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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the efforts to develop a vaccine for human immunodeficiency virus (HIV), attention has focused on sub-Saharan Africa, where large populations at risk for HIV infection could be studied easily. Cross cultural bioethics must be examined to address the ethical implications and cultural obstacles of such research. Autonomy and informed consent are difficult to achieve in cultures with limited personal choice. In some cultures, individual personhood is secondary to social relationships in the tribe or village. Language barriers, illiteracy, and the lack of knowledge about modern science all make it difficult to adequately inform participants. While the Helsinki Declaration emphasizes that a subject's well-being takes precedence over the interests of science and society, health policy decisions in nonautonomous populations often place state interests over the individual. Political sensitivities have been aroused by attempts to attribute the origin of AIDS to western or central Africa, leading political controversy and discrimination against Africans. Foreign researchers often exclude African participation once they have obtained the body fluid samples for study. Without joint collaboration and education, human research in developing countries can easily become exploitative. Justice dictates that research subjects be chosen for scientific reasons, not due to easy availability or ability to be manipulated. In vaccine development, Africans should not experience a disproportionate amount of risk without an equal share in the benefits. Furthermore, malnutrition, malaria, tuberculosis, and many other diseases present more urgent health problems to the developing world than AIDS. The health care priorities of the developing nations must be considered.
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PMID:Ethical considerations of human investigation in developing countries: the AIDS dilemma. 317 36

Since Plasmodium falciparum malaria is a frequent cause of anemia among African children, and blood transfusions, unscreened for human immunodeficiency virus (HIV) antibody, are used frequently in the treatment of children with severe malaria, the relationships between malaria, transfusions, and HIV seropositivity were investigated in a pediatric population in Kinshasa, Zaire. In a cross-sectional survey of 167 hospitalized children, 112 (67%) had malaria, 78 (47%) had received transfusions during the current hospitalization, and 21 (13%) were HIV seropositive. Ten of the 11 seropositive malaria patients had received transfusions during the current hospitalization; pretransfusion specimens were available for four of these children and were seronegative. Of all blood transfusions, 87% were administered to malaria patients, and there was a strong dose-response association between transfusions and HIV seropositivity. A review of 1000 emergency ward records demonstrated that 69% of transfusions were administered to malaria patients, and 97% of children who received transfusions had pretransfusion hematocrits of 0.25 or less (less than or equal to 25%). The treatment of malaria with blood transfusions is an important factor in the exposure of Kinshasa children to HIV infection.
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PMID:The association between malaria, blood transfusions, and HIV seropositivity in a pediatric population in Kinshasa, Zaire. 327 15

The possible associations between Plasmodium falciparum malaria and HIV (human immunodeficiency virus) seropositivity were investigated in 1986 at the Mama Yemo Hospital in Kinshasa, Zaire. No significant difference was found in the HIV seropositivity rate of 164 children presenting with P. falciparum malaria (1.2%) and 169 healthy controls (0.6%). Secondly, no association was found between P. falciparum slide positivity (51.6%) and HIV seropositivity (3.8%) among 1046 children presenting to the hospital with medical complaints. Infants less than 6 months old had the lowest slide-positivity rate, but among infected children the younger ones more frequently had high parasitaemias. HIV seropositivity rates were highest for children less than 6 months old. In older children, seropositivity was strongly associated with a history of blood transfusion. Thus, in Kinshasa children, P. falciparum malaria is a major public health problem; perinatal transmission and blood transfusions constitute important mechanisms of HIV infection; and P. falciparum does not appear to act as an opportunistic agent in children infected with HIV.
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PMID:Absence of association between Plasmodium falciparum malaria and human immunodeficiency virus infection in children in Kinshasa, Zaire. 332

The study of human malaria has been hampered by the lack of small animal models for the human-infecting malarial parasites. To approach this problem, the erythrocytic stages of the human malarial parasite Plasmodium falciparum were adapted to in vitro growth in the presence of ascites fluid from mice homozygous for the severe-combined immunodeficiency (scid) mutation. Human red blood cells (hRBCs) infected with these adapted parasites were then injected i.p. into nonobese diabetic scid/scid (NOD/LtSz-scid) mice. With daily supplemental intraperitoneal boosts of uninfected hRBCs, parasites were detected in the peripheral circulation of these mice for an average of 7 d after injection. Splenectomy of NOD/LtSz-scid mice increased both the level and duration of parasitemia in the periphery, and it also promoted the circulation of mature sexual stage parasites (gametocytes). When Anopheline mosquitoes were allowed to feed on the splenectomized mice, the gametocytes were ingested by the mosquitoes and developed into oocysts in the mosquito midguts. To our knowledge, these results are the first demonstration of human malarial parasite propagation in mice and transmission of these parasites to the invertebrate vector.
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PMID:Maintenance of the human malarial parasite, Plasmodium falciparum, in scid mice and transmission of gametocytes to mosquitoes. 776 12

The cytokine tumor necrosis factor (TNF-alpha) is a pleotrophic polypeptide that plays a significant role in brain immune and inflammatory activities. TNF-alpha is produced in the brain in response to various pathological processes such as infectious agents [e.g., human immunodeficiency virus (HIV) and malaria], ischemia, and trauma. TNF-alpha mRNA is rapidly produced in response to brain ischemia within 1 h, reaches a peak at 6-12 h post ischemia, and subsides 1-2 days later. TNF-alpha mRNA expression corresponds in a temporal fashion to other cytokines such as interleukin (IL)-6, cytokine-induced neutrophil chemoattractant (KC), and IL-1 and precedes the infiltration of inflammatory cells into the injured zone. TNF-alpha is present early in neuronal cells in and around the ischemic tissue (penumbra), yet at later time points, the peptide is found in macrophages in the infarcted tissue. TNF-alpha has been demonstrated to cause expression of proadhesive molecules on the endothelium, which results in leukocyte accumulation, adherence, and migration from capillaries into the brain. Furthermore, TNF-alpha activates glial cells, thereby regulating tissue remodeling, gliosis, and scar formation. Thus, evidence is emerging in support of a role for TNF-alpha in injury induced by infectious, immune, toxic, traumatic, and ischemic stimuli. TNF-alpha promotes inflammation by stimulation of capillary endothelial cell proinflammatory responses and thereby provides leukocyte adhesion and infiltration into the ischemic brain. The evidence generated so far suggests that agents that suppress TNF-alpha's production or actions will reduce leukocyte infiltration into ischemic brain regions and thereby diminish the extent of tissue loss.
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PMID:Cytokines, inflammation, and brain injury: role of tumor necrosis factor-alpha. 788 Jul 18

Blood transfusions are an important route for HIV transmission in Africa. To explore whether transfusions are necessary in the case management of childhood anemia, a randomized trial was performed in Ifakara, Tanzania, a holoendemic malaria region. 116 children were randomized to receive either treatment for malaria and hookworm alone or, in addition, a transfusion of whole blood which had been tested negative for antibodies against the human immunodeficiency virus. Mean packed cell volume (PCV) at admission was 14.0% in the transfusion and 14.4% in the no transfusion group. Children were followed up for 8 weeks with measurements of PCV at 2 days, 4 weeks and 8 weeks after study entry. PCV was similar in both groups after 4 and 8 weeks (22.9% in the transfusion and 23.6% in the no transfusion group). There was a trend towards more hospital admissions and deaths in the no transfusion group; however, 95% confidence intervals included both a beneficial and an adverse effect of blood transfusions. The costs and benefits of transfusion for childhood anemia in countries with a high HIV prevalence need to be considered carefully before a rational treatment policy can be adopted. For that purpose, a larger randomized trial is urgently needed.
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PMID:Childhood anemia in Africa: to transfuse or not transfuse? 790 37

Cryptococcal meningitis is an uncommon infection globally, including Nigeria. This systemic fungal infection often is associated with immunodeficiency. The most common causes of meningitis in Nigeria in the 2-3 year age group are the malaria parasites and bacteria. The concomitant infections of Cryptococcal neoformans and Plasmodium falciparum are uncommon. We present here the report of a case of fatal cryptococcal meningitis with malaria infection in a 2 year old child from Nigeria (one of the malaria endemic regions of the world). This case emphasizes the importance of doing a combination of fungal and bacterial cultures as well as looking for malarial parasites in the determination of etiological agents of meningitis in any hospital in Africa. We suggest that cerebrospinal fluid from meningitis cases must be cultured using Sabouraud dextrose agar and any growth on the agar must be examined using Indian ink.
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PMID:Cryptococcal meningitis with malaria. A case report. 793 35

Malaria and human immunodeficiency virus (HIV) infection are major health problems in many areas in Sub-Saharan Africa. An interaction between malaria and HIV infection has been postulated, since both produce similar cellular immune responses, with a lowering of the CD4/CD8 lymphocyte ratio. The frequency of malaria parasitemia was examined in children born to HIV-seropositive and seronegative mothers attending regular postnatal visits. A prospective study on mother-to-infant transmission of HIV had been underway since 1989 in Queen Elizabeth Central Hospital, Blantyre, a major hospital in urban Malawi. Standard HIV serology was performed on pregnant women, after obtaining consent. To reduce the effect of selection bias and seasonality, HIV seropositive (case) and seronegative (control) mothers and their infants were enrolled at delivery. Children included in the study were 503 born to 494 HIV-seropositive mothers and 540 born to 536 HIV-seronegative mothers. At each 3-monthly postpartum visit a Giemsa-stained thick blood film from the child was examined for malaria parasites. Children born to HIV-seropositive mothers were tested for HIV antibodies at 12 and 18 months of age. Of the 353 children born to HIV-seropositive mothers, 82 children (23.2%) were found to be HIV seropositive by enzyme-linked immunosorbent assay and Western blotting at 12 and 18 months. No statistically significant difference was found in frequency of malaria parasitemia by maternal or infant HIV serostatus after controlling for child's age. There was, however, a significant trend of increase in high parasitemia with age, irrespective of the HIV serostatus of the mother or the child. The frequency of parasitemia was higher in the wet season than in the dry season. This study suggests that maternal or infant HIV infection does not alter susceptibility to, or the clinical course of, malaria in infants.
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PMID:Childhood malaria parasitaemia and human immunodeficiency virus infection in Malawi. 803 59

The retrovirus LP-BM5 murine leukemia virus induces murine AIDS in C57BL/6 mice that has many similarities with human AIDS; Plasmodium berghei ANKA causes experimental cerebral malaria in the same strain of mice. The outcome of malaria infection was studied in mice concurrently infected with the two pathogens. The retrovirus significantly reduced the gravity of the neurological manifestations associated with Plasmodium berghei ANKA infection. The protection against experimental cerebral malaria induced by murine AIDS increased with duration of viral infection and, hence, with the severity of the immunodeficiency. Interleukin 10, principally from splenic T cells, was shown to play a crucial role in this protection.
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PMID:Murine AIDS protects mice against experimental cerebral malaria: down-regulation by interleukin 10 of a T-helper type 1 CD4+ cell-mediated pathology. 805 63

Rheumatoid factor is of limited value in the diagnosis of rheumatoid arthritis (RA) in West Africa. Consequent upon previous findings, we have studied the role of the absence of antibodies to malaria and human immunodeficiency virus (HIV) as well as the presence of the hepatitis B surface antigen (HBsAg) as diagnostic markers of rheumatoid arthritis in West Africa. We have found a significant association (p < 0.001) between RA and titre of HBsAg, but only between RA and malaria (p < 0.05) when sera with low malaria antibodies were studied. No correlation between either HBsAg or malaria and rheumatoid factor was found and no RA patient was either HIV-1 or HIV-2 positive.
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PMID:The absence of antibodies to malaria and human immunodeficiency virus, and the presence of hepatitis B surface antigen as diagnostic markers of rheumatoid arthritis. 812 6


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