Nanoparticle-Based Histidine-Rich Protein-2 Assay for the Detection of the Malaria Parasite Plasmodium falciparum.

A nanoparticle-based assay for detection and quantification of Plasmodium falciparum histidine-rich protein 2 (HRP2) in urine and serum is reported. The assay uses magnetic beads conjugated with anti-HRP2 antibody for protein capture and concentration, and antibody-conjugated quantum dots for optical detection. Western blot analysis demonstrated that magnetic beads allow the concentration of HRP2 protein in urine by 20-fold. The concentration effect was achieved because large volume of urine can be incubated with beads, and magnetic separation can be easily performed in minutes to isolate beads containing HRP2 protein. Magnetic beads and quantum dots conjugated to anti-HRP2 antibodies allows the detection of low concentrations of HRP2 protein (0.5 ng/mL), and quantification in the range of 33-2,000 ng/mL corresponding to the range associated with non-severe to severe malaria. This assay can be easily adapted to a noninvasive point-of-care test for classification of severe malaria.

Orina oscura e ictericia como signos de peligro en malaria por Plasmodium falciparum en Colombia / Dark urine and jaundice as warning signs in Plasmodium falciparum malaria in Colombia

INTRODUCCIÓN: el reconocimiento temprano de signos de peligro en el paciente con malaria permite identificar tempranamente el paciente en riesgo de hacer complicaciones clínicas, para ofrecerle un tratamiento adecuado y oportuno. La ictericia y orina oscura son signos frecuentes que pueden alertar sobre la instauración de una malaria complicada. OBJETIVO: estudiar en el paciente malárico la relación entre ictericia y orina oscura con disfunción hepática o renal y anemia, para establecer su utilidad como signos de peligro. MÉTODOS: se analizó información clínica y de laboratorio de 199 pacientes con malaria por Plasmodium falciparum, de un estudio de casos y controles realizado en Colombia. Se estudió la asociación entre orina oscura e ictericia con alteraciones del uroanálisis, pruebas de función hepática y renal, y hemoglobina. RESULTADOS: hubo asociación entre orina oscura y hemoglobinuria (OR= 236; 63-867), hematuria (OR= 3,2; 1,6-6,6), proteinuria (OR= 2,3; 1-5,3) y bilirrubinuria (OR= 2,1; 1-4,4). La ictericia estuvo presente en 31 por ciento de pacientes con disfunción renal (OR= 2,7; 1,1-6,4) y en 22 por ciento de pacientes con disfunción hepática (OR= 2,1; 0,9-4,5). Se encontró alta probabilidad de presentar ictericia en los pacientes con bilirrubina sérica total >25,6 µmol/L (OR= 6,1; 2,7-13,4) y nitrógeno ureico en sangre> 7,14 mmol/L (OR= 3,5; 1,4-8,5). CONCLUSIONES: la ictericia es un signo de peligro en el paciente malárico que se asocia con disfunción hepática y renal. La orina oscura no se asoció con disfunción renal o hepática, pero se explicó por bilirrubinuria, hematuria y proteinuria, que pueden ser indicadores tempranos de daño; debe estudiarse la orina oscura para aclarar su relación con el daño renal y hepático en malaria.

INTRODUCTION: early recognition of warning signs in malarial patients allows timely identification of the patient at risk of severe malaria and provides opportune treatment. Jaundice and dark urine are frequent signs that can alert to the occurrence of severe malaria. OBJECTIVE: to study the relationship between jaundice and dark urine with impaired liver and/or kidney function and anemia in malarial patients, and explore their role as warning signs. METHOD: clinical and laboratory data from 199 patients with Plasmodium falciparum malaria, belonging to a case control study conducted in Colombia, were analyzed. the association between dark urine and jaundice with impairment in the urine analysis, the hepatic and renal function test, and hemoglobin were studied. RESULTS: there was association between dark urine and hemoglobinuria (OR= 236, 63-867), hematuria (OR=3.2, 1.6-6.6), proteinuria (OR= 2.3, 1-5.3) and bilirubinuria (OR=2.1, 1-4.4). Jaundice was present in 31 percent of patients who had renal dysfunction (OR= 2.7, 1.1-6.4) and in 22 percent of those with liver dysfunction (OR= 2.1, 0.9-4.5). Jaundice was more likely in patients with total bilirubin > 25.6 µmol/L (OR= 6.1, 2.7-13.4) and blood ureic nitrogen > 7.14 mmol/L (OR= 3.5, 1.4-8.5). CONCLUSIONS: jaundice in patients with malaria may be considered as a warning sign associated with liver and kidney dysfunction. Dark urine was not associated with kidney or liver dysfunction, but was related to bilirubinuria, hematuria and proteinuria, which can be early indicators of failure; dark urine must be studied to clarify its relationship with liver and kidney failure in malaria.

[Dark urine and jaundice as warning signs in Plasmodium falciparum malaria in Colombia]. / Orina oscura e ictericia como signos de peligro en malaria por Plasmodium falciparum en Colombia.

INTRODUCTION: early recognition of warning signs in malarial patients allows timely identification of the patient at risk of severe malaria and provides opportune treatment. Jaundice and dark urine are frequent signs that can alert to the occurrence of severe malaria. OBJECTIVE: to study the relationship between jaundice and dark urine with impaired liver and/or kidney function and anemia in malarial patients, and explore their role as warning signs. METHOD: clinical and laboratory data from 199 patients with Plasmodium falciparum malaria, belonging to a case control study conducted in Colombia, were analyzed, the association between dark urine and jaundice with impairment in the urine analysis, the hepatic and renal function test, and hemoglobin were studied. RESULTS: there was association between dark urine and hemoglobinuria (OR = 236, 63-867), hematuria (OR = 3.2, 1.6-6.6), proteinuria (OR = 2.3, 1-5.3) and bilirubinuria (OR = 2.1, 1-4.4). Jaundice was present in 31 % of patients who had renal dysfunction (OR = 2.7, 1.1-6.4) and in 22 % of those with liver dysfunction (OR = 2.1, 0.9-4.5). Jaundice was more likely in patients with total bilirubin > 25.6 micromol/L (OR = 6.1, 2.7-13.4) and blood ureic nitrogen > 7.14 mmol/L (OR = 3.5, 1.4-8.5). CONCLUSIONS: jaundice in patients with malaria may be considered as a warning sign associated with liver and kidney dysfunction. Dark urine was not associated with kidney or liver dysfunction, but was related to bilirubinuria, hematuria and proteinuria, which can be early indicators of failure; dark urine must be studied to clarify its relationship with liver and kidney failure in malaria.

[Danger signs in the malaria patient]. / Signos de peligro en el paciente con malaria.

Danger signs are clinical indicators of severity and are useful to predict complications or death. In the malaria patient, clinical or parasitological signs can be easily be recognized during the acute phase of the illness that indicate serious complications. Danger signs include neurological change, abnormal breathing pattern, persistent vomiting and diarrhea, jaundice, bleeding, dark urine, delayed capillary refill, intense pallor, hyperpyrexia, hyperparasitemia and schizontemia. Timely recognition of these signs can lead to a decrease in cases with complications and deaths.

Community-based program for malaria case management in the Brazilian Amazon.

In areas of drug-resistant malaria, control programs may restrict chemotherapy until malaria has been confirmed via microscopy to contain costs and toxicity. In Brazil, patients travel to centralized laboratory posts (FNS) at great cost for diagnosis and treatment. A program was established through the bars of a mining town offering free dipstick diagnosis and mefloquine treatment on a 24-hr basis; falciparum malaria dipstick tests are accurate and easy to use. Outcomes were compared with historical data and results of a neighboring non-intervention village. Guidelines for dipstick use and treatment were followed for 98% of visits. The number of FNS visits was reduced from 2,316 (expected) to 1,097 (observed) with 626 dipstick tests applied. Ninety-five percent of those who visited the FNS experienced onset of malaria symptoms in the town where the FNS was located. There was an unexpected doubling of the malaria hospital admission rate. We demonstrate that dipstick testing can be used in a sustainable, community-based program that should be applicable in a wide variety of settings.

Detection of antigens in urine of patients with acute falciparum and vivax malaria infections.

Using an antigen-capture, dot-blot assay, antigens were detected in the urine of 50 patients infected with Plasmodium falciparum. Antigens were also detected in 12/15 patients who had no detectable parasitemias 1-2 weeks after chemotherapy. By Western blotting and immunoprecipitation, four predominant antigens were identified with the following molecular masses (Mr) and isoelectric points (pI): antigen 1, 200 kDa, pI 6.4-6.27; antigen 2, 180 kDa, pI 5.2-4.8; antigen 3, 150 kDa, pI 5.5; antigen 4, 96 kDa, pI 5.1-4.8. These antigens were heat stable to 100 degrees C for 5 min. Antigens were also detected in the urine of 35 patients with acute P. vivax infections by Western blotting and dot-blot analysis and 10/10 patients three weeks following chemotherapy. The antigens had Mr of 200, 170, and 130 kDa.