scholarly journals The Diversity, Multiplicity of Infection and Population Structure of P. falciparum Parasites Circulating in Asymptomatic Carriers Living in High and Low Malaria Transmission Settings of Ghana

Genes ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 434 ◽  
Author(s):  
Zakaria Abukari ◽  
Ruth Okonu ◽  
Samuel B. Nyarko ◽  
Aminata C. Lo ◽  
Cheikh C. Dieng ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Population Structure ◽  
Malaria Transmission ◽  
Parasite Prevalence ◽  
Transmission Intensity ◽  
Multiplicity Of Infection ◽  
Malaria Transmission Intensity ◽  
Ms Analysis ◽  
Greater Accra Region ◽  
Low Malaria Transmission

Background: Diversity in Plasmodium falciparum poses a major threat to malaria control and elimination interventions. This study utilized 12 polymorphic microsatellite (MS) markers and the Msp2 marker to examine diversity, multiplicity of infection (MOI) as well as the population structure of parasites circulating in two sites separated by about 92 km and with varying malaria transmission intensities within the Greater Accra Region of Ghana. Methods: The diversity and MOI of P. falciparum parasites in 160 non-symptomatic volunteers living in Obom (high malaria transmission intensity) and Asutsuare (low malaria transmission intensity) aged between 8 and 60 years was determined using Msp2 genotyping and microsatellite analysis. Results: The prevalence of asymptomatic P. falciparum carriers as well as the parasite density of infections was significantly higher in Obom than in Asutsuare. Samples from Asutsuare and Obom were 100% and 65% clonal, respectively, by Msp2 genotyping but decreased to 50% and 5%, respectively, when determined by MS analysis. The genetic composition of parasites from Obom and Asutsuare were highly distinct, with parasites from Obom being more diverse than those from Asutsuare. Conclusion: Plasmodium falciparum parasites circulating in Obom are genetically more diverse and distinct from those circulating in Asutsuare. The MOI in samples from both Obom and Asutsuare increased when assessed by MS analysis relative to MSP2 genotyping. The TA40 and TA87 loci are useful markers for estimating MOI in high and low parasite prevalence settings.

scholarly journals Molecular characterization of Plasmodium falciparum PHISTb proteins as potential targets of naturally-acquired immunity against malaria

2020 ◽  
Vol 5 ◽  
pp. 136
Author(s):  
Tony I. Isebe ◽  
Joel L. Bargul ◽  
Bonface M. Gichuki ◽  
James M. Njunge ◽  
James Tuju ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
The Gambia ◽  
Antibody Responses ◽  
Transmission Intensity ◽  
Parasite Development ◽  
Natural Immunity ◽  
Malaria Transmission Intensity ◽  
Transmission Region ◽  
Antibody Levels

Background: Plasmodium falciparum causes the deadliest form of malaria in humans. Upon infection, the host’s infected red blood cells (iRBCs) are remodelled by exported parasite proteins in order to provide a niche for parasite development and maturation. Methods: Here we analysed the role of three PHISTb proteins Pf3D7_0532400, Pf3D7_1401600, and Pf3D7_1102500 by expressing recombinant proteins and evaluated antibody responses against these proteins using immune sera from malaria-exposed individuals from Kenya and The Gambia in Africa. Results: Our findings show that children and adults from malaria-endemic regions recognized the three PHISTb proteins. Responses against the PHISTb proteins varied with malaria transmission intensity in three different geographical sites in Kenya (Siaya and Takaungu) and The Gambia (Sukuta). Antibody responses against PHISTb antigens Pf3D7_1102500 and Pf3D7_1401600 were higher in Sukuta, a low transmission region in the Gambia, as compared to Siaya, a high transmission region in western Kenya, unlike Pf3D7_0532400. Anti-PHIST responses show a negative correlation between antibody levels and malaria transmission intensity for two PHIST antigens, Pf3D7_1102500 and Pf3D7_1401600. However, we report a correlation in antibody responses between schizont extract and Pf3D7_0532400 (p=0.00582). Acquisition of anti-PHIST antibodies was correlated with exposure to malaria for PHISTb protein Pf3D7_0532400 (p=0.009) but not the other PHIST antigens Pf3D7_1102500 and Pf3D7_1401600 (p=0.507 and p=0.15, respectively, CI=95%). Children aged below 2 years had the lowest antibody levels, but the responses do not correlate with age differences. Conclusions: Collectively, these findings provide evidence of natural immunity against PHISTb antigens that varies with level of malaria exposure and underscore potential for these parasite antigens as possible serological markers to P. falciparum infection aimed at contributing to malaria control through vaccine development.

scholarly journals Molecular characterization of Plasmodium falciparum PHISTb proteins as potential targets of naturally-acquired immunity against malaria

2021 ◽  
Vol 5 ◽  
pp. 136
Author(s):  
Tony I. Isebe ◽  
Joel L. Bargul ◽  
Bonface M. Gichuki ◽  
James M. Njunge ◽  
James Tuju ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Negative Correlation ◽  
The Gambia ◽  
Antibody Responses ◽  
Transmission Intensity ◽  
Parasite Development ◽  
Malaria Transmission Intensity ◽  
Transmission Region ◽  
Antibody Levels

Background: Plasmodium falciparum causes the deadliest form of malaria in humans. Upon infection, the host’s infected red blood cells (iRBCs) are remodelled by exported parasite proteins to provide a niche for parasite development and maturation. Methods: Here we analysed the role of three PHISTb proteins Pf3D7_0532400, Pf3D7_1401600, and Pf3D7_1102500 by expressing recombinant proteins and evaluated antibody responses against these proteins using immune sera from malaria-exposed individuals from Kenya and The Gambia in Africa. Results: Children and adults from malaria-endemic regions recognized the three PHISTb proteins. Responses against PHISTb proteins varied with malaria transmission intensity in three different geographical sites in Kenya (Siaya and Takaungu) and The Gambia (Sukuta). Antibody responses against PHISTb antigens Pf3D7_1102500 and Pf3D7_1401600 were higher in Sukuta, a low transmission region in Gambia, compared to Siaya, a high transmission region in western Kenya, unlike Pf3D7_0532400. Anti-PHIST responses indicate negative correlation between antibody levels and malaria transmission intensity for Pf3D7_1102500 and Pf3D7_1401600. We report a correlation in antibody responses between schizont and gametocyte extract, but this is not statistically significant (cor=0.102, p=0.2851, CI=95%) and, Pf3D7_0532400 (cor=0.11, p=0.249, CI=95%) and Pf3D7_1401600 (cor=0.02, p=0.7968, CI=95%). We report a negative correlation in antibody responses between schizont and Pf3D7_1102500 (cor=-0.008, p=0.9348, CI=95%). There is a correlation between gametocyte extract and Pf3D7_1401600 (cor=-0.0402, p=0.6735, CI=95%), Pf3D7_1102500 (cor=0.0758, p=0.4271, CI=95%) and Pf3D7_0532400 (cor=0.155, p=0.1028, CI=95%). Acquisition of anti-PHIST antibodies correlates with exposure to malaria for Pf3D7_0532400 (p=0.009) but not Pf3D7_1102500 and Pf3D7_1401600 (p=0.507 and p=0.15, respectively, CI=95%). Children aged below 2 years had the lowest antibody levels which do not correlate with age differences. Conclusions: Collectively, these findings provide evidence of natural immunity against PHISTb antigens that varies with level of malaria exposure and underscore their potential as possible serological markers to P. falciparum infection aimed at contributing to malaria control through vaccine development.

scholarly journals PO 8562 SECRETED OOKINETE PROTEIN AS A MARKER OF INFECTIOUS BITES FOR ASSESSING TRANSMISSION DYNAMICS AT THE POPULATION LEVEL

2019 ◽  
Vol 4 (Suppl 3) ◽  
pp. A53.2-A53
Author(s):  
Kingsley Badu
Keyword(s):  
Malaria Transmission ◽  
Rainy Season ◽  
Parasite Prevalence ◽  
Transmission Intensity ◽  
Igg Antibody ◽  
Subtle Difference ◽  
Targeted Interventions ◽  
Malaria Transmission Intensity ◽  
Twofold Increase ◽  
Immunogenic Peptides

BackgroundAs malaria transmission intensity declines, the heterogeneity in infectious burden becomes pronounced. There is thus the need for more sensitive tools to identify micro-geographic areas of higher risk for targeted interventions. We sought to evaluate several immunogenic peptides of P. falciparum, secreted ookinete and sporozoite proteins (PSOP24) and possibly validate specific short sequence immunogenic peptides as an infectious bite marker for assessing malaria transmission intensity and dynamics.MethodsWe conducted four cross-sectional serological and parasitological surveys within one peri-urban and one rural community about 3 km apart, in South-western Ghana. The field surveys were conducted from November 2012 to July 2014 across dry and rainy seasons. Several bioinformatics models were used to predict the immunogenic epitopes of PSOP24 peptides. Total IgG antibody response were determined for three most promising peptides (PSOP24–374, PSOP24–375 and PSOP24–377), together with MSP119, CSP and salivary gland antigen. Alongside we determined parasite prevalence and density as well as the entomological inoculation rates.ResultsPeptide PSOP24-377 showed seasonal variation with a twofold increase in IgG response in the high-transmission rainy season. This collaborates with the twofold increase in IgG response to the mosquito salivary antigen gSG6-P1. Also, PSOP24-377 was able to show a subtle difference from Ayeigbekorpe to Odumase during the dry season and a high sero-prevalence between the two communities during the rainy season. This was in contrast with gSG6-P1 because, while PSOP24-377 measures sero-response to infectious bites, gSG6-P1 measure responses to only vector exposure. The immune response variation determined by PSOP24-377 correlated with parasite prevalence and the entomological inoculation rates.ConclusionThe preliminary data points to the potential of PSOP24-377 as an infectious bite marker. This may be exploited as a routine surveillance tool for monitoring malaria transmission at the community level.

scholarly journals Dynamics and role of antibodies to Plasmodium falciparum merozoite antigens in children living in two settings with differing malaria transmission intensity

Vaccine ◽  
2016 ◽  
Vol 34 (1) ◽  
pp. 160-166 ◽  
Author(s):  
David Tiga Kangoye ◽  
Victorine Atanase Mensah ◽  
Linda Muthoni Murungi ◽  
Irene Nkumama ◽  
Issa Nebie ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Transmission Intensity ◽  
Malaria Transmission Intensity ◽  
Falciparum Merozoite ◽  
Merozoite Antigens
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