Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transfusion-associated malaria is often severe or even fatal, because diagnosis is frequently delayed and it complicates an already serious underlying disorder. Detection of infected donors is difficult in endemic areas due to the lack of a suitable donor screening test. Blood smear staining techniques show poor results due to the low parasite concentration in many infected persons, and the antibody detection test is not helpful due to the universal presence of antibody in healthy donors in these areas. For comparative evaluation of various screening tests, 9131 blood smears from voluntary donors and a group of patients were screened by Giemsa staining. Ten (0.10%) subjects showed parasitaemia, whereas Acridine Orange fluorescence staining showed 13 (0.14%) parasitaemia in almost the same number of smears screened on the same samples. Significantly high levels of malarial antibody were detected in 12.6% and 19.86% of subjects by indirect fluorescent antibody and enzyme-linked immunoassay tests, respectively. Malarial antigen detection by monoclonal antibody showed positive results in 9.48% of subjects, demonstrating excellent results and showing direct evidence of infection. We recommend that this should be adopted as a screening technique by transfusion services in endemic areas in order to prevent post transfusion malaria.
 ...
PMID:Malaria screening to prevent transmission by transfusion: an evaluation of techniques. 178 79

A total of 18,845 blood samples were tested by the Acridine Orange (AO) quantitative buffy coat (QBC) method, under white light and UV light and compared with thick blood films, for the detection of malarial parasites. The positivity rate was 25% by the AO-QBC technique and was 18% by the thick film technique. The increased sensitivity, combined with the rapidity and simplicity of the AO-QBC technique, establishes its superiority over the conventional thick film method, in the sentinel surveillance of malaria, in endemic areas. The comparative unit price of the AO-QBC test and conventional microscopy is Rs. 38.00 and Rs. 14.00 respectively. But, the ancillary advantages of the AO-QBC method over the conventional method more than offset the cost difference.
 ...
PMID:Evaluation of acridine-orange staining of centrifuged parasites in malarial infection. 897 39

The need to have rapid and accurate confirmation of malaria parasitaemia prompted us to evaluate the direct Acridine Orange (AO) stain method in comparison to the traditional Giemsa Stain (GS) method in the detection of malaria parasites in patients with presumptive diagnosis of malaria. We evaluated the sensitivity and specificity of the AO method as well as the durability of the fluorescence microscope. Out of 400 patients with presumptive diagnosis of malaria, 209 (52.3%) and 197 (49.3%) had malaria parasites as detected by GS and AO methods respectively, the difference being statistically insignificant. The sensitivity and specificity of AO method compared to the gold standard (GS) method were 94.1% and 100% respectively. At parasite count below 5,000 per microlitre of blood, the sensitivity of AO method decreased to 90.2% but the difference was not statistically significant. The positive and negative predictive values were 100% and 94.1% respectively at all levels of parasite count. The mean duration to get results of malaria parasite diagnosis by GS and AO methods were 35 and 5 minutes respectively. The limitation of the AO method was frequent blowing of the fluorescence microscope bulb. It is concluded that if the bulb system of the fluorescence microscope can be improved, the AO method could be included among other methods for the detection of malaria parasites in clinical settings.
 ...
PMID:Appraisal of the acridine orange method for rapid malaria diagnosis at three Tanzanian district hospitals. 1049 50

The response to standard chloroquine treatment was evaluated, by microscopical examination of blood-smears, among 81 soldiers diagnosed with Plasmodium vivax malaria in South Korea in 1996. The smears were prepared pre-treatment and 3, 14 and 28 days after starting chemotherapy. Parasitaemias were determined after staining the smears with Giemsa's stain. Blood samples from the patients who were not smear-negative by day 3 were carefully checked for parasites, by staining smears with Acridine Orange and by a PCR-based assay. Only two of the patients appeared to be parasitaemic on day 14 and were therefore considered treatment failures. Although both were apparently cured after additional therapy with the same regimen, one had a recurrence 8 months later. Most cases of recent, resurgent malaria in South Korea therefore appear to sensitive to chloroquine.
 ...
PMID:Response to chloroquine of Plasmodium vivax among South Korean soldiers. 1070 2

One hundred years ago, Giemsa's stain was employed for the first time for malaria diagnosis. Giemsa staining continues to be the method of choice in most malarious countries, although, in the recent past, several alternatives have been developed that exhibit some advantages. Considerable progress has been made with fluorescent dyes, particularly with Acridine Orange (AO). The literature on the discovery, development and validation of the AO method for malaria diagnosis is reviewed here. Compared with conventional Giemsa staining, AO shows a good diagnostic performance, with sensitivities of 81.3%-100% and specificities of 86.4%-100%. However, sensitivities decrease with lower parasite densities, and species differentiation may occasionally be difficult. The most notable advantage of the AO method over Giemsa staining is its promptness; results are readily available within 3-10 min, whereas Giemsa staining may take 45 min or even longer. This is an important advantage for the organization of health services and the provision of effective treatment of malaria cases. The national malaria control programme of Tanzania, together with the Japan International Co-operation Agency, began to introduce the AO method in Tanzania in 1994. So far, AO staining has been introduced in 70 regional and district hospitals, and 400 laboratory technicians have been trained to use the method. The results of this introduction, which are reviewed here and have several important implications, indicate that AO is a viable alternative technique for the laboratory diagnosis of malaria in highly endemic countries.
 ...
PMID:Acridine Orange for malaria diagnosis: its diagnostic performance, its promotion and implementation in Tanzania, and the implications for malaria control. 1253 26

The New World primate Aotus nancymaae is susceptible to infection by the human malaria parasite Plasmodium vivax and has therefore been recommended by the World Health Organization as a model for malaria vaccine candidate evaluation. We report the isolation, adaptation, titration and genetic characterization of a P. vivax wild strain in splenectomized A. nancymaae monkeys. Parasitemia remained high after 22 passages, reaching 7.88% by Giemsa and Acridine Orange staining and Real-Time PCR determination, making this P. vivax strain a highly infective and reliable asset to be used in P. vivax biological studies and vaccine development.
 ...
PMID:A highly infective Plasmodium vivax strain adapted to Aotus monkeys: quantitative haematological and molecular determinations useful for P. vivax malaria vaccine development. 1292 28

Both human malarial parasite Plasmodium vivax and mouse malaria parasite Plasmodium yoelii use Duffy protein as the receptor for invasion and they preferentially invade reticulocytes. Recently, it has been shown that P. yoelii invades mouse reticulocytes by a Duffy independent pathway. Parasite invasion is generally visualized by time consuming staining procedures with dyes like Giemsa or Wright-Giemsa. Fluorochromatic dye like Acridine Orange has been used for instantaneous detection of parasites in RBCs. Acridine Orange binds to both DNA and RNA but with different emission spectra; and the binding can be distinguished with a fluorescent microscope using a green or a red filter, respectively. We have used this differential emission of Acridine Orange to determine P. yoelii invasion into erythrocytes and reticulocytes of Duffy positive and Duffy knockout mice. Moreover, we show that this method can be used to determine the maturity of reticulocytes in the peripheral blood of anemic mice.
 ...
PMID:Plasmodium yoelii: a differential fluorescent technique using Acridine Orange to identify infected erythrocytes and reticulocytes in Duffy knockout mouse. 1580 82

Conventional Giemsa stained peripheral blood smear examination for demonstration of malarial parasites remains the gold standard for diagnosis of malaria in developing endemic countries. However this technique is time consuming, requires training and may give poor results in cases with low parasitaemia. To overcome these problems and improve diagnostic accuracy two newer tests have been studied and compared with standard Giemsa staining. These are the wet mount fluorescence microscopy of Acridine Orange stained thin blood films (A.O.) and the Quantitative Buffy Coat technique (Q.B.C) for diagnosis of malaria. A.O. staining was found to be 97.5% sensitive and 100% specific for detection of all stages and species of malarial parasite. The Q.B.C assay was found to be 100% sensitive and 97.5% specific for diagnosis of malaria. A.O. staining was very fast and the species identification was easy once the staining was optimised. The Q.B.C. test required considerable amount of practice, costly equipment, however it was fast and in our study was found to be highly sensitive.
 ...
PMID:Evaluation of the direct acridine orange staining method and Q.B.C. test for diagnosis of malaria in Delhi, India. 1590 57