| efficacy of sulfadoxine-pyrimethamine and mefloquine for the treatment of uncomplicated plasmodium falciparum malaria in the amazon basin of peru. | in vivo antimalarial drug efficacy studies of uncomplicated plasmodium falciparum malaria at an isolated site in the amazon basin of peru bordering brazil and colombia showed >50% rii/riii resistance to sulfadoxine-pyrimethamine but no evidence of resistance to mefloquine. | 2004 | 15330070 |
| limited diversity of anopheles darlingi in the peruvian amazon region of iquitos. | anopheles darlingi is the most important malaria vector in the amazon basin of south america, and is capable of transmitting both plasmodium falciparum and p. vivax. to understand the genetic structure of this vector in the amazonian region of peru, a simple polymerase chain reaction (pcr)-based test to identify this species of mosquito was used. a random amplified polymorphic dna-pcr was used to study genetic variation at the micro-geographic level in nine geographically separate populations of ... | 2006 | 16896125 |
| decline in sulfadoxine-pyrimethamine-resistant alleles after change in drug policy in the amazon region of peru. | the frequency of alleles with triple mutations conferring sulfadoxine-pyrimethamine (sp) resistance in the peruvian amazon basin has declined (16.9% for dhfr and 0% for dhps compared to 47% for both alleles in 1997) 5 years after sp was replaced as the first-line treatment for plasmodium falciparum malaria. microsatellite analysis showed that the dhfr and dhps alleles are of common origin. | 2008 | 18025120 |
| [cost-effectiveness ratio of using rapid tests for malaria diagnosis in the peruvian amazon]. | to determine the cost-effectiveness ratios of three options for diagnosing malaria at the local health provider in 50 communities near the peruvian amazon. | 2009 | 19695126 |
| plasmodium falciparum and plasmodium vivax infections in the peruvian amazon: propagation of complex, multiple allele-type infections without super-infection. | outcrossing potential between plasmodium parasites is defined by the population-level diversity (pld) and complexity of infection (coi). there have been few studies of pld and coi in low transmission regions. since the 1995-1998 peruvian amazon epidemic, there has been sustained transmission with < 0.5 p. falciparum and < 1.6 p. vivax infections/person/year. using weekly active case detection, we described pld by heterozygosity (h(e)) and coi using p. falciparum pfmsp1-b2 and p. vivax pvmsp3alph ... | 2009 | 19996422 |
| mefloquine pharmacokinetics and mefloquine-artesunate effectiveness in peruvian patients with uncomplicated plasmodium falciparum malaria. | artemisinin-based combination therapy (act) is recommended as a means of prolonging the effectiveness of first-line malaria treatment regimens. different brands of mefloquine (mq) have been reported to be non-bioequivalent; this could result in sub-therapeutic levels of mefloquine with decreased efficacy. in 2002, mefloquine-artesunate (mq-as) combination therapy was adopted as the first-line treatment for uncomplicated plasmodium falciparum malaria in the amazon region of peru. although mq resi ... | 2009 | 19358697 |
| dynamics of malaria drug resistance patterns in the amazon basin region following changes in peruvian national treatment policy for uncomplicated malaria. | monitoring changes in the frequencies of drug-resistant and -sensitive genotypes can facilitate in vivo clinical trials to assess the efficacy of drugs before complete failure occurs. peru changed its national treatment policy for uncomplicated malaria to artesunate (art)-plus-mefloquine (mq) combination therapy in the amazon basin in 2001. we genotyped isolates collected in 1999 and isolates collected in 2006 to 2007 for mutations in the plasmodium falciparum dihydrofolate reductase (pfdhfr) an ... | 2009 | 19258269 |
| genetic diversity of vaccine candidate antigens in plasmodium falciparum isolates from the amazon basin of peru. | several of the intended plasmodium falciparum vaccine candidate antigens are highly polymorphic and could render a vaccine ineffective if their antigenic sites were not represented in the vaccine. in this study, characterization of genetic variability was performed in major b and t-cell epitopes within vaccine candidate antigens in isolates of p. falciparum from peru. | 2008 | 18505558 |
| unusual pattern of plasmodium falciparum drug resistance in the northwestern peruvian amazon region. | high levels of plasmodium falciparum resistance to both chloroquine (cq) and sulfadoxine-pyrimethamine (sp) have been documented throughout the amazon basin of south america. because of reports about the persistent efficacy of both of these drugs in the northwestern peruvian amazon region, we carried out an evaluation of the therapeutic efficacy of chloroquine (25 mg/kg) and sp (25 mg/kg of the sulfadoxine component) for the treatment of uncomplicated p. falciparum infections at two sites: ullpa ... | 2007 | 17426158 |
| clustered local transmission and asymptomatic plasmodium falciparum and plasmodium vivax malaria infections in a recently emerged, hypoendemic peruvian amazon community. | there is a low incidence of malaria in iquitos, peru, suburbs detected by passive case-detection. this low incidence might be attributable to infections clustered in some households/regions and/or undetected asymptomatic infections. | 2005 | 15975146 |
| modifying national malaria treatment policies in peru. | between 1998 and 2001, the peruvian ministry of health made sweeping changes in its malaria treatment policies in response to a resurgence of disease and the spread and intensification of antimalarial drug resistance. on the pacific coast, the first-line treatment for uncomplicated plasmodium falciparum malaria was changed to combination therapy with sulfadoxine-pyrimethamine plus artesunate; in the amazon region, mefloquine-artesunate combination therapy was introduced. with these changes in tr ... | 2004 | 15683069 |
| endemic malaria in the peruvian amazon region of iquitos. | a cross-sectional study was conducted in the peruvian amazon to test the hypothesis that a reservoir of asymptomatic malaria parasitemic patients would form the basis for continuing malaria endemicity in the region. active surveillance yielded a plasmodium spp. slide-positive prevalence of 4.2% (43 of 1,023) and a polymerase chain reaction (pcr)-positive prevalence of 17.6% (144 of 819). plasmodium vivax prevalence was 2.9% and 14.2% while plasmodium falciparum prevalence was 1.3% and 2.6% by mi ... | 2003 | 12932096 |
| practical aspects of in vivo antimalarial drug efficacy testing in the americas. | the world health organization (who) has developed guidelines for in vivo antimalarial drug efficacy testing for plasmodium falciparum and plasmodium vivax in areas with low-to-moderate transmission, such as the americas. these guidelines are used widely by ministries of health and national malaria control programs to assess the efficacy of their first-line and second-line drugs for the treatment of malaria and to provide the information necessary to update national malaria treatment policies. fo ... | 2003 | 12875285 |
| efficacy of mefloquine and a mefloquine-artesunate combination therapy for the treatment of uncomplicated plasmodium falciparum malaria in the amazon basin of peru. | in the amazon basin of peru, more than 50% of patients with uncomplicated plasmodium falciparum malaria fail to respond to treatment with chloroquine or sulfadoxine-pyrimethamine. to assist the national malaria control program in identifying an alternative first-line therapy for this region, we conducted a trial of the safety and efficacy of mefloquine (mq) compared with mefloquine-artesunate (mq-as) combination therapy. patients with uncomplicated p. falciparum infections between the ages of 5 ... | 2003 | 12812355 |
| lack of prediction of mefloquine and mefloquine-artesunate treatment outcome by mutations in the plasmodium falciparum multidrug resistance 1 (pfmdr1) gene for p. falciparum malaria in peru. | we assessed whether mutations in the plasmodium falciparum multidrug-resistance gene 1 (pfmdr1) (c1034s, d1042n, and y1246d) would predict treatment outcome during a 28-day in vivo treatment trial in the peruvian amazon. mefloquine (mq) was compared with mefloquine-artesunate (mq-as) in a randomized, multi-clinic protocol for the first time in the americas. of 115 patients enrolled in the in vivo arm, 97 patients were eligible for molecular analysis. all 97 patients remained parasite-free during ... | 2003 | 12557835 |
| the epidemiology of malaria in an epidemic area of the peruvian amazon. | a longitudinal study of malariometric indicators and their association with potential risk factors was conducted during august 1997-july 1998 at padre cocha, a village of 1,400 residents in the peruvian amazon. the incidence of plasmodium falciparum infections during the study year was 166/1,000 persons; that of p. vivax was 826/1,000 persons. the mean duration of symptoms prior to diagnosis was 2 days; presenting geometric mean parasite densities were 3,976 parasites/microl for p. falciparum in ... | 2000 | 10813480 |
| prevalence of antibody to plasmodium falciparum antigens among feral saimiri monkeys in the amazon basin region of peru. | | 1997 | 9416571 |
| quantification of plasmodium falciparum malaria from complex infections in the peruvian amazon using quantitative pcr of the merozoite surface protein 1, block 2 (pfmsp1-b2): in vitro dynamics reveal density-dependent interactions. | the majority of plasmodium falciparum field isolates are defined as complex infections because they contain multiple genetically distinct clones. studying interactions between clones in complex infections in vivo and in vitro could elucidate important phenomena in malaria infection, transmission and treatment. using quantitative pcr (qpcr) of the p. falciparum merozoite surface protein 1, block 2 (pfmsp1-b2), we provide a sensitive and efficient genotyping method. this is important for epidemiol ... | 2012 | 22339946 |
| rapid diagnostic tests for malaria diagnosis in the peruvian amazon: impact of pfhrp2 gene deletions and cross-reactions. | in the peruvian amazon, plasmodium falciparum and plasmodium vivax malaria are endemic in rural areas, where microscopy is not available. malaria rapid diagnostic tests (rdts) provide quick and accurate diagnosis. however, pfhrp2 gene deletions may limit the use of histidine-rich protein-2 (pfhrp2) detecting rdts. further, cross-reactions of p. falciparum with p. vivax-specific test lines and vice versa may impair diagnostic specificity. | 2012 | 22952633 |
| modelling the potential of focal screening and treatment as elimination strategy for plasmodium falciparum malaria in the peruvian amazon region. | focal screening and treatment (fsat) of malaria infections has recently been introduced in peru to overcome the inherent limitations of passive case detection (pcd) and further decrease the malaria burden. here, we used a relatively straightforward mathematical model to assess the potential of fsat as elimination strategy for plasmodium falciparum malaria in the peruvian amazon region. | 2015 | 25948081 |
| plasmodium falciparum malaria in the low transmission peruvian amazon is associated with immunologic memory. | the development of clinical immunity to plasmodium falciparum malaria is thought to require years of parasite exposure, a delay often attributed to difficulties in developing protective antibody levels. in this study we evaluated several p. falciparum vaccine-candidate antigens, including apical membrane antigen-1 (ama-1), circumsporozoite protein (csp), erythrocyte binding antigen (eba-175), and the 19kd region of merozoite surface protein-1 (msp1(19)). after observing a more robust antibody re ... | 2012 | 22252876 |
| sexual recombination is a signature of a persisting malaria epidemic in peru. | the aim of this study was to consider the impact that multi-clone, complex infections have on a parasite population structure in a low transmission setting. in general, complexity of infection (minimum number of clones within an infection) and the overall population level diversity is expected to be minimal in low transmission settings. additionally, the parasite population structure is predicted to be clonal, rather than sexual due to infrequent parasite inoculation and lack of recombination be ... | 2011 | 22039962 |
| efficacy and effectiveness of mefloquine and artesunate combination therapy for uncomplicated plasmodium falciparum malaria in the peruvian amazon. | we evaluated the efficacy and effectiveness of mefloquine (mq) plus artesunate (as) to treat patients with uncomplicated malaria in the peruvian amazon basin in april 2005-march 2006. patients ≥ 1 year of age with fever (axillary temperature ≥ 37.5°c) or history of fever and plasmodium falciparum monoinfection were included. patients received antimalarial treatment with mq (12.5 mg/kg/day for two days) and as (4.0 mg/kg/day for three days) either by directly observed therapy or without directly ... | 2011 | 21896825 |
| antibodies directed against merozoite surface protein-6 are induced by natural exposure to plasmodium falciparum in a low transmission environment. | malaria caused by plasmodium falciparum is a major cause of global infant mortality, and there is currently no licensed vaccine that provides protection against infection or disease. several p. falciparum vaccine targets have undergone early testing, but many more candidates remain with little data to support their development. plasmodium falciparum merozoite surface protein 6 (pfmsp6) is a candidate of particular interest because it is a member of the pfmsp3 multi-gene family, raising the possi ... | 2011 | 21585398 |
| plasmodium falciparum genetic diversity maintained and amplified over five years of a low transmission endemic in the peruvian amazon. | p. falciparum entered into the peruvian amazon in 1994, sparking an epidemic between 1995 and 1998. since 2000, there has been sustained, low p. falciparum transmission. the malaria immunology and genetics in the amazon project has longitudinally followed members of the community of zungarococha (n=1,945, 4 villages) with active household and health center-based visits each year since 2003. we examined parasite population structure and traced the parasite genetic diversity temporally and spatial ... | 2010 | 21109587 |
| genome scanning of amazonian plasmodium falciparum shows subtelomeric instability and clindamycin-resistant parasites. | here, we fully characterize the genomes of 14 plasmodium falciparum patient isolates taken recently from the iquitos region using genome scanning, a microarray-based technique that delineates the majority of single-base changes, indels, and copy number variants distinguishing the coding regions of two clones. we show that the parasite population in the peruvian amazon bears a limited number of genotypes and low recombination frequencies. despite the essentially clonal nature of some isolates, we ... | 2010 | 20829224 |
| limited variation in vaccine candidate plasmodium falciparum merozoite surface protein-6 over multiple transmission seasons. | plasmodium falciparum merozoite surface protein-6 (pfmsp6) is a component of the complex proteinacious coat that surrounds p. falciparum merozoites. this location, and the presence of anti-pfmsp6 antibodies in p. falciparum-exposed individuals, makes pfmsp6 a potential blood stage vaccine target. however, genetic diversity has proven to be a major hurdle for vaccines targeting other blood stage p. falciparum antigens, and few endemic field studies assessing pfmsp6 gene diversity have been conduc ... | 2010 | 20497564 |
| the plasmodium falciparum merozoite surface protein-1 19 kd antibody response in the peruvian amazon predominantly targets the non-allele specific, shared sites of this antigen. | plasmodium falciparum re-emerged in iquitos, peru in 1994 and is now hypoendemic (< 0.5 infections/person/year). purportedly non-immune individuals with discrete (non-overlapping) p. falciparum infections can be followed using this population dynamic. previous work demonstrated a strong association between this population's antibody response to pfmsp1-19kd and protection against febrile illness and parasitaemia. therefore, some selection for pfmsp1-19kd allelic diversity would be expected if the ... | 2010 | 20047674 |
| prevalence and risk of plasmodium falciparum and p. vivax malaria among pregnant women living in the hypoendemic communities of the peruvian amazon. | the amazon region of iquitos, peru is hypoendemic for plasmodium vivax and p. falciparum. there is limited information regarding the epidemiology of malaria during pregnancy in this region. passive surveillance for clinical malaria among pregnant women was conducted in eight health posts in 2004 and 2005. community-based active surveillance was conducted to determine the incidence of malarial infection among pregnant women in the community of zungarococha in 2004 and 2005. passive surveillance d ... | 2007 | 17827359 |
| [congenital malaria in a hospital in iquitos, peru]. | to determine the frequency and clinical features of newborns with congenital malaria in the hospital de apoyo of iquitos in the peruvian amazon. | 2015 | 26338383 |
| malaria in brazil, colombia, peru and venezuela: current challenges in malaria control and elimination. | in spite of significant progress towards malaria control and elimination achieved in south america in the 2000s, this mosquito-transmitted tropical disease remains an important public health concern in the region. most malaria cases in south america come from amazon rain forest areas in northern countries, where more than half of malaria is caused by plasmodium vivax, while plasmodium falciparum malaria incidence has decreased in recent years. this review discusses current malaria data, policies ... | 2017 | 28676055 |
| micro-heterogeneity of malaria transmission in the peruvian amazon: a baseline assessment underlying a population-based cohort study. | understanding the dynamics of malaria transmission in diverse endemic settings is key for designing and implementing locally adapted and sustainable control and elimination strategies. a parasitological and epidemiological survey was conducted in september-october 2012, as a baseline underlying a 3-year population-based longitudinal cohort study. the aim was to characterize malaria transmission patterns in two contrasting ecological rural sites in the peruvian amazon, lupuna (lup), a riverine en ... | 2017 | 28778210 |