| modern immunological approaches to assess malaria transmission and immunity and to diagnose plasmodial infection. | the present paper reviews our recent data concerning the use of immunological methods employing monoclonal antibodies and synthetic peptides to study malaria transmission and immunity and to diagnose plasmodial infection. as concerns malaria transmission, we studied the main vectors of human malaria and the plasmodial species transmitted in endemic areas of rondônia state, brazil. the natural infection of anopheline was evaluated by immunoradiometric assay (irma) using monoclonal antibodies to a ... | 1992 | 1342707 |
| human igg responses against the n-terminal region of the merozoite surface protein 1 of plasmodium vivax. | the complete primary structure of the gene encoding the merozoite surface protein 1 of plasmodium vivax (pvmsp-1) revealed the existence of interspecies conserved regions among the analogous proteins of other plasmodia species. here, three dna recombinant clones expressing 50, 200 and 500 amino acids from the n-terminal region of the pvmsp-1 protein were used on elisa and protein immunoblotting assays to look at the igg antibody responses of malaria patients from the brazilian amazon region of r ... | 1992 | 1343729 |
| low frequency of anti-plasmodium falciparum circumsporozoite repeat antibodies and rate of high malaria transmission in endemic areas of rondonia state in northwestern brazil. | in areas studied in the rondonia state of brazil, a high rate of malaria transmission and a low prevalence of anti-(nanp)4 antibodies are reported. the entomologic data are comparable to those observed in some malaria-endemic areas of africa and asia. however, the frequency of individuals with antibodies to the immunodominant epitope of the circumsporozoite protein of plasmodium falciparum recorded in the four localities of rondonia state was very low when compared with the frequencies recorded ... | 1992 | 1621896 |
| comparative susceptibility of anopheline mosquitoes to plasmodium falciparum in rondonia, brazil. | five anopheline species, anopheles deaneorum, an. albitarsis, an. triannulatus, an. oswaldoi, and an. mediopunctatus were compared to an. darlingi for susceptibility to infection by p. falciparum in costa marques, rondonia, brazil. laboratory reared f1 an. darlingi and anopheline test species were allowed to feed at the same time on falciparum malaria patients who had gametocytes in their blood, and who had not yet been treated with quinine. mosquitoes were dissected and examined for oocysts on ... | 1991 | 1858963 |
| natural malaria infections in anophelines in rondonia state, brazilian amazon. | the use of an immunoassay for the detection of plasmodium falciparum and p. vivax circumsporozoite (cs) antigens in anophelines has recently incriminated other malaria vectors besides anopheles darlingi in the brazilian amazon. in this study we analyzed 12,336 field-collected anophelines from endemic areas in rondonia for plasmodial infection. sixty-one specimens from 6 species were positive: 47 an. darlingi, 5 an. triannulatus, 4 an. albitarsis, 2 an. braziliensis, 2 an. strodei, and 1 an. oswa ... | 1990 | 2200290 |
| anti-resa (pf 155) antibodies in malaria patients from pará and rondonia, brazil. | | 1990 | 2256777 |
| study on the natural history of malaria in areas of the rondonia state-brazil and problems related to its control. | | 1988 | 3065908 |
| [biology of amazonian anopheles. xii. occurrence of anopheles species, transmission dynamics and malaria control in the urban area of ariquemes (rondônia)]. | | 1988 | 3065910 |
| [treatment of 75 patients with malaria caused by plasmodium falciparum, in porto velho (rondonia), with mefloquine]. | | 1988 | 3078220 |
| [characterization of plasmodium falciparum strains of the state of rondonia, brazil, using microtests of sensitivity to antimalarials, enzyme typing and monoclonal antibodies]. | | 1987 | 3324280 |
| malaria diagnosis: identification of an anti-40-kda polypeptide antibody response associated with active or recent infection and study of the igg/igm ratio of antibodies to blood-stage plasmodium falciparum antigens. | the need for an alternative methodology to assess disease activity in the case of malaria led us to evaluate the usefulness of studying the humoral immune response to establish the diagnosis of past or recent malaria. for this purpose, we analyzed sera from 439 individuals living in endemic areas of the amazon region (ariquemes, rondonia). individuals were classified according to the number and the date of past crises. the enzyme-linked immunosorbent assay (elisa) was performed to evaluate the i ... | 1995 | 7624288 |
| 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 |
| 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 |
| [mefloquine chemoprophylaxis of malaria in the brazilian amazonia]. | in a randomised double-blind study 122 volunteers living in an endemic malarious area in amazonian rondônia state were divided into 4 groups to study malaria suppression. . the first group received 500 mg of mefloquine every month, group ii 250 mg every two weeks, group iii a tablet of fansidar (500 mg sulphadoxine + 25mg pyrimethamine) a week and group iv placebo. acute attacks of malaria occurred in one individual in group i, 2 subject in group ii, and 6 individuals in groups iii and iv. prote ... | 1993 | 8146390 |
| longitudinal study of naturally acquired humoral immune responses against the merozoite surface protein 1 of plasmodium vivax in patients from rondonia, brazil. | a longitudinal study on the naturally acquired humoral immune responses against the merozoite surface protein 1 of plasmodium vivax (pvmsp-1) was performed in malaria patients from the brazilian amazon region of rondonia. we have previously cloned and expressed a recombinant protein, icb2-5, that encodes 508 amino acids from the n-terminal portion of the pvmsp-1 protein. this affinity-purified polypeptide was tested by an enzyme-linked immunosorbent assay in a one-year longitudinal study using s ... | 1993 | 8372960 |
| a field trial with lambda-cyhalothrin (icon) for the intradomiciliary control of malaria transmitted by anopheles darlingi root in rondonia, brazil. | a two stage field trial comparing the effects of lambdacyhalothrin (icon) and ddt when used as residual sprays on the inside surfaces of houses, was conducted in the machadinho and jaru areas of rodonia, brazil, in 1987 and 1988. in 1987 houses along two 16 km contiguous stretches of a main and a side road were sprayed and the effects on malaria vectors monitored for the succeeding year. in the second stage approximately 55,000 houses in both districts were sprayed with icon and the effect on ma ... | 1995 | 8546036 |
| prevalence of antibodies to potential malaria vaccine antigens in an endemic area of the state of rondônia (brazil). | | 1995 | 8551954 |
| antibody responses to plasmodium falciparum sporozoite-, liver- and blood-stage synthetic peptides in migrant and autochthonous populations in malaria endemic areas. | this study evaluates the differences in host immune responses to defined plasmodial antigens in four geographically different regions in which malaria is endemic. sera from 527 individuals were tested for the presence of antibodies specific for three types of plasmodial antigen: liver-stage antigen (lsa-1), blood-stage antigen (spf 70) and circumsporozoite (cs) antigen (nanp)4. the individuals taking part in the study comprised: patients with transfusional malaria due to plasmodium falciparum or ... | 1995 | 9137641 |
| evaluation of spf66 malaria vaccine efficacy in brazil. | this paper reports the efficacy results of the randomized, placebo-controlled, field trial of spf66 malaria vaccine in costa marques, rondonia, brazil. this region is characterized by the seasonal distribution of plasmodium falciparum and p. vivax infections, and the recent occupation by migrants from nonendemic areas. a total of 800 individuals of both sexes, ranging in age from seven to 60 years, were included in the study. of the initial cohort, 572 participants completed the vaccination sche ... | 1998 | 9546423 |
| a study of antibody and t cell recognition of rhoptry-associated protein-1 (rap-1) and rap-2 recombinant proteins and peptides of plasmodium falciparum in migrants and residents of the state of rondonia, brazil. | humoral and cellular responses were examined among natives and migrants in an area of the amazon region of brazil. rhoptry-associated protein-1 (rap-1) and rap-2 expressed in escherichia coli expression systems, a peptide corresponding to the epitope bound by inhibitory anti-rap-1 antibodies, and four other rap-1 and rap-2 synthetic peptides were used in these studies. plasma from the native population had greater igg reactivity to the n-terminal third of rap-1 than the migrant population; both ... | 1998 | 9715934 |
| allelic diversity at the merozoite surface protein-1 locus of plasmodium falciparum in clinical isolates from the southwestern brazilian amazon. | nucleotide sequences of each variable block in the plasmodium falciparum merozoite surface protein-1 gene (pfmsp-1) may be grouped into one of two or three possible allelic types, named after the reference isolates mad20, k1, and ro33. allelic diversity at this locus basically results from different combinations of allelic types in variable blocks. we used a polymerase chain reaction (pcr)-based strategy to type the variable blocks 2, 4a, 4b, and 10 of the pfmsp-1 gene of p. falciparum isolates ... | 1998 | 9749647 |
| 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 |
| [malaria in the region of campinas, são paulo, brazil, 1980 to 1994]. | according to epidemiological data, from 1980 to 1994, 2,781 cases of malaria were registered as follows: dir xii-campinas (49.3%), dir xv-piracicaba (41.3%) and dir xx-são joão da boa vista (9.4%). the plasmodium vivax was found in 70.6% of the patients; plasmodium falciparum in 25.4% and 4% of the patients presented a mixed infection. the epidemiological classification showed that 95% of the cases came from the states of rondônia, mato grosso and par. the masculine sex, between the age of 20 to ... | 2000 | 10881119 |
| 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 |
| mutations in plasmodium falciparum dihydrofolate reductase and dihydropteroate synthase of isolates from the amazon region of brazil. | since the late 1970s pyrimethamine-sulfadoxine (ps; fansidartm hoffman-laroche, basel) has been used as first line therapy for uncomplicated malaria in the amazon basin. unfortunately, resistance has developed over the last ten years in many regions of the amazon and ps is no longer recommended for use in brazil. in vitro resistance to pyrimethamine and cycloguanil (the active metabolite of proguanil) is caused by specific point mutations in plasmodium falciparum dihydrofolate reductase (dhfr), ... | 2000 | 10998224 |
| geographical patterns of allelic diversity in the plasmodium falciparum malaria-vaccine candidate, merozoite surface protein-2. | the polymorphic merozoite surface protein-2 (msp-2) of plasmodium falciparum is a major malaria-vaccine candidate. in the present study, pcr and hybridization with allelic-specific probes were used to type the msp-2 gene from isolates from hypo-endemic brazil (n = 113), meso-endemic vietnam (n = 208) and holo-endemic tanzania (n = 67). the typing methods were designed to group isolates into the dimorphic allelic families fc27 and ic1 and to detect possible between-family recombination events. th ... | 2001 | 11299119 |
| high prevalence of asymptomatic plasmodium vivax and plasmodium falciparum infections in native amazonian populations. | the epidemiology of malaria in 2 riverine localities in rondĵnia, brazilian western amazĵnia, was assessed by a 1-year study at portuchuelo, and a cross-sectional survey at riverine communities at rio machado (= ji-parana). plasmodium spp. infections were diagnosed by light microscopy and by polymerase chain reaction (pcr) amplification of ribosomal dna. pcr was 6-7 times more efficient than microscopy for detecting plasmodial infections. both plasmodium vivax and plasmodium falciparum infection ... | 2002 | 12224567 |
| chloroquine-resistant plasmodium falciparum from porto velho, brazil. | | 1963 | 14044739 |
| antibody response profiles induced by plasmodium falciparum glutamate-rich protein in naturally exposed individuals from a brazilian area endemic for malaria. | the goal of this study was to evaluate the antibody response induced by plasmodium falciparum glutamate-rich protein (glurp) in naturally exposed individuals from the brazilian amazon region (rondonia state). the results showed that most individuals had igg against two well-defined regions within p. falciparum glurp, the relatively conserved n-terminal nonrepeat region (r0) and the immunodominant repeat region (r2), 67% and 79%, respectively. the peptides s4 from r2 (53%) and p11 from r0 (49%) w ... | 2005 | 16354819 |
| mutations in the pfmdr1, cg2, and pfcrt genes in plasmodium falciparum samples from endemic malaria areas in rondonia and pará state, brazilian amazon region. | the objectives of this study were to investigate the molecular basis for plasmodium falciparum resistance to chloroquine in isolates from the brazilian amazon and to identify polymorphisms in the pfmdr1 gene, codons 184, 1042, and 1246, the kappa and gamma regions of the cg2 gene, and the k76t mutation of the pfcrt gene, in order to calculate the distribution of polymorphism within each target gene, comparing samples from distinct geographic areas, using allele-specific polymerase chain reaction ... | 2006 | 17096048 |
| 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 |
| 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 |
| 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 |
| 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 |
| the dynamics of transmission and spatial distribution of malaria in riverside areas of porto velho, rondônia, in the amazon region of brazil. | the study area in rondônia was the site of extensive malaria epidemic outbreaks in the 19(th) and 20(th) centuries related to environmental impacts, with large immigration flows. the present work analyzes the transmission dynamics of malaria in these areas to propose measures for avoiding epidemic outbreaks due to the construction of two hydroelectric power plants. a population based baseline demographic census and a malaria prevalence follow up were performed in two river side localities in the ... | 2010 | 20169070 |
| 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 |
| 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 |
| evaluation of allelic forms of the erythrocyte binding antigen 175 (eba-175) in plasmodium falciparum field isolates from brazilian endemic area. | abstract: background: the plasmodium falciparum erythrocyte binding antigen-175 (eba-175) is an antigen considered to be one of the leading malaria vaccine candidates. eba-175 mediates sialic acid-dependent binding to glycophorin a on the erythrocytes playing a crucial role during invasion of the p. falciparum in the host cell. dimorphic allele segments, termed c-fragment and f-fragment, have been found in high endemicity malaria areas and associations between the dimorphism and severe malaria h ... | 2011 | 21615944 |
| hepatitis b infection is associated with asymptomatic malaria in the brazilian amazon. | areas that are endemic for malaria are also highly endemic for hepatitis b virus (hbv) infection. nevertheless, it is unknown whether hbv infection modifies the clinical presentation of malaria. this study aimed to address this question. | 2011 | 21625634 |
| histidine-rich protein 2 (pfhrp2) and pfhrp3 gene deletions in plasmodium falciparum isolates from select sites in brazil and bolivia. | more than 80% of available malaria rapid diagnostic tests (rdts) are based on the detection of histidine-rich protein-2 (pfhrp2) for diagnosis of plasmodium falciparum malaria. recent studies have shown the genes that code for this protein and its paralog, histidine-rich protein-3 (pfhrp3), are absent in parasites from the peruvian amazon basin. lack of pfhrp2 protein through deletion of the pfhrp2 gene leads to false-negative rdt results for p. falciparum. we have evaluated the extent of pfhrp2 ... | 2017 | 28301474 |