| plasmodium falciparum: sensitivity to chloroquine in vivo in three ecological zones in ghana. | 4690 children aged 6-15 years in 5 urban and 4 rural communities in 3 ecological zones in ghana were screened from june 1988 to december 1990 to provide suitable candidates for the world health organization standard in vivo test for susceptibility of plasmodium falciparum to chloroquine. 1880 (40.1%) had parasitaemia, mostly (83.7-98.6%) due to p. falciparum infection. of the 626 in vivo tests performed, 570 (91.1%) showed sensitivity to chloroquine and 56 (8.9%) responses were classified as res ... | 1992 | 1412638 |
| patterns of malaria morbidity and mortality in children in northern ghana. | a malaria prevalence survey was carried out in young children in northern ghana between october 1990 and september 1991, in an area with continuous mortality and morbidity surveillance. there was marked seasonal variation in malaria deaths, reported fevers, parasite rates and mean parasite densities, with parasite rates reaching 85-94% in the wet season. the monthly numbers of malaria deaths were highly correlated with rainfall in the previous 2 months (r = 0.90, p < 0.001). parasite rates were ... | 1994 | 7570811 |
| impact of spatial distribution of permethrin-impregnated bed nets on child mortality in rural northern ghana. | effects of the distribution in space of permethrin (insecticide)-impregnated bed nets (iibns) on child mortality were studied in a randomized controlled trial of iibns in a an area highly endemic for plasmodium falciparum malaria in rural northern ghana. eight hundred sixty-two deaths occurred among children 6-59 months of age during 16,841 child-years-at-risk. mortality increased with the distance from health facilities but not with proximity to identifiable anopheline breeding sites (reservoir ... | 1998 | 9684633 |
| the impact of insecticide-treated bednets on malaria and anaemia in pregnancy in kassena-nankana district, ghana: a randomized controlled trial. | the impact of insecticide-treated bednet use on malaria and anaemia in pregnancy was assessed, as a supplementary study, in a major who/tdr-supported bednet trial in northern ghana between july 1994 and april 1995. the study area was divided into 96 clusters of compounds, with 48 clusters being randomly allocated to intervention. all pregnant women were included in the study but the focus was on primigravidae and secundigravidae. 1961 pregnant women were recruited into the study--1033 (52.7%) in ... | 2001 | 11555433 |
| incidence of symptomatic and asymptomatic plasmodium falciparum infection following curative therapy in adult residents of northern ghana. | adult residents of holoendemic malaria regions in africa have a naturally acquired immunity (nai) to malaria that renders them more resistant to new infections, limits parasitemia, and reduces the frequency and severity of illness. given such attributes, it is not clear how one might evaluate drug or vaccine efficacy in adults without serious confounding. to determine symptomatic and asymptomatic malaria attack rates in adults of northern ghana, 197 men and women underwent curative therapy for a ... | 2001 | 11561704 |
| molecular epidemiology of plasmodium falciparum infections among asymptomatic inhabitants of a holoendemic malarious area in northern ghana. | age dependence of malaria infection was assessed in an age-stratified cluster sample of 308 individuals from kassena-nankana district of northern ghana during june and july 2000. overall prevalence of plasmodium falciparum by microscopy was 70%, with the maximum among 5-9 year olds. parasite density was highest (geometric mean 1922/microl blood) in 1-2 year olds. eighty-two per cent of samples were positive by polymerase chain reaction (pcr), and restriction fragment length polymorphism typing o ... | 2002 | 12000651 |
| efficacy of chloroquine in the treatment of uncomplicated, plasmodium falciparum malaria in northern ghana. | chloroquine (cq) resistance in plasmodium falciparum contributes to growing malaria-attributable morbidity and mortality in sub-saharan africa. however, the extent and degree of such resistance vary considerably between endemic areas. data on cq resistance in northern ghana are almost entirely lacking. the therapeutic efficacy of cq in uncomplicated malaria was therefore assessed, in a standard, 14-day protocol, in 225 children aged <5 years in tamale, in the northern region of ghana. early trea ... | 2002 | 12061971 |
| does radical cure of asymptomatic plasmodium falciparum place adults in endemic areas at increased risk of recurrent symptomatic malaria? | a cohort of 197 adults in kassena-nankana district (northern ghana) was radically cured of malaria parasites to study subsequent incidence of malaria infection. during the following 20 weeks of the malaria transmission season, 49% experienced clinical attacks associated with plasmodium falciparum parasitaemia. in a group of 202 adults identically followed-up 1 year later without being treated, only 38% experienced such episodes (log-rank test for equality of survivor functions, p=0.035). clinica ... | 2002 | 12100443 |
| seasonal malaria attack rates in infants and young children in northern ghana. | the incidence density of infection and disease caused by plasmodium falciparum in children aged six to 24 months living in the holoendemic sahel of northern ghana was measured during the wet and dry seasons of 1996 and 1997. at the beginning of each season, a cohort composed of 259 and 277 randomly selected children received supervised curative therapy with quinine and fansidar and primaquine for those with normal glucose-6-phosphate dehydrogenase activity. the 20 weeks of post-therapy follow-up ... | 2002 | 12139221 |
| mortality in a seven-and-a-half-year follow-up of a trial of insecticide-treated mosquito nets in ghana. | a 17% efficacy in preventing all-cause mortality in children aged 6-59 months was previously reported from a cluster-randomized controlled trial of insecticide-treated mosquito nets (itns) carried out in the kassena-nankana district of northern ghana from july 1993-june 1995. a follow-up until the end of 2000 found no indication in any age group of increased mortality in the itn group after the end of the randomized intervention. these results should further encourage the use of itns as a malari ... | 2002 | 12625130 |
| renal dysfunction in children with uncomplicated, plasmodium falciparum malaria in tamale, ghana. | in a study performed in tamale, in the northern region of ghana, cystatin c, a new and sensitive indicator of the glomerular filtration rate (gfr), was used to estimate the frequency of renal dysfunction in 78 children with uncomplicated, plasmodium falciparum malaria. the excretion in urine of albumin, immunoglobulin g and alpha1-microglobulin was also investigated. plasma concentrations of cystatin c were found to be elevated in 17% of the children, indicating subclinical impairment of renal f ... | 2003 | 12831520 |
| detection of malaria sporozoites by standard elisa and vectesttm dipstick assay in field-collected anopheline mosquitoes from a malaria endemic site in ghana. | we compared the vectesttm dipstick assay for detection of plasmodium sporozoites in anopheles vectors of malaria with standard circumsporozoite (cs) microplate elisa for detection of plasmodium falciparum circumsporozoite protein (pfcsp) in anopheles mosquitoes. mosquitoes were collected from a malaria endemic site (kassena nankana district) in northern ghana. of 2620 randomly sampled mosquitoes tested, the standard cs-elisa gave a sporozoite rate of 10.8% compared with 11.2% by vectesttm, which ... | 2003 | 14629768 |
| malaria transmission dynamics at a site in northern ghana proposed for testing malaria vaccines. | we studied the malaria transmission dynamics in kassena nankana district (knd), a site in northern ghana proposed for testing malaria vaccines. intensive mosquito sampling for 1 year using human landing catches in three micro-ecological sites (irrigated, lowland and rocky highland) yielded 18 228 mosquitoes. anopheles gambiae s.l. and anopheles funestus constituted 94.3% of the total collection with 76.8% captured from the irrigated communities. other species collected but in relatively few numb ... | 2004 | 14728621 |
| short communication: prevalence of mutations associated with resistance to atovaquone and to the antifolate effect of proguanil in plasmodium falciparum isolates from northern ghana. | atovaquone-proguanil has recently been introduced for the treatment and prophylaxis of malaria. however, resistance of plasmodium falciparum is increasingly reported. we assessed p. falciparum polymorphisms associated with resistance to atovaquone (cytochrome b, cytb) and to cycloguanil, the active compound of proguanil (dihydrofolate reductase, dhfr) in 100 isolates from northern ghana. none of these exhibited cytb codon 268 mutations. moreover, no dhfr v16a, s108t or i164l mutations linked wit ... | 2004 | 14996365 |
| allelic dimorphism of the erythrocyte binding antigen-175 (eba-175) gene of plasmodium falciparum and severe malaria: significant association of the c-segment with fatal outcome in ghanaian children. | the erythrocyte binding antigen-175 (eba-175) on plasmodium falciparum merozoites mediates sialic acid dependent binding to glycophorin a on host erythrocytes and, therefore, plays a crucial role in cell invasion. dimorphic allele segments have been found in its encoding gene with a 342 bp segment present in fcr-3 strains (f-segment) and a 423 bp segment in camp strains (c-segment). possible associations of the dimorphism with severe malaria have been analysed in a case-control study in northern ... | 2004 | 15140262 |
| limited influence of haptoglobin genotypes on severe malaria in ghanaian children. | haptoglobin (hp) polymorphisms in sub-saharan africa have been associated with an increased risk of severe malaria. however, available data are inconclusive. we examined the role of hp polymorphisms in susceptibility to plasmodium falciparum infection and to severe malaria in northern ghana. three groups each of 290 age and sex-matched children with severe malaria, children with asymptomatic p. falciparum infection and aparasitaemic healthy controls were studied. hp typing was based on pcr. in a ... | 2005 | 15960705 |
| chloroquine blood concentrations and molecular markers of chloroquine-resistant plasmodium falciparum in febrile children in northern ghana. | plasmodium falciparum malaria is a predominant reason for health care utilization among children in sub-saharan africa. despite the spread of resistance, chloroquine (cq) is the most commonly used antimalarial. little is known about the pattern of cq use and resistance to the drug prior to attendance at a health care facility, and its impact on clinical presentation in children attending health care facilities in endemic regions. in a cross-sectional study among 840 febrile children presenting a ... | 2003 | 16117966 |
| plasmodium falciparum dhfr but not dhps mutations associated with sulphadoxine-pyrimethamine treatment failure and gametocyte carriage in northern ghana. | both use of sulphadoxine-pyrimethamine (sp) and sp-resistance of plasmodium falciparum are increasing in sub-saharan africa. mutations in the p. falciparum dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes can predict treatment failure of sp, however, the degree of this relationship varies regionally. in northern ghana, pre-treatment dhfr/dhps genotypes were examined in 126 children and associations with pcr-corrected sp treatment outcome and gametocyte carriage were analy ... | 2005 | 16135198 |
| an immigration-death model to estimate the duration of malaria infection when detectability of the parasite is imperfect. | immigration-death models are proposed to analyse the infection dynamics in longitudinal studies of panels of heavily parasitized human hosts where parasites have been typed at regular intervals by pcr. immigration refers to the acquisition of a new parasitic genotype, occurring at rate lambda, and death refers to the clearance of a parasitic genotype (with rate mu). the models assume that corresponding to each observed process which is the detection or failure to detect a parasitic genotype, is ... | 2005 | 16143990 |
| concurrence of plasmodium falciparum dhfr and crt mutations in northern ghana. | both chloroquine (cq) and sulfadoxine-pyrimethamine (sp) are failing drugs in much of sub-saharan africa. previous findings suggest an association between resistance to cq and to sp in vivo, in vitro, and on the molecular level. | 2005 | 16164748 |
| age and seasonal variation in the transition rates and detectability of plasmodium falciparum malaria. | the effect of acquired immunity on the duration of plasmodium falciparum infections is unclear, although this is an important term in models of malaria transmission. it is problematical to determine the duration of infections because of the difficulty of distinguishing persisting infections from new ones, and because parasite densities are often transiently below the limit of detection. we recently developed a dynamic model for infection incidence, clearance and detection of multiple genotype p. ... | 2006 | 16393349 |
| comparison of pcr-rflp and genescan-based genotyping for analyzing infection dynamics of plasmodium falciparum. | parameters describing the infection dynamics of plasmodium falciparum are important determinants of the potential impact of interventions and are potential outcome measurements for malaria intervention trials. low parasite densities, periodic sequestration of parasites, and the presence of multiple concurrent infections make it essential to use molecular techniques to estimate the force of infection and duration of infections in endemic areas. we now compare two approaches for tracking individua ... | 2006 | 16760501 |
| large-scale surveillance of plasmodium falciparum crt(k76t) in northern ghana. | surveillance of plasmodium falciparum crt(k76t) [pfcrt(k76t)], a resistance marker of chloroquine and, limitedly, amodiaquine, in >4,000 children in northern ghana revealed a prevalence of 79%. pfcrt(k76t) was heterogeneously distributed and associated with chloroquine use, low parasitemia, and the dry season. widespread chloroquine resistance challenges the regional life span of amodiaquine as a partner drug in artemisinin combination therapy. | 2007 | 17562799 |
| hla-drb1*04 allele is associated with severe malaria in northern ghana. | several associations between specific hla alleles and susceptibility or resistance to plasmodium falciparum malaria have been previously reported, but no associations have been confirmed in multiple populations. we studied associations between hla-a, -b, and drb1 alleles and severe malaria in northern ghana. we analyzed hla-drb1*04 in 4,032 subjects from a severe malaria case-control study, 790 severe malaria cases, 1,611 mild malaria controls, and 1631 asymptomatic controls. the presence of hla ... | 2008 | 18256425 |
| multiplicity of plasmodium falciparum infection following intermittent preventive treatment in infants. | intermittent preventive treatment in infants with sulphadoxine-pyrimethamine (ipti-sp) reduces malaria morbidity by 20% to 33%. potentially, however, this intervention may compromise the acquisition of immunity, including the tolerance towards multiple infections with plasmodium falciparum. | 2010 | 20796302 |
| antibody levels to multiple malaria vaccine candidate antigens in relation to clinical malaria episodes in children in the kasena-nankana district of northern ghana. | abstract: | 2011 | 21529376 |
| seroprevalence of antibodies against plasmodium falciparum sporozoite antigens as predictive disease transmission markers in an area of ghana with seasonal malaria transmission. | as an increasing number of malaria-endemic countries approach the disease elimination phase, sustenance of control efforts and effective monitoring are necessary to ensure success. mathematical models that estimate anti-parasite antibody seroconversion rates are gaining relevance as more sensitive transmission intensity estimation tools. models however estimate yearly seroconversion and seroreversion rates and usually predict long term changes in transmission, occurring years before the time of ... | 2016 | 27875594 |
| carriage of sub-microscopic sexual and asexual plasmodium falciparum stages in the dry season at navrongo, ghana. | we investigated the prevalence of sub-microscopic plasmodium falciparum infections and gametocyte carriage in asymptomatic individuals in navrongo in northern ghana, an area of seasonal malaria transmission. | 2016 | 28579627 |