Parasite-specific lactate dehydrogenase for the diagnosis of Plasmodium falciparum infection in an endemic area in West Uganda

The measurement of parasite lactate dehydrogenase (pLDH) has been presented as an easy and rapid method for the diagnosis of malaria in humans. In order to evaluate the sensitivity and specificity of such a test we examined blood samples from 429 Ugandan patients. While pLDH activity was significantly linked to parasitaemia, sensitivity and specificity were found to be rather low at 58.8 and 62.2% respectively. The positive and negative predictive values failed to meet necessary standards. We conclude that the methods of measurement of pLDH activity in malaria infection, although potentially useful for the fast diagnosis of malaria, need to be improved to be of true value in endemic areas.     

Automated detection of malaria-associated intraleucocytic haemozoin by Cell-Dyn CD4000 depolarization analysis

Laboratory tests for malaria are only performed if there is clinical suspicion of the disease, and a missed diagnosis contributes substantially to morbidity and mortality. Malaria parasites produce haemozoin, which is able to depolarize light and this allows the automated detection of malaria during routine complete blood count analysis (CBC) with some Abbott Cell-Dyn instruments. In this study, we evaluated the Cell-Dyn CD4000 with 831 blood samples submitted for malaria investigations. Samples were categorized as malaria negative (n = 417), convalescent malaria (n = 64) or malaria positive (n = 350) by reference to thin/thick film microscopy, 'rapid test' procedures, polymerase chain reaction analysis and clinical history. With regard to CD4000 depolarization analysis, a malaria positive CD4000 pattern was ascribed to samples that showed one or more abnormal depolarizing purple events, which corresponded to monocytes containing ingested malaria pigment (haemozoin). Positive CD4000 patterns were observed in 11 of 417, 50 of 64 and 281 of 350 of malaria negative, convalescent malaria and malaria positive samples respectively. The specificity and positive predictive values for malaria (active and convalescent) were very high (97.4 and 96.8%, respectively), while sensitivity and negative predictive values were 80.0 and 83.0% respectively. Depolarization analysis was particularly effective for Plasmodium falciparum malaria but there was lower detection sensitivity for White compared with Black African patients. CD4000 90 degrees depolarization vs 0 degrees analysis revealed a proportion of samples with small nonleucocyte-associated depolarizing particles. Appearance of such events in the form of a discrete cluster was associated with P. vivax rather than P. falciparum infection.     

Automated detection of malaria pigment: feasibility for malaria diagnosing in an area with seasonal malaria in northern Namibia

OBJECTIVE: To evaluate the feasibility of automated malaria detection with the Cell-Dyn 3700 (Abbott Diagnostics, Santa Clara, CA, USA) haematology analyser for diagnosing malaria in northern Namibia. METHODS: From April to June 2003, all patients with a positive blood smear result and a subset of patients with no suspicion of malaria were included. Blood smear and a venous blood sample (to determine haemoglobin, platelet and malaria pigment levels) were collected from each patient. Malaria pigment test characteristics, correlations with blood parameters and pigment clearance time were calculated. Finally, a subset of blood samples was run twice to evaluate the consistency of test outcome. RESULTS: Two hundred and eight patients were included. Ninety had a positive blood smear result of which 84 tested positive for malaria pigment and 118 patients had a negative blood smear result of which four tested positive for malaria pigment. Test characteristics as compared with microscopy were as follows: sensitivity 0.93, specificity 0.97, positive predictive value 0.95, negative predictive value 0.95. Rerun of the blood samples resulted in a change of diagnosis in 14%. After 4 weeks, 33% of patients with an initially positive pigment result still tested positive. Malaria pigment was found to be negatively correlated with haemoglobin. CONCLUSIONS: Automated detection of malaria pigment is a useful diagnostic tool in this semi-rural area. In low-risk malaria season, the test can be used for diagnosing malaria because of the high sensitivity. In high-risk malaria season, the test can be used for excluding malaria in case of a negative pigment result because of the high specificity.     

单采血浆相关性疟疾合并艾滋病病毒感染的研究

目的了解单采血浆相关性疟疾病例中,艾滋病病毒(HIV)感染情况。方法对1993-2005年间单采血浆相关性疟疾病例和非疟疾既往单采血浆供血者进行调查和采集血标本,采用快速蛋白印迹试验或酶联免疫吸附试验检测HIV抗体,初筛阳性者再用蛋白印迹试验进行确认;对现症疟疾病例的血标本用吉氏液染色-光学显微镜(油镜)检查疟原虫。结果 220例单采血浆相关性疟疾病例的HIV感染率为30.0%(66/220),3 008例非疟疾单采血浆供血者的HIV感染率为2.4%(72/3 008)。1993年12月和1994年1月采集并检测的上述两人群,HIV抗体均为阴性;而1995年3月至2005年采集并检测的上述两人群,HIV阳性率则分别为43.4%(66/152)和2.4%(72/2 958)。单采血浆相关性疟疾为间日疟,感染的HIV为HIV-1型。结论单采血浆相关性疟疾病例的HIV感染率较高。     

国产试剂RDT诊断疟疾效果评价

目的将国产试剂疟疾快速诊断试验（RDT）检测结果与镜检结果及进口试剂RDT和PCR结果进行比较,评价国产试剂RDT诊断疟疾的效果。方法收集160例疟疾病人或疑似疟疾病人血样,分别采用两种RDT、镜检和PCR进行检测,对检测结果进行比较。结果160份血样采用国产、进口试剂RDT及镜检和PCR检测疟疾感染,阳性率分别为45．00％、47．50％、41．25％和42．50％,经配对资料的Х^2检验,差异无统计学意义（P〉0．05）;镜检和PCR法均检出2例卵形疟,而国产和进口试剂RDT均为阴性。以镜检为标准．到产试剂RDT检测间日疟和恶性疟的敏感度为94％,特异度87%,假阳性率13％,假阴性率6％,阳性预测值83％,阴性预测值95％;以PCR为标准,国产试剂RDT检测间日疟和恶性疟的敏感度为94％,特异度89％,假阳性率11％,假阴性率6％,阳性预测值83％,阴性预测值95％。国产试剂RDT与进口试剂RDT检测结果比较差异无统计学意义（Kappa=0．95,P〉0．05）。结论国产试剂RDT与进口试剂RDT检测结果高度一致,在基层可取代进口试剂RDT进行疟疾病例主动监测。     

Malaria diagnosis and treatment administered by teachers in primary schools in Tanzania

A school health programme in Mwera Division, Pangani District included treatment of malaria attacks occurring in children during school time. A combination of symptoms (headache, muscle/joint pains, feeling feverish) and oral temperature > or = 37.5 degrees C was used for the diagnosis of malaria. Chloroquine (25 mg/kg given over 3 days) was used for treatment. Malariometric surveys on children aged 7-15 years (mean 10 years) were conducted once a year (1995-1997). Plasmodium falciparum accounted for 100% of infections and the parasite prevalence varied between 32.7 and 35.3% from 1995 to 1997. The number of malaria cases (cases/1000 registered school children) diagnosed and treated by school teachers was 159 (67) in 1995, 324 (124) in 1996, 348 (128) in 1997 and 339 (108) in 1998. Children in grades 1-4 (age 7-13) accounted for 64.6% of cases. Symptoms and oral temperature were recorded for 1258 children. Of those, 992 (78.9%) complained of fever and at least one other symptom when presenting to teachers, 98 (7.8%) had fever as their only complaint and 168 (13.5%) presented without a perception of fever, but with other symptoms. Of these children, 36 (21.4%) had a temperature > or =37.5 degrees C. The sensitivity of "feeling feverish" was 96.5% with a specificity of 54.5%. The positive predictive value of feeling feverish was 89.9% and the negative predictive value 78.6%. Blood slides were prepared from 55.3 and 37.2% of children diagnosed by teachers during 1995 and 1996, respectively, and 71.4% were found positive. Among children who fulfilled the algorithm criteria 75.0% had a positive blood slide. With little training and regular supervision it was feasible for school teachers to make a presumptive diagnosis of malaria. We conclude that teachers can play a major role in school health programmes and are willing to be involved in health matters as long as they are supported by health and educational authorities.     

Microscopy and outpatient malaria case management among older children and adults in Kenya

OBJECTIVE: To evaluate the accuracy of routine malaria microscopy, and appropriate use and interpretation of malaria slides under operational conditions in Kenya. METHODS: Cross-sectional survey, using a range of quality of care assessment tools, at government facilities with malaria microscopy in two Kenyan districts of different intensity of malaria transmission. All patients older than 5 years presenting to outpatient departments were enrolled. Two expert microscopists assessed the accuracy of the routine malaria slide results. RESULTS: We analysed 359 consultations performed by 31 clinicians at 17 facilities. Clinical assessment was suboptimal. Blood slide microscopy was performed for 72.7% of patients, who represented 78.5% of febrile patients and 51.3% of afebrile patients. About 95.5% of patients with a positive malaria microscopy result and 79.3% of patients with a negative result received antimalarial treatment. Sulphadoxine-pyremethamine monotherapy was more commonly prescribed for patients with a negative test result (60.7%) than for patients with a positive result (32.4%). Conversely, amodiaquine or quinine were prescribed for only 14.7% of patients with a negative malaria microscopy result compared to 57.7% of patients with a positive result. The prevalence of confirmed malaria was low in both high (10.0%) and low-(16.3%) transmission settings. Combining data from both settings, the sensitivity of routine microscopy was 68.6%; its specificity, 61.5%; its positive predictive value, 21.6% and its negative predictive value, 92.7%. CONCLUSIONS: The potential benefits of microscopy are currently not realised because of the poor quality of routine testing and irrational clinical practices. Ambiguous clinical guidelines permitting treatment of older children and adults with a negative blood slide also undermine rational use of antimalarial drugs.     

Efficacy of a rapid test to diagnose Plasmodium vivax in symptomatic patients of Chiapas, Mexico

OBJECTIVE: To evaluate, under laboratory conditions, the sensitivity and specificity of a rapid diagnostic test (OptiMAL), based on immunoreactive strips, to detect Plasmodium vivax infection in febrile patients in Southern Chiapas, Mexico. MATERIAL AND METHODS: The presence of parasites in blood samples of 893 patients was investigated by Giemsa-stained thick blood smear microscopic examination (gold standard). A blood drop from the same sample was smeared on immunoreactive strips to investigate the presence of the parasite pLDH. Discordant results were resolved by PCR amplification of the parasite's 18S SSU rRNA, to discard infection. RESULTS: OptiMAL had an overall sensitivity of 93.3% and its specificity was 99.5%. Its positive and negative predictive values were 96.5% and 98.9%, respectively. Signal intensity in OptiMAL strips correlated well with the parasitemia density in the blood samples (r = 0.601, p = 0.0001). CONCLUSION: This rapid test had acceptable sensitivity and specificity to detect P. vivax under laboratory conditions and could be useful for malaria diagnosis in field operations in Mexico.     

环介导等温扩增检测恶性疟原虫的应用研究

目的探讨环介导等温扩增(loop-mediated isothermal amplification,LAMP)检测恶性疟患者血中疟原虫的敏感性和特异性。方法收集恶性疟患者和健康人血液样品,分别用LAMP、镜检法和巢式PCR检测恶性疟原虫,计算LAMP的敏感度、特异度、阳性预测值和阴性预测值,并与巢式PCR进行比较。结果共检测78份恶性疟患者和30份健康人血样,其中72份患者血样LAMP检测为阳性,以镜检法为金标准,LAMP筛检的灵敏度为92.3%,特异度为100%,阳性预测值和阴性预测值分别为100%和83.3%;以巢式PCR为参考,LAMP筛检的灵敏度为97.2%,特异度为94.4%。结论 LAMP方法检测恶性疟原虫的敏感度和特异度与巢式PCR方法相近,可应用于现场恶性疟检测。     

Automated detection of malaria‐associated intraleucocytic haemozoin by Cell‐Dyn CD4000 depolarization analysis

Summary Laboratory tests for malaria are only performed if there is clinical suspicion of the disease, and a missed diagnosis contributes substantially to morbidity and mortality. Malaria parasites produce haemozoin, which is able to depolarize light and this allows the automated detection of malaria during routine complete blood count analysis (CBC) with some Abbott Cell‐Dyn instruments. In this study, we evaluated the Cell‐Dyn CD4000 with 831 blood samples submitted for malaria investigations. Samples were categorized as malaria negative (n = 417), convalescent malaria (n = 64) or malaria positive (n = 350) by reference to thin/thick film microscopy, ‘rapid test’ procedures, polymerase chain reaction analysis and clinical history. With regard to CD4000 depolarization analysis, a malaria positive CD4000 pattern was ascribed to samples that showed one or more abnormal depolarizing purple events, which corresponded to monocytes containing ingested malaria pigment (haemozoin). Positive CD4000 patterns were observed in 11 of 417, 50 of 64 and 281 of 350 of malaria negative, convalescent malaria and malaria positive samples respectively. The specificity and positive predictive values for malaria (active and convalescent) were very high (97.4 and 96.8%, respectively), while sensitivity and negative predictive values were 80.0 and 83.0% respectively. Depolarization analysis was particularly effective for Plasmodium falciparum malaria but there was lower detection sensitivity for White compared with Black African patients. CD4000 90° depolarization vs 0° analysis revealed a proportion of samples with small nonleucocyte‐associated depolarizing particles. Appearance of such events in the form of a discrete cluster was associated with P. vivax rather than P. falciparum infection.     

镜检、抗原检测和核酸检测方法在疟疾诊断中的应用比较

目的 比较镜检、抗原检测(RDT)和核酸检测(PCR)三种方法对疟原虫的检测效果,为基层选择合适的 诊断方法提供依据。 方法 收集腾冲市 2015-2018 年发热病人的血样进行疟疾检测,以确诊结果为标准,对比分析镜检、RDT 和 PCR 三种疟疾检测方法的敏感性、特异性、阳性预测值、阴性预测值等指标。 结果 610 份血样中,阴性 295 份,阳性 315 份,其中恶性疟 67 份、间日疟 245 份、混合感染 2 份、三日疟 1 份。 与确诊结果比较,镜检、RDT 和 PCR 的灵敏度分别为 95. 87%、94. 60%和 99. 37%,特异度均为 100%;假阴性率分别为 4. 13%、5. 40%和 0. 63%,阴性预 测值分别为 95. 78%、94. 55%和 99. 33%;假阳性率均为 0,阳性预测值均为 100%;三种方法与确诊结果的总符合率分别 为 97. 87%、97. 70%和 99. 67%,Kappa 检验结果显示均与确诊结果高度一致(P 均<0. 001);对单一虫种恶性疟的检测, 镜检、RDT 和 PCR 的符合率分别为 88. 06%、100%和 97. 01%;对其他三种疟原虫检测的符合率,分别为 97. 97%、 93. 9%和 100%。 结论 三种检测方法均具有较高的敏感性和特异性,但综合考虑当前防治工作实际,抗原检测(RDT) 更适宜在基层推广和使用。     

多重PCR快速检测恶性疟和间日疟的研究

目的 建立一种简便快速、能同时检测恶性疟和间日疟的核酸检测方法。方法 针对两种疟原虫18S rRNA基因设计2对(3条引物),优化引物浓度与退火温度,建立可扩增出两种疟原虫基因片段的多重PCR。并进行最低检测限确定和临床标本检测,以镜检法为金标准分析灵敏度和特异度等指标。结果 该方法可扩增出431 bp(恶性疟原虫)和341 bp(间日疟原虫)基因片段,最低检测限为10²copies/反应,检测临床标本的结果与镜检法无差别(P＞0.05),敏感度为93.55%,特异度为70.83%,阳性预测值为89.23%,阴性预测值为80.95%。结论 所建立的多重PCR方法可快速检测疟疾感染并鉴别分型,灵敏度高,值得推广。     

Automated detection of haemozoin-containing monocytes for the diagnosis of malaria in microscopically negative cases during pregnancy

Plasmodium falciparum sequesters in the placenta. Cell-Dyn^® automated flow cytometric haematology analysers have the capacity to detect haemozoin-containing circulating leukocytes during routine FBC analysis. In Lambaréné, Gabon, 685 FBCs of pregnant women were analysed, yielding 86.8% sensitivity and 78.5% specificity compared to microscopy. In a subset of 37 Cell-Dyn^® positive but microscopy negative samples, PCR detected five positive cases. This methodology may serve as an adjunct rapid diagnostic tool for malaria during pregnancy, even in microscopically negative cases.     

Evaluation of Diagnos Malaria Stix test (antigen detection assay) for diagnosis of malaria

Malaria is one of the most common parasitic infection in India. The diagnosis largely depends on peripheral blood smear examination. Newer diagnostic methods like various antigen detection assays are now in use for prompt diagnosis and treatment. This study was done to determine the effectiveness of Diagnos Malaria Stix (antigen detection) assay in diagnosis of malaria. This involves detection of PfHRP-2 antigen and P.V. specific pLDH antigen. 162 patients with signs and symptoms of malaria included in the study. Leishman stained blood smear examination was done for all patients. Commercially available Diagnos Malaria Stix assay was used. Diagnos Malaria Stix showed sensitivity, specificity positive and negative predictive values of 100% each while Sensitivity, specificity, positive and negative predictive values of Leishman stained blood smear examination were 45.45%, 100%, 100% and 92% respectively.     

山东省14例输入性卵形疟原虫wallikeri亚种的鉴定

目的 对山东省14例输入性卵形疟原虫wallikeri亚种进行鉴定分析。方法 收集14例输入性疟疾病例,进行快速疟疾诊断试纸条检测(RDT)、血涂片镜检、NP-1993常规巢式PCR鉴定和卵形疟原虫wallikeri(P. ovale wallikeri)亚种的特异性PCR检测。PCR扩增产物测序后,进行Blast比对分析。结果 14例患者RDT检测结果:泛疟原虫(非恶性疟)阳性12例,阴性2例;镜检结果,13例卵形疟原虫,1例间日疟原虫;NP-1993常规巢式PCR结果,14例样本4种疟原虫引物扩增结果均为阴性。P. ovale wallikeri亚种的特异性PCR检测结果:14例样本均能扩增到P. ovale wallikeri亚种特异性条带780 bp。Blast分析测序结果,检索结果为P. ovale wallikeri亚种。结论 14 例镜检阳性、NP-1993常规巢式PCR检测阴性的输入性疟疾病例均确诊为P. ovale wallikeri亚种感染。     

Pyuria as a screening test for detection of urinary tract infection in patients on long-term hemodialysis

INTRODUCTION. This study was conducted to evaluate the sensitivity and specificity of pyuria detection in centrifuged urine samples of patients on hemodialysis, and its relationship with urinary tract infection. MATERIALS AND METHODS. Clean-catch midstream urine samples of 90 hemodialysis patients (34 women and 56 men) were obtained and divided into two parts for examination of urine sediment and urine culture. Pyuria was defined as the presence of more than 10 leukocytes per high-power field of microscope. RESULTS. Ninety patients with a mean age of 52.8 ± 14.2 and a mean period of dialysis of 3.3 ± 2.3 years were studied. Forty-five participants had pyuria and only 16 (35.5%) of them had a positive urine culture for infection. Pyuria and urinary tract infection were present in 52.9% and 29.4% of the women and 48.2% and 10.7% of the men, respectively. The sensitivity and specificity of pyuria screening for urinary tract infection was 100% and 61.8%, respectively. The positive and negative predictive values were 35.5% and 100%, respectively. CONCLUSIONS. In patients on hemodialysis, because of the low specificity and positive predictive values, samples with positive pyuria should be cultured to confirm urinary tract infections.     

Sensitive detection and accurate monitoring of Plasmodium vivax parasites on routine complete blood count using automatic blood cell analyzer (DxH800(TM))

Introduction: Plasmodium vivax malaria is one of the most important infectious diseases plaguing humanity and causes significant mortality and morbidity worldwide. The gold standard of P. vivax malaria diagnosis is the microscopy of blood smears. Although microscopy is a rapid, cost‐effective, and readily applicable method, it has many disadvantages, including low sensitivity, specificity, and precision. Therefore, there is a clear need for an effective screening test for P. vivax malaria detection both in high‐prevalence areas and developed countries. Methods: A total of 1761 complete blood count (CBC) samples generated by the automated hematology analyzer (DxH 800?; Beckman Coulter Inc., Miami, FL, USA) were retrospectively analyzed. The sample pool contained 123 samples from 52 P. vivax malaria patients and 1504 nonmalarial samples including 509 patients with leukopenia (white blood cell <2000/μL) and 134 normal subjects. Results: The P. vivax malaria samples exhibited easily recognizable typical malaria signals on the nucleated red blood cell (nRBC) plots (sensitivity 100%) in DxH 800?. All 1504 samples without P. vivax infection were negative for malaria signal (specificity 100%). The size of P. vivax malaria signals correlated roughly with the parasite burden. Conclusion: DxH800? provides very sensitive and specific, easily recognizable P. vivax malaria signals on routine CBC without need for the additional reagents or special procedures.     

An analysis of interleukin-8, interleukin-6 and C-Reactive protein serum concentrations to predict fever, gram-negative bacteremia and complicated infection in neutropenic cancer patients

Summary  A prospective study was performed to assess the potential value of interleukin (IL)-8, IL-6, and C-reactive protein (CRP) serum levels to predict fever, gram-negative bacteremia and complicated infection in neutropenic patients with cancer. Serum samples were obtained three times a week during 208 neutropenic episodes following cytotoxic chemotherapy. Fever of any cause developed during 104 out of 191 evaluable episodes. Serum levels of neither cytokine nor CRP were predictive of fever within more than 24 h before its onset. Unlike CRP, both IL-6 and IL-8 serum levels were significantly different between microbiologically documented infections and unexplained fevers. The highest values of IL-6 and IL-8 were observed in episodes of gram-negative bacteremia. Using receiver-operating-characteristic curves, the analysis of cytokine levels measured around the onset of fever indicated that IL-8 is potentially useful for predicting gram-negative bacteremia, with a high negative predictive value of >90% and a moderate positive predictive value of 50% (sensitivity, 70%; specificity, 91%). In patients with persistent fever, predictions of further clinical complications, defined as prolonged fever of more than 7 days’ duration, pneumonia, shock and/or death due to infection, were best predicted by IL-6. With an IL-6 cutoff value of 250 pg/ml in samples obtained 8 to 32 h after onset of fever, the positive predictive value was 92%, the negative predictive value 91% (sensitivity, 85%; specificity, 95%). The positive predictive value of IL-6 in samples obtained another 24h later from patients still febrile remained >90%, but the negative predictive value dropped to 47%. In any of the analyses, the predictive values of CRP levels were poor and inferior to either cytokine. These findings may have clinical value in identifying subgroups of patients requiring different therapeutic approaches.     

Informed decision-making before changing to RDT: a comparison of microscopy, rapid diagnostic test and molecular techniques for the diagnosis and identification of malaria parasites in Kassala, eastern Sudan

Objectives Rapid diagnostic tests (RDTs) are promoted for the diagnosis of malaria in many countries. The question arises whether laboratories where the current method of diagnosis is microscopy should also switch to RDT. This problem was studied in Kassala, Sudan where the issue of switching to RDT is under discussion. Methods Two hundred and three blood samples were collected from febrile patients suspected of having malaria. These were subsequently analysed with microscopy, RDT (SD Bioline P.f/P.v) and PCR for the detection and identification of Plasmodium parasites. Results Malaria parasites were detected in 36 blood samples when examined microscopically, 54 (26.6%) samples were found positive for malaria parasites by RDT, and 44 samples were positive by PCR. Further analysis showed that the RDT used in our study resulted in a relatively high number of false positive samples. When microscopy was compared with PCR, an agreement of 96.1% and k = 0.88 (sensitivity 85.7% and specificity 100%) was found. However, when RDT was compared with PCR, an agreement of only 81.2 and k = 0.48 (sensitivity 69% and specificity 84%) was found. Conclusion PCR has proven to be one of the most specific and sensitive diagnostic methods, particularly for malaria cases with low parasitaemia. However, this technique has limitations in its routine use under resource‐limited conditions, such as our study location. At present, based on these results, microscopy remains the best option for routine diagnosis of malaria in Kassala, eastern Sudan.     

3种检测方法在中缅边境疟疾无症状感染者筛查中的比较

目的比较3种不同检测方法对疟疾无症状感染者的检出能力,并了解中缅边境地区的疟疾无症状感染水平。方法2014年7月在中缅边境地区云南省盈江县选择那邦镇、支那乡和缅甸拉咱安置点等3个调查点,采集调查对象血样,制作厚薄血膜和滤纸血标本,分别采用显微镜观察、荧光定量PCR和超敏PCR检测疟原虫感染情况。结果共采集387份血样,显微镜观察检出6例无症状感染者(间日疟5例、恶性疟1例),感染检出率为1.6%;荧光定量PCR检出13例无症状感染者(间日疟12例、恶性疟1例),感染检出率为3.4%;超敏PCR检出38例无症状感染者(间日疟29例、恶性疟9例),感染检出率为9.8%。以显微镜观察为疟原虫感染诊断的金标准,荧光定量PCR检测无症状感染者的灵敏度为100%,特异性为98.2%;超敏PCR检测无症状感染者的灵敏度为100%,特异性91.6%。超敏PCR结果显示,那邦镇的无症状感染检出率最高,为17.1%(22/129),其次为缅甸拉咱难民安置点,为10.0%(11/110),支那乡最低,为3.4%(5/148),3个调查点的感染检出率差异有统计学意义(P<0.05)。检出虫种以间日疟原虫为主,占76.3%,恶性疟原虫占23.7%;女性无症状感染检出率为10.7%(23/215),高于男性的8.7%(15/172),两者差异无统计学意义(P>0.05)。不同年龄组以15~29岁的无症状感染检出率最高,为17.5%(10/57),各年龄组间差异无统计学意义(P>0.05)。结论超敏PCR对疟疾无症状感染者的检出率高于荧光定量PCR和显微镜观察。中缅边境地区人群中存在一定比例的疟疾无症状感染者。