scholarly journals Genetic diversity and dynamics of Plasmodium falciparum and P. vivax populations in multiply infected children with asymptomatic malaria infections in Papua New Guinea

Parasitology ◽  
2000 ◽  
Vol 121 (3) ◽  
pp. 257-272 ◽  
Author(s):  
M. C. BRUCE ◽  
M. R. GALINSKI ◽  
J. W. BARNWELL ◽  
C. A. DONNELLY ◽  
M. WALMSLEY ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Papua New Guinea ◽  
Median Duration ◽  
Antigenic Variation ◽  
Asymptomatic Malaria ◽  
Older Children ◽  
Asymptomatic Children ◽  
Episode Duration ◽  
Over Time

We describe the dynamics of co-infections of Plasmodium falciparum and P. vivax in 28 asymptomatic children by genotyping these species using the polymorphic loci Msp2 and Msp3α, respectively. The total number of Plasmodium spp. infections detected using 3 day sampling over 61 days varied between 1 and 14 (mean 6·6). The dynamics of P. falciparum and P. vivax genotypes varied greatly both within and amongst children. Periodicity in the detection of P. falciparum infections is consistent with the synchronous replication of individual genotypes. Replication synchrony of multiple co- infecting genotypes was not detected. In 4-year-old children P. falciparum genotype complexity was reduced and episodes lasted significantly longer (median duration > 60 days) when compared to children aged 5–14 years (median duration 9 days). P. vivax genotype complexity was not correlated with age but the episode duration was also longer for this species in 4-year-olds than in older children but was not as long as P. falciparum episodes. Recurrence of P. falciparum and P. vivax genotypes over weeks was observed. We interpret these major fluctuations in the density of genotypes over time as the result of the mechanism of antigenic variation thought to be present in these Plasmodium species.

scholarly journals Age- and species-specific duration of infection in asymptomatic malaria infections in Papua New Guinea

Parasitology ◽  
2000 ◽  
Vol 121 (3) ◽  
pp. 247-256 ◽  
Author(s):  
M. C. BRUCE ◽  
C. A. DONNELLY ◽  
M. PACKER ◽  
M. LAGOG ◽  
N. GIBSON ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Papua New Guinea ◽  
Age Groups ◽  
New Guinea ◽  
Asymptomatic Malaria ◽  
Older Children ◽  
Statistical Assessment ◽  
Duration Of Infection ◽  
Species Specific ◽  
Frequent Sampling

The burden and duration of asymptomatic malaria infections were measured in residents of the malaria endemic village of Gonoa, Madang Province, Papua New Guinea. Plasmodium falciparum, P. vivax and P. malariae infections in people aged 4 years to adulthood were compared. Frequent sampling at 3-day intervals for up to 61 days allowed assessment of individual episodes of infection. Statistical assessment of P. falciparum detection revealed a periodicity consistent with synchronous replication of this species over periods up to 27 days. The duration of P. falciparum episodes was longer across all age groups than that of P. vivax and P. malariae. A trend for decreasing duration with age was also noted in data from each species. This was most prominent in P. falciparum infections: median duration in 4-year-olds was > 48 days compared with a median between 9 and 15 days in older children and adults. The results are consistent with the slow acquisition of immunity to antigenically diverse Plasmodium populations and suggest a faster rate of acquisition to P. vivax and P. malariae than to P. falciparum.

Plasmodium falciparum msp1 and msp2 genetic diversity in parasites isolated from symptomatic and asymptomatic malaria subjects in the South of Benin

2022 ◽  
Author(s):  
Hamirath Odée Lagnika ◽  
Azizath Moussiliou ◽  
Romuald Agonhossou ◽  
Pierre Sovegnon ◽  
Oswald Yédjinnavênan Djihinto ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Asymptomatic Malaria ◽  
The South

scholarly journals Prevalence of Asymptomatic Malaria Infections in Seemingly Healthy Children, the Rural Dzanga Sangha Region, Central African Republic

2021 ◽  
Vol 18 (2) ◽  
pp. 814
Author(s):  
Krzysztof Korzeniewski ◽  
Emilia Bylicka-Szczepanowska ◽  
Anna Lass
Keyword(s):  
Plasmodium Falciparum ◽  
Central African Republic ◽  
Diagnostic Methods ◽  
World Health ◽  
Asymptomatic Malaria ◽  
Healthy Children ◽  
African Countries ◽  
South West ◽  
Asymptomatic Children ◽  
Health Organization

According to the World Health Organization 94% of global malaria cases and 94% of global malaria deaths have been reported from Africa. Unfortunately, it is difficult to determine the exact prevalence of disease in some African countries due to a large number of asymptomatic cases. The aim of this study was to assess the prevalence of malaria infections in seemingly healthy children living in the Central African Republic (CAR). CareStartTM Malaria HRP2 rapid diagnostic test (RDT) targeting Plasmodium falciparum was used to test a group of 500 asymptomatic children aged 1-15 years old (330 settled Bantu and 170 semi-nomadic BaAka Pygmies) inhabiting the villages in the Dzanga Sangha region (south-west CAR) in March 2020. In total, 32.4% of asymptomatic Bantu and 40.6% of asymptomatic Pygmy children had a positive result of malaria RDT. Our findings allowed us to demonstrate the high prevalence of asymptomatic malaria infections in south-west CAR. RDTs seem to be a useful tool for the detection of Plasmodium falciparum in areas with limited possibilities of using other diagnostic methods, such as light microscopy and molecular biology.

scholarly journals Gametocyte Carriage After Seasonal Malaria Chemoprevention in Plasmodium Falciparum Infected Asymptomatic Children 

2020 ◽  
Author(s):  
Abdullahi Ahmad ◽  
Aurelia Prom ◽  
John Bradley ◽  
Mamadou Ndiath ◽  
Blessed Etoketim ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Comparison Group ◽  
Conditional Logistic Regression ◽  
Asymptomatic Malaria ◽  
Gametocyte Carriage ◽  
Treatment Comparison ◽  
Asymptomatic Children ◽  
Seasonal Malaria Chemoprevention ◽  
Before And After ◽  
Chi Squared

Abstract BackgroundTreatment of clinical Plasmodium falciparum malaria with sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ) is associated with increased post-treatment gametocyte carriage. The effect of seasonal malaria chemoprevention (SMC) with SP and AQ on gametocyte carriage was assessed in asymptomatic Plasmodium falciparum infected children. MethodsThe study was carried out in eastern Gambia. Asymptomatic malaria infected children aged 24-59 months old eligible for SMC (SMC group) and children 5-8 years that did not receive SMC treatment (comparison group) were recruited. Baseline gametocyte prevalence was determined by molecular methods before SMC administration and 13 days after. Gametocyte carriage between the groups was compared using the Chi-squared test and within person using conditional logistic regression.ResultsDuring the 2017 and 2018 malaria transmission seasons, 65 and 75 children were recruited in the SMC and comparison groups respectively. Before SMC administration, gametocyte prevalence was 10.7% (7/65) in the SMC group and 13.3% (10/75) in the comparison group (p=0.64). At day 13 after SMC administration, this was 9.4%, (5/53) for the SMC group and 12.7%, (9/71) for the comparison group (p=0.57). Within the SMC group, gametocyte carriage before and after SMC administration was similar (OR 0.6, 95% CI 0.14 – 2.51) (p=0.48).ConclusionIn this study with relative low gametocyte prevalence prior to SMC treatment, no evidence was observed that SMC increased gametocyte carriage in asymptomatic malaria infected children.

scholarly journals Population structure and diversity of Plasmodium falciparum in children with asymptomatic malaria living in different ecological zones of Ghana

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Linda Eva Amoah ◽  
Zakaria Abukari ◽  
Maame Esi Dawson-Amoah ◽  
Cheikh Cambel Dieng ◽  
Eugenia Lo ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Population Structure ◽  
Coastal Zone ◽  
Primary Schools ◽  
Physical Distance ◽  
Asymptomatic Malaria ◽  
Coastal Zones ◽  
Forest Zone ◽  
Ecological Zones

Abstract Background Genetic diversity in Plasmodium falciparum populations can be used to describe the resilience and spatial distribution of the parasite in the midst of intensified intervention efforts. This study used microsatellite analysis to evaluate the genetic diversity and population dynamics of P. falciparum parasites circulating in three ecological zones of Ghana. Methods A total of 1168 afebrile children aged between 3 to 13 years were recruited from five (5) Primary schools in 3 different ecological zones (Sahel (Tamale and Kumbungu), Forest (Konongo) and Coastal (Ada and Dodowa)) of Ghana. Asymptomatic malaria parasite carriage was determined using microscopy and PCR, whilst fragment analysis of 6 microsatellite loci was used to determine the diversity and population structure of P. falciparum parasites. Results Out of the 1168 samples examined, 16.1 and 39.5% tested positive for P. falciparum by microscopy and nested PCR respectively. The genetic diversity of parasites in the 3 ecological zones was generally high, with an average heterozygosity (He) of 0.804, 0.787 and 0.608 the rainy (peak) season for the Sahel, Forest and Coastal zones respectively. The mean He for the dry (off-peak) season were 0.562, 0.693 and 0.610 for the Sahel, Forest and Coastal zones respectively. Parasites from the Forest zone were more closely related to those from the Sahel than from the Coastal zone, despite the Coastal zone being closer in physical distance to the Forest zone. The fixation indexes among study sites ranged from 0.049 to 0.112 during the rainy season and 0.112 to 0.348 during the dry season. Conclusion A large asymptomatic parasite reservoir was found in the school children during both rainy and dry seasons, especially those in the Forest and Sahel savannah zones where parasites were also found to be related compared to those from the Coastal zone. Further studies are recommended to understand why despite the roll out of several malaria interventions in Ghana, high transmission still persist.

scholarly journals Prevalence of Asymptomatic Malaria Infections in the Rural Dzanga Sangha Region, Central African Republic, 2020

2020 ◽  
Author(s):  
Krzysztof Korzeniewski ◽  
Emilia Bylicka-Szczepanowska ◽  
Anna Lass
Keyword(s):  
Plasmodium Falciparum ◽  
Central African Republic ◽  
Diagnostic Methods ◽  
World Health ◽  
Asymptomatic Malaria ◽  
Healthy Children ◽  
African Countries ◽  
South West ◽  
Asymptomatic Children ◽  
The Mean

According to the World Health Organization 94% of global malaria cases and 94% of global malaria deaths have been reported from Africa. Unfortunately, it is difficult to determine the exact prevalence of disease in some African countries due to a large number of asymptomatic cases. The aim of this study was to assess the prevalence of malaria infections in seemingly healthy children living in the Central African Republic (CAR). CareStartTM Malaria HRP2 Pf Ag RDT targeting Plasmodium falciparum was used to test a group of 500 asymptomatic children aged 1-15 years old (330 settled Bantu and 170 semi-nomadic BaAka Pygmies) inhabiting the villages in the Dzanga Sangha region (south-west CAR) in March 2020. 32.4% of asymptomatic Bantu and 40.6% of asymptomatic Pygmy children had a positive result of malaria RDT. The mean age of the study participants with RDT (+) was 8.7 in Bantu and 7.0 years in Pygmies; the mean body temperature was 36.8oC in both groups; the mean haemoglobin level was 10.6 g/dL and 10.1 g/dL, respectively. Our findings allowed us to demonstrate the high prevalence of asymptomatic malaria infections in south-west CAR. RDTs seem to be a useful tool for the detection of Plasmodium falciparum in areas with limited possibilities of using other diagnostic methods, such as light microscopy and molecular biology.

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