Asymptomatic carriage of microsporidia (ACM) has not been described in patients living with HIV (PLHIV) in Tunisia. To determine the prevalence of ACM in PLHIV followed at Tunis la Rabta hospital, describe its clinical features and course, and identify the species involved. This prospective study (2005-2009) included 71 asymptomatic PLHIV compared with 37 PLHIV with diarrhea. One stool sample per patient was examined by microscopy after Weber staining and by PCR. Species identification was confirmed by specific PCR and sequencing. In cases of ACM, a second stool sample was examined in 2010 and a clinical check-up took place in 2013. The prevalence of ACM in asymptomatic PLHIV was 11.3 % (8/71). PCR was more sensitive than microscopy (P = 0.0047). ACM was associated with stage C of HIV infection (P = 0.008) and CD4 T cells <100/μl (P = 0.033). The species involved were E. intestinalis (6 cases) and E. bieneusi (2 cases). Six PLHIV remained asymptomatic with negative stool examinations, but two developed digestive signs. ACM is common among Tunisian PLHIV and it appears to be associated with E. intestinalis.

The microsporidian species Enterocytozoon bieneusi is a major cause of chronic diarrhea and malabsorption in patients with AIDS. Genotyping was performed on seven E. bieneusi strains for the first time in Tunisia. All the strains were isolated from stool samples of humans with immunodeficiency virus (HIV) infection. Analysis of the ribosomal RNA gene internal transcribed spacer (rDNA ITS) allowed the identification of three distinct genotypes previously described in other studies. Genotypes D and B were characterized in four and two respectively. The Peruvian genotype (Peru 8) was detected in the last isolate. These results indicate a genetic diversity in E. bieneusi strains from HIV Tunisian patients and suggest the coexistence of both zoonotic and anthroponotic route of transmission.

Microsporidiosis and cryptosporidiosis are emerging opportunistic infections responsible for intestinal manifestations that are often severe in immunocompromised patients. A case of microsporidiosis-cryptosporidiosis coinfection is reported in an HIV-infected newborn. The patient was a 17-day-old female, exclusively breastfed and with no contact with animals. Microsporidiosis and cryptosporidiosis were diagnosed after systematic screening in stool samples using both specific staining and PCR. Two species of microsporidia, Encephalitozoon intestinalis and Enterocytozoon bieneusi, and Cryptosporidium hominis were identified. The contamination of the newborn probably resulted from direct human-to-human transmission during close contact with the mother (who had diarrhea and refused stool sampling). This report highlights the usefulness of the screening of intestinal microsporidiosis and cryptosporidiosis in HIV-infected subjects for better management.

ABSTRACT Current methods for diagnosis of visceral leishmaniasis (VL) require invasive sampling procedures such as visceral aspiration and/or blood drawing. The use of diagnostic tests using oral fluid, which is easier to collect, would be more simple and practical for VL diagnosis, especially under field conditions. Oral fluids from 37 VL patients and 40 healthy controls were collected using Oracol devices. Blood samples and oral fluid specimens from both groups were analyzed by recombinant protein K39 (rK39) enzyme-linked immunosorbent assay and quantitative real-time PCR. Detection of antibodies in the oral fluid had a sensitivity of 100% and a specificity of 97.5%. Antibody levels measured in serum and oral fluid showed a significant positive correlation (ρ = 0.655 and P = 0.01). Detection of Leishmania DNA in oral fluid had a sensitivity of 94.6% and a specificity of 90%. The median parasite load estimated in blood was 133 parasites/ml (interquartile range [IR], 10 to 1,048), whereas that in oral fluid specimens was 3 parasites/ml (IR, 0.41 to 92). However, there was no significant linear relationship between parasite loads assessed in the two biological samples (ρ = 0.31 and P = 0.06). VL diagnosis based on specific antibody detection and Leishmania DNA identification using oral fluid samples was equivalent in accuracy to that using blood and therefore is promising for clinical use.

Aim. - Intestinal microsporidiosis are among the most frequent opportunistic diseases in immuno-compromised subjects. This study aimed to evaluate the contribution of PCR for a better detection and species identification of microsporidia in stool specimens of HIV-infected patients.Patients and methods. - Stool samples obtained from 119 HIV-infected Tunisian subjects were screened for intestinal microsporidiosis by light microscopy using Weber's modified Trichrome stain and by a PCR method using universal primers V1/PMP2 which amplified a common fragment of the small subunit rRNA gene of microsporidia. The obtained PCR products were then sequenced using an ABI PRISM 377 DNA sequencer.Results. - The results showed a better sensitivity of PCR in the detection of microsporidia with an infection rate of 14.3% significantly higher than that of 6.7% obtained by light microscopy (p = 0.03). As previously described, intestinal microsporidiosis was associated with low CD4 cell counts; 23.9% infection rate in patients having CD4 cell count under 200/mm(3) against 5.6% in patients with higher CD4 cell count (p = 0.008). The sequencing of 15 out of the 17 positive PCR products has confirmed in all cases the species identified based on the PCR fragment size i.e., 250 pb for Enterocytozoon bieneusi (seven cases) and about 270 pb for Encephalitozoon intestinalis (nine cases); one case revealed a double infection.Conclusion. - PCR proved to be more effective than classical Trichrome stain for the diagnosis of intestinal microsporidiosis. Moreover, the ability of PCR to identify the species involved could also be useful for cases management. (C) 2009 Elsevier Masson SAS. All rights reserved.

Dielectric investigations in the temperature and frequency ranges 150 - 450K and 10 2 - 10 5 Hz respectively show that the compositions x = 0.2 and x = 0.4 of the solid solution Rb1-x(NH4)(x)HSO4 are ferroelectric below T-c = 285K and T-c = 295K respectively. The symmetry of room temperature phase is P-21/C for both investigated compositions. Alternative current complex impedance measurements were performed on this ferroelectric and superconductor material at high temperatures. An impedance relaxation was observed. In addition, to the ferroelectric properties, a modest level of conductivity at high temperatures, which was attributed to the motion of H+ proton, was observed for both compositions but this conductivity is more pronounced at low and high temperatures for the composition x = 0.2.

The crystal structures of the title compounds were solved using the single-crystal X-ray diffraction technique. At room temperature CsKSO4Te(OH)(6) was found to crystallize in the monoclinic system with Pn space group and lattice parameters: a = 12.5463(6) angstrom; b = 6.5765(2) angstrom; c = 12.6916(7) angstrom; beta = 106.53(2)degrees; V = 1003.914(4) angstrom(3); Z = 4 and D-calc = 3.29 g/cm(3). The structural refinement has led to a reliability factor of R-1 = 0.0284 (wR(2) = 0.064) for 7577 independent reflections. Rb1.25K0.75SO4Te(OH)(6) material possesses a monoclinic structure with space group P2(1)/a and cell parameters: a = 11.3411(6) angstrom; b = 6.5819(2) angstrom; c = 13.5730(8) angstrom; beta = 106.860(10)degrees; V = 969.62(10) angstrom(3); Z = 4 and D = 3.16(3) g/cm(3). The residuals are R-1 = 0.0297 and wR(2) = 0.0776 for 3336 independent reflections. The main interest of these structures is the presence of two different and independent anionic groups (TeO66- and SO42-) in the same crystal.Complex impedance measurements (Z* = Z'-iZ") have been undertaken in the frequency and temperature ranges 20-10(6) Hz and 400-600 K, respectively. The dielectric relaxation is studied in the complex modulus formalism M*. (C) 2006 Elsevier Inc. All rights reserved.

Single crystals of RbK(SO4).Te(OH)(6) are obtained by slow evaporation at room temperature. The frequency and temperature dependencies of the real part of the permittivity, epsilon(r)', show that this material presents three phase transitions at T-1 = 490 K, T-2 = 535 K and T-3 = 580 K. DSC measurements on RbK(SO4).Te(OH)(6) have been carried out in the temperature ranges 350-650 K. It reveal three endothermic peaks at around T-1, T-2 and T-3. Complex impedance measurements are performed on this material at various temperatures. A substantial jump of the conductivity, attributed to the motion of H+, is observed at high temperatures. This behavior indicates the presence of superprotonic phase transition in RbK(SO4).Te(OH)(6). Raman spectra of RbK(SO4).Te(OH)(6), recorded at various temperatures (300-550 K) in the frequency range 200-1200 cm(-1). confirm the presence of the phase transitions and especially the ferroelectric and the superprotonic phase transition. (C) 2004 Elsevier B.V. All rights reserved.

Differential scanning calorimetry (DSC), dielectric constant, ac conductivity and Raman spectroscopy measurements are used to study the phase transitions of K2(SO4)·Te(OH)6 crystal between 300 and 550 K. Two phase transitions are observed: a ferroelectric to paraelectric phase transition at 480 K and a transition between a low-temperature ordered state and a superionic conductivity state at 490 K. Dielectric data in the region 20–0.2 106 Hz show a pronounced dispersion relaxation frequency which obeys the Arrhenius law and two dielectric peaks, respectively, at 480 and 490 K. Raman scattering data provide evidence for the several phase transitions observed.

Single crystals of CsK(SO4)·Te(OH)6 are obtained by slow evaporation at room temperature. Differential scanning calorimetry (DSC) measurements have been carried out in the temperature range 350–650K. It reveals three anomalies in the studied temperature range. Complex impedance measurements are performed on this material as a function of both temperature and frequency. The electric conduction and dielectric relaxation have been studied. The temperature dependence of DC conductivity indicates that the sample became an ionic conductor at high temperature. The frequency dependence of conductivity follows the Jonscher’s dynamic law. The high level of conductivity at high temperature is explained by the dynamical disordering of protons between the neighboring SO4 groups. This behavior indicates the presence of superprotonic phase transition in CsK(SO4)·Te(OH)6.

Three phase transitions have been detected by dielectric measurements and Raman scattering on polycrystalline samples of RbK(SO4)Te(OH)6, RbCs(SO4)Te(OH)6 and CsK(SO4)Te(OH)6. The temperature and frequency dependencies of the real part of the permittivity, ε′r, revealed a first peak at T1=490, 485 and 495 K, respectively, for RbK(SO4)Te(OH)6, RbCs(SO4)Te(OH)6 and CsK(SO4)Te(OH)6. This peak was attributed to a structural order–disorder phase transition. The second anomaly, observed at T2=535, 560 and 575 K, respectively, for the three materials, characterizes a ferroelectric–paraelectric phase transition. The third anomaly, however, is detected at T3=580, 580 and 595 K and was attributed to the superprotonic phase transition. The superprotonic conductivity introduces a significant dispersion in the evolution of the real part of the permittivity in the investigated frequency range. The Raman spectra of polycrystalline RbK(SO4)Te(OH)6, RbCs(SO4)Te(OH)6 and CsK(SO4)Te(OH)6 materials, recorded at various temperatures (300–550 K), is investigated in the frequency range 200–1200 cm−1. An assignment of the important band due to the internal vibrations is proposed. The evolution of Raman spectra with temperature shows some changes characterizing the phase transitions in these materials.