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P. Falciparum Infection (p + falciparum_infection)
Selected AbstractsAutomated detection of malaria-associated intraleucocytic haemozoin by Cell-Dyn CD4000 depolarization analysisINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 2 2003C.S. Scott 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. [source] Malaria in Brazilian Military Personnel Deployed to AngolaJOURNAL OF TRAVEL MEDICINE, Issue 5 2000COL L. Jose Sanchez Background: Malaria represents one of the most important infectious disease threats to deployed military forces; most personnel from developed countries are nonimmune personnel and are at high risk of infection and clinical malaria. This is especially true for forces deployed to highly-endemic areas in Africa and Southeast Asia where drug-resistant malaria is common. Methods: We conducted an outbreak investigation of malaria cases in Angola where a total of 439 nonimmune Brazilian troops were deployed for a 6-month period in 1995,1996. A post-travel medical evaluation was also performed on 338 (77%) of the 439 soldiers upon return to Brazil. Questionnaire, medical record, thick/thin smear, and serum anti- Plasmodium falciparum antibody titer (by IFA) data were obtained. Peak serum mefloquine (M) and methylmefloquine (MM) metabolite levels were measured in a subsample of 66 soldiers (42 cases, 24 nonmalaria controls) who were taking weekly mefloquine prophylaxis (250 mg). Results: Seventy-eight cases of malaria occurred among the 439 personnel initially interviewed in Angola (attack rate = 18%). Four soldiers were hospitalized, and 3 subsequently died of cerebral malaria. Upon return to Brazil, 63 (19%) of 338 soldiers evaluated were documented to have had clinical symptoms and a diagnosis of malaria while in Angola. In addition, 37 (11%) asymptomatically infected individuals were detected upon return (< 1% parasitemia). Elevated, post-travel anti- P. falciparum IFA titers (, 1:64) were seen in 101 (35%) of 292 soldiers tested, and was associated with a prior history of malaria in-country (OR = 3.67, 95% CI 1.98,6.82, p < .001). Noncompliance with weekly mefloquine prophylaxis (250 mg) was associated with a malaria diagnosis in Angola (OR = 3.75, 95% CI 0.97,17.41, p = .03) but not with recent P. falciparum infection (by IFA titer). Mean peak levels (and ratios) of serum M and MM were also found to be lower in those who gave a history of malaria while in Angola. Conclusions: Malaria was a significant cause of morbidity among Brazilian Army military personnel deployed to Angola. Mefloquine prophylaxis appeared to protect soldiers from clinical, but not subclinical, P. falciparum infections. Mefloquine noncompliance and an erratic chemoprophylaxis prevention policy contributed to this large outbreak in nonimmune personnel. This report highlights the pressing need for development of newer, more efficacious and practical, prophylactic drug regimens that will reduce the malaria threat to military forces and travelers. [source] Antigenic cross-reactivity between different alleles of the Plasmodium falciparum merozoite surface protein 2PARASITE IMMUNOLOGY, Issue 11-12 2003Ingrid Felger SUMMARY The polymorphic domain of the gene encoding Plasmodium falciparum merozoite surface protein 2 (MSP2) was PCR amplified from blood of malaria patients, genotyped, and 19 distinct fragments were cloned and expressed in E. coli. The reactivity of naturally occurring antibodies against this panel of recombinant MSP2 antigens was tested using 67 homologous or heterologous sera from a serum bank of travel clinic patients. Sera from semi-immune individuals strongly recognized almost all recombinant antigens. Sera from primary infected patients either did not react at all (9 sera), or reacted weakly against varying numbers of antigens (39 sera). The antigens that showed reactions were mostly of the allelic family corresponding to the infecting clone, but in very few cases also of the alternative allelic family. Single clone infections and repeated samples from the same individual were analysed in greater detail. Thus, we were able to quantify cross-reactivity induced by a single P. falciparum infection. Within the two allelic families of MSP2, cross-reactivity was observed between some but not all alleles of the same family, whereas antibodies cross-reactive between variants belonging to different allelic families were detected in only a few cases. [source] ,+ -Thalassaemia and pregnancy in a malaria endemic region of Papua New GuineaBRITISH JOURNAL OF HAEMATOLOGY, Issue 2 2006A. O'Donnell Summary The effect of maternal ,+ -thalassaemia on pregnancy was assessed in the north coastal region of Papua New Guinea (PNG), where malaria is hyperendemic and ,+ -thalassaemia is extremely common. In a prospective study of 987 singleton hospital deliveries, we correlated maternal , -globin genotype with markers of reproductive fitness (age in primigravidae, gravidity, pregnancy interval and the number of miscarriages and stillbirths), Plasmodium falciparum(P. falciparum) infection of the mother and placenta, maternal haemoglobin, preterm delivery and birthweight. The frequency of the ,, genotype in mothers was 0·61. Markers of reproductive fitness were similar in women with and without ,+ -thalassaemia. Median haemoglobin concentration during pregnancy and after delivery was about 1·0 g/dl lower in homozygous ,+ -thalassaemia than in women with a normal , - globin genotype (P , 0·001). The frequency of placental P. falciparum infection and systemic malaria infection after delivery showed no consistent relationship to , -globin genotype. The frequency of preterm delivery and low birthweight did not vary significantly according to maternal , -globin genotype. Maternal ,+ -thalassaemia does not affect reproductive fitness or susceptibility to malaria during pregnancy. Although median haemoglobin concentration was significantly lower in mothers homozygous for ,+ -thalassaemia than those with a normal , -globin genotype, this did not result in an adverse outcome of pregnancy. [source] Performance of the Now Malaria rapid diagnostic test with returned travellers: a 2-year retrospective study in a French teaching hospitalCLINICAL MICROBIOLOGY AND INFECTION, Issue 11 2005F. Durand Abstract Malaria caused by Plasmodium falciparum remains the major life-threatening parasitic infection in the world. The number of cases in non-endemic countries continues to increase, and it is important that misdiagnosis of malaria should not occur, especially in non-immune travellers, because of the high risk of a fatal outcome. In a retrospective study of 399 sera, the Now Malaria rapid test was compared with the quantitative buffy coat (QBC) test and microbiological examination of thin blood films. Compared with the QBC test and thin blood films, the Now Malaria test had sensitivity and specificity values of 96.4% and 97%, respectively, for the detection of pure P. falciparum infection. A negative predictive value of 99.4% allows this test to be included in diagnostic strategies for patients presenting with clinical suspicion of malaria. Two false-negative results were associated with low levels of parasitaemia in the specimens. Thus, use of the Now Malaria test alone to detect P. falciparum infection in non-endemic countries could lead to misdiagnosis of malaria. This rapid diagnostic test should therefore be performed in association with another prompt traditional method such as examination of thin blood films. [source] | ||||||||||