasitologic and serologic data indicated that chemotherapy acts throughout the course of infection in a long-lasting process in which the decrease of specific antibody production is related to the reduction of the live parasite load.