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1.
Coexistence of two species of Plasmodium in a single host has disrupted the diagnosis and treatment of malaria. This study was designed to evaluate the ability of rapid diagnostic test (RDT) kits for the diagnosis of mixed-species malaria infections in southeastern Iran. A total of 100 malaria patients were included in the study out of 164 randomly suspected symptomatic malaria patients from May to November 2012. Nested polymerase chain reaction (PCR) was also used to judge the ability of microscopy versus RDT kits for detecting mixed species. The sensitivity of light microscopy for the detection of mixed-species malaria infections was 16.6% (95% confidence interval [CI] = 3–49.1). Nested PCR revealed 12 patients with mixed-species infection. The CareStart Pv/Pf Combo kit detected 58% of the mixed-species infections, which were determined by nested PCR (sensitivity = 58.3%; 95% CI = 28.5–83.5). For identifying P. falciparum, P. vivax, and mixed-species infections, the concordance rates (kappa statistics) of microscopy and CareStart Pv/Pf Combo kit with nested PCR were 0.76 and 0.79, respectively (P = 0.001). This study underlines the effectiveness of RDT kits to improve the differentiation of mixed-species malaria infections in endemic areas where the prevalence of chloroquine resistance is high.  相似文献   

2.
In a prospective study amongst febrile travellers returning from malaria-endemic areas to Berlin, Germany, two rapid malarial antigen detection tests were compared for the diagnosis of vivax malaria with routine microscopy. With ICT Malaria P.f./P.v.((R)), 664 samples of 492 patients were examined. 17 patients had vivax malaria, out of which 11 infections were missed (35.3% sensitivity). With OptiMal((R)), 659 samples of 539 patients were examined. 22 patients had vivax malaria, and all infections were identified correctly (100% sensitivity). Specificity was 100% with both tests. The ICT Malaria P.f./P.v.((R)) is advertised for layman use during travel, and the literature was reviewed with respect to the question of suitability of these devices for self-testing. It is concluded that with the ICT Malaria P.f./P.v.((R)), the detection of non-falciparum (i.e. predominantly vivax) malaria is unreliable, and test interpretation for medically untrained individuals particularly in distress might be too complicated even after proper instruction.  相似文献   

3.
In Myanmar, we tested two rapid malaria immunochromatographic kits: the OptiMAL assay for the detection of parasite lactate dehydrogenase (pLDH), and the ICT Malaria P.f./P.v. test for histidine-rich protein 2 (PfHRP2) and panmalarial antigens. A total of 229 patients were examined, of whom 133 were found to be malaria positive by Giemsa microscopy. Both OptiMAL and ICT gave lower sensitivities than previously reported. ICT sensitivity for Plasmodium falciparum and non-falciparum parasites were 86.2 and 2.9%, respectively; specificity was 76.9 and 100%, respectively. OptiMAL sensitivity for P. falciparum and non-falciparum parasites were 42.6 and 47.1%, respectively; specificity was 97.0 and 96.9%, respectively. The sensitivity of both tests for the detection of both P. falciparum and non-falciparum parasites increased with parasite density. Several explanations for these results are explored. Our results raise particular concern over batch quality variations of malaria rapid diagnostic devices (MRDDs).  相似文献   

4.
The immunochromatographic tests with HRP-2 antigen (histidine-rich protein) Vision Biotech Pf Rapid Malaria Test was performed in 291 children under 5 years presenting fever or history of fever (malaria presumptive cases) admitted to Children Out-Patient Department of the Modilon Hospital in Madang, in a high malaria risk area of Papua New Guinea. The results of the tests were compared to the results of the parasitic examination of the peripheral blood with light microscopy (thick and thin smears). The HRP-2 test showed very high sensitivity (95.4%) and specificity (94.1%) for Plasmodiumfalciparum parasitaemia and none or very low sensitivity and specificity for other malaria species. The HRP-2 test detected both asexual and sexual stages of the Plasmodium falciparum parasites. The test did not show significant changes in detection of different levels of parasitaemia. These findings enable to conclude that the HRP-2 immunochromatographic assay can be very helpful to diagnose Plasmodium falciparum malaria when microscopy examination is not available, but as qualitative tests can be difficult for interpretation especially in high malaria risk areas. Therefore it can require re-examination of blood with microscopy to confirm species and development stages of Plasmodium spp. and to assess parasite load.  相似文献   

5.
Objective To evaluate 4 rapid malaria diagnostic kits (RDTs) in Korea: OptiMAL test, SD BIOLINE Malaria Ag P.f/Pan test, Humasis Malaria P.f/Pan antigen test and CareStart? Malaria Pf/Pv Combo test. Methods Hundred malaria patients with Plasmodium vivax (P. vivax) and 100 healthy volunteers were recruited. The results from earlier four RDTs were compared with the reference standard, the Giemsa‐stained traditional microscopic diagnosis. Results Compared with the reference standard, the sensitivity and specificity for Plasmodium vivax were 92.7 and 100% for SD BIOLINE Malaria Ag P.f/Pan; and 94.6% and 100% for OptiMAL; 95.5% and 100% for both Humasis Malaria P.f/Pan antigen test and CareStart? Malaria Pf/Pv Combo test. Conclusion The performances of all four malaria RDT kits were acceptable, although Humasis Malaria P.f/Pan antigen test and CareStartTM Malaria Pf/Pv Combo test gave superior performances with ROK isolates.  相似文献   

6.
The accuracy of techniques for the diagnosis of malaria are usually compared with optical microscopy, which is considered to be a gold standard. However, microscopy is prone to error and therefore makes it difficult to assess the reliability of other diagnostic techniques. We did a systematic review to assess the specificity and sensitivity of diagnostic techniques in different settings, using a statistical method that avoided defining a gold standard. Performance varied depending on species of the malaria parasite, level of parasitaemia, and immunity. Overall, histidine-rich protein 2 (HRP2)-based dipsticks showed a high sensitivity (92.7%) and specificity (99.2%) for Plasmodium falciparum in endemic areas. The acridine orange test was more sensitive (97.1%) in detecting P falciparum in epidemiological studies, with a specificity of 97.9%. In the absence of a gold standard, HRP2 dipsticks and acridine orange could provide an alternative for detecting falciparum infections in endemic areas and epidemiological studies, respectively. Microscopy still remains more reliable in detecting non-falciparum infections.  相似文献   

7.
PCR-based ELISA technique for malaria diagnosis of specimens from Thailand   总被引:2,自引:0,他引:2  
We performed a field evaluation of polymerase chain reaction (PCR)-based enzyme-linked immuno-sorbent assays (ELISA) for the diagnosis of malaria. A commercially available PCR-ELISA microplate hybridization (MPH) assay was used. Blood specimens were collected from 300 volunteers seeking care at malaria clinics in Thailand. Examination of 200 high power fields by Giemsa-stained thick and thin smear (GTTS) revealed 51 P. falciparum (Pf), 45 P. vivax (Pv), seven mixed Pf-Pv infections. These plus a random sample of 48 GTTS-negative specimens were selected for this study. All 151 specimens were processed for parasite DNA extraction and assayed by PCR-MPH. The target DNA sequence of the 18S small subunit ribosomal RNA (SSUrRNA) gene was amplified by PCR and hybridized with species-specific probes for Pf, Pv, P. malariae (Pm) and P. ovale (Po) immobilized in the wells of the microtiter plate and detected by colorimetric assay. Colour development was assessed at an optical density (OD) of 405 nm. An absorbance reading of > or = 0.1 was used as a positive cut-off. In comparison with GTTS results, PCR-MPH sensitivity was 91.4% (53/58, 95% CI 84.2-98.6) for Pf, 94.2% (49/52, 87.9-100) for Pv and specificity was 95.8% (46/48, 95% CI 90.2-100). There was statistically significant positive correlation between parasite densities < or = 7000/microl blood and absorbance reading, suggestive of PCR-MPH being semiquantitative. PCR-MPH also detected additional Pf and Pv cases as well as Pm and Po.  相似文献   

8.
Lack of experience on the part of involved laboratory personnel frequently complicates swift diagnosis of imported falciparum malaria in non-endemic areas. Diagnostic tools based on the dipstick principle for the detection of plasmodial histidine-rich protein 2 have been marketed for several years and have been extensively evaluated. Recently, a test kit capable of detecting antigen of Plasmodium falciparum and P. vivax has been introduced. In order to evaluate this newly available tool, specimens from 664 patients were screened during the course of a prospective multicentre study within the European Network on Imported Infectious Disease Surveillance (TropNetEurop). Among the screened specimens, samples from 82 patients (12.3%) were positive for falciparum malaria using expert microscopy. A further 17 samples were positive for vivax malaria. The evaluated test kit performed with a sensitivity of 87.8% and a specificity of 99% for detection of falciparum malaria. Respective values for vivax malaria were 76.5% and 100%. Dipstick tests have the potential of improving the speed and accuracy of the diagnosis of falciparum malaria, especially if non-specialized laboratories are involved. However, decreased values of sensitivity and specificity, in comparison with expert microscopy, still impose a clear limit on the usefulness of the currently available kits.  相似文献   

9.
The NOW® Malaria Test, an immunochromatographic test (ICT), was evaluated to determine its ability to quantitatively detect malaria parasites using 100 blood samples from Thailand, including 50 Plasmodium falciparum (Pf) infections and 50 P. vivax (Pv) infections. Intensities of the thickness of the visible bands of the positive ICT were compared with the parasite densities. In cases of Pf infection, the intensities of both HRP-2 bands (T1 bands: Pf specific bands) and aldolase bands (T2 bands: pan-Plasmodium bands) correlated with the parasite densities. The intensities of T2 bands in Pf positive samples showed better correlation with the parasite densities than the T1 bands. In the cases of Pv infection, the intensities of T2 bands were also well correlated with parasite density. These results suggest that the ICT is useful not only for rapid detection of malaria parasites but also for estimating parasite density.  相似文献   

10.
5种市售弓形虫抗体检测试剂盒的评价   总被引:10,自引:0,他引:10  
目的 评价国内公司研制的 5种弓形虫抗体检测试剂盒。方法 以敏感性、特异性、符合率和Youden指数作分析指标 ,比较 5种试剂盒对国外进口的 2种弓形虫抗体试剂盒筛选出的弓形虫IgG或IgM阳性血清和正常人血清的检测结果。结果 A、B、C 3种IgM试剂盒的检测敏感性和特异性分别为 0和 92 1%、6 7%和 10 0 %、以及 13 3%和 85 7% ,Youden指数分别为 - 0 0 8、0 0 7和 - 0 0 1,基本无诊断价值。A’、B’ 2种IgG试剂盒的检测敏感性分别为 96 4 %和 32 1% ,特异性为 98 4 %和 96 8% ,Youden指数为 0 95和 0 2 9。A’试剂盒与进口IgG试剂盒的符合率达到 97 8% ,诊断价值较大 ,而B’试剂盒与进口试剂盒的符合率仅为 76 9% ,A’、B’ 2种试剂盒之间的符合率也只有 76 9%。结论 国内研制的市售弓形虫试剂盒的检测效果与质量存在一定的问题 ,尤以IgM试剂盒为甚。  相似文献   

11.
The performance of two histidine-rich protein type-2-based malaria rapid diagnostic tests (mRDTs) was examined in a rural area with a high prevalence of malaria and human immunodeficiency virus type-1 (HIV-1) infection in 113 and 445 febrile patients ≥ 15 years of age with and without HIV-1 infection, respectively. Patients were tested for HIV-1 infection by using a standard assay and for Plasmodium falciparum by using two mRDTs and microscopy. When microscopy was used as the gold standard, both mRDTs performed similarly in patients with and without HIV-1 infection: Bioline SD Malaria Antigen P.f, sensitivity 94.4% (95% confidence interval [CI]: 81.3-99.3%) versus 97.1% (95% CI:92.8-99.2%) and specificity 50.6% (95% CI: 39.0-62.2%) versus 47.2% (95% CI: 41.4-53.1%); and ICT diagnostics Malaria Pf, sensitivity 94.4% (95% CI: 81.3-99.3%) versus 97.1% (95% CI: 92.8-99.2%) and specificity 50.6% (95% CI:39.0-62.2%) versus 50.3% (95% CI: 44.4-56.1%). Infection with HIV-1 does not appear to affect the performance of these histidine-rich protein type-2 (HRP-2)-based mRDTs.  相似文献   

12.
The OptiMAL assay, a new immunochromatographic "dipstick" test for malaria based on detection of Plasmodium lactate dehydrogenase (pLDH), is purported to detect infections of approximately 200 parasites/microL of blood and to differentiate between Plasmodium falciparum and non-P. falciparum. We evaluated OptiMAL performance by comparing the test strip interpretations of two independent readers with consensus results obtained independently by expert malaria microscopists. Unbiased measures of sensitivity were derived by applying the OptiMAL test for detection and differentiation of light, asymptomatic infections by P. falciparum and Plasmodium vivax. OptiMAL readings were separated in time to determine whether the reaction signal was stable. Microscopy identified infections in 225 of 505 individuals screened; those with P. falciparum (n = 170) averaged 354 asexual forms/microL and P. vivax/Plasmodium malariae (n = 112) averaged 216 asexual forms/microL of blood. Concordance between OptiMAL and microscopy was 81% and 78% by the two independent readings. The assay's sensitivity for detection of any malaria species was 60.4% and 70.2% respectively and specificity was 97% and 89%. Most cases identified by microscopy as P. falciparum were graded as negative or non-falciparum by both OptiMAL readers. OptiMAL false negatives as well as misidentifications were related to low parasitemias (< 500/microL). The OptiMAL assay demonstrated 88-92% sensitivity for detecting infections of 500-1,000 parasites/microL, a range covering the mean parasitemia of primary symptomatic P. falciparum infections in malaria-na?ve Indonesian transmigrants. This device was markedly less sensitive than expert microscopy for discriminating between malaria species and is presently unsuited for use as an epidemiological screening tool. The OptiMAL assay is not approved for diagnostic use but is commercially available for research purposes only.  相似文献   

13.
Logistic, economic and technical factors limit rapid access to microscopic confirmation of symptomatic diagnosis of malaria in many rural areas in endemic countries such as Myanmar. A study was conducted to evaluate a rapid on-site immunochromatographic test (ICT Malaria Pf/Pv) for detection of Plasmodium falciparum and P. vivax in two villages in the Taikkyi region of Myanmar. The ICT Malaria tests were performed by a volunteer health worker (VHW) in Yae-Aye-San village and by a professionally trained midwife (MW) in Kankone village. A total of 1000 symptomatic patients participated in the study by providing blood samples for an ICT test and for microscopy. The ICT performance indices, relative to microscopy, were better for the trained MW compared with the less experienced VHW. For P. falciparum and/or P. vivax infections, the sensitivities were 82.7% for the VHW compared with 93.7% for the MW. For P. falciparum infections, the sensitivities were 82.2% for the VHW and 91.3% for the MW, while the corresponding values for P. vivax infections were 66.7 and 79%, respectively. Although the test kit appeared to perform better in more experienced hands, this study questions whether this difference is related to the use of the ICT Malaria Pf/Pv test kit, or related to other factors such as differences in the quality of blood slides prepared by the VHW and MW for microscopic examination. Overall, the results suggest that a rapid diagnostic assay such as the ICT Malaria Pf/Pv test kit can be used in rural settings by relatively inexperienced persons, such as VHWs, with a reasonable degree of sensitivity, thus providing on-site confirmation of symptomatic diagnosis of malaria.  相似文献   

14.
The NOW ICT Malaria P.f./P.v. for Whole Blood (Binax, Inc., Portland, ME) is a new malaria rapid diagnostic device that represents a technical advance over previous assays, such as ICT Malaria P.f./P.v. and ICT Malaria P.f.. We evaluated this device in March 2001 in symptomatic patients at malaria clinics in Maesod, Thailand. Microscopic examination of Giemsa-stained blood smears was the reference standard. In 246 patients, microscopy showed 32 (13.0%) infected with Plasmodium falciparum, 63 (25.6%) with P. vivax, 6 (2.4%) with mixed infections of P. falciparum and P. vivax, 5 (2.0%) with P. malariae, and 140 (56.9%) negative. Sensitivity for P. falciparum was 100% and specificity was 96.2% (200 of 208; 95% confidence interval [CI] = 92-98). For P. vivax, sensitivity was 87.3% (55 of 63; 95% CI = 77-93) and specificity was 97.7% (173 of 177; 95% CI = 95-99), but all the four false-positive results were microscopically positive for P. malariae; thus, specificity for non-falciparum Plasmodium was 100%. These results suggest improved performance over NOW ICT predecessors.  相似文献   

15.
We assessed the performance of two new commercially available rapid diagnostic tests (RDTs) for malaria (SD Bioline Malaria Ag Pf test and Ag Pf/Pan test) in 200 patients with uncomplicated malaria between August and October 2007 in Madagascar. Results of the two RDTs were compared with those obtained by microscopy and real-time polymerase chain reaction. The sensitivity and specificity for detection of Plasmodium falciparum were 93% and 98.9%, respectively, for the SD Bioline Malaria Ag Pf test and 92.9% and 98.9% for the SD Bioline Malaria Ag Pf/Pan test. The sensitivity of the SD Bioline Malaria Ag Pf/Pan test was much lower for detection of other species (63.6%). The sensitivity of the two new assays decreased to 77.3% at parasitemia levels < 100 parasites/microL for detection of P. falciparum.  相似文献   

16.
In this study, we evaluated the usage of the Pan Malaria IgG CELISA test in the diagnosis of malarial infections in Siverek-Sanliurfa, Turkey, where malarial infection is endemic and there are minimal health services available. The Pan Malaria IgG CELISA (Cellabs) test, which uses recombinant antigens and detects exposure to all four forms of malaria (P. falciparum, P. vivax, P. ovale and P. malariae) was used as individuals. Using the consensus microscopy results as the standard, sensitivity of ELISA for detection of any malarial infection in the rural populations was 83%, specificity was 85%. These results show that the performance of ELISA for the detection of any malarial infection is adequate for acute- and post-emergency situations and rural populations when the alternative is just clinical diagnosis.  相似文献   

17.
We report the identification of mixed Plasmodium infections in four recent patients with malaria clinically refractory to empiric chloroquine therapy using the rapid antigen detection kit, NOW ICT Malaria Pf/Pv. A rapid in vitro immunodiagnostic test, the NOW ICT Malaria Pf/Pv test kit was used for the detection of circulating Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) antigens in whole blood. Peripheral blood microscopy confirmed mixed-species infection in all the cases. Thick and thin peripheral blood films were made and stained with Giemsa stain and examined by both hospital laboratory staff and an experienced parasitologist who was blinded to the results of the rapid malarial antigen tests. Four recent patients (all male; mean age, 24 years) with mixed malarial infection were identified. All the subjects were males working for an oil company in a coastal area of Pakistan, and all had been diagnosed presumptively with malaria based on clinical grounds (without microbiologic confirmation), and were treated empirically with chloroquine without clinical response. Semiquantitative malaria counts via microscopy were as follows: P. vivax, scanty (2 patients) and moderate (2 patients); for P. falciparum--scanty (1 patient), moderate (2 patients), and heavy (1 patient). The present case series, although limited by the small number of patients with proven mixed P. falciparum-P. vivax infection, highlights the usefulness of the rapid antigen test in a highly malarious region of Pakistan where chloroquine resistance is prevalent. Although there was full concordance between the results of blood smear microscopy and rapid antigen testing, these techniques are potentially most useful when there is a discrepancy with microscopy findings. Accurate and rapid diagnosis of parasites, particularly in cases of mixed P. falciparum and P. vivax infection, is of immense importance for individual patient management and in reducing the burden of disease, especially in regions of chloroquine resistance.  相似文献   

18.
The histological study of the placenta is useful in the diagnosis of malaria during pregnancy. However, the scarcity of parasites and pigment in many malarial infections renders their identification difficult. We have tested the accuracy of standard and polarisation microscopy in the evaluation of 500 placental specimens from an area of high malarial endemicity in Tanzania. Standard microscopy showed a low sensitivity (50.3% for parasites, 40.5% for pigment), due to poor detection rates in cases with scant parasites (12.7% for <1%; 97.8% for >5% parasitised erythrocytes, P<0.001) or minimal pigment deposition (42.4% versus 84.5% when severe, P<0.001). The use of polarisation microscopy significantly increased the sensitivity of detection of pigment to 100% and parasites to 98.1% because of the marked birefringence of hemozoin present in mature stage parasites which accumulate in the placenta. Formalin pigment shares many properties with hemozoin, but the use of neutral buffered formalin prevented the formation of formalin pigment in placentas even after long periods of fixation. In conclusion, polarisation microscopy is a simple tool that markedly increases the sensitivity of the detection of malaria infection in the placenta and has good specificity when used on tissues fixed in neutral formalin. This method can be useful to investigators working in the malaria field.  相似文献   

19.
Bivalent rapid diagnostic tests are promising diagnostic tools for Plasmodium falciparum and P. vivax. Their diagnostic performance was evaluated against thick blood smear to assist national malaria control programs. A cross-sectional study was conducted to evaluate the performance of CareStart against thick blood smears among 398 acute febrile patients visiting the Felegeselam Health Center in December of 2011. Thick blood smears were examined under 100× objectives to diagnose Plasmodium species. Similarly, CareStart Malaria Pf/Pv Combo Test was performed as per the manufacturer''s instruction. The ability of CareStart Malaria Pf/Pv Combo Test to diagnose Plasmodium malaria was very good, with 99.8% (95% confidence interval = 97.7–100%) sensitivity and 97.7% (95% confidence interval = 94.6–99.1%) specificity. The sensitivity and specificity of the CareStart Test is comparable with the thick blood smear in diagnosing malaria. Hence, it is preferable to use the CareStart Malaria Pf/Pv Combo Test instead of microscopy in areas where microscopic diagnosis is limited.  相似文献   

20.

Objective

To evaluate the diagnostic performance of CareStart™ Malaria Pf/Pv Combo test relative to microscopy for the diagnosis of falciparum and vivax malaria in Ethiopia.

Methods

668 febrile patients visiting two health centers in Wondo Genet, southern Ethiopia, involved in this study in 2008. Giemsa-stained thin and thick blood smears were prepared and microscopically examined under a 100× oil immersion microscope objective for Plasmodium species identification and determination of parasitaemia, respectively. CareStart™ Malaria Pf/Pv Combo test and Paracheck Pf® test were performed as per the manufacturers’ instruction.

Findings

The diagnostic validity of CareStart™ Malaria Pf/Pv Combo test for the diagnosis of Plasmodium falciparum were very good with sensitivity of 99.4%, specificity of 98%, positive predictive value of 94.4% and negative predictive value of 99.8%. Sensitivity, specificity, positive predictive value and negative predictive value of the test for the diagnosis of P. vivax were 99.4%, 98.2%, 94.5% and 99.8%, respectively. The diagnostic performance of CareStart™ Malaria Pf/Pv Combo test is comparable to that of Paracheck Pf® test for the diagnosis of P. falciparum (sensitivity 99.4%, specificity 98.2%).

Conclusion

Although CareStart™ Malaria Pf/Pv Combo test and Paracheck Pf® test have comparable diagnostic performance for the diagnosis of P. falciparum, CareStart™ Malaria Pf/Pv Combo test has the added advantage of diagnosing P. vivax. Hence, it is preferable to use CareStart™ Malaria Pf/Pv Combo test for the diagnosis of malaria in areas where microscopy is not accessible and where malaria due to P. falciparum and P. vivax are co-endemic as in Ethiopia.  相似文献   

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