ABSTRACT
BACKGROUND: Rapid diagnostic tests (RDTs) are the current complement to microscopy for ensuring prompt malaria treatment. We determined the performance of three candidate RDTs (Paracheck™-Pf, SD Bioline malaria Ag-Pf and SD Bioline malaria Ag-Pf/pan) for rapid diagnosis of malaria in the Central African Republic. METHODS: Blood samples from consecutive febrile patients who attended for laboratory analysis of malaria at the three main health centres of Bangui were screened by microscopy and the RDTs. Two reference standards were used to assess the performance of the RDTs: microscopy and, a combination of microscopy plus nested PCR for slides reported as negative, on the assumption that negative results by microscopy were due to sub-patent parasitaemia. RESULTS: We analysed 436 samples. Using the combined reference standard of microscopy + PCR, the sensitivity of Paracheck™-Pf was 85.7% (95% CI, 80.8-89.8%), that of SD Bioline Ag-Pf was 85.4% (95% CI, 80.5-90.7%), and that of SD Bioline Ag-Pf/pan was 88.2% (95% CI, 83.2-92.0%). The tests performed less well in cases of low parasitaemia; however, the sensitivity was > 95% at > 500 parasites/µl. CONCLUSIONS: Overall, SD Bioline malaria Ag-Pf and SD Bioline malaria Ag-Pf/pan performed slightly better than Paracheck™-Pf. Use of RDTs with reinforced microscopy practice and laboratory quality assurance should improve malaria treatment in the Central African Republic.
Subject(s)
Diagnostic Tests, Routine/methods , Malaria, Falciparum/diagnosis , Plasmodium falciparum , Adolescent , Adult , Aged , Central African Republic , Child , Child, Preschool , Cross-Sectional Studies , Female , Fever/diagnosis , Humans , Infant , Male , Microscopy/methods , Middle Aged , Parasitemia/diagnosis , Polymerase Chain Reaction/methods , Reproducibility of Results , Sensitivity and Specificity , Young AdultABSTRACT
BACKGROUND: Environmentally driven immune activation was suggested to contribute to high rates of HIV-1 infection in Africa. We report here a study of immune activation markers and susceptibility to HIV-1 infection in vitro of forty-five highly exposed uninfected partners (EUs) of HIV-1 infected individuals in Central African Republic, in comparison with forty-four low-risk blood donors (UCs). RESULTS: Analysis of T lymphocyte subsets and activation markers in whole blood showed that the absolute values and the percentage of HLA-DR+CD4 T cells and of CCR5+CD4 T cells were lower in the EUs than in the UCs (p = 0.0001). Mutations in the CCR5 coding region were not found in either group. Susceptibility to in vitro infection of unstimulated peripheral blood mononuclear cells, prior of PHA activation, was decreased in EUs compared to UCs, either using a CXCR4-tropic or a CCR5-tropic HIV-1 strain (p = 0.02 and p = 0.05, respectively). Levels of MIP-1beta, but not of MIP-1alpha or RANTES, in the supernatants of PHA-activated PBMC, were higher in the EUs than in the UCs (p = 0.007). CONCLUSION: We found low levels of CD4 T cell activation and reduced PBMC susceptibility to HIV-1 infection in Central African EUs, indicating that both may contribute to the resistance to HIV-1 infection.
Subject(s)
CD4-Positive T-Lymphocytes/virology , HIV Seronegativity/immunology , HIV-1 , Adolescent , Adult , Africa, Central , Biomarkers/blood , CD4-Positive T-Lymphocytes/immunology , Chemokine CCL3 , Chemokine CCL4 , Chemokine CCL5/blood , Chemokines, CC/blood , Chemokines, CC/metabolism , Female , HLA-DR Antigens/blood , Humans , Immunity, Innate , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/virology , Lymphocyte Activation , Macrophage Inflammatory Proteins/blood , Male , Middle Aged , Receptors, CCR5/blood , Receptors, CCR5/geneticsABSTRACT
To study the progression of HIV-1 infection and coreceptor usages in Central African Republic, clinical data, plasma viral load, and coreceptor usage of sequential HIV-1 isolates were analyzed in a seroincident prospective cohort (PRIMOCA). Twenty-three HIV-1 infected individuals from the Central African Armed Forces were followed from 1995 to 2000. Viruses were isolated from 17 patients at various time points after seroconversion and their coreceptor usage was examined using GHOST cells expressing CD4 and one of the HIV-1 chemokine coreceptors CCR5, CXCR4, BOB/GPR15, and Bonzo/STRL33/CXCR6. Eleven patients died from AIDS. Eight of them died between 2 and 5 years after seroconversion, after a brief symptomatic stage. Patients who rapidly progressed to AIDS and death displayed the highest viral loads after seroconversion. All isolates obtained soon after seroconversion used CCR5, albeit, in some cases, CXCR4, BOB, or Bonzo were also used. Most isolates remained R5 (59 out of 61 isolates), although viruses using CXCR4 appeared in some cases of progression to AIDS. In several cases, a broad tropism was observed during the course of infection, with a frequent usage of BOB and Bonzo in addition to CCR5. Rapid progression to disease and short survival time among Central African HIV-1 patients appear more frequent than those reported in industrialized countries. Viral coreceptor used was mainly CCR5, but, interestingly, a large part of isolates also used BOB and Bonzo. However, there was no strict correlation between the clinical outcome and extended viral tropism.
