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

The relationship between splenomegaly and visceral leishmaniasis (VL) was investigated during a cross-sectional study in 2,941 individuals in Baringo District, Kenya, where both malaria and VL are endemic. Spleen size was correlated with presence of malaria parasites in thick blood films and with evidence of present or past Leishmania donovani infection as determined by serology and history. Marked splenomegaly (Hackett grade 3 or greater) significantly correlated with present or previous leishmanial infection (chi 2 = 53.5; p < 0.001) whereas moderate splenomegaly (Hackett grade 1 or 2) significantly correlated with malaria parasitaemia (chi 2 = 73.03; p < 0.001). The presence of antimalarial antibodies did not contribute to the differentiation of the cause of splenomegaly. The diagnostic significance of splenomegaly in this population is discussed.
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PMID:Splenomegaly in Baringo District, Kenya, an area endemic for visceral leishmaniasis and malaria. 748

Recent studies have identified genes involved in resistance to intracellular pathogens. Such genes include the murine MHC class I gene, Ld (toxoplasmosis), HLA-BW53, HLA DRB1* 1302-DQ B10s01 and TNF2 (malaria), murine Nramp (toxoplasmosis, leishmaniasis and tuberculosis), gene(s) modulating the T-helper type 1 and type 2 dichotomy (leishmaniasis, leprosy and HIV infection) and the natural killer cell complex (cytomegalovirus infection). There also have been other advances in immunogenetics that have led to a better understanding of resistance to intracellular pathogens. These include effector mechanisms of immune response genes and factors modulating genetic susceptibility. Identification of genes that determine resistance/susceptibility (and their effector mechanisms) has impacted on vaccine development. Immunogenetics has been important in characterizing roles of TCR genes, superantigens, and host genes that play a role in molecular mimicry in disease pathogenesis. In addition, recent work with gene knockout, recombinant inbred or congenic, mutant, consomic, and transgenic mice, positional cloning, mouse/human gene homologies to identify candidate human resistance genes, and the rapid expansion of the gene transcription maps of the human genome, have been important in analysis of resistance to intracellular pathogens.
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PMID:Immunogenetics in the analysis of resistance to intracellular pathogens. 749 19

Leishmania protozoans are the causative agents of leishmaniasis, a major parasitic disease in humans. During their life cycle, Leishmania protozoans exist as flagellated promastigotes in the sand fly vector and as nonmotile amastigotes in the mammalian hosts. The promastigote-to-amastigote transformation occurs in the phagolysosomal compartment of the macrophage cell and is a critical step for the establishment of the infection. To study this cytodifferentiation process, we differentially screened an amastigote cDNA library with life cycle stage-specific cDNA probes and isolated seven cDNAs representing amastigote-specific transcripts. Five of these were closely related (A2 series) and recognized, by Northern (RNA) blot analyses, a 3.5-kb transcript in amastigotes and in amastigote-infected macrophages. Expression of the amastigote-specific A2 gene was induced in promastigotes when they were transferred from culture medium at 26 degrees C and pH 7.4 to medium at 37 degrees C and pH 4.5, conditions which mimic the macrophage phagolysosomal environment. A2 genes are clustered in tandem arrays, and a 6-kb fragment corresponding to a unit of the cluster was cloned and partially sequenced. An open reading frame found within the A2-transcribed region potentially encoded a 22-kDa protein containing repetitive sequences. The recombinant A2 protein produced in Escherichia coli cells was specifically recognized by immune serum from a patient with visceral leishmaniasis. The A2 protein repetitive element has strong homology with an S antigen of Plasmodium falciparum, the protozoan parasite responsible for malaria. Both the A2 protein of Leishmania donovani and the S antigen of P. falciparum are stage specific and developmentally expressed in mammalian hosts.
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PMID:Developmental gene expression in Leishmania donovani: differential cloning and analysis of an amastigote-stage-specific gene. 754 21

A retrospective analysis was carried out on census data collected from house-to-house surveys during 1991-1992 in 4 areas endemic for Andean cutaneous leishmaniasis (uta) in the Department of Lima, Peru. Major changes in mean annual incidence in susceptible persons have taken place in these sites during the last 60 years. In particular, there is strong support for the hypothesis that, from the 1950s to the 1970s, the transmission rate was temporarily suppressed, largely as a by-product of the DDT house spraying campaign against malaria. These results are consistent with (i) anecdotal evidence, contemporary with the spraying campaign, and (ii) the official Ministry of Health records for the annual number of uta cases in the Departments of Lima and Ancash.
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PMID:The fall and rise of Andean cutaneous leishmaniasis: transient impact of the DDT campaign in Peru. 757 Aug 13

Prevalence and disease manifestations of visceral leishmaniasis (VL) were studied in a Somali village in an area which has long been known to be endemic for VL. Demographic data were collected from 102 households, comprising 438 inhabitants. Clinical examination was performed of 306 individuals, 72% of the 426 eligible persons. Of these, 276 (90%) agreed to give blood and 246 (80%) to be skin tested with leishmanin. Leishmanin reactions were positive; in 26% anti-Leishmania antibodies were detected in 11%, and splenomegaly was recorded in 14% (23% of those who were seropositive). Malaria was hypoendemic and therefore unlikely to be responsible for more than 10% of the cases with splenomegaly. Three of the seropositive villagers with splenomegaly complained of feeling ill. The remaining 91 sero- and/or leishmanin-positive individuals had no complaint regarding their health and had not experienced any long period of illness. There was a slight over-representation of males in the group of sero- and/or leishmanin-positive villagers, possibly due to a gender-associated difference in exposure to the parasite. Among the patients with clinical VL treated at Mogadishu hospitals during 1989 and 1990, the male/female ratio was 3.3:1, which may indicate a selection of male patients for hospital care. Most patients were < or = 15 years old, suggesting that the highest risk of becoming clinically ill was among children.
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PMID:Visceral leishmaniasis in Somalia: prevalence of markers of infection and disease manifestations in a village in an endemic area. 757 Aug 62

Leishmaniasis is a spectrum of diseases ranging in severity from cutaneous (CL), post-kala-azar dermal (PKDL), and diffuse cutaneous (DCL) to mucocutaneous (MCL) and visceral (VL) infections that are endemic in 86 tropical and subtropical countries around the world, accounting for 75,000 deaths per year. Different forms of leishmaniases are generally caused by different distinct species of Leishmania having a digenetic life cycle alternating between an aflagellated amastigote form replicative within the macrophages of the host and a flagellated promastigote form that multiplies within the gut of the sandfly. VL, MCL, PKDL, DCL, and CL forms of the disease can be arranged on a priority basis in accordance with the humoral immune responses of host. Generally, the cell-mediated immunity, particularly the delayed-type hypersensitivity to leishmanial antigens, is associated with CL, MCL, PKDL, and cured VL cases. The serodiagnosis of leishmaniasis appears to be an alternative to parasite detection in biopsy samples either by the staining of amastigotes or by culturing the amastigotes, which transform to a promastigote form and replicate. A battery of immunological procedures have been developed or adapted to demonstrate either humoral or cell-mediated immune responses against Leishmania for diagnosis and epidemiological survey. The sensitivity and specificity of such diagnostic methods depend on the type, source, and purity of antigen employed, as some of the leishmanial antigens have common cross-reactive epitopes shared with other microorganisms, particularly Trypanosoma, Mycobacteria, Plasmodia, and Schistosoma. Serodiagnostic techniques for the detection of antileishmanial antibodies have been employed with about 72 to 100, 23 to 90, 83, and 33 to 100% success in VL, CL, MCL, and PKDL patients, respectively. The Leishmanin skin test (LST) is useful to detect MCL and CL, with about 100 and 84% success, respectively. In PKDL, the gradual fall of antileishmanial antibody titer to some extent and the rise of delayed hypersensitivity to the parasite antigen are the characteristic features associated with the chronicity of the disease. The use of whole promastigote as the source of antigens in the direct agglutination test (DAT) and immunofluorescent test (IFAT) gave cross-reactions with the sera of leprosy, tuberculosis, and African trypanosomiasis patients. Again, the use of cell-free extracts of promastigotes generally gave false positive results with the sera of normal human and Chagas' disease, leprosy, tuberculosis, and malaria patients in enzyme-linked immunosorbent assay (ELISA), dot ELISA, immunodiffusion, immunoelectrophoresis, and counter-current immunoelectrophoresis tests.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Serodiagnosis of leishmaniasis. 763 32

Seroepidemiologic studies using the indirect immunofluorescent antibody test (IFAT) are valuable in malaria control programs in identifying local foci of malaria, in diagnosing malaria in asymptomatic, low-parasitemia blood donors in nonendemic countries, in detecting imported malaria and preventing its introduction into new areas, and in excluding recurrent fever from causes other than malaria. Because other diseases may occur in areas where malaria is prevalent, the aim of this work, using the IFAT, was to determine the frequency of cross-reactions between blood-stage antigens of Plasmodium falciparum and antibodies present in the serum of individuals with leishmaniasis, toxoplasmosis and Chagas' disease. Since malaria transmission does not occur in the study area (State of Minas Gerais, Brazil) where these other diseases are present, we studied sera from individuals living in this area who had never been in the areas endemic for malaria in the Amazon region. Positive reactivity of sera with blood malaria antigens evaluated by IFAT at dilutions > or = 1:40 was detected in 19 (38%) of 50 individuals with cutaneous leishmaniasis, five (62%) of eight individuals with visceral leishmaniasis, 14 (32%) of 44 individuals with Chagas' disease, four (11%) of 36 individuals with toxoplasmosis, and in none of the 14 uninfected controls. All 23 of the control malaria sera from the endemic area (State of Mato Grosso, Brazil) were positive at high dilutions. We found no correlation between titers of the IFAT with malaria and the specific antigens used for serodiagnosis of the other protozoan infections studied. At dilutions of 1:20 and 1:40, the sensitivity of the IFAT test was 100% and specificity was 52% and 72%, respectively. At a dilution of 1:80, the sensitivity was 86% and the specificity was 90%.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cross-reactivity between antibodies in the sera of individuals with leishmaniasis, toxoplasmosis, and Chagas' disease and antigens of the blood-stage forms of Plasmodium falciparum determined by indirect immunofluorescence. 767 25

The availability of DDT led to a revolution in insect pest control. However, in the 1970's it was banned or its use restricted in many countries because it was accumulating in the environment. It was suggested that this could have a deleterious effect on human health. However, these effects, particularly carcinogenesis, have never been clearly proved in humans. Furthermore, accumulation is significantly lower in the tropical than temperature environment. DDT can therefore be continued to be used as a spray in houses, where it is sequestrated by mud walls. It is mainly used against anopheles (mosquitoes) for malaria control and phlebotomus (sand flies) for control of leishmaniasis. However, the value of DDT is restricted by the resistance of many vector species; and its excitatory-repellent effect which does not allow interruption of malaria transmission in highly endemic areas (for example Northern Cameroun).
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PMID:[DDT and public health]. 792 98

Vector-borne diseases including dengue, yellow fever, Japanese encephalitis, malaria, leishmaniasis, and filariasis remain severe public health problems in most of the countries in which they are endemic. In some cases, their incidence is increasing and they are spreading to new geographic areas. For a number of the infections, the most effective manner of controlling their transmission is through control of their vectors. However, in some instances, such as dengue and Chagas' disease, there is no alternative. Most countries that are endemic for vector-borne diseases maintain vector control services, and most large tropical and semitropical cities also have pest control programs, mainly against pest mosquitoes. Virtually all of the vector and pest control programs depend on the use of insecticides formulated as larvicides, adulticides, baits, or insecticide impregnated bed nets. For many years, the development of new insecticides for use in public health programs was encouraged and supported by multilateral and bilateral health agencies, including the implementation of field trials in endemic areas. Due to the development of insecticide resistance, toxicologic and environmental considerations, and the cost of development and of registration, the number of compounds available for use has declined while the number of new insecticides submitted for laboratory and field trials to the World Health Organization has dwindled even more. The recrudescence of vector-borne diseases, the rapid pace of urbanization, lagging development of environmental services in many tropical cities, and difficulties encountered in ensuring the community's cooperation in its own protection through environmental measures make imperative the continued availability of pesticides for public health use. Since only the pesticide manufacturing industry has the combination of technical and financial resources to promulgate the research and development of new pesticides and pesticide groups, it is suggested that governments, bilateral, and multilateral organizations explore the manner in which they can assist industry in the development of new compounds and guarantee the continued availability of effective and safe pesticides for vector-control programs.
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PMID:What role for insecticides in vector control programs? 802 77

The use of pyrethroid-treated fabrics against disease vectors is a well-accepted vector control strategy worldwide. Most studies have assessed the merits of using impregnated bednets, but this prevention strategy is inappropriate for many households in many communities due to incompatible cultural norms, high cost, the lack of conventional western style beds, sleeping arrangements which differ between cultures, and differences between housing construction styles in rural communities. The International Center of Insect Physiology and Ecology recently developed a technology using cotton wall cloth, Mbu cloth, to control vectors of malaria and leishmaniasis in rural communities in Kenya. Other fabrics such as polyester have even improved the technology by making the cloth lighter and cheaper. The authors evaluated the effect of permethrin-treated Mbu cloth on malaria parasitemia prevalences and malaria morbidity in a population of over 10,000 for a period of 3 years in the Marigat area of Baringo District, Kenya. 2000 houses were fitted with the cloth. The prevalence of malaria parasites was reduced an overall 73% in the treated area. Control areas saw a 30% initial increase in the rate of malaria parasite prevalence followed by a reduction of 31%. Slight reductions in spleen rates were also observed in the control and treated areas, but were insignificant between the surveys and among the villages.
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PMID:Malaria prevalence and morbidity in relation to the use of permethrin-treated wall cloths in Kenya. 802 47


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