Gold Standard Microscopy Research Articles

Loop-Mediated Isothermal Amplification for Diagnosis of Zoonotic Malaria.

Zoonotic malaria, caused by Plasmodium knowlesi, Plasmodium cynomolgi, Plasmodium coatneyi, and Plasmodium inui, is a significant global health concern. The gold standard microscopy, while widely used for malaria diagnosis, faces limitations in differentiating between malaria species. Polymerase chain reaction (PCR), despite its accuracy, is characterized by high costs and time-consuming procedures. This study aims to develop and validate a rapid and accurate diagnostic test for detecting four simian Plasmodium species by using loop-mediated isothermal amplification (LAMP). Loop-mediated isothermal amplification is a cost-effective and faster molecular testing alternative for malaria diagnosis. The project involved designing specific primers, testing sensitivity and specificity against various parasites (including human Plasmodium species, protozoa, and helminths), and evaluating the LAMP assay using 60 macaque samples infected with simian Plasmodium. The LAMP assay exhibited a sensitivity profile enabling the detection of P. knowlesi, P. coatneyi, and P. cynomolgi across a concentration gradient from 5 × 108 down to 5 × 105 parasites/µL. Notably, P. inui was detectable at 5 × 108 parasites/µL. Furthermore, the specificity of the primer tailored for the four simian Plasmodium species was proven, as it produced a positive amplification exclusively for the respective target species and generated negative results for nontarget species. The results indicated that the LAMP assay is capable of detecting simian Plasmodium within a short span of 60 minutes, without any false positives from other samples. This new test has the potential to revolutionize malaria diagnosis, surveillance, and control, thereby mitigating the impact of zoonotic malaria in regions of endemicity.

Distribution of Malaria Infection Among Different Genotypes in Three Senatorial Zones of Taraba State Nigeria

Malaria infection is recognized as a severe public health problem linked to most cases of morbidity and mortality in malaria endemic areas. The study was used to determine the distribution of malaria infection among the different genotypes in three senatorial zones in Taraba state. The study employed a community and laboratory based cross sectional study. The electrophoresis machine was used to determine the genotypes of the research subjects while Rapid diagnostic technique and the gold standard microscopy was used to determine the prevalence of malaria infection. The haematology auto-analyzer (Sysmex XTI 2000) was used to determine the haematological parameters of the subjects. A total of 3084 blood samples was obtained by venepuncture. The distribution of the genotypes are AA 1721 (55.8%), AS 966 (31.3%) and SS 397 (12.9%). The overall prevalence of malaria was 620 (20.1%). Malaria infection was highest in the southern senatorial zone (29.1%) than in the north and central zones (p<0.05). Infection was high with the males (21.2%), age-related malaria infection was significant (p<0.05) with age 1-10yrs recording the highest infection (28.0%). No significant difference (p>0.00) was recorded in the marital status of the patient with the widows/widower having 23.4% while degree of infection was significant for education-related infection (p<0.05) with the non-educated subjects recording highest infection (34.4%). Occupational related prevalence was significant (p<0.05) with high infection among traders (162 (28.7%). Significant difference was recorded in the marital status with the widow/widower recording a high prevalence of malaria 112 (23.4%). Our finding in the current study confirm that malaria remains a major challenge and there is need for periodic prophylactic administration of malaria drugs in the treatment regime of sickle cell anaemia patients. Keywords: Malaria infection, genotypes, distribution, senatorial zones, Taraba State, Nigeria

Accuracy of Haematology Analyzer in the Diagnosis of Malaria in Comparison with Gold Standard Microscopy

Objective: To assess the accuracy of Haematology analyzer in the diagnosis of malaria in comparison with gold standard microscopy.
 Methodology: A cross-sectional study was conducted at the Pakistan Institute of Medical Sciences and the Pakistan Atomic Energy Commission in Islamabad, Pakistan. The study was conducted for around six months, from May 2023 to October 2023. The Mindray BC-6200 haematology analyzer was utilised to evaluate a total of 191 samples, comprising 127 samples from that were infected with malaria and 64 samples from healthy controls. When the presence of malaria parasites, identified as Plasmodium vivax and Plasmodium falciparum, was detected in dyed thick blood film, a microscopy examination was carried out as a reference. Analyse-it v4.92.3 was used to create the receiver operating characteristic (ROC) curve analysis. The agreement between BC-6200 and light microscopy was assessed using the Kappa value.
 Results: The InR by BC-6200's sensitivity and specificity for P. falciparum and P. vivax infections. The sensitivity of the InR by BC-600 for P. falciparum and P. vivax was 27.9% and 85.5%, respectively. The specificity of the InR by BC-6200 for P. vivax and P. falciparum was 82.7% and 86.5%, respectively. The infection densities in microscopy varied statistically significantly between the various InR groups (χ2 = 14.50, P < 0.005).An analysis was conducted on the correlation between the cell blood count and the count of InR in both the P. vivax and P. falciparum-infected patient groups. The results showed a clear correlation between InR (P. vivax group R2 = 0.87) and ΔWBC (WBCDIFF–WBCBASO). In the Mindray BC-6200 haematology analyzer, WBCBASO represents the number of WBC counting in the BASO channel with severe membrane degradation, while WBCDIFF represents the number of WBC counting in the DIFF channel with mild lyse. The volume distribution widths of RBC, HGB, and red blood cells did not differ substantially. The reticulocyte characteristics of the P. vivax/P. falciparum patient group and control group differed significantly (P<0.02), although RBC, HGB, and red blood cell volume distribution width (RDW) did not differ significantly (P > 0.05). There was a significant difference (P<0.02) in the PLT count between the P. vivax/P. falciparum patient groups and the control group.
 Conclusion: The results imply that malaria might be screened for in a clinical setting using the BC-6200 haematology analyzer's "InR" flag and "InR#/InR‰" parameters.

A bibliometric analysis: Ca2+ fluxes and inflammatory phenotyping by flow cytometry in peripheral blood mononuclear cells.

The immune system, composed of organs, tissues, cells, and proteins, is the key to protecting the body from external biological attacks and inflammation. The latter occurs in several pathologies, such as cancers, type 1 diabetes, and human immunodeficiency virus infection. Immunophenotyping by flow cytometry is the method of choice for diagnosing these pathologies. Under inflammatory conditions, the peripheral blood mononuclear cells (PBMCs) are partially activated and generate intracellular pathways involving Ca2+-dependent signaling cascades leading to transcription factor expression. Ca2+ signaling is typically studied by microscopy in cell lines but can present some limitations to explore human PBMCs, where flow cytometry can be a good alternative. In this review, we dived into the research field of inflammation and Ca2+ signaling in PBMCs. We aimed to investigate the structure and evolution of this field in a physio-pathological context, and then we focused our review on flow cytometry analysis of Ca2+ fluxes in PBMCs. From 1984 to 2022, 3865 articles on inflammation and Ca2+ signaling in PBMCs were published, according to The Clarivate Web of Science (WOS) database used in this review. A bibliometric study was designed for this collection and consisted of a co-citation and bibliographic coupling analysis. The co-citation analysis was performed on 133 articles: 4 clusters highlighted the global context of Ca2+ homeostasis, including chemical probe development, identification of the leading players in Ca2+ signaling, and the link with chemokine production in immune cell function. Next, the bibliographic coupling analysis combined 998 articles in 8 clusters. This analysis outlined the mechanisms of PBMC activation, from signal integration to cellular response. Further explorations of the bibliographic coupling network, focusing on flow cytometry, revealed 21 articles measuring cytosolic Ca2+ in PBMCs, with only 5 since 2016. This final query showed that Ca2+ signaling analysis in human PBMCs using flow cytometry is still underdeveloped and investigates mainly the cytosolic Ca2+ compartment. Our review uncovers remaining knowledge gaps of intracellular players involved in Ca2+ signaling in PBMCs, such as reticulum and mitochondria, and presents flow cytometry as a solid option to supplement gold-standard microscopy studies.

Detection of Schistosma heamatobium among Orphanage Children Attending Jarma UK Orphanage Home and Bakin Gulbi Primary School Sokoto

Urinary schistosomiasis or Bilharzia caused by fluke worm Schistosoma haematobium (S. haematobium) is one of the seventeen (17) neglected tropical diseases associated with serious health problems and morbidities. It affects over 200 million people globally with an estimated death rate of more than 200, 000 annually and very common in Sub-Saharan African countries. The aim of the study was to determine the prevalence and associated risk factors of S. haematobium and provide epidemiological data in part of Nigeria. This cross-sectional study was carried out on 202 consenting participants, using both male and female attending Jarma Uk Orphanage home and Bakin Gulbi primary school. Detection and evaluation were done using Gold Standard Microscopy and commercially available Rapid Detection Test strips. Statistical analysis was carried out using a statistical package (SPSS version 26). A prevalence of 34(16.8%) among 202 from gold standard microscopy and 13(6.4%) circulating cathodic antigen (CCA) were obtained. High infection risk was observed among participant on swimming as a recreational activity 32(15.8%) at p<0.046 A gender prevalence of 26 (12.87%) and 8 (3.96%) at p<0.067 from male and female respectively were obtained. Female at the age group 11-15 had 27 (13.36%), and those with agriculture as recreational activity had the least infection risk 2(0.99%). This study showed that CCA has a less sensitivity and specificity than gold standard microscopy.

Diagnostic Value of Plasmotec Malaria-3 Antigen Detection on Gold Standard Microscopy

Plasmotec Malaria-3 is a rapid malaria diagnostic test that uses four-line tests and targets three malaria proteins,namely Plasmodium falciparum specific protein (HRP-2), Plasmodium vivax-specific LDH (Pv-LDH) and non-specificPlasmodium LDH (pLDH). Microscopy as a gold standard has many disadvantages and the availability of malaria RapidDiagnostic Tests (RDTs) in detecting three proteins is still very limited. This study aimed to determine the diagnostic value of® ® Plasmotec Malaria-3 against gold standard microscopy, comparing the Plasmotec Malaria-3 and microscopy antigen® species detection, determining the Parasitemia Index (PI) cut-off using Plasmotec Malaria-3. This study was across-sectional study with 105 whole blood samples obtained from the Merauke Papua General Hospital which fulfilled theinclusion and exclusion criteria. Samples were examined by thick and thin drops and then examined with Plasmotec®® Malaria-3. Diagnostic values of Plasmotec Malaria-3 against the microscopy were Sn 100%, Sp 98.04%, PPV 98.18%, NPV® 100%, LR + 51, LR-0, diagnostic accuracy of 99.05%. Comparison of Plasmodium species between Plasmotec Malaria-3 and® microscopy was not significantly different, p-value = 0.172. The cut-off of PI in P.falciparum and P.vivax in PlasmotecMalaria-3 based on the Receiver Operating Characteristic (ROC) curve could not be determined with AUC=0.577,p-value=0.385 and AUC=0.423, p-value=0.385, respectively. This study concluded that the comparison of Plasmodium® species between Plasmotec Malaria-3, and microscopy was not significantly different. This study suggested that further® research is needed to find the diagnostic value of non-falciparum and non-vivax Plasmodium against Plasmotec Malaria-3.

Evaluation of SD Bioline Malaria Antigen Plasmodium Falciparum / Panmalarial for Diagnosis of Malaria in Hospital Raja Permaisuri Bainun Ipoh

Introduction: Rapid Diagnostic Tests (RDTs) for malaria has improved malaria manageme nt.Objectives: This study was conducted to evaluate the performance of SD Bioline Malaria Antigen Plasmodium falciparum/Panmalarial compared to gold standard microscopy using Giemsa staining for diagnosis of malaria in Hospital Raja Permaisuri Bainun Ipoh.Method: Microscopy and RDT diagnosis were performed on 377 blood samples. In this study, the SD Bioline Malaria Antigen Plasmodium falciparum/Panmalarial Rapid Diagnostic Tests (RDT) detecting Histidine Rich Protein II and Plasmodium lactate dehydrogenase antigens were used. Blood film malaria parasite examination was carried out as the reference.Results: Malaria parasites were identified by microscopy in 61 individuals and RDT positively tested in 27 (44.3%) patients. The sensitivity and specificity of SD Bioline Malaria Antigen Plasmodium falciparum/Panmalarial was 44.2% (95% CI, 31.8 to 57.5) and 100% (95% CI, 98.6 to 100.0) respectively. The positive predictive value (PPV) for SD Bioline Malaria Antigen Plasmodium falciparum/Panmalarial was 100% (95% CI, 84.5 to 100) and the negative predictive value (NPV) was 90% (95% CI, 86.6 to 93.1).Discussion: The SD Bioline Malaria Antigen Plasmodium falciparum/ Panmalarial test showed excellent results in the diagnosis of endemic Plasmodium falciparum infections. This SD Bioline Antigen Plasmodium falciparum/ Panmalarial loses validity for low parasitemia. These results confirm the validity of SD Bioline Antigen Plasmodium falciparum/ Panmalarial in malaria diagnosis must be complemented by microscopy.Conclusion: This examination has demonstrated that the SD Bioline Malaria Antigen Plasmodium falciparum/ Panmalarial cannot be utilized as an elective strategy contrasted with the best quality level Giemsa staining (BFMP). These outcomes affirm that whenever supplemented by microscopy, SD Bioline Malaria Antigen Plasmodium falciparum/ Panmalarial are substantial in malaria analysis.International Journal of Human and Health Sciences Supplementary Issue: 2019 Page: 47

False-negative malaria rapid diagnostic test results and their impact on community-based malaria surveys in sub-Saharan Africa

Surveillance and diagnosis of Plasmodium falciparum malaria relies predominantly on rapid diagnostic tests (RDT). However, false-negative (FN) RDT results are known to occur for a variety of reasons, including operator...

The risk of transfusion transmitted malaria and the need for malaria screening of blood donors in Abuja, Nigeria

Background: Blood transfusion saves life but it is also a major risk factor in the transmission of certain infections such as malaria, which remains a public health problem in tropical and sub-Saharan Africa. Methodology: This study investigated the prevalence of malaria among 550 blood donors aged 18 to 60 years from blood bank units of some selected hospitals in Federal Capital Territory (FCT), Abuja, using gold standard microscopy for malaria parasite detection. Results: Two hundred and fifty two (45.8%) donors were positive for malaria parasites. Replacement donors had higher prevalence rate of malaria compared to voluntary donors. The distribution of infection on the basis of age revealed the highest prevalence rate of malaria among the 20- 29yrs age group. The rate of infection among the males and the females was not significantly different ( p >0.05). No association was observed between the blood group types and the rate of malaria infection ( p > 0.05). Conclusion: A high prevalence of malaria parasitaemia was observed among blood donors in FCT, Abuja, Nigeria in this study. The introduction of malaria screening as part of routine screening for blood donation and the provision of modern blood screening equipment within healthcare facilities are highly advocated. Keywords: Blood, Malaria, Microscopy, ABO Blood group

Parasitic infections and risk factors associated with Amoebiasis among pregnant women attending antenatal clinics in primary health care centres in Lagos Mainland, Lagos, Nigeria

The prevalence of amoebiasis was investigated among pregnant women using a gold standard microscopy method. Stool samples were collected from pregnant women, from two primary health care centers (Iwaya and Ebute-metta). The study involved 203 pregnant women during their visits to the antenatal clinic in Primary health centres at Lagos Mainland from June – October, 2016. Each participant was interviewed using questionnaires to relate prevalence and risk factors to their socio-demographic characteristics. Among these pregnant women, 120 respondents provided their stool samples and this was parasitologically screened with 0.8% prevalence of Entamoeba histolytica infection, 7.5% with Entamoeba Coli, 0.5% with Ascaris lumbricoides, and 0.8% infection with Hookworm. A prevalence of 0.8% for the mixed infection of Ascaris lumbricoides with Entamoeba histolytica, and a prevalence of 1.7% for the mixed infection of Entamoeba coli and Entamoeba histolytica was recorded. Significant association (p<0.05), was established between infection and diarrhoea, and the residence of the pregnantwomen.Socio - demographic factors like age, sex, socio-economic status, type of toilet, source of drinking water (p>0.05) showed no significant association with amoebiasis prevalence. In conclusion, E. histolytica infection is generally low in Lagos state owing to good environmental sanitation within Lagos metropolis. Efforts should therefore be geared towards its elimination by provision of water for Lagos residents.

Platelet count and indices in acute uncomplicated Malaria in Kano, Nigeria

Background: Quantitative and qualitative abnormalities of platelets are common among patients with malaria infection, and these correlate with severity. Few studies documented platelet changes in uncomplicated malaria in the endemic regions. This study aimed to describe the changes in platelet counts (PLTs) and automated platelet indices in uncomplicated malaria infection in a Nigerian population. Materials and Methods: This is a comparative cross-sectional study of 152 patients presenting with symptoms of uncomplicated malaria to the general outpatient Department of Aminu Kano Teaching Hospital, Kano, Nigeria. Malaria diagnosis was made using gold-standard microscopy of Giemsa-stained thick blood smear, while PLTs and indices (mean platelet volume [MPV], plateletcrit [PCT], platelet distribution width [PDW] and platelet-large cell ratio [P-LCR]) were determined using automated haematology analyser. Data were analysed using STATA v13 and results presented in descriptive terms. P =0.05 was considered statistically significant. Results: There were more female 8 (51.3%) than male 74 (48.7%) patients. A total of 84 patients (55.3%) were malaria positive. The prevalence of malaria-positive smears was higher in males 48 (31.6%) and among the age groups of 5–14 and 15–24 years (13.8% each). Thrombocytopenia was seen in 15 (19.7%) and 2 (2.6%) of malaria-positive and malaria-negative individuals, respectively, and the difference was statistically significant (P = 0.001). Platelet indices reveal significant differences in the MPV (P = 0.0016) and P-LCR (P = 0.0265) between malaria-positive and malaria-negative patients. Although both lower mean PLT and PCT, and higher PDW were found in malaria-positive than in malaria-negative individuals, this difference was not statistically significant (P > 0.05). Conclusion: This study showed that abnormalities in PLT and indices are more common among patients with an acute febrile illness who are malaria positive than those who are malaria negative.

Performance of Microscopy Method and Rapid Diagnostic Tests in Malaria Diagnosis amongst Pregnant Women in Lagos, Southwest Nigeria

Malaria infection in pregnancy is a major public health problem which poses serious life threats to pregnant mothers and foetuses. Accurate diagnosis and prompt treatment of pregnancy associated malaria (PAM) are important in preventing adverse pregnancy outcomes. This study compared the diagnostic performance of two rapid diagnostic tests (RDTs), parasite lactate dehydrogenase (PLDH) based Optimal IT and parasite aldolase base Dr. Grey’s with the gold standard microscopy in pregnant women. Blood samples of 113 pregnant women were collected from two hospitals in Lagos and screened for malaria parasite by Giemsa stained smear and two malaria rapid diagnostic tests, Optimal IT parasite lactate dehydrogenase and Dr. Grey aldolase. The results showed that, out of 113 blood samples screened, 23 (20.4%), 51 (45.1%) and 14 (12.4%) were positive by microscopy, Aldolase and PLDH respectively. 17 (33.3%) and 34 (66.7%) of the aldolase positive samples were positive and negative by microscopy respectively. 11 (21.6%) of the aldolase positive samples were positive for both microscopy and PLDH. Of the positive samples, 34 (66.7%) were negative for both microscopy and PLDH. 3 (13.0%) were positive by microscopy but negative by aldolase and PLDH (RDTs). There was no statistically significant difference between the performances of the different RDTs. This study revealed that microscopy, the gold standard underestimated the real burden of malaria during pregnancy and aldolase (RDT) performed better than microscopy and PLDH, the other RDT in diagnosing pregnant-associated malaria.

Evaluation of enzyme immunoassay based on detection of pLDH antigen for the diagnosis of malaria

Introduction: Timely diagnosis of malaria is a challenge in most endemic areas due to lack of resources. The methods most commonly used are microscopy, regarded as the gold standard, and rapid dipstick tests (RDT) which detect antigens in blood. Enzyme-Linked ImmunoSorbent Assay (ELISA) based tests are fast and easy to perform especially when large number of samples have to be tested. p-LDH is a highly sensitive marker of malaria in blood The present study was done to assess the diagnostic performance of a p-LDH based ELISA on samples from clinically suspected malaria patients. Methods: We tested the sensitivity and specificity of a pLDH based, commercially available ELISA kit on both microscopy positive and negative samples. Microscopy was done for all suspected malaria patients and of these 146 samples (73 positive and 73 negative) were tested by the ErbaLisa PAN (LDH) malaria ELISA kit as well SD Bioline malaria antigen test (RDT) based on detection of both HRP-2 and p-LDH common to all four species. Results: The sensitivity of Elisa was 95.9% while specificity was 93.2 % compared to gold standard microscopy while RDTs had 91.8 % sensitivity and 86.3 % specificity. All 67 samples positive by both microscopy and RDT were also positive by ELISA. Conclusion: p-LDH based ELISA promises to be a cost effective and reliable option for diagnosis of malaria in endemic areas like India.

Malaria and Hepatitis B co-infection in patients with febrile illnesses attending general outpatient unit of the Murtala Muhammed Specialist Hospital, Kano, Northwest Nigeria

Malaria and Hepatitis B Virus (HBV) infections are co-endemic throughout much of the tropical and sub-Saharan Africa and both present major threat to public health. A study on the prevalence of HBV and Malaria co-infection was carried out on 200 patients presenting with fever at the General Outpatient Department (GOPD) of the Murtala Muhammed Specialist Hospital (MMSH), Kano using Gold Standard microscopy and rapid diagnostic test (RDT). The effect of mono and co-infection on hematological parameters was also investigated. Fifty one (25.5%) out of the 200 patients studied were Malaria positive. Females had higher prevalence rate(18%) of Malaria infection than males with 7.5%. Age group 15-24 had the highest Malaria prevalence (11%) followed by age group 25-34 with 6.5%. Higher mean parasite density (1,200/il) was recorded among subjects with monoinfection of Malaria than mean parasite density (518/il) obtained among the co-infected. Mean parasite density was higher in female than male subjects. Thirteen (6.5%) subjects were HBV positive. Males had higher rate of infection with 4.5% prevalence than females with 2.0%. Nine individuals representing 4.5% of the total population had co-infection with higher prevalence (3%) among the males. Age groups 25-34 were observed to have high co-infection rate of 1.5% and the least prevalence was observed among the age group 15-24 with 0.5% prevalence for both males and females. Hematological evaluation carried out on all the categories of subjects shows significant difference in mean values of PCV (P=0.041), Hb (P=0.018) between the co-infection group and those with malaria infection and control groups. However, no significant difference (P>0.05) was observed in the values of WBC, PLT and Red cell indices among the co-infected and other test group. It was concluded that co-infection with the two ailments had no profound effect on hematologic parameters. Keywords : Co-Infection, Hepatitis B, Kano, Malaria, MMSH, Prevalence

Evaluation of case management of uncomplicated malaria in Haiti: a national health facility survey, 2012.

BackgroundMalaria is a public health concern in Haiti, although there are limited data on its burden and case management. National malaria guidelines updated in 2012 recommend treatment with chloroquine and primaquine. In December 2012, a nationally-representative cross-sectional survey of health facilities (HFs) was conducted to determine malaria prevalence among febrile outpatients and malaria case management quality at baseline before scale-up of diagnostics and case management training.MethodsAmong all 833 HFs nationwide, 30 were selected randomly, in proportion to total HFs per region, for 2-day evaluations. Survey teams inventoried HF material and human resources. Outpatients of all ages were screened for temperature >37.5 °C or history of fever; those without severe symptoms were consented and enrolled. Providers evaluated and treated enrolled patients according to HF standards; the survey teams documented provider-ordered diagnostic tests and treatment decisions. Facility-based test results [microscopy and malaria rapid diagnostic tests (RDTs)] were collected from HF laboratories. Blood smears for gold-standard microscopy, and dried blood spots for polymerase chain reaction (PCR) were obtained.ResultsMalaria diagnostic capacity, defined as completing a test for an enrolled patient or having adequate resources for RDTs or microscopy, was present in 11 (37 %) HFs. Among 459 outpatients screened, 257 (56 %) were febrile, of which 193 (75 %) were eligible, and 153 (80 %) were enrolled. Among 39 patients with facility-level malaria test results available on the survey day, 11 (28 %) were positive, of whom 6 (55 %) were treated with an anti-malarial. Twenty-seven (95 %) of the 28 patients testing negative were not treated with an anti-malarial. Of 114 patients without test results available, 35 (31 %) were presumptively treated for malaria. Altogether, 42 patients were treated with an anti-malarial, one (2 %) according to Haiti’s 2012 guidelines. Of 140 gold-standard smears, none were positive, although one patient tested positive by PCR, a more sensitive technique. The national prevalence of malaria among febrile outpatients is estimated to be 0.5 % (95 % confidence interval 0–1.7 %).ConclusionsMalaria is an uncommon cause of fever in Haitian outpatients, and limited, often inaccurate, diagnostic capacity at baseline contributes to over diagnosis. Scale-up of diagnostics and training on new guidelines should improve malaria diagnosis and treatment in Haiti.

English

Malaria presents a diagnostic challenge in most tropical countries. Rapid detection of the malaria parasite and early treatment of infection still remain the most important goals of disease management. Therefore, performance characteristics of the indigenous RDTs was determined among children with suspected malaria fever attending pediatrics OPD or admitted in indoor of UP RIMS n R Saifai central India, to assess whether this rapid diagnostic test (RDT) could be used for diagnosis of malaria and results were compared with Gold Standard microscopy test. We also assessed the logical utilization of RDTs to monitor treatment outcome. MATERIALS AND METHODS: 03 months to 12 years old children who were presented with acute fever without any focus to the OPD or IPD of our department from May 2011 to April 2013 were selected for the study. A finger prick blood sample was collected from each clinically suspected case of malaria to prepare blood smear and for testing with the RDT after taking informed consent. The blood smears were read by an experienced microscopist blinded to the RDT results and clinical status of the subjects. The figures for specificity, sensitivity, accuracy and predictive values were calculated using microscopy as gold standard. RESULTS: Analysis revealed that overall sensitivity, specificity and accuracy of the RDT were approx. 90%, while RDT is useful to confirm the diagnosis of new symptomatic cases of suspected malaria infection, the persistence of parasite antigen leading to false positives even after clearance of asexual Parasitaemia has limited its utility as a prognostic tool. The study showed that RDTs was easy to use, reliable and cheap for diagnosing new malaria cases, and is an appropriate test for the use in the fields and remote areas.

Evaluation of two new rapid diagnostic tests (RDTs) for the diagnosis of malaria

Rapid diagnostic tests (RDTs) address the need for accurate diagnosis of malaria, particularly in resource limited settings. In this study, two malaria RDTs were compared with gold standard microscopy: On Site Pf/Pv test detecting Plasmodium falciparum-specific histidine rich protein-2 (Pf HR P2) and P. vivax-specific parasitic lactate dehydrogenase (pLDH) antigens; and SD Bioline anti-Pf/Pv test detecting anti-HR P2 and anti-pL DH antibodies for the diagnosis of P. falciparum and P. vivax infections, respectively. For OnSite test, the overall sensitivity was found 96.2% , specificity 98.2% , positive predictive value (PPV ) 98.2% , negative predictive value (NPV ) 96.4% and agreement with microscopy was found to be 0.94. On the other hand SD Bioline test, the overall sensitivity was 75.4%, specificity 83.7%, PPV 84.3% , NPV 74.5% and agreement with microscopy was 0.59. These data revealed that the R DT based on antigen detection (Onsite test) was more reliable than that based on the antibody detection (SD Bioline test).DOI: http://dx.doi.org/10.3329/bjmm.v5i2.16931 Bangladesh J Med Microbiol 2011; 05 (02): 11-15

Detection and Species Identification of Malaria Parasites by Isothermal tHDA Amplification Directly from Human Blood without Sample Preparation

We report the clinical and analytical performance of an isothermal thermophilic helicase-dependent amplification assay for blood Plasmodium parasite detection and species-level identification. The assay amplifies the 18S rRNA gene fragment of all Plasmodium species and uses a species-specific probe and a pan-malarial probe to definitively identify Plasmodium falciparum from other infectious Plasmodium species. Amplicon-probe hybridization products are detected with a disposable dipstick enclosed in a cassette. With a pan-malarial-positive and P. falciparum-negative result, an additional test is performed to detect if the pan-malarial-positive band was the result of the presence of Plasmodium vivax. The assay uses only 2 μL of human whole blood directly for a 50-μL amplification reaction, without any pre-amplification processing. The clinical performance of the assay was validated using 88 samples from New York patients suspected of malaria or babesiosis. The overall sensitivity of the assay was 96.6% (95% CI, 87.3% to 99.4%), and the specificity was 100% (95% CI, 85.4% to 100%), compared with gold standard microscopy and a laboratory-developed molecular assay, respectively. The analytical sensitivity was 50 copies of DNA per assay or 200 parasites per microliter of blood, and the assay can detect samples with parasitemia levels <1%. This novel molecular diagnostic assay requires minimal laboratory instrumentation and uses un-processed blood as input; it can be readily performed in the field.