Evaluation of light microscopy and rapid diagnostic test for the detection of malaria under operational field conditions: a household survey in Ethiopia.

BACKGROUND: In most resource-poor settings, malaria is usually diagnosed based on clinical signs and symptoms and not by detection of parasites in the blood using microscopy or rapid diagnostic tests (RDT). In population-based malaria surveys, accurate diagnosis is important: microscopy provides the gold standard, whilst RDTs allow immediate findings and treatment. The concordance between RDTs and microscopy in low or unstable transmission areas has not been evaluated. OBJECTIVES: This study aimed to estimate the prevalence of malaria parasites in randomly selected malarious areas of Amhara, Oromia, and Southern Nations, Nationalities and Peoples' (SNNP) regions of Ethiopia, using microscopy and RDT, and to investigate the agreement between microscopy and RDT under field conditions. METHODS: A population-based survey was conducted in 224 randomly selected clusters of 25 households each in Amhara, Oromia and SNNP regions, between December 2006 and February 2007. Fingerpick blood samples from all persons living in even-numbered households were tested using two methods: light microscopy of Giemsa-stained blood slides; and RDT (ParaScreen device for Pan/Pf). RESULTS: A total of 13,960 people were eligible for malaria parasite testing of whom 11,504 (82%) were included in the analysis. Overall slide positivity rate was 4.1% (95% confidence interval [CI] 3.4-5.0%) while ParaScreen RDT was positive in 3.3% (95% CI 2.6-4.1%) of those tested. Considering microscopy as the gold standard, ParaScreen RDT exhibited high specificity (98.5%; 95% CI 98.3-98.7) and moderate sensitivity (47.5%; 95% CI 42.8-52.2) with a positive predictive value of 56.8% (95% CI 51.7-61.9) and negative predictive value of 97.6% (95% CI 97.6-98.1%) under field conditions. CONCLUSION: Blood slide microscopy remains the preferred option for population-based prevalence surveys of malaria parasitaemia. The level of agreement between microscopy and RDT warrants further investigation in different transmission settings and in the clinical situation

The Evaluation of a Rapid In Situ HIV Confirmation Test in a Programme with a High Failure Rate of the WHO HIV Two-Test Diagnostic Algorithm

BACKGROUND: Concerns about false-positive HIV results led to a review of testing procedures used in a Médecins Sans Frontières (MSF) HIV programme in Bukavu, eastern Democratic Republic of Congo. In addition to the WHO HIV rapid diagnostic test algorithm (RDT) (two positive RDTs alone for HIV diagnosis) used in voluntary counselling and testing (VCT) sites we evaluated in situ a practical field-based confirmation test against western blot WB. In addition, we aimed to determine the false-positive rate of the WHO two-test algorithm compared with our adapted protocol including confirmation testing, and whether weakly reactive compared with strongly reactive rapid test results were more likely to be false positives. METHODOLOGY/PRINCIPAL FINDINGS: 2864 clients presenting to MSF VCT centres in Bukavu during January to May 2006 were tested using Determine HIV-1/2 and UniGold HIV rapid tests in parallel by nurse counsellors. Plasma samples on 229 clients confirmed as double RDT positive by laboratory retesting were further tested using both WB and the Orgenics Immunocomb Combfirm HIV confirmation test (OIC-HIV). Of these, 24 samples were negative or indeterminate by WB representing a false-positive rate of the WHO two-test algorithm of 10.5% (95%CI 6.6-15.2). 17 of the 229 samples were weakly positive on rapid testing and all were negative or indeterminate by WB. The false-positive rate fell to 3.3% (95%CI 1.3-6.7) when only strong-positive rapid test results were considered. Agreement between OIC-HIV and WB was 99.1% (95%CI 96.9-99.9%) with no false OIC-HIV positives if stringent criteria for positive OIC-HIV diagnoses were used. CONCLUSIONS: The WHO HIV two-test diagnostic algorithm produced an unacceptably high level of false-positive diagnoses in our setting, especially if results were weakly positive. The most probable causes of the false-positive results were serological cross-reactivity or non-specific immune reactivity. Our findings show that the OIC-HIV confirmation test is practical and effective in field contexts. We propose that all double-positive HIV RDT samples should undergo further testing to confirm HIV seropositivity until the accuracy of the RDT testing algorithm has been established at programme level

Immunohaematological reference values in human immunodeficiency virus-negative adolescent and adults in rural northern Tanzania

<p>Abstract</p> <p>Background</p> <p>The amount of CD4 T cells is used for monitoring HIV progression and improvement, and to make decisions to start antiretroviral therapy and prophylactic drugs for opportunistic infections. The aim of this study was to determine normal reference values for CD4 T cells, lymphocytes, leucocytes and haemoglobin level in healthy, HIV negative adolescents and adults in rural northern Tanzania.</p> <p>Methods</p> <p>A cross sectional study was conducted from September 2006 to March 2007 in rural northern Tanzania. Participants were recruited from voluntary HIV counselling and testing clinics. Patients were counselled for HIV test and those who consented were tested for HIV. Clinical screening was done, and blood samples were collected for CD4 T cell counts and complete blood cell counts.</p> <p>Results</p> <p>We enrolled 102 participants, forty two (41.2%) males and 60 (58.8%) females. The mean age was 32.6 ± 95% CI 30.2–35.0. The mean absolute CD4 T cell count was 745.8 ± 95% CI 695.5–796.3, absolute CD8 T cells 504.6 ± 95% CI 461.7–547.5, absolute leukocyte count 5.1 ± 95% CI 4.8–5.4, absolute lymphocyte count 1.8 ± 95% CI 1.7–1.9, and haemoglobin level 13.2 ± 95% CI 12.7–13.7. Females had significantly higher mean absolute CD4 T cell count (p = 0.008), mean absolute CD8 T cell count (p = 0.009) and significantly lower mean haemoglobin level than males (p = 0.003)</p> <p>Conclusion</p> <p>Immunohaematological values found in this study were different from standard values for western countries. Females had significantly higher mean CD4 T cell counts and lower mean haemoglobin levels than males. This raises the issue of the appropriateness of the present reference values and guidelines for monitoring HIV/AIDS patients in Tanzania.</p

Determination and analysis of film reject rate at eight selected governmental diagnostic X-ray facilities in Tigray Region, Northern Ethiopian

Background: In radiography examination, it is common to encounter patients undergoing repeated X-ray exposure after the rejection of a film image due to poor image quality. This subjects the patients to unnecessary radiation exposure and extra cost for the facility. This fact has required to investigate the causes of film rejection in common X-ray examinations. Aims: This study aims to obtain images, which are adequate for the clinical diagnostic purpose with minimum radiation dose to the patient in X-ray radiographic examination using film rejects analysis. Methods: A prospective, crosssectional study design was carried out for 3 months. The film rejection rate data were collected using standardized checklist as recommended by the National Radiation Protection Authority and International Atomic Energy Agency. Daily recordings were compiled by frontline radiographers and senior physicians. Statistical Analysis Used: Data were analyzed descriptively using SPSS of version 23 software. Results: Overall rejection rate was 319 (10.02%) in 3183 X-ray exposures. The rejection rates by hospitals are 33.7% in Adwa, 13% in Aksum, 9.6% in Suhul, 9.2% in AbiAdi, 7.7% in Humera, 7% in Wukro, 4.3% in Lemlem Karl, and 2.9% in Alamata General Hospitals. Conclusions: Rejected films were found to have been caused by numerous factors including incorrect exposure, poor technical judgment, patient motion, and improper film processing. Hence, strategies need to be developed within medical imaging departments to improve the situation

Essential Oil of Otostegia integrifolia Benth: Composition, Antimicrobial and Antioxidant Activities

Composition, antioxidant and antimicrobial activities of the essential oil of Otostegia integrifolia Benth. were studied. GC/MS analyses revealed the presence of 37 constituents representing 84.88% of the oil with α- pinene (31.33%), 1-octen-3-ol (11.78%) and trans-caryophyllene (11.35%) constituting more than 50% of its components. When tested for its antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH), the oil reduced DPPH in a concentration dependent manner with an EC50 value of 5.32 μl/ml. Similarly, the oil was shown to possess strong and broad spectrum antimicrobial activity against several Gram-positive and Gram -negative bacterial strains as well as fungal pathogens. The minimum inhibitory concentration (MIC) of the oil ranged from 5 to 100 μg/ml and 50 to 100 μg/ml against the bacterial and fungal strains tested, respectively. The oil (MIC=5 μg/ml) was found to be more potent than ciprofloxacin (MIC=10 μg/ml) against some E. coli strains. The antifungal activity of the oil was either comparable to or better than griseofulvin against most of the fungal pathogens tested. The study provides evidence for an excellent broadspectrum antimicrobial and significant antioxidant activity of O. integrifolia essential oil, a possible explanation for the traditional use of the plant.Keywords: essential oil, Otostegia integrifolia, α-pinene, 2,2-diphenyl-1-picrylhydrazyl, antimicrobial activit

Expression of chemokine receptors CCR5 and CXCR4 on CD4+ T cells and plasma chemokine levels during treatment of active tuberculosis in HIV-1-coinfected patients.

The pathogenesis of persistently elevated plasma HIV viremia in patients coinfected with tuberculosis (TB) during anti-TB treatment in Africans remains unknown. We examined the expression of chemokine receptors CCR5 and CXCR4 on CD4+ T cells and plasma chemokine levels of macrophage inflammatory protein (MIP)-1a, MIP-1b, regulated on activation normal T expressed and secreted (RANTES), and stromal cell–derived factor (SDF)-1a among TB patients with HIV coinfection during the first 2 months of anti-TB treatment. During treatment of TB, the plasma HIV-1 load and CD4+ T-cell count remained unchanged. Levels of CCR5 and CXCR4 expression on CD4+ T cells as well as plasma levels of chemokines remained persistently elevated during anti-TB treatment. Persistently elevated plasma HIV viremia also paralleled persistently elevated expressions of activated CCR5+ or CXCR4+ CD4+ T cells. These results suggest that increased expression of CCR5 and CXCR4 on an activated CD4+ T-cell population coupled with persistently elevated chemokines may provide a suitable condition for continuous replication of HIV associated with TB coinfection. This, in turn, may contribute, at least in part, to the observed persistently elevated plasma HIV viremia in coinfected patients despite anti-TB treatment

Evaluation of rapid assays for screening and confirming HIV-1 infection in Ethiopia.

To evaluate a simple and rapid testing strategy to diagnose HIV infection in Ethiopia, we subjected a panel of 688 sera with known HIV serologic status (confirmed by ELISA/WB or double ELISA) to 3 rapid assays: Determine HIV-1/2, Capillus HIV-1/2 and Serocard HIV. Samples were obtained from participants in a cohort study on HIV-infection (72%), from tuberculosis patients (18%) and from participants in surveillance studies among police recruits and commercial sex workers (10%). The panel consisted of 249 HIV-1 positive samples, of which 68 were HIV-1 subtype C and 1 HIV-1 subtype A, and 439 HIV-1 negative samples. Determine and Capillus were 100% sensitive and 99.8% specific, Serocard was 100% sensitive and specific. On retrospective evaluation, both parallel (samples tested simultaneously by two rapid assays) and serial (samples tested by two consecutive rapid assays) testing algorithms were 100% sensitive and specific when compared to ELISA/WB or double ELISA testing strategy. In conclusion rapid assays have high sensitivity and specificity. HIV serodiagnosis based on rapid assays may therefore be a valuable alternative in voluntary counselling and testing centres and in facilities where sophisticated laboratories are not available