| malaria seroepidemiology: comparison between indirect fluorescent antibody test and enzyme immunoassay using bloodspot eluates. | blood sampling on filter paper is a current practice in malaria seroepidemiological studies by indirect fluorescent antibody test (ifat). there is, however, scant comparative information about the use of bloodspot eluates for detection of malarial igg antibodies simultaneously by ifat and enzyme immunoassay (elisa). here we report data obtained by both serological methods done on 219 bloodspot eluate samples collected in a rural community in brazilian amazon basin (alto paraíso, ariquemes munici ... | 1992 | 1308565 |
| a randomized clinical trial with high dose of chloroquine for treatment of plasmodium falciparum malaria in brazil. | this clinical trial compared parasitological efficacy, levels of in vivo resistance and side effects of oral chloroquine 25 mg/kg and 50 mg/kg in 3 days treatment in plasmodium falciparum malaria with an extended followed-up of 30 days. the study enrolled 58 patients in the 25 mg/kg group and 66 in the 50 mg/kg group. all eligible subjects were over 14 years of age and came from amazon basin and central brazil during the period of august 1989 to april 1991. the cure rate in the 50 mg/kg group wa ... | 1992 | 1342112 |
| epidemiological distribution of plasmodium falciparum drug resistance in brazil and its relevance to the treatment and control of malaria. | with the use of a simple formulary, filled by health agents was established a monitoring programme for responses of p. falciparum to the antimalarial drugs. this monitoring programme is emphasized for the knowledge of the epidemiology of the drug resistance and the control of malaria falciparum in amazon basin where occurs more than 95% of brazilian malaria cases every year. it was demonstrated that still now 4-aminoquinolines have a great importance for the mortality control in areas where just ... | 1992 | 1343711 |
| plasmodium falciparum: restricted polymorphism of t cell epitopes of the circumsporozoite protein in brazil. | we examined the extent of variation of the 3' region of the circumsporozoite gene among plasmodium falciparum isolates through amplification of a selected dna fragment followed by dna sequencing. a total of 32 isolates were analyzed, of which 24 were from amazon endemic areas in brazil and 8 from widely separated geographical regions in the world. among brazilian isolates only 2 variants were detected: 19 displayed the same sequence of strain 7g8 whereas the 4 remaining isolates differed from th ... | 1990 | 1699781 |
| prevalence of the dihydrofolate reductase asn-108 mutation as the basis for pyrimethamine-resistant falciparum malaria in the brazilian amazon. | pyrimethamine resistance in cultivated laboratory isolates of plasmodium falciparum is linked to the dihydrofolate reductase mutation asn-108, a mutation that acts by interrupting drug binding within the active site of the enzyme. to determine the prevalence of this mutation in endemic regions harboring pyrimethamine-resistant malaria, we used a mutation-specific polymerase chain reaction assay to survey p. falciparum strains from a wide section of the brazilian amazon. mutations were identified ... | 1991 | 1951858 |
| infrequency of asymptomatic malaria in an endemic area in amazonas, brazil. | | 1988 | 3074390 |
| malaria in humaita county, state of amazonas, brazil. xix--evaluation of clindamycin for the treatment of patients with plasmodium falciparum infection. | | 1988 | 3076023 |
| [characterization of 15 strains of plasmodium falciparum in 8 areas of the brazilian amazon region]. | | 1986 | 3077192 |
| [in vivo resistance of plasmodium falciparum to 4-aminoquinolines and to a sulfadoxine-pyrimethamine combination. ii. study of manaus, amazonas 1983-1984]. | | 1986 | 3077193 |
| [malaria in the municipality of humaitá, state of amazonas. xxi. prevalence of glucose-6-phosphate dehydrogenase in a population sample and in patients with plasmodium falciparum malaria]. | | 1987 | 3331490 |
| frequency of human leukocyte antigen (hla) in patients with malaria and in the general population of humaitá county, amazonas state, brazil. | | 1987 | 3333875 |
| malaria at humaita county, amazonas state, brazil. xvii--immune response in patients with plasmodium falciparum according to gametocytes. | | 1985 | 3914695 |
| [malaria and intestinal parasitosis in indians of the nadeb-maku tribe, state of amazonas, brazil]. | | 1984 | 6385212 |
| [malaria in the municipality of humaitá, state of amazonas. xiii - use of clindamycin in the treatment of patients with plasmodium falciparum infection]. | | 1982 | 6764284 |
| malaria at humaita county, amazonas state, brazil. xvi - gametocytes and lymphocytes studied in patients with plasmodium falciparum. | | 1982 | 6764285 |
| [resistance of plasmodium falciparum in the brazilian amazonas to the combination of sulfadoxine and pyrimethamine]. | | 1982 | 6764287 |
| [in vivo resistance of plasmodium falciparum to the combination of sulfamethoxazole and trimethoprim in the brazilian amazonas]. | | 1982 | 6764288 |
| malaria at humaita county, amazonas state, brazil. some aspects. | | 1982 | 6764289 |
| [in vivo resistance of plasmodium falciparum to the combination of sulfadoxine and pyrimethamine, at riii level, in amazonas, brazil]. | | 1982 | 6764290 |
| prevalence of chloroquine-resistant falciparum malaria in the brazilian amazon. | the prevalence of chloroquine-resistant falciparum malaria was determined for humans living at 28 different sites in the brazilian amazon. blood samples obtained from each patient were defibrinated, placed in vials containing 0.5% glucose and or chloroquine and incubated for 24 hours at 39-40 degrees c without agitation. in vitro sensitivity of the parasite to four different concentrations of chloroquine was determined for each sample. after 24 hours of incubation, trophozoites of plasmodium fal ... | 1981 | 7020444 |
| [malaria in the municipality of humaitá, state of amazonas. iii - clinical and developmental aspects]. | | 1981 | 7046012 |
| [malaria in the municipality of humaitá, state of amazonas. v - serological aspects of plasmodium falciparum and plasmodium berghei antigens]. | | 1981 | 7046014 |
| [malaria in the municipality of humaitá, state of amazonas. ix - incidence of blood group systems in inhabitants of the region and in patients]. | | 1981 | 7046015 |
| [malaria in the municipality of humaitá, state of amazonas. xi - parasitological aspects]. | | 1981 | 7046016 |
| the malarial impact on the nutritional status of amazonian adult subjects. | the anthropometric (body weight, height, upper arm circumference, triceps and subescapular skinfolds; quetelet index and arm muscle circumference) and blood biochemistry (proteins and lipids) parameters were evaluated in 93 males and 27 females, 17-72 years old voluntaries living in the malarial endemic area of humaita city (southwest amazon). according to their malarial history they were assembled in four different groups: g1--controls without malarial history (n:30); g2--controls with malarial ... | 1995 | 7569636 |
| antibody response against plasmodium falciparum exoantigens and somatic antigens: a longitudinal survey in a rural community in rondônia, western brazilian amazon. | three clinical and sero-epidemiological cross-sectional surveys involving 50 subjects were performed at six-month intervals in urupá, a rural community characterized by unstable malaria transmission, situated in rondônia state, western brazilian amazon. between the surveys, a clinically and parasitologically passive surveillance was established in this community and 48 malaria attacks (28 due to plasmodium falciparum and 20 due to plasmodium vivax) were recorded in this cohort of 50 subjects. se ... | 1994 | 7942353 |
| anaemia, iron deficiency and malaria in a rural community in brazilian amazon. | to assess the incidence of anaemia, iron deficiency and malaria in a malaria-endemic community. | 1994 | 8055848 |
| prevalence and levels of igg and igm antibodies against plasmodium falciparum and p. vivax in blood donors from rondônia, brazilian amazon. | antibodies of igg and igm isotypes reacting with plasmodium falciparum and p. vivax thicksmear antigens were searched for by the indirect fluorescent antibody test (ifat) in a random sample of 230 blood donors at the transfusion centre of porto velho (hemeron), rondônia state, western brazilian amazon. a high prevalence of igg seropositivity (32% against p. falciparum, 24% against p. vivax and 37% against either p. falciparum or p. vivax antigens) was detected among them, despite the fact that c ... | 1993 | 8107588 |
| a new antimalarial quassinoid from simaba guianensis. | two antimalarial quassinoids, gutolactone [1] and simalikalactone d [2], have been characterized by bioactivity-directed fractionation from the bark of simaba guianensis collected near manaus, brazil. compound 2 was previously isolated from simaba multiflora and quassia africana and shown to be an active antimalarial in vitro. this is the first occurrence of 1. the structure of the novel quassinoid was established by spectral methods including 2d nmr spectroscopy. | 1993 | 8289064 |
| tumor necrosis factor alpha interferon gamma and macrophage stimulating factor in relation to the severity of plasmodium falciparum malaria in the brazilian amazon. | we compared the tumor necrosis factor (tnf-alpha), interferon gamma (ifn-gamma) and granulocyte-macrophage colony stimulating factor (gm-csf) serum levels in 87 patients with malaria from the brazilian amazon. they included asymptomatic infected individuals and symptomatic patients with mild disease or severe malaria with or without cerebral involvement. as controls we examined individuals living in endemic areas without past history of malaria. the tnf-alpha serum levels were increased in patie ... | 1995 | 8650740 |
| a seroprevalence and descriptive epidemiological study of malaria among indian tribes of the amazon basin of brazil. | data on the seroprevalences of plasmodium falciparum, p. vivax, and p. malariae in four isolated indian tribes of the amazon basin in brazil, as determined by ifat, were re-analysed. age-, sex- and tribe-specific geometric mean antibody titres and externally standardized prevalence ratios were calculated for each parasite species. correlation coefficients and prevalence odds ratios were also calculated for multiple infections with different combinations of the three plasmodium species. titres of ... | 1996 | 8762403 |
| malaria diagnosis: standardization of a polymerase chain reaction for the detection of plasmodium falciparum parasites in individuals with low-grade parasitemia. | in brazil, no study has been done concerning the detection of malaria parasites by polymerase chain reaction (pcr) related to the diagnosis of plasmodium falciparum malaria. in the present report we describe a highly sensitive methodology for malaria diagnosis using a nested pcr method based on amplification of the p126 p. falciparum gene detected by simple ethidium bromide staining. the p. falciparum palo alto strain (culture samples) was serially diluted in blood from an uninfected donor to a ... | 1996 | 8875568 |
| humoral immune response to the 72 kda heat shock protein from plasmodium falciparum in populations at hypoendemic areas of malaria in western brazilian amazon. | the heat-shock protein pf72/hsp70-1 from the human malaria parasite plasmodium falciparum has been suggested as a potential candidate antigen for a multivalent vaccine. we have investigated the prevalence and levels of igg antibodies to the recombinant protein pfr44, derived from pf72/hsp70-1, in individuals from different age groups living in candeias do jamari, an amazonian town characterized by unstable and hypoendemic malaria transmission. blood were collected from a household-based random s ... | 1997 | 9107363 |
| in vivo and in vitro plasmodium falciparum resistance to chloroquine, amodiaquine and quinine in the brazilian amazon. | in order to study the chemoresistance of plasmodium falciparum to commonly used antimalarial drugs in brazil the authors have studied ten patients with falciparum malaria, acquired in the brazilian amazon region. patients were submitted to in vivo study of drug sensitivity, after chemotherapy with either 4-aminoquinolines (chloroquine or amodiaquine) or quinine. adequate drug absorption was confirmed by standard urine excretion tests for antimalarials. eight patients could be followed up to 28 d ... | 1997 | 9394520 |
| allelic diversity at the merozoite surface protein-1 (msp-1) locus in natural plasmodium falciparum populations: a brief overview. | the merozoite surface protein-1 (msp-1) locus of plasmodium falciparum codes for a major asexual blood-stage antigen currently proposed as a major malaria vaccine candidate. the protein, however, shows extensive polymorphism, which may compromise its use in sub-unit vaccines. here we compare the patterns of allelic diversity at the msp-1 locus in wild isolates from three epidemiologically distinct malaria-endemic areas: the hypoendemic southwestern brazilian amazon (n = 54), the mesoendemic sout ... | 1998 | 9830530 |
| cellular responses to plasmodium falciparum major surface antigens and their relationship to human activities associated with malaria transmission. | in brazil, two types of activities have led to the worsening of malarial transmission in the amazon region: prospecting/mining and agricultural settlements. in the present study, we analyze the cellular response of 52 of these individuals (14 gold-miners and 38 farmers) living within the same endemic area. two plasmodium falciparum major surface antigens (recombinant proteins) were used for cellular proliferative assays: circumsporozoite protein and merozoite surface protein-1. the frequency of ... | 1999 | 10348247 |
| antimalarial drug susceptibility testing of plasmodium falciparum in brazil using a radioisotope method. | from march 1996 to august 1997, a study was carried out in a malaria endemic area of the brazilian amazon region. in vivo sensitivity evaluation to antimalarial drugs was performed in 129 patients. blood samples (0.5 ml) were drawn from each patient and cryopreserved to proceed to in vitro studies. in vitro sensitivity evaluation performed using a radioisotope method was carried out with the cryopreserved samples from september to december 1997. thirty-one samples were tested for chloroquine, me ... | 1999 | 10585659 |
| malaria control in an agro-industrial settlement of rondônia (western amazon region, brazil). | a malaria control pilot project was developed in the urupá agro-industrial farm that is situated in the state of rondônia (western amazon region, brazil). around 180 inhabitants had been surveyed for the past five years. the control measures were based on (1) training a community agent to perform on the spot microscopical diagnosis of malaria and to treat the uncomplicated cases of malaria; (2) limiting the use of insecticides to a short period before the high transmission season. this resulted ... | 2000 | 10733729 |
| plasmodium falciparum: a comparative analysis of the genetic diversity in malaria-mesoendemic areas of brazil and madagascar. | for a better definition of the polymorphic features of plasmodium falciparum parasite populations, the polymerase chain reaction (pcr) typing technique was used to investigate the genetic diversity and complexity of parasites harbored by acute p. falciparum carriers from three yet unexplored malaria-mesoendemic areas with different transmission levels: two localities in northwestern brazil (ariquemes and porto velho) and a village in madagascar (ankazobe). a total of 89 dna samples were analyzed ... | 2000 | 10952272 |
| temporal and spatial distribution of the variants of merozoite surface protein-1 (msp-1) in plasmodium falciparum populations in brazil. | the polymorphic, merozoite surface protein-1 (msp-1) of plasmodium falciparum, an antigen of the parasite's asexual blood-stages, is a major malaria-vaccine candidate. nucleotide sequences of each variable domain or block of this antigen may be grouped into one of three possible allelic types (k1, mad20 and ro33), and 24 major types of the msp-1 gene may be defined, as unique combinations of allelic types in these variable blocks. isolates collected from the brazilian amazon, over a period of 14 ... | 2000 | 11144809 |
| analysis of the pfcrt k76t mutation in plasmodium falciparum isolates from the amazon region of brazil. | | 2001 | 11372042 |
| measles vaccine coverage and immune response in children of caiabi and metuktire indian tribes living in malarial endemic area: parque indígena do xingu, central brazil. | measles vaccination efficiency was evaluated in children from two indian tribes - caiabi and metuktire - living in the amazon region, in the parque indigena do xingu (pix). the population sample, selected at random, made up 37 caiabi and 28 metuktire children, aged from 20-75 months (40%). for operational and epidemiological reasons, measles vaccine is given from 6 months of age. the average age of children when they received the vaccine was 11.5 months for the first dose and 20 months for the s ... | 2001 | 11444333 |
| sequence diversity and linkage disequilibrium within the merozoite surface protein-1 (msp-1) locus of plasmodium falciparum: a longitudinal study in brazil. | the merozoite surface protein-1 (msp-1) is a major vaccine candidate for the asexual blood stage of malaria. we examined both the extent of sequence diversity in block 17, the 3' end of msp-1 gene coding for a 19-kda polypeptide (msp-1(19)) putatively involved in red blood cell binding, and the patterns of linkage disequilibrium between polymorphic sites throughout the msp-1 locus. the parasite population sample consisted of plasmodium falciparum isolates collected between 1985 and 1998 in rondĵ ... | 2001 | 11456319 |
| in vitro evaluation of quinidine sensitivity in brazilian plasmodium falciparum isolates: comparative analysis to quinine and chloroquine. | falciparum malaria represents a serious and an increasing world public health problem due to the acquired parasite's resistance to the most available drugs. in some endemic areas, quinidine, a diastereoisomer of the antimalarial quinine, has been employed for replacing the latter. in order to evaluate the use of quinidine as an alternative to the increasing loss of quinine effectiveness in brazilian p. falciparum strains, as has been observed in the amazon area, we have assayed quinidine, quinin ... | 2001 | 11558003 |
| differential antibody recognition of four allelic variants of the merozoite surface protein-2 (msp-2) of plasmodium falciparum. | the merozoite surface protein-2 (msp-2) is a major vaccine candidate for the asexual blood stage of plasmodium falciparum. msp-2 is essentially dimorphic, and allelic families are named after the representative isolates fc27 and ic1. the polymorphic central region contains immunodominant repeats, which vary in number, length, and sequence within and between allelic families. we have examined the antibody recognition of repeat regions from both msp-2 allelic families expressed as recombinant fusi ... | 2001 | 11596920 |
| [malaria control in brazil: 1965 to 2001]. | this paper reviews malaria control initiatives in brazil, from the malaria eradication campaign (campanha de erradicação da malária), which was launched in 1965 and was based on spraying dichlorodiphenyltrichloroethane (ddt) and on administering antimalarial drugs, to the implementation, in 2000, of the program for intensification of malaria control in the nine-state legal amazon region of brazil (plano de intensificação das ações de controle da malária na amazônia legal), which was implemented ... | 2002 | 12049032 |
| association of the igg response to plasmodium falciparum merozoite protein (c-terminal 19 kd) with clinical immunity to malaria in the brazilian amazon region. | the antibody response to the c-terminal 19-kd fragment of plasmodium falciparum merozoite surface protein-1 (pfmsp1-19) was investigated in groups of subjects living in areas of brazil with different levels of malaria transmission. the prevalence and the levels of igg to pfmsp1-19 increased with the time of exposure and were positively correlated with the absence of clinical symptoms in parasitemic patients. the frequency of positive response and the mean level of igg were higher in areas where ... | 2002 | 12201577 |
| plasmodium falciparum: analysis of transcribed var gene sequences in natural isolates from the brazilian amazon region. | parasite isolates from brazilian western amazonian patients suffering from uncomplicated falciparum malaria were matured in vitro and their var gene transcripts were analysed by rt-pcr and sequencing. additionally, the cytoadherence patterns of these isolates were determined by panning techniques using transfected cho cell lines expressing different surface receptors. all of the isolates tested showed between 4 and 13 different var gene transcripts per isolate. several of these transcripts were ... | 2002 | 12427465 |
| malaria during pregnancy in a reference centre from the brazilian amazon: unexpected increase in the frequency of plasmodium falciparum infections. | malaria remains globally the most important parasitic disease of man. data on its deleterious effects during pregnancy have been extensively documented in hyperendemic, holoendemic, and mesoendemic areas from africa and asia where plasmodium falciparum is responsible for almost all infections. however, knowledge about malaria during pregnancy in areas where transmission is unstable and p. vivax is the most prevalent species, such as the brazilian amazon, is scarce. here, we report a preliminary ... | 2004 | 15057341 |
| pfcrt polymorphism and the spread of chloroquine resistance in plasmodium falciparum populations across the amazon basin. | the widespread occurrence of drug-resistant malaria parasites in south america presents a formidable obstacle to disease control in this region. to characterize parasite populations and the chloroquine-resistance profile of plasmodium falciparum in the amazon basin, we analyzed a dna segment of the pfcrt gene, spanning codons 72-76, and genotyped 15 microsatellite (ms) markers in 98 isolates from 6 areas of brazil, peru, and colombia where malaria is endemic. the k76t mutation, which is critical ... | 2004 | 15216481 |
| invasion profiles of brazilian field isolates of plasmodium falciparum: phenotypic and genotypic analyses. | the invasion of red blood cells (rbcs) by plasmodium falciparum is dependent on multiple molecular interactions between erythrocyte receptors and parasite ligands. invasion studies using culture-adapted parasite strains have indicated significant receptor heterogeneity. it is not known whether this heterogeneity reflects the parasite invasion arsenal in the field. we have studied the invasion phenotypes of 14 distinct field isolates from the legal amazon areas of brazil by using erythrocyte inva ... | 2004 | 15385490 |
| genetic structure of plasmodium falciparum populations in the brazilian amazon region. | after a major increase in incidence between the 1970s and the 1990s, the brazilian amazon region now accounts for the most cases of plasmodium falciparum malaria in the americas. polymorphism of 10 microsatellite loci in the p. falciparum genome was studied in 196 isolates obtained from 5 populations in the region. there was significant multilocus linkage disequilibrium, particularly within populations with lower proportions of mixed-genotype infections. however, most multilocus genotypes in dif ... | 2004 | 15478058 |
| genetic polymorphism of the serine rich antigen n-terminal region in plasmodium falciparum field isolates from brazil. | in this work we investigated the frequency of polymorphism in exon ii of the gene encoding most of the amino-terminal region of the serine rich antigen (sera) in plasmodium falciparum field samples. the blood samples were collected from p. falciparum infected individuals in three areas of the brazilian amazon. two fragments have been characterized by polymerase chain reaction: one of 175 bp corresponding to the repeat region with 5 octamer units and one other of 199 bp related to the 6 repeat oc ... | 2005 | 15867963 |
| [seroprevalence of hepatitis b and malaria infection in lábrea, brazilian western amazon: estimates of coinfection rates]. | the amazon region is known for the high occurrence of hepatitis b virus (hbv) infection, and accounts for more than 98% of malaria cases in brazil. despite the controversy, it has been proposed that when associated they may lead to important effects in the natural history of both infections. this study estimates the prevalence of coinfection within general population of an endemic region of hbv and malaria in the brazilian amazon. the prevalence of hbsag was 3.3% (95% ci 2.1%-5.1%,) and total an ... | 2005 | 15895171 |
| asymptomatic carriers of plasmodium spp. as infection source for malaria vector mosquitoes in the brazilian amazon. | we have described the existence of asymptomatic carriers of plasmodium vivax and plasmodium falciparum infections in native amazon populations. most of them had low parasitemias, detected only by polymerase chain reaction (pcr). because they remain symptomless and untreated, we wanted to determine whether they could infect anopheles darlingi root, the main brazilian vector, and act as disease reservoirs. fifteen adult asymptomatic patients (pcr positive only) were selected, and experimental infe ... | 2005 | 16363160 |
| successful treatment of plasmodium falciparum malaria with a six-dose regimen of artemether-lumefantrine versus quinine-doxycycline in the western amazon region of brazil. | this randomized, open-label study compared a three-day, six-dose regimen of artemether-lumefantrine with a five-day, 19-dose regimen of quinine-doxycycline for the treatment of plasmodium falciparum malaria in the western amazon region of brazil. all patients remained hospitalized during their treatment and the study assessments were scheduled daily from the start of treatment (day 0) through day 6. by day 3, the percentage of infected patients was 0% in the artemether-lumefantrine group and 48. ... | 2006 | 16407341 |
| [coinfection between hepatitis b virus and malaria: clinical, serologic and immunologic aspects]. | the amazon region is known for a high prevalence of hepatitis b infection, and accounts for more than 90% of malaria cases in brazil. it has been suggested that the occurrence of coinfections may be important, and may influence the natural history of both diseases. this study evaluated 545 patients with acute malaria, in coari, western brazilian amazon. 333 (61.1%) presented plasmodium vivax malaria, 193 (35.4%) plasmodium falciparum and 19 (3.5%) mixed infections. the hbsag prevalence was 4.2% ... | 2006 | 16501762 |
| extense variant gene family repertoire overlap in western amazon plasmodium falciparum isolates. | in order to find a molecular basis for observations of relatively fast developing immunity to malarial infections in the western amazon region, the partial var, stevor and rif gene repertoires of nine different plasmodium falciparum isolates collected in 1985 and 2000-2004 were evaluated. in contrast to previous results from south east asia, the variant gene repertoire in brazilian isolates is rather small and redundant. while the individual var repertoire sizes of brazilian strains did not diff ... | 2006 | 16938359 |
| molecular screening of plasmodium sp. asymptomatic carriers among transfusion centers from brazilian amazon region. | the transmission of malaria in brazil is heterogeneous throughout endemic areas and the presence of asymptomatic plasmodium sp. carriers (apcs) in the brazilian amazon has already been demonstrated. malaria screening in blood banks is based on the selection of donors in respect to possible risks associated with travel or residence, clinical evidence and/or inaccurate diagnostic methods thereby increasing the probability of transfusion-transmitted infection. we evaluated the frequency of apcs in ... | 2007 | 17384812 |
| [changes in the epidemiological pattern of malaria in a rural area of the middle rio negro, brazilian amazon: a retrospective analysis]. | a retrospective study on reported malaria cases in the municipality (county) of barcelos, amazonas state, brazil, was performed from 1992 to 2004, emphasizing the high endemic area along the padauiri, an affluent of the rio negro. 16,795 cases were reported, 10,318 (61.4%) from the rural area and 6,477 (38.6%) from the urban area. mean annual parasite index for the period was 136.7 per 1,000 inhabitants in the urban area and 613.6 per 1,000 in the rural area of barcelos and 708.9 per 1,000 in th ... | 2007 | 17435877 |
| [evaluation of the optimal-it and ict p.f./p.v. rapid dipstick tests for diagnosing malaria within primary healthcare in the municipality of manaus, amazonas]. | malaria is routinely diagnosed using the thick blood smear test. however, this technique requires the training of microscopists and may be time-consuming. a concordance study was conducted on two dipstick tests (optimal-it and ict p.f./p.v.) and the thick blood smear test, within primary healthcare in manaus. | 2007 | 17486264 |
| urban malaria in the brazilian western amazon region i: high prevalence of asymptomatic carriers in an urban riverside district is associated with a high level of clinical malaria. | cross sectional studies on malaria prevalence was performed in 2001, 2002, and 2004 in vila candelária, an urban riverside area of porto velho, rondônia, in the brazilian western amazon, followed by longitudinal surveys on malaria incidence. vila candelária is a working class district, provided with electricity, water supply, and basic sanitation. previous preliminary surveys indicated high malaria incidence in this community. at the end of year 2000 regular diagnostic and treatment measures for ... | 2007 | 17568930 |
| microsatellite characterization of plasmodium falciparum from symptomatic and non-symptomatic infections from the western amazon reveals the existence of non-symptomatic infection-associated genotypes. | in western amazon areas with perennial malaria transmission, long term residents frequently develop partial immunity to malarial infection caused either by plasmodium falciparum or p. vivax, resulting in a considerable number of non-symptomatically infected individuals. for yet unknown reasons, these individuals sporadically develop symptomatic malaria. in order to identify if determined parasite genotypes, defined by a combination of eleven microsatellite markers, were associated to different o ... | 2007 | 17568933 |
| prevalence and level of antibodies to the circumsporozoite protein of human malaria parasites in five states of the amazon region of brazil. | the aim of this study was to determine the prevalence of malaria infection and antibodies against the repetitive epitopes of the circumsporozoite (cs) proteins of plasmodium falciparum, p. malariae, p. vivax vk210, p. vivax vk247, and p. vivax-like in individuals living in the states of rondônia, pará, mato grosso, amazonas, and acre. active malaria transmission was occurring in all studied sites, except in acre. p. falciparum was the predominant species in pará and rondônia and p. vivax in mato ... | 2007 | 17568943 |
| naturally acquired antibodies to merozoite surface protein (msp)-1(19) and cumulative exposure to plasmodium falciparum and plasmodium vivax in remote populations of the amazon basin of brazil. | to infer recent patterns of malaria transmission, we measured naturally acquired igg antibodies to the conserved 19-kda c-terminal region of the merozoite surface protein (msp)-1 of both plasmodium vivax (pvmsp-1(19)) and plasmodium falciparum (pfmsp-1(19)) in remote malaria-exposed populations of the amazon basin. community-based cross-sectional surveys were carried out between 2002 and 2003 in subjects of all age groups living along the margins of the unini and jaú rivers, northwestern brazil. ... | 2007 | 18209933 |
| similar cytokine responses and degrees of anemia in patients with plasmodium falciparum and plasmodium vivax infections in the brazilian amazon region. | the mechanisms of malarial anemia induction are poorly understood, but cytokines and autoantibodies are considered to play important roles. this work aimed at evaluating the degree of anemia and the plasmatic profile of the cytokines tumor necrosis factor alpha (tnf-alpha), gamma interferon (ifn-gamma), interleukin-12 (il-12), migration inhibitory factor (mif), and il-10 and the monocyte chemotactic protein-1 (mcp-1) chemokine, as well as evaluating the presence of antibodies directed to compone ... | 2008 | 18256207 |
| plasmodium falciparum from pará state (brazil) shows satisfactory in vitro response to artemisinin derivatives and absence of the s769n mutation in the serca-type pfatpase6. | to evaluate the in vitro efficacy of artesunate (atn) and artemether (ath) against plasmodium falciparum isolates from the brazilian amazon state of pará and to search for mutations and/or altered copy numbers in the putative resistance-associated pfcrt, pfmdr1 and pfatpase6 genes. | 2008 | 18304266 |
| in vitro antiplasmodial activity of extract and constituents from esenbeckia febrifuga, a plant traditionally used to treat malaria in the brazilian amazon. | esenbeckia febrifuga (rutaceae) is a plant traditionally used to treat malaria in the brazilian amazon region. ethanol extract of stems displayed a good antiplasmodial activity against plasmodium falciparum strains w-2 (ic(50) 15.5+/-0.71 microg/ml) and 3 d7 (ic(50) 21.0+/-1.4 microg/ml). two coumarins (bergaptene 1 and isopimpinellin 2), five alkaloids (flindersiamine 3, kokusaginine 4, skimmiamine 5, gamma-fagarine 6 and 1-hydroxy-3-methoxy-n-methylacridone, 7), besides a limonoid (rutaevine 8 ... | 2008 | 18337075 |
| mixed plasmodium falciparum infections and its clinical implications in four areas of the brazilian amazon region. | the aim of this study was to assess the prevalence pattern of mixed-plasmodium falciparum malaria infections in brazil by molecular diagnosis and to address its clinically important features. dna was extracted from 115 thick blood film p. falciparum human blood positive samples using the phenol-chloroform method, followed by a semi-nested pcr protocol with species-specific primers. seventy-three percent of p. falciparum single infections and 26.95% of mixed infections were found. amongst mixed i ... | 2008 | 18468567 |
| malaria vectors in areas of plasmodium falciparum epidemic transmission in the amazon region, brazil. | the main vectors of malaria in brazil are anopheles darlingi, an. aquasalis, and some species of the an. albitarsis complex, whereas others have questionable importance with regard to the disease transmission. to identify these vectors in the state of pará, brazil, in a high-prevalence p. falciparum area, 565 anophelines were captured and identified while the seasonal variation and daily biting activity were determined. of the seven anopheline species (an. strodei, an. albitarsis s.l., an. rondo ... | 2008 | 18541762 |
| ampelozyziphus amazonicus ducke (rhamnaceae), a medicinal plant used to prevent malaria in the amazon region, hampers the development of plasmodium berghei sporozoites. | most medicinal plants used against malaria in endemic areas aim to treat the acute symptoms of the disease such as high temperature fevers with periodicity and chills. in some endemic areas of the brazilian amazon region one medicinal plant seems to be an exception: ampelozyziphus amazonicus, locally named "indian beer" or "saracura-mira", used to prevent the disease when taken daily as a cold suspension of powdered dried roots. in previous work we found no activity of the plant extracts against ... | 2008 | 18599059 |
| evaluation of the genetic polymorphism of plasmodium falciparum p126 protein (sera or serp) and its influence on naturally acquired specific antibody responses in malaria-infected individuals living in the brazilian amazon. | the plasmodium falciparum p126 protein is an asexual blood-stage malaria vaccine candidate antigen. antibodies against p126 are able to inhibit parasite growth in vitro, and a major parasite-inhibitory epitope has been recently mapped to its 47 kda n-terminal extremity (octamer repeat domain--or domain). the or domain basically consists of six octamer units, but variation in the sequence and number of repeat units may appear in different alleles. the aim of the present study was to investigate t ... | 2008 | 18667071 |
| [molecular diagnosing of malaria in a tertiary care center in the brazilian amazon region]. | the routine test for diagnosing malaria is still the thick blood smear, despite its known decreased sensitivity and specificity in situations of low parasite density and mixed infections. the polymerase chain reaction is increasingly being used for molecular detection and identification of plasmodium species, due to its higher sensitivity and specificity. nested pcr was performed on whole-blood samples from 344 patients with acute febrile syndrome who came to a tertiary healthcare center in mana ... | 2008 | 18853011 |
| genetic polymorphisms in tlr4, cr1 and duffy genes are not associated with malaria resistance in patients from baixo amazonas region, brazil. | the main purpose of this research was to analyze the relation of the genetic polymorphisms frequently expressed by antigen-presenting cells, erythrocytes and malaria susceptibility/resistance with the human malaria infection cases. the sample used consisted of 23 plasmodium vivax (pv)- and p. falciparum (pf)-infected patients, and 21 healthy individuals as a control group, from the baixo amazonas population in pará, brazil. the asp299gly polymorphisms in the toll-like receptor 4 (tlr4), and gly4 ... | 2008 | 19048480 |
| comparative hematologic analysis of uncomplicated malaria in uniquely different regions of unstable transmission in brazil and colombia. | information on malaria-associated anemia in adult patients is scarce in south american populations. from 2004 to 2006, malaria patients 18 to 45 years of age were recruited in a descriptive cross-sectional study from two different towns: manaus, in the brazilian amazon (120 patients) where plasmodium falciparum incidence is lower ( approximately 20%), and in tumaco on the colombian pacific coast (126 patients) where p. falciparum incidence is higher ( approximately 90%). relationships between he ... | 2009 | 19141853 |
| development of a polymerase chain reaction (pcr) method based on amplification of mitochondrial dna to detect plasmodium falciparum and plasmodium vivax. | in this study we standardized a new technical approach in which the target mitochondrial dna sequence (mtdna) is amplified using a simple but sensitive pcr method as a tool to detect plasmodium falciparum and plasmodium vivax. specific primers were designed to hybridize with cytochrome c oxidase genes of p. falciparum (cox iii) and p. vivax (cox i). amplification products were obtained for all positive samples, presenting homology only for species-specific mtdna. sensitivity and specificity were ... | 2009 | 19426660 |
| malaria is associated with poor school performance in an endemic area of the brazilian amazon. | approximately 40% of the world's population is at risk for malaria. in highly endemic tropical areas, malaria is a major cause of morbidity and mortality during infancy. there is a complex interrelationship between malaria, malnutrition and intestinal helminths, and this may impair cognitive development in children. the aim of this study was to determine the relationship between malaria and school performance in children living in an endemic area where plasmodium vivax is the species responsible ... | 2009 | 19835584 |
| the south american plasmodium falciparum var gene repertoire is limited, highly shared and possibly lacks several antigenic types. | the plasmodium falciparum var gene family encodes large variant antigens, which are important virulence factors, and also targets of the humoral host response. the frequently observed mild outcomes of falciparum malaria in many places of the amazon area prompted us to ask whether a globally restricted variant (var) gene repertoire is present in currently circulating and older isolates of this area. by exhaustive analysis of var gene tags from 89 isolates and clones taken during many years from a ... | 2010 | 20079817 |
| malaria in brazil: an overview. | malaria is still a major public health problem in brazil, with approximately 306,000 registered cases in 2009, but it is estimated that in the early 1940s, around six million cases of malaria occurred each year. as a result of the fight against the disease, the number of malaria cases decreased over the years and the smallest numbers of cases to-date were recorded in the 1960s. from the mid-1960s onwards, brazil underwent a rapid and disorganized settlement process in the amazon and this migrato ... | 2010 | 20433744 |
| towards a precise test for malaria diagnosis in the brazilian amazon: comparison among field microscopy, a rapid diagnostic test, nested pcr, and a computational expert system based on artificial neural networks. | accurate malaria diagnosis is mandatory for the treatment and management of severe cases. moreover, individuals with asymptomatic malaria are not usually screened by health care facilities, which further complicates disease control efforts. the present study compared the performances of a malaria rapid diagnosis test (rdt), the thick blood smear method and nested pcr for the diagnosis of symptomatic malaria in the brazilian amazon. in addition, an innovative computational approach was tested for ... | 2010 | 20459613 |
| [malaria among women aged 10 to 49 years, according to sivep-malaria, manaus, state of amazonas, 2003-2006]. | the sivep-malaria epidemiological surveillance information system has been in use for notification of malaria cases diagnosed in brazil since 2003. this study analyzed malaria cases notified among women aged 10 to 49 years between 2003 and 2006, according to the presence or absence of pregnancy. | 2010 | 20563501 |
| frequency of abo blood group system polymorphisms in plasmodium falciparum malaria patients and blood donors from the brazilian amazon region. | we investigated the abo genotypes and heterogeneity of the o alleles in plasmodium falciparum-infected and non-infected individuals from the brazilian amazon region. sample collection took place from may 2003 to august 2005, from p. falciparum malaria patients from four endemic regions of the brazilian amazon. the control group consisted of donors from four blood banks in the same areas. dna was extracted using the easy-dna(tm) extraction kit. abo genotyping was performed using pcr/rflp. there w ... | 2010 | 20677133 |
| severe rhabdomyolysis caused by plasmodium vivax malaria in the brazilian amazon. | severe rhabdomyolysis (creatine phosphokinase = 29,400 u/l) developed in a 16-year-old boy from manaus, brazil, after he started treatment with chloroquine for infection with plasmodium vivax. treatment led to myoglobinuria and acute renal failure. after hemodialysis, the patient improved and a muscle biopsy specimen showed no myophosphorylase or deaminase deficiency. this case of rhabdomyolysis associated with p. vivax infection showed no comorbidities. the pathogenesis is still unclear. althou ... | 2010 | 20682866 |
| cost effectiveness of optimal® rapid diagnostic test for malaria in remote areas of the amazon region, brazil. | in areas with limited structure in place for microscopy diagnosis, rapid diagnostic tests (rdt) have been demonstrated to be effective. | 2010 | 20937094 |
| population genetics of gypb and association study between gypb*s/s polymorphism and susceptibility to p. falciparum infection in the brazilian amazon. | merozoites of plasmodium falciparum invade through several pathways using different rbc receptors. field isolates appear to use a greater variability of these receptors than laboratory isolates. brazilian field isolates were shown to mostly utilize glycophorin a-independent invasion pathways via glycophorin b (gpb) and/or other receptors. the brazilian population exhibits extensive polymorphism in blood group antigens, however, no studies have been done to relate the prevalence of the antigens t ... | 2011 | 21283638 |
| anti-malarial, anti-trypanosomal, and anti-leishmanial activities of jacaranone isolated from pentacalia desiderabilis (vell.) cuatrec. (asteraceae). | leishmaniasis, chagas disease, and malaria affect the poorest population around the world, with an elevated mortality and morbidity. in addition, the therapeutic alternatives are usually toxic or ineffective drugs especially those against the trypanosomatids. in the course of selection of new anti-protozoal compounds from brazilian flora, the ch(2)c(l2) phase from meoh extract obtained from the leaves of pentacalia desiderabilis (vell.) cuatrec. (asteraceae) showed in vitro anti-leishmanial, ant ... | 2011 | 21614544 |
| gestational malaria associated to plasmodium vivax and plasmodium falciparum placental mixed-infection followed by foetal loss: a case report from an unstable transmission area in brazil. | gestational malaria is a multi-factorial syndrome leading to poor outcomes for both the mother and foetus. although an unusual increasing in the number of hospitalizations caused by plasmodium vivax has been reported in brazil, mortality is rarely observed. this is a report of a gestational malaria case that occurred in the city of manaus (amazonas state, brazil) and resulted in foetal loss. the patient presented placental mixed-infection by plasmodium vivax and plasmodium falciparum after diagn ... | 2011 | 21708032 |
| chemoresistance of plasmodium falciparum and plasmodium vivax parasites in brazil: consequences on disease morbidity and control. | in brazil, malaria still remains a clinically important febrile syndrome for local populations and travelers, occurring mostly in the amazon basin. this review aims to report the main efforts employed to control this disease since the 1940s and the emergence of plasmodium falciparum and plasmodium vivax chemoresistance to chloroquine and sulphadoxine-pyrimethamine among other drugs. additionally, in vivo, in vitro and molecular studies as well as malaria chemoresistance consequences on disease m ... | 2011 | 21881770 |
| Pharmaceutical services for endemic situations in the Brazilian Amazon: organization of services and prescribing practices for Plasmodium vivax and Plasmodium falciparum non-complicated malaria in high-risk municipalities. | ABSTRACT: | 2011 | 22050832 |
| malaria control in an amazon municipality. | this study aimed to evaluate the organization of malaria control actions in the indigenous population of the municipality of são gabriel da cachoeira, amazonas, am, brazil, from 2003 to 2007. this is an ecological study to evaluate the impact of control measures. statistical analysis of the indicators revealed that the number of cases showed an increasing trend, with the highest numbers occurring in the rural areas. the same trend was observed for the annual parasite index (api), however the hig ... | 2011 | 22249662 |
| plasmodium vivax landscape in brazil: scenario and challenges. | brazil is the largest country of latin america, with a considerable portion of its territoritory within the malaria-endemic amazon region in the north. furthermore, a considerable portion of its territory is located within the amazon region in the north. as a result, brazil has reported half of the total malaria cases in the americas in the last four decades. recent progress in malaria control has been accompanied by an increasing proportion of plasmodium vivax, underscoring a need for a better ... | 2016 | 27708190 |
| integrated vector management targeting anopheles darlingi populations decreases malaria incidence in an unstable transmission area, in the rural brazilian amazon. | studies on vector behaviour should be conducted in order to evaluate the effectiveness of vector control measures on malaria protection in endemic areas of latin america, where p. vivax predominates. this work aims to investigate the fauna of anopheline mosquitoes and verify the impact of integrated vector management in two colonization projects in the careiro municipality, western brazilian amazon. | 2012 | 23088224 |
| natural plasmodium infection in monkeys in the state of rondônia (brazilian western amazon). | simian malaria is still an open question concerning the species of plasmodium parasites and species of new world monkeys susceptible to the parasites. in addition, the lingering question as to whether these animals are reservoirs for human malaria might become important especially in a scenario of eradication of the disease. to aid in the answers to these questions, monkeys were surveyed for malaria parasite natural infection in the amazonian state of rondônia, brazil, a state with intense envir ... | 2013 | 23731624 |
| detection of plasmodium falciparum and plasmodium vivax subclinical infection in non-endemic region: implications for blood transfusion and malaria epidemiology. | in brazil, malaria is endemic in the amazon river basin and non-endemic in the extra-amazon region, which includes areas of são paulo state. in this state, a number of autochthonous cases of malaria occur annually, and the prevalence of subclinical infection is unknown. asymptomatic infections may remain undetected, maintaining transmission of the pathogen, including by blood transfusion. in these report it has been described subclinical plasmodium infection in blood donors from a blood transfus ... | 2014 | 24906577 |
| natural antibody response to plasmodium falciparum merozoite antigens msp5, msp9 and eba175 is associated to clinical protection in the brazilian amazon. | antibodies have an essential role in the acquired immune response against blood stage p. falciparum infection. although several antigens have been identified as important antibody targets, it is still elusive which antigens have to be recognized for clinical protection. herein, we analyzed antibodies from plasmas from symptomatic or asymptomatic individuals living in the same geographic area in the western amazon, measuring their recognition of multiple merozoite antigens. | 2013 | 24373342 |
| historical shifts in brazilian p. falciparum population structure and drug resistance alleles. | previous work suggests that brazilian plasmodium falciparum has limited genetic diversity and a history of bottlenecks, multiple reintroductions due to human migration, and clonal expansions. we hypothesized that brazilian p. falciparum would exhibit clonal structure. we examined isolates collected across two decades from amapá, rondônia, and pará state (n = 190). by examining more microsatellites markers on more chromosomes than previous studies, we hoped to define the extent of low diversity, ... | 2013 | 23554964 |
| cross-reactive anti-pfclag9 antibodies in the sera of asymptomatic parasite carriers of plasmodium vivax. | the pfclag9 has been extensively studied because their immunogenicity. thereby, the gene product is important for therapeutics interventions and a potential vaccine candidate. antibodies against synthetic peptides corresponding to selected sequences of the plasmodium falciparum antigen pfclag9 were found in sera of falciparum malaria patients from rondônia, in the brazilian amazon. much higher antibody titres were found in semi-immune and immune asymptomatic parasite carriers than in subjects su ... | 0 | 23440122 |
| effect of artesunate-mefloquine fixed-dose combination in malaria transmission in amazon basin communities. | studies in south-east asia have suggested that early diagnosis and treatment with artesunate (as) and mefloquine (mq) combination therapy may reduce the transmission of plasmodium falciparum malaria and the progression of mq resistance. | 2012 | 22905900 |
| pfatp6 molecular profile of plasmodium falciparum isolates in the western brazilian amazon. | anti-malarial drug resistance has emerged as one of the biggest challenges confronting the worldwide effort to control malaria. the appearance of chloroquine and multi-drug resistance had devastating effects on therapeutic efficacy of former first-line agents. artemisinin has proven to be an excellent therapeutic alternative to fill the void in chemotherapeutic options left by resistance mechanisms. at the time of introduction, no resistance to artemisinins had been recorded, and artemisinins de ... | 2012 | 22487143 |
| challenges for malaria elimination in brazil. | brazil currently contributes 42 % of all malaria cases reported in the latin america and the caribbean, a region where major progress towards malaria elimination has been achieved in recent years. in 2014, malaria burden in brazil (143,910 microscopically confirmed cases and 41 malaria-related deaths) has reached its lowest levels in 35 years, plasmodium falciparum is highly focal, and the geographic boundary of transmission has considerably shrunk. transmission in brazil remains entrenched in t ... | 2016 | 27206924 |