Diagnosis Of Falciparum Malaria Research Articles

Evolution of pfhrp2 and pfhrp3 deletions in Equatorial Guinea between the pre– and post–RDT introduction

BackgroundPfhrp2 and pfhrp3 deletions are threatening Plasmodium falciparum malaria diagnosis by rapid diagnostic tests (RDT) due to false negatives. This study assesses the changes in the frequencies of pfhrp2 and pfhrp3 deletions (pfhrp2Del and pfhrp3Del, respectively) and the genes in their flaking regions, before and after RDT introduction in Equatorial Guinea.MethodsA total of 566 P. falciparum samples were genotyped to assess the presence of pfhrp2 and pfhrp3 deletions and their flanking genes. The specimens were collected 18 years apart from two provinces of Equatorial Guinea, North Bioko (Insular Region) and Litoral Province (Continental Region). Orthologs of pfhrp2 and pfhrp3 genes from other closely related species were used to compare sequencing data to assess pfhrp2 and pfhrp3 evolution. Additionally, population structure was studied using seven neutral microsatellites.ResultsThis study found that pfhrp2Del and pfhrp3Del were present before the introduction of RDT; however, they increased in frequency after their use, reaching more than 15%. Haplotype networks suggested that pfhrp2Del and pfhrp3Del emerged multiple times. Exon 2 of pfhrp2 and pfhrp3 genes had high variability, but there were no significant changes in amino acid sequences.ConclusionsBaseline sampling before deploying interventions provides a valuable context to interpret changes in genetic markers linked to their efficacy, such as the dynamic of deletions affecting RDT efficacy.

The effect of paracetamol on the parasitological diagnosis of Plasmodium falciparum malaria

Objectives: Up until the present time, malaria represents an immense public health problem worldwide with a significant morbidity and mortality rate in many developing countries including Sudan. The use of antipyretics and analgesics in the settings of malaria has been a matter of contention over a vast period of time. Now, it is widely believed among the public and some health professionals in Sudan that the antipyretic and analgesic paracetamol disturbs the accuracy of the parasitological diagnosis of malaria. This study investigates the magnitude and effects of that belief through a descriptive study and examines the actual effect of paracetamol on the parasitological diagnosis of falciparum malaria through a clinical trial. Material and Methods: This is a conjoined study that includes a prospective and descriptive study and a randomized, placebo-controlled, double-blind, and parallel-group clinical trial. The descriptive study included 846 participants from various states in Sudan. The targeted study subjects were the public and health professionals and the study was conducted utilizing an online-based questionnaire. The clinical trial included 325 patients with uncomplicated falciparum attending two primary healthcare outpatient clinics in Gezira state, Sudan. The patients were randomly allocated to receive either placebo tablets or 500 mg of oral paracetamol after the first blood smear sample was taken. The second blood smear samples were taken 2 h after taking treatment. Parasite density estimation and other parasitological data were obtained from each sample before and after treatment. Results: The majority of the public thinks that paracetamol affects the parasitological diagnosis of malaria (76.21%, n = 330/433). Personal experience and family and friends were the most dominant information sources for the public (31.20% and 28.01% respectively), while scholarly articles were the most common source of information for the health professional group (45.03%, n = 186/413). No significant differences between the parasitological findings acquired before and after taking the treatments among both the paracetamol group (P = 0.22) and the placebo group (P = 0.12). The parasite density mean for the paracetamol group differed by 16.31 P/μL after taking paracetamol, while the placebo group parasite density mean differed by 15.34 P/μL. The treatments did not inflict impacts on the advanced microscopic features of Plasmodium falciparum blood smears. Conclusion: Paracetamol does not affect the parasitological diagnosis of falciparum malaria.

Severe Falciparum Malaria with Multiple Complications in Sanglah Hospital Denpasar

Malaria is caused by Plasmodium, which is transmitted through the bite of infected female Anopheles mosquitoes. Plasmodium falciparum causes the most severe form of malaria and can be life-threatening. A 63-year-old male with decreased consciousness, fever, chills, vomiting, and joint pain. The patient works in the Ivory Coast, malaria-endemic areas. Physical examination found clouding of consciousness and jaundice. Laboratory examination results are leukocytosis with eosinophilia and thrombocytopenia, increased of Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), total bilirubin, direct and indirect bilirubin, Blood Urea Nitrogen (BUN), creatinine, decreased of estimated Glomerular Filtration Rate (e-GFR), decreased random plasma glucose. Urinalysis showed macroscopic hematuria, positive blood, and protein are found, and erythrocyte sediment is increased. A blood gas analysis examination revealed metabolic acidosis. Rapid Diagnostic Test (RDT) showed positive for Plasmodium falciparum. The blood smear showed leukocytosis with eosinophilia and thrombocytopenia and the ring-form trophozoites stage of Plasmodium falciparum. The definitive diagnosis of falciparum malaria is confirmed by microscopic peripheral blood smear and malaria RDT for antigen detection. An overall investigation concluded the patient diagnosed is severe falciparum malaria with various complications including hypoglycemia, jaundice, and acute kidney failure. The patient died on the first day after being treated in Sanglah Hospital, Denpasar.

Malaria among under-five children in rural communities of Al-Mahweet governorate, Yemen

BackgroundMalaria burden among under-five children living in endemic areas of Yemen is largely unknown due to the lack of community-based studies. Therefore, this study determined the prevalence and risk factors associated with falciparum malaria among under-five children in rural communities of Al-Mahweet governorate, Yemen.MethodsThis community-based, cross-sectional study recruited 400 under-five children from two rural districts of Al-Mahweet governorate in December 2019. Demographic characteristics (gender, age, education and occupation of the child’s parents, and household size) and risk factors associated with malaria were collected through interviews with children’s caregivers using a structured questionnaire. Finger-prick blood was screened for Plasmodium falciparum and non-falciparum species using rapid diagnostic tests (RDTs), and duplicate Giemsa-stained thick and thin blood films were examined for malaria parasites. The density of asexual P. falciparum stages was also estimated. Data were then analysed, and the agreement between the results of thick-film microscopy and RDTs for diagnosing falciparum malaria was assessed using the kappa index. Statistical significance was set at a P-value of < 0.05.ResultsPlasmodium falciparum was prevalent among 9.8% (95% CI 7.0–13.1) of under-five children in the rural communities of Al-Mahweet, with a median asexual parasite density of 763 ± 2606 parasites/μl of blood (range: 132–4280) and low-to-moderate parasitaemia levels. Approximately one-third of microscopy-confirmed cases were gametocyte carriers. Multivariable logistic regression analysis confirmed that age of three years or older (AOR = 5.6, 95% CI 1.6–19.8; P = 0.007), not sleeping under a mosquito net the previous night of the survey (AOR = 8.0, 95% CI 2.4–27.4; P = 0.001), sleeping outdoors at night (AOR = 4.4, 95% CI 2.0–10.0; P < 0.001), and absence of indoor residual spraying (IRS) during the last year (AOR = 4.2, 95% CI 1.9–9.4; P < 0.001) were the independent predictors of falciparum malaria among under-five children in the rural communities of Al-Mahweet. The observed percentage agreement between thick-film microscopy and RDTs was 98.5%, with a very good agreement (k-index = 0.9) between the two methods for falciparum malaria diagnosis that was statistically significant.ConclusionApproximately one in ten under-five children in rural communities of Al-Mahweet is infected with P. falciparum based on microscopy and RDTs. Age of three years or older, not sleeping under mosquito nets, sleeping outdoors at night and absence of IRS can independently predict falciparum malaria among them. The very good agreement between thick-film microscopy and RDTs for diagnosing falciparum malaria in children supports the usefulness of using RDTs in such resource-limited rural communities.

Performance Evaluation of Nested Polymerase Chain Reaction (Nested PCR), Light Microscopy, and Plasmodium falciparum Histidine-Rich Protein 2 Rapid Diagnostic Test (PfHRP2 RDT) in the Detection of Falciparum Malaria in a High-Transmission Setting in Southwestern Nigeria.

Malaria remains a major public health challenge worldwide. In order to ensure a prompt and accurate malaria diagnosis, the World Health Organization recommended the confirmatory parasitological diagnosis of malaria by microscopy and malaria rapid diagnostic test (RDT) prior to antimalarial administration and treatment. This study was designed to evaluate the performance of nested polymerase chain reaction (nested PCR), light microscopy, and Plasmodium falciparum histidine-rich protein 2 rapid diagnostic test (PfHRP2 RDT) in the detection of falciparum malaria in Akure, Nigeria. A cross-sectional and hospital-based study involving 601 febrile volunteer participants was conducted in Akure, Nigeria. Approximately 2-3 mL venous blood samples were obtained from each study participant for parasitological confirmation by microscopy and PfHRP2-based malaria RDT. Thick and thin films were prepared and viewed under the light microscope for parasite detection, parasite density quantification, and species identification, respectively. Dry blood spot samples were prepared on 3MM Whatman filter paper for nested PCR. The overall prevalence of microscopy, PfHRP2 RDT, and nested PCR were 64.89% (390/601), 65.7% (395/601), and 67.39% (405/601), respectively. The estimates of sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and Youden's j index of microscopy and RDT were 96.30, 100.00, 100.00, 92.89, 97.50, 0.963, and 95.06, 94.90, 97.47, 90.29, 95.01, and 0.899, respectively. Malaria RDT recorded higher false negativity, compared microscopy (4.94% vs. 3.70%). A near perfect agreement was reported between microscopy and nested PCR, and between PfHRP2 RDT and nested PCR with Cohen's kappa (k) values of 0.94 and 0.88, respectively. This study revealed that PfHRP2 RDT and microscopy continues to remain sensitive and specific for falciparum malaria diagnosis in the study area.

Efficacy of Plasmodium falciparum histidine-rich protein 2 ( Pfhrp 2) rapid diagnostic test (RDT) and microscopy in the detection of falciparum malaria among symptomatic patients in Akure, Nigeria.

Accurate diagnosis and prompt treatment are highly essential in the management of malaria, which is one of the deadliest infectious diseases worldwide, particularly in tropical and sub-tropical regions including Nigeria. This study was designed to evaluate the efficacy of malaria histidine-rich protein 2-based rapid diagnostic test (RDT) and microscopy in the diagnosis of falciparum malaria in Nigeria. This was a cross-sectional and hospital-based study. The standard method of microscopy was used as the gold standard. Giemsa stained thick and thin smears were prepared to count and detect malaria parasite species. Also, a malaria histidine-rich protein 2-based RDT was used to detect malaria parasites and diagnostic efficacy were determined through the measure of sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), diagnostic accuracy and Youden Index (J). The result showed that out of the total 303 individuals examined, a total malaria prevalence of 67.0% and 68.0% were recorded for micr oscopy and RDT, respectively. Additionally, the sensitivity (95% C.I), specificity (95% C.I), PPV (95% C.I), and NPV (95% C.I) of RDT compared to microscopy were 97.54 (94.36-98.94), 92.00 (85.00-95.89), 96.12 (92.53-98.02), and 94.85 (88.50- 97.78), respectively. The diagnostic accuracy (95% C.I) and Youden Index (J) were 95.71 (92.77- 97.70) and 0.89, respectively. Conclusively, our study revealed that RDT continues to remain efficacious. Thus, while malaria diagnosis by microscopy which is the gold standard remains the major method of malaria detection, it should be complemented by rapid diagnostic test (RDT), particularly in high malaria endemic regions where mean parasite density of patients are usually high.

Early Clinical Diagnosis of Falciparum Malaria Helps Reduction in Morbidity and Mortality among Children

Early Clinical Diagnosis of Falciparum Malaria Helps Reduction in Morbidity and Mortality among Children

REFRACTORY ANEMIA AND PANCYTOPENIA AS PRESENTATIONS OF FALCIPARUM MALARIA IN POPULATION OF KHYBER PAKHTUNKHWA, PAKISTAN

Background: Falciparum malaria is a common disease in our area. Apart from its classical presentation, at times it may present with refractory anemia or pancytopenia. The aim of this study was to determine the refractory anemia and pancytopenia as complications of falciparum malaria and apart from peripheral blood smears the significance of rapid antigen tests and bone marrow examination in the diagnosis of falciparum malaria. Material &amp; Methods: The descriptive study included 200 consecutive cases of fever and refractory anemia or pancytopenia from 2011 to 2014. Stratification of patients according to the clinical scenario included Group-A having fever with refractory anemia and Group-B with fever and pancytopenia. A detailed history, thorough clinical examination, and pertinent laboratory tests were performed. All patients were treated with antimalarial drugs and followed-up for eight weeks. The pre and post treatment hematologic parameters were compared. Results: Among the 200 patients, 85 were males and 115 females. The age ranged from 15 to 55 years. Stratification of patients on clinical scenario revealed 175(87.5%) patients with fever and refractory anemia (Group-A). Among these, 125(62.5%) patients were reported smear positive for P. falciparum. In the remaining 50 smear negative patients rapid antigen tests were performed and all were reported positive. In 25 patients of Group B with fever and pancytopenia, the peripheral smear for malaria was positive only in 5 patients. In the remaining 20 cases both the peripheral blood smears and rapid antigen tests were reported negative. Bone marrow examination was planned to confirm the bone marrow suppression as the cause of peripheral pancytopenia, to exclude leukemia and to identify P. falciparum. The bone marrow examination revealed P. falciparum in all these cases. All the patients had a dramatic response to treatment with antimalarials in terms of disappearance of fever and correction of anemia and bone marrow rescue with reversal of pancytopenia to normal counts. Conclusion: Plasmodium falciparum should be considered in all cases of prolonged fever with refractory anemia or pancytopenia in malaria endemic areas, even with negative smear and rapid antigen tests. Bone examination is mandatory for the diagnosis in such cases. There is dramatic response of such patients to treatment with antimalarial drugs and hematinics.

Plasmodium falciparum histidine-rich protein 2 diversity in Ghana

BackgroundIn the absence of microscopy, Plasmodium falciparum histidine-rich proteins 2 (PfHRP2)-based rapid diagnostic tests (RDTs) are recommended for the diagnosis of falciparum malaria, particularly in endemic regions. However, genetic variability of the pfhrp2 gene threatens the usefulness of the test due to its impact on RDT sensitivity. This study aimed to investigate the diversity of pfhrp2 in malaria cases among children in Ghana.MethodsA cross-sectional study was conducted at the Adidome Government Hospital in the Volta Region of Ghana. A total of 50 children with mean age of 6.6 ± 3.5 years and diagnosed falciparum malaria were included. Blood samples were collected for complete blood count, malaria parasite identification and counting using auto analyzer and microscopy, respectively. DNA was isolated from blood-spotted Whatman filters, amplified and sequenced. Nucleotide sequences were translated in silico to corresponding amino acids and the deduced amino acids sequences were analyzed for diversity using Mega X.ResultsThe number of repeats and number of each repeat within PfHRP2 varied between isolates. Twelve rare PfHRP2 repeat types, two of which are previously unreported, were identified in this study. The HRP2 sequence obtained in this study shared high similarities with isolates from Kenya. Using Baker’s regression model, Group B was the highest occurring type (58.0%). Screening of all sequences for epitopes recognized by PfHRP2-specific monoclonal antibodies (mAbs), the predominant motif was AHHAADAHH, which is recognized by the C1-13 mAbs.ConclusionThis study reports diversity of P. falciparum HRP2 in samples from Ghanaian children with symptomatic malaria. The findings of this study highlight the existence of extra amino acid repeat types which adds to the PfHRP2 antigenic variability.

Evaluation of Loop Mediated Isothermal Amplification (LAMP) for Diagnosis of Plasmodium falciparum in Wad Medani City, Gezira State, Sudan

Plasmodium falciparum considered as the most serious form of species causes malaria compared with other species. Diagnosis of falciparum malaria in Sudan remain a major problem, the laboratory diagnosis depends solely on microscopy and RDTs. Loop mediated isothermal amplification (LAMP) assay is a molecular technique done in isothermal temperature using simple, inexpensive instruments for detection of falciparum malaria. The aim of the study is to evaluate the diagnostic performance of loop mediated isothermal amplification (LAMP) assay for detection of P. falciparum and compare with microscopic detection. A cross sectional hospital based study conducted on 220 blood samples collected from participants suspected to have falciparum malaria attending Wad Medani Teaching Hospitals and 26 healthy participants during the period November 2018 to January 2019. Thick blood films were done and used for P. falciparum detection. The extracted DNA by TE buffer was amplified by LAMP assay targeting 18S rRNA gene. Data were analyzed using Medical calculator (MedCalc) programs (V. 16). The results showed that the sensitivity, specificity, positive predictive value, negative predictive values were 99.1%, 84.6%, 53.2%, 99.8% respectively. Validation of LAMP diagnostic performance revealed that area under the curve is 0.919, while Weighted Kappa is 0.866. The study concluded that the LAMP assay had the identical diagnostic performance compared with microscopy in diagnosis of Plasmodium falciparum malaria. This gives a relative effortlessness application of LAMP assay in Sudan after availing the required logistics.

Anesthetic Implications of Malarial Infection in a Child

Malaria is a life-threatening mosquito-borne parasitic disease, with a wide clinical spectrum and multisystem involvement. It is associated with high rates of mortality and morbidity worldwide, particularly in Africa and Southeast Asia. Cases are now being reported in developed countries resulting from global and international travel. Given the varied presentation and multisystem involvement, patients with malaria may present for surgery, thereby necessitating anesthetic care. We present a 4-year-old child from Burkina Faso, Africa, with a known diagnosis of Plasmodium falciparum malaria, who presented for anesthetic care for a magnetic resonance imaging of the lumbar spine, requiring general anesthesia. The etiology and presentation of malaria are discussed and its end-organ involvement is reviewed with emphasis on the anesthetic implications of the disease. J Med Cases. 2019;10(3):84-88 doi: https://doi.org/10.14740/jmc3267

C-reactive protein as a prognostic marker of Plasmodiumfalciparum malaria severity.

Plasmodiumfalciparum malaria causes wide variety of clinical symptoms ranging from a mild febrile illness to life-threatening complications. For prevention of the severity and early diagnosis, evaluation of potential biomarkers is much needed. C-reactive protein (CRP) is an acute phase protein and well-recognized marker of inflammation in the body. It is synthesized by liver in response to pro-inflammatory responses and has correlation with complications associated with malaria. The study was aimed to assess, if it could serve as a predictive marker for malaria disease severity. In the present study, 74 P. falciparum patients and 22 healthy controls were enrolled. Turbidimetric immunoassay was used to measure the CRP in serum samples of all the study participants. Mann-Whitney U-test for continuous data and chi-square test for categorical data were used to compare all malaria cases vs. healthy control group and uncomplicated vs. severe malaria groups. Using receiver operating characteristic (ROC) analysis, best threshold value was determined for CRP in severe malaria patients. CRP level was significantly elevated in all malaria case groups (1.6 mg/dl IQ 1-2.6) as compared to healthy controls (0.10 mg/dl IQ 0.1-0.20), with p-value <0.0001. Further, CRP level was significantly higher in the severe malaria group (2 mg/dl IQ 1.8-3.9) as compared to the uncomplicated malaria group (1.4 mg/dl IQ 1-2.47) and healthy control group (0.10 mg/dl IQ 0.10-0.20), with p-value <0.05. The present study findings suggest that CRP level can be used to differentiate severe malaria from uncomplicated malaria. Elevated CRP level could be helpful in early prediction of the disease severity in patients infected with P. falciparum and may play an important role in diagnosis of falciparum malaria where improper initial test and clinical manifestations like fever may be absent even with a high load of parasite.

Antibiotic Therapy in Adults with Malaria (ANTHEM): High Rate of Clinically Significant Bacteremia in Hospitalized Adults Diagnosed with Falciparum Malaria.

It has been believed that concomitant bacteremia is uncommon in adults hospitalized with falciparum malaria. Accordingly, the World Health Organization treatment guidelines presently only recommended additional antibacterial therapy in these patients if they have a clinical syndrome compatible with serious bacterial infection. Admission blood cultures were collected from 20 consecutive adults in Myanmar, hospitalized with a positive immunochromatographic test and blood film, suggesting a diagnosis of falciparum malaria; four (20%) had bacteremia with a clinically significant pathogen. These case series' data were pooled with a previously published multicenter study from Myanmar which had also collected blood cultures in adults hospitalized with a diagnosis of falciparum malaria. Among 87 patients in the two studies, 13 (15%) had clinically significant bacteremia on admission, with Gram-negative organisms in 10 (77%) and Staphylococcus aureus in the remaining three (23%). Bacteremic patients had more severe disease than non-bacteremic patients (median [interquartile range] respiratory coma acidosis malaria score 2 [1-4] versus 1 [1-2], P = 0.02) and were more likely to die (2/13 [15%] versus 1/74 [1%], P = 0.01). However, bacterial coinfection was suspected clinically in a minority of bacteremic patients (5/13 [38%] compared with 13/70 [19%] of non-bacteremic patients, P = 0.11). Concomitant bacteremia in adults diagnosed with falciparum malaria may be more common than previously believed and is difficult to identify clinically in resource-poor settings. Death is more common in these patients, suggesting that clinicians should have a lower threshold for commencing empirical antibacterial therapy in adults diagnosed with falciparum malaria in these locations than is presently recommended.

Evaluation of rapid PfHRP-2/pLDH-based tests in diagnosing microscopy-confirmed falciparum malaria in Hodeidah governorate, Yemen

Along with the determination of malaria infection rate among suspected patients attending hospitals in Hodeidah governorate, the present study evaluated the accuracy of Plasmodium falciparum histidine-rich protein-2 (PfHRP-2)/parasite-specific lactate dehydrogenase (pLDH)-based rapid diagnostic test (RDT) for the diagnosis of microscopy-confirmed falciparum malaria. An overall malaria infection rate of 19.3% (57/295) among suspected patients attending hospitals was microscopically confirmed. The sensitivity of thin blood films for the detection of malaria parasites was 79.0% compared to thick films and was greatly affected by the parasite density, being 65.0% or less at parasite densities of ≤1000 parasites/μl of blood. Compared to light microscopy, the present study revealed sensitivity levels of 100.0% (95% CI: 92.0–100.0) vs. 94.7% (95% CI: 84.2–98.6), specificity levels of 97.3% (95% CI: 89.8–99.5) vs. 100.0% (95% CI: 93.9–100.0), positive predictive values of 89.9% (95% CI: 88.3–99.0) vs. 100.0 (95% CI: 91.6–100.0) and negative predictive values of 100.0% (95% CI: 93.9–100.0) vs. 98.7% (95% CI: 89.3–98.7) for the PfHRP-2 and pLDH components of SD BIOLINE® RDT, respectively, for falciparum malaria diagnosis. Therefore, the overall accuracy levels of the PfHRP-2 and pLDH components of the investigated RDT for the diagnosis of microscopy-confirmed falciparum malaria are 98.5% (95% CI: 94.6–99.6) and 97.7% (95% CI: 93.5–99.2), respectively.

Implications of Parasites Lacking Plasmodium falciparum Histidine-Rich Protein 2 on Malaria Morbidity and Control When Rapid Diagnostic Tests Are Used for Diagnosis.

Rapid diagnostic tests (RDTs) are an important tool for malaria diagnosis, with most using antibodies against Plasmodium falciparum histidine-rich protein 2 (PfHRP2). Reports of P. falciparum lacking this protein are increasing, creating a problem for diagnosis of falciparum malaria in locations without quality-assured microscopy. An agent-based stochastic simulation model of P. falciparum transmission was used to investigate the selective pressure exerted on parasite populations by use of RDTs for diagnosis of symptomatic cases. The model considered parasites with normal, reduced, or no PfHRP2, and diagnosis using PfHRP2-only or combination RDTs. Use of PfHRP2-only RDTs in communities where a PfHRP2-negative parasite was introduced during the simulation resulted in transmission of the parasite in >80% of cases, compared with <30% for normal or PfHRP2-reduced parasites. Using PfHRP2-only RDTs in the presence of PfHRP2-negative parasites caused an increase in prevalence, reduced RDT positivity within symptomatic patients but no change in the number of antimalarial treatments due to false-negative RDT results. Diagnosis with PfHRP2/Pf-Plasmodium lactate dehydrogenase combination RDTs did not select for PfHRP2-negative parasites. The use of PfHRP2-only RDTs is sufficient to select P. falciparum parasites lacking this protein, thus posing a significant public health problem, which could be moderated by using PfHRP2/Pf-Plasmodium lactate dehydrogenase combination RDTs.

Improving the Specificity of Plasmodium falciparum Malaria Diagnosis in High-Transmission Settings with a Two-Step Rapid Diagnostic Test and Microscopy Algorithm.

Poor specificity may negatively impact rapid diagnostic test (RDT)-based diagnostic strategies for malaria. We performed real-time PCR on a subset of subjects who had undergone diagnostic testing with a multiple-antigen (histidine-rich protein 2 and pan-lactate dehydrogenase pLDH [HRP2/pLDH]) RDT and microscopy. We determined the sensitivity and specificity of the RDT in comparison to results of PCR for the detection of Plasmodium falciparum malaria. We developed and evaluated a two-step algorithm utilizing the multiple-antigen RDT to screen patients, followed by confirmatory microscopy for those individuals with HRP2-positive (HRP2+)/pLDH-negative (pLDH-) results. In total, dried blood spots (DBS) were collected from 276 individuals. There were 124 (44.9%) individuals with an HRP2+/pLDH+ result, 94 (34.1%) with an HRP2+/pLDH- result, and 58 (21%) with a negative RDT result. The sensitivity and specificity of the RDT compared to results with real-time PCR were 99.4% (95% confidence interval [CI], 95.9 to 100.0%) and 46.7% (95% CI, 37.7 to 55.9%), respectively. Of the 94 HRP2+/pLDH- results, only 32 (34.0%) and 35 (37.2%) were positive by microscopy and PCR, respectively. The sensitivity and specificity of the two-step algorithm compared to results with real-time PCR were 95.5% (95% CI, 90.5 to 98.0%) and 91.0% (95% CI, 84.1 to 95.2), respectively. HRP2 antigen bands demonstrated poor specificity for the diagnosis of malaria compared to that of real-time PCR in a high-transmission setting. The most likely explanation for this finding is the persistence of HRP2 antigenemia following treatment of an acute infection. The two-step diagnostic algorithm utilizing microscopy as a confirmatory test for indeterminate HRP2+/pLDH- results showed significantly improved specificity with little loss of sensitivity in a high-transmission setting.

Improving the Specificity of Plasmodium falciparum Malaria Diagnosis in High-Transmission Settings with a Two-Step Rapid Diagnostic Test and Microscopy Algorithm

Improving the Specificity of Plasmodium falciparum Malaria Diagnosis in High-Transmission Settings with a Two-Step Rapid Diagnostic Test and Microscopy Algorithm

Evaluation of some haemostatic parameters in falciparum malaria and HIV co-infection

Background: Studies from sub-Saharan Africa where malaria is endemic have observed high incidences of malaria and HIV co-infection. It has long been accepted that malaria causes alterations in haemostatic parameters and that HIV is associated with a wide range of haematological changes. We assessed the effect of the overlap of these infections on routine haemostatic parameters.Method: The study involved 337 subjects grouped according to their HIV and malaria status: Group 1 ‘Asymptomatic HIV seropositive, Plasmodium falciparum positive’ (n = 61); Group 2 ‘Asymptomatic HIV seropositive, P. falciparum negative’ (n = 73); Group 3 ‘Symptomatic HIV seropositive, P. falciparum positive’ (n = 49); Group 4 ‘Symptomatic HIV positive P. falciparum negative’ (n = 56); Group 5 ‘Control HIV negative, P. falciparum positive’ (n = 52) and Group 6 ‘Control HIV negative, P. falciparum negative’ (n = 46). Blood samples were taken for HIV testing, diagnosis of falciparum malaria and malaria parasite density counts. Citrated samples were used within one hour of collection for prothrombin time (PT) and activated partial thromboplastin time (APTT). CD4+ T cell counts, platelet count and haematocrit (Hct) were also performed.Results: Our results demonstrate greater alterations in APTT, PT and platelet count with prolongation of APTT, PT and lower platelet counts in HIV and malaria co-infection. In spite of this, the co-infected subjects with mild to moderate parasitaemia did not show a bleeding tendency; however, the risk is higher in severe malaria.Conclusion: These results suggest that co-infected subjects with severe malaria have a higher risk of bleeding and would require greater monitoring.

Pattern of drug prescription for the treatment of falciparum malaria in a medical college in Eastern India

Background: Drug prescription pattern for the treatment of falciparum malaria differs widely from place to place; but there is also some intra organizational variation of prescription pattern of anti-malarial drugs for the treatment of falciparum malaria.Aims and Objectives: The present study was planned to study the drug utilization pattern for the treatment of falciparum malaria in a tertiary care teaching hospital in eastern India.Materials and Methods: It was a hospital based study conducted in the department of medicine among the patients admitted with confirmed diagnosis of falciparum malaria. Drugs prescribed, average number of drugs per prescription, percentage of drugs prescribed in generic name, percentage of prescription with co-prescription of antibiotics, percentage of prescription having at least an injection prescribed, percentage of drugs prescribed from essential drug list or formulary and average drug cost per prescription are the parameters studied in this study.Results: Average number of drugs per prescription in the present study was 3.96. Artesunate and Mefloquine were the most common anti-malarial drugs prescribed among study subjects. 22.9% patients received oral Chloroquine as anti-malarial drug. 43.3% prescriptions had antibiotics co-prescribed. Only 16.9% drugs were prescribed in generic name. 85.4% of the prescribed drugs were from essential drug list. Average drug cost per patient was Rs. 282/- with minimum of Rs. 55/- and maximum of Rs. 1750/-.Conclusion: Though Artesunate combination therapy is getting popularized gradually but a sizable proportion of patients (22.9%) were prescribed with oral Chloroquine therapy. Generic prescription of drugs should be encouraged among the physicians. Multi-centric study regarding drug prescription can give a broader picture in changing scenario.Asian Journal of Medical Sciences Vol.7(4) 2016 80-83

Field evaluation of a PfHRP-2/pLDH rapid diagnostic test and light microscopy for diagnosis and screening of falciparum malaria during the peak seasonal transmission in an endemic area in Yemen.

BackgroundMalaria is a public health threat in Yemen, with 149,451 cases being reported in 2013. Of these, Plasmodium falciparum represents 99 %. Prompt diagnosis by light microscopy (LM) and rapid diagnostic tests (RTDs) is a key element in the national strategy of malaria control. The heterogeneous epidemiology of malaria in the country necessitates the field evaluation of the current diagnostic strategies, especially RDTs. Thus, the present study aimed to evaluate LM and an RDT, combining both P. falciparum histidine-rich protein-2 (PfHRP-2) and Plasmodium lactate dehydrogenase (pLDH), for falciparum malaria diagnosis and survey in a malaria-endemic area during the transmission season against nested polymerase chain reaction (PCR) as the reference method.MethodsA household-based, cross-sectional malaria survey was conducted in Mawza District, a malaria-endemic area in Taiz governorate. A total of 488 participants were screened using LM and PfHRP-2/pLDH RDT. Positive samples (160) and randomly selected negative samples (52) by both RDT and LM were further analysed using 18S rRNA-based nested PCR.ResultsThe sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the RDT were 96.0 % (95 % confidence interval (CI): 90.9–98.3), 56.0 % (95 % CI: 44.7–66.8), 76.3 % (95 % CI: 69.0–82.3), and 90.4 % (95 % CI: 78.8–96.8), respectively. On the other hand, LM showed sensitivity of 37.6 % (95 % CI: 29.6–46.3), specificity of 97.6 % (95 % CI: 91.7–99.7), PPV of 95.9 % (95 % CI: 86.3–98.9), and NPV of 51.3 % (95 % CI: 43.2–59.2). The sensitivity of LM dropped to 8.5 % for detecting asymptomatic malaria. Malaria prevalence was 32.8 % (32.1 and 37.5 % for ≥10 and <10 years, respectively) with the RDT compared with 10.7 % (10.8 and 9.4 % for age groups of ≥10 and <10 years, respectively) with LM. Among asymptomatic malaria individuals, LM and RDT-based prevalence rates were 1.6 and 25.6 %, respectively. However, rates of 88.2 and 94.1 % of infection with P. falciparum were found among patients who reported fever in the 48 h prior to the survey by LM and PfHRP-2/pLDH RDT, respectively.ConclusionsThe PfHRP-2/pLDH RDT shows high sensitivity for the survey of falciparum malaria even for asymptomatic malaria cases. Although the RDT had high sensitivity, its high false-positivity rate limits its utility as a single diagnostic tool for clinical diagnosis of malaria. On the other hand, low sensitivity of LM indicates that a high proportion of malaria cases is missed, underestimating the true prevalence of malaria in the community. Higher NPV of PfHRP-2/pLDH RDT than LM can give a straightforward exclusion of malaria among febrile patients, helping to avoid unnecessary presumptive treatments.