Malaria and anemia

Anemia due to infection is a major health problem in endemic areas for young children and pregnant women. The anemia is caused by excess removal of nonparasitized erythrocytes in addition to immune destruction of parasitized red cells, and impaired compensation for this loss by bone marrow dysfunction. The pathogenesis is complex, and a predominant mechanism has not been identified. Certain parasite and host characteristics may modify the anemia. Concomitant infections and nutritional deficiencies also contribute to anemia and may interact with the malarial infection. Few preventive strategies exist, and the management of severe malarial anemia with blood transfusion carries a risk of HIV transmission. The current increase in malaria-specific childhood mortality in sub-Saharan Africa attributed to drug-resistant infection is likely partly related to an increase in severe anemia. This review summarizes recent findings on the pathogenesis and epidemiology of malarial anemia.     

Malaria in pregnancy: priorities for research

Research on the important topic of malaria in pregnancy has been relatively neglected. The seven technical reviews in this special issue on malaria in pregnancy provide an overview of current knowledge on key aspects of malaria in pregnancy and highlight the gaps where more research is needed. In this paper, we prioritise research needs, focusing on areas of research likely to lead to improvements in maternal and child health in malaria endemic areas in the near or mid term. We have selected the following as the highest priorities for research: identification of new safe and effective drugs to treat malaria in pregnancy; identification of new drugs to replace sulfadoxine-pyrimethamine for intermittent preventive treatment in pregnancy; identification of optimum combinations of control measures in different epidemiological settings; and determination of optimum ways of scaling-up the use of insecticide-treated mosquito nets and intermittent preventive treatment.     

Micronutrient malnutrition and the pathogenesis of malarial anemia

Malaria is a leading cause of morbidity and mortality worldwide, and anemia is a common and sometimes serious complication of Plasmodium falciparum infection. Although micronutrient malnutrition is usually highly prevalent in malaria endemic areas, the contribution of micronutrient deficiencies to malarial anemia is often overlooked. Recent investigation suggests that micronutrients such as vitamin A, vitamin E, and zinc, may improve the morbidity of malaria through immune modulation and alteration of oxidative stress. Micronutrients are also involved in the pathogenesis of anemia and likely play a role in malarial anemia, but many clinical trials have not specifically addressed the impact of micronutrient supplementation on malarial anemia. Further work is needed to assess the effect of both clinic and community-based micronutrient interventions on malarial anemia in infants, children, and pregnant women.     

Malaria and anemia in antenatal women in Blantyre, Malawi: a twelve-month survey

Malaria and anemia are common in pregnant African women. We screened 4,764 Malawian women at first antenatal visits for malaria and anemia. A total of 42.7% had a malaria infection, which was more common and of higher density in primigravidae (prevalence = 47.3%, geometric mean = 332 parasites/microl) and teenagers (49.8%, 390/microl) than in multigravidae (40.4%, 214/microl) or older women (40.6%, 227/microl). However, 35% of gravida 3+ women were parasitemic. A total of 57.2% of the women was anemic (hemoglobin < 11 g/dl), with moderate anemia (7.0-8.9 g/dl) in 14.9% and severe anemia (< 7 g/dl) in 3.2%. Prevalences of malaria and anemia were highest in the rainy season. Women with moderate/severe anemia had higher parasite prevalences and densities than women with mild/no anemia. Logistic regression showed that age, season, and trimester of presentation were significantly associated with the prevalence of malaria, but gravidity was not. In this urban setting, age and season are more important than gravidity as predictors of malaria at first antenatal visit, and parasitemia is frequent in women of all gravidities.     

Malaria in adolescence: burden of disease, consequences, and opportunities for intervention

The problem of malaria in adolescence has largely been overshadowed by the huge burden of disease in young children. A substantial number of adolescents are at risk from malaria infection, but the burden of disease and consequences of infection in this age-group have rarely been studied. Our understanding of specific risk factors and beneficial interventions for adolescents is also limited. Data show that, from an adolescent viewpoint, malaria is a common cause of clinical illness and a preventable cause of death, even in areas of stable malaria transmission. Younger adolescents might be at a higher risk than older adolescents, because of immunological and hormonal factors. There are limited data about the adverse consequences of malaria in non-pregnant adolescents. However, in pregnant adolescents, the consequences of malaria are of great concern and simple interventions might lead to a substantial benefit. Malaria infection in adolescents is an under-recognised problem, and the prevention, diagnosis, and treatment of malaria should have a high priority within adolescent health programmes.     

Malaria and human immunodeficiency virus infection as risk factors for anemia in infants in Kisumu,western Kenya

The role of maternal and pediatric infection with human immunodeficiency virus type 1 (HIV-1) and malaria as risk factors for anemia was determined in a birth cohort of infants born to mothers participating in a study of the interaction between placental malaria and HIV infection, in Kisumu, Kenya. Between June 1996 and April 2000, 661 infants born to 467 HIV-seropositive and 194 HIV-seronegative mothers were monitored monthly from birth. At each visit a questionnaire was completed and a blood sample was collected for the determination of hemoglobin levels and detection of malaria and HIV. Anemia was common and increased from 13.6% at one month to 75% at six months and remained high throughout the second half of infancy. Placental malaria, infant malaria, and HIV infection of the infant were all associated with infant anemia in a multivariate model, adjusting for other co-variates found to be associated with infant anemia. The HIV-infected infants with malaria parasitemia had lower mean hemoglobin levels compared with HIV-uninfected infants, or HIV-infected infants without malaria, suggesting that HIV-infected infants are particularly vulnerable to the adverse consequences of malaria at this age. Early detection and prompt treatment of infant malaria and treatment of anemia as part of the study protocol failed to prevent most of the infants from becoming anemic. Although not proven effective in this study, micronutrient supplementation should be prospectively assessed in HIV-infected infants as a means of preventing anemia.     

Effect of maternal malnutrition and anemia on the endocrine regulation of fetal growth

Fetal growth retardation is a result of a complex pathology caused by multiple factors of fetal, placental, and maternal origin. Hormones and growth factors released as a result of maternal-fetal physiological interactions play an importance role in fetal well being and fetal outcome. Intrauterine Growth Retardation (IUGR) is associated with significant perinatal and childhood morbidity. It is estimated that 13.7 million infants are born annually with IUGR, comprising 11% of all births in developing countries. Both maternal malnutrition and anemia are associated with various degrees of fetal growth retardation. The relationship between decreasing birth weight percentiles and increasing fetal morbidity and mortality has been demonstrated by several investigators and epidemiological studies suggest that IUGR is a significant risk factor for the subsequent development of chronic hypertension, ischemic heart disease, diabetes, and obstructive lung disease in adult life (Barker's Hypothesis). Maternal anemia and/or malnutrition are recognized to be the most frequent cause of IUGR and SGA birth in developing countries like India. In order to investigate adaptive mechanisms by the fetus to overcome the growth disadvantage caused due to maternal nutritional limitations, we examined the quantitative variations in hormonal and growth factor profiles in paired cord blood and maternal samples obtained from neonates born to malnourished and/or anemic mothers. The results of our study show that: 1) The percentage of small for gestational age (SGA) neonates born to malnourished and anemic mothers was significantly higher than those born to mothers who were either malnourished or anemic; 2) Significantly higher levels of GH, PRL, HPL and IGF-1 were observed in the cord blood of neonates born to malnourished and anemic mothers indicative of an adaptive response on part of the fetus to over come an in-utero growth disadvantage; 3) The anoxemia-related fetal perturbations may have unique features that make them distinct from nutrient deficiency-related IUGR. Thus, these novel observations are relevant to the context of the ongoing scientific debate on Barker's hypothesis.     

慢性阻塞性肺疾病伴发营养不良的机制及其干预研究进展

目前研究表明,慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)除了会出现特征性的肺部病理改变外,也可以引起全身(或称肺外)的不良反应,即COPD的肺外效应(全身效应).其中营养不良是COPD常见的肺外效应,其对疾病的发展及预后有着重要影响.以下就目前国内外有关CO...     

Improved detection of malnutrition by medical housestaff following focused-teaching intervention

We examined the influence of a brief, small group teaching intervention, which used current patients as examples, 01 the detection of malnutrition by medical housestaff. We re viewed 100 consecutive patient admissions before and 61 ad missions 1 month after the intervention for any mention o malnutrition in admitting, progress, or discharge notes and compared the result with the number of patients diagnosed as malnourished by dietitians. Before the intervention, in terns correctly identified 4 (14%) of 28 malnourished patients. After the intervention, the same interns correctly identified 15 (94%) of 16 malnourished patients (p=.0004) We conclude that this brief teaching intervention was effective in increasing the awareness and detection of malnutrition by interns.     

尿毒症血液透析患者炎症反应与营养状态及贫血的关系

目的　探讨尿毒症血液透析患者炎症反应与营养状态和贫血的关系。　方法　抽取 4 8例尿毒症血液透析患者 ,透析前静脉血检测C反应蛋白 (CRP)、白细胞介素 6 (IL - 6 )、血肌酐 (Scr)、血清白蛋白 (AIb)、血清铁蛋白 (SF)及血红蛋白 (Hb) ,根据透析前CRP水平分为正常组 (CRP <5mg L)与升高组 (CRP >5mg L) ,并比较两组患者蛋白代谢率 (nPCR)水平及促红细胞生成素 (EPO)剂量。　结果　CRP升高患者同时有IL - 6水平上调 ,伴有近期感染的发生率明显高于正常组 ;透析前血浆CRP水平为 (2 0 2± 1 2 4)mg L ,Alb与CRP和IL6水平呈负相关 (P <0 0 1 ) ,与Scr及SF无相关关系 (P <0 0 5 ) ;与Hb水平呈负相关 ;EPO治疗剂量与CRP和IL - 6水平呈正相关 (P <0 0 5 )。　结论　尿毒症血透患者血清CRP和IL - 6是炎症反应较好的预测指标 ,而炎症反应在营养不良和贫血中起重要的作用。     

Malaria in the first 6 months of life in urban African infants with anemia.

A total of 446 infants in the first 6 months of life who presented at an urban children's hospital with complaints of any illness whatsoever were recruited into a study with the aim of determining the contribution of malaria to infant morbidity in a malaria-endemic urban area in Nigeria. Sixty-eight of the infants were in their first month of life and 79, 77, 61, 97, and 64 were in their second, third, fourth, fifth and sixth month of life, respectively. Overall, 107 (24.0%) infants were clinically diagnosed as having malaria. This included 3 who were in the first month of life, 12 in the second, 15 in the third, 17 in the fourth, 33 in the fifth, and 27 in the sixth months of life (4.4, 15.2, 19.5, 27.9, 34.0, and 42.1%, respectively). Laboratory investigations confirmed 35 (32.7%) of those clinically diagnosed and 86 (25.4%) of those not clinically diagnosed (n = 339) as having malaria parasitemia, giving an overall malaria parasite rate of 27.1% among the infants. Acute respiratory infection was the major diagnosis (41.3%) among those that were not initially diagnosed as malaria but turned out to have malaria parasitemia followed by gastroenteritis (11.8%) and failure to growth (1.5%). Overall geometric mean parasite density was 202.5 parasites/microL of blood (range, 12-65,317 parasites/microL of blood). The mean hematocrit of infants with parasites (33.0%) was significantly lower (P < 0.005) than that of infants without parasites (35.1%). The mean hematocrit of infants with malaria parasites in each age group was lower than that of infants without malaria parasites in the corresponding age group. Among the infants with malaria parasites, those aged 2 to 2.9 months recorded the lowest mean hematocrit (30.1%), and those aged < 1 month recorded the highest mean hematocrit (42.7%). Axillary temperature increased and hematocrit decreased with increase in parasite density. The percentage of infants with anemia likewise increased as the parasite density increased. Plasmodium falciparum was present in all infected infants, but mixed infection with P. malariae was present in only 2.5% of infections. Analysis of our data suggests an urgent need for health education of caretakers and for training of clinicians for increased awareness of malaria as an important cause of illness and anemia in infants aged < 6 months so as to reduce children's wasting due to an easily preventable and treatable disease.     

Malaria infection in pregnant women in Zaire: the effects and the potential for intervention

In five maternity centres in urban and rural Zaire we evaluated the maternal prevalence of Plasmodium falciparum parasitaemia and recorded fever, the frequency of abortions and stillbirths, newborn birth weights and the feasibility of delivering antimalarial chemoprophylaxis. Women in their first and second pregnancy, compared to others (greater than or equal to third pregnancies), had a higher frequency of parasitaemia (38 v. 15%, respectively, P less than 0.001), higher parasite densities (geometric mean densities 927 per mm3 v. 277 per mm3, respectively, P = 0.01), higher rates of stillbirths and low birth weight babies (24% v. 6.4%, P less than 0.001). On average, pregnant women first attended prenatal clinics in the sixth to seventh month of gestation and made three to four visits before delivery. In these areas of Zaire, antimalarial interventions during pregnancy would have the largest impact if they were targeted to women in their first and second pregnancy. In the study areas, maternal attitudes and prenatal care-seeking behaviours do not appear to be barriers to providing an antimalarial intervention.     

Malaria, leprosy and dapsone

Although the preventive action of dapsone against P. falciparum malaria was known for many years, there was no report about the incidence of P. falciparum malaria in leprosy patients treated with dapsone, especially from areas of Southeast Asia where both leprosy and malaria are endemic. Therefore, two clinic-based malaria surveys were undertaken at a gap of 12 years, comprising 506 lepromatous leprosy patients and 499 febrile nonleprosy control subjects. Both the surveys showed that the lepromatous patients treated with MDT had only P. vivax malaria (incidence comparable to the febrile nonleprosy controls) with complete freedom from P. falciparum. On the contrary, control sujects not taking any-leprosy drugs and staying with the leprosy patients at the same beggars' home, had both P. vivax and P. falciparum malaria. It is postulated that dapsone provided protection against P. falciparum among leprosy patients.