Faculty Opinions recommendation of RTS,S/AS01E immunization increases antibody responses to vaccine-unrelated Plasmodium falciparum antigens associated with protection against clinical malaria in African children: a case-control study.

Author(s):  
Toshihiro Horii ◽  
Nirianne Palacpac
2021 ◽  
Author(s):  
FASSIATOU OLUWATOSIN TAIROU ◽  
Abdoulaye Diallo ◽  
Ousmane Sy ◽  
Aminatou Kone ◽  
Isaac Akhenaton Manga ◽  
...  

Abstract Background: In Senegal, malaria morbidity has shapely felt down over these past years. However, malaria epidemiology remains heterogeneous with persisting transmission in the southeastern part of the country and more important number of cases arising among older children and adolescents. Little is known about factors associated with clinical malaria among this group. A better understanding of malaria transmission among this new vulnerable group will guide future interventions targeting these key populations. This study aimed to identify factors associated with clinical malaria among adolescents in Senegal. Methods: A case control study was conducted from November to December 2020 in four health posts located in Saraya district. Cases were defined as adolescents (10-19 years) with uncomplicated malaria episode with fever (Temperature>37.5°) or history of fever and a positive malaria RDT. Controls were from the same age group, living in the neighborhood of the case, presenting a negative RDT. A standardized, pre-tested questionnaire was administered to each participant followed by home visit to assess participant’s living conditions. Factors associated with clinical malaria was assessed using a Stepwise Logistic regression analysis.Results: In total, 492 individuals were recruited (246 cases and 246 controls). In a multivariate analysis, factors associated with clinical malaria included non-use of bed net (aOR=2.65; 95% CI =1.58 - 4.45), non-use of other preventive measures (aOR=2.51; 95% CI=1.53 - 4.11) and indoor sleeping (aOR=3.22; 95%CI =1.66- 6.23). Protective factors included age of 15-19 years (aOR=0.38; 95% CI 0.23 - 0.62), absence of stagnant water around the house (aOR=0.27; 95% CI=0.16 - 0.44), having a female as head of household (aOR=0.47; 95% CI=0.25 - 0.90), occupation such as apprentice (OR=0.24; 95%CI=0.11 - 0.52).Conclusions: The study revealed that environmental factors and non-use of malaria preventive measures are the main determinant of malaria transmission among adolescents living in areas with persisting malaria transmission in Senegal. Strategies aiming at improving disease awareness and access to health care interventions such as LLIN are thus needed to improve malaria control and prevention among these vulnerable groups.


Blood ◽  
2004 ◽  
Vol 104 (7) ◽  
pp. 2003-2006 ◽  
Author(s):  
Frank P. Mockenhaupt ◽  
Stephan Ehrhardt ◽  
Sabine Gellert ◽  
Rowland N. Otchwemah ◽  
Ekkehart Dietz ◽  
...  

Abstract The high frequency of α+-thalassemia in malaria-endemic regions may reflect natural selection due to protection from potentially fatal severe malaria. In Africa, bearing 90% of global malaria morbidity and mortality, this has not yet been observed. We tested this hypothesis in an unmatched case-control study among 301 Ghanaian children with severe malaria and 2107 controls (62% parasitemic). In control children, α+-thalassemia affected neither prevalence nor density of Plasmodium falciparum. However, heterozygous α+-thalassemia was observed in 32.6% of controls but in only 26.2% of cases (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.56-0.98). Protection against severe malaria was found to be pronounced comparing severe malaria patients with parasitemic controls (adjusted OR in children < 5 years of age, 0.52; 95% CI, 0.34-0.78) and to wane with age. No protective effect was discernible for homozygous children. Our findings provide evidence for natural selection of α+-thalassemia in Africa due to protection from severe malaria.


2015 ◽  
Vol 56 (4) ◽  
pp. 292 ◽  
Author(s):  
RichardK.D. Ephraim ◽  
Worlanyo Tashie ◽  
Hope Agbodzakey ◽  
SamuelAsamoah Sakyi ◽  
Samuel Essien-Baidoo ◽  
...  

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Gloria Cuu ◽  
Victor Asua ◽  
Stephen Tukwasibwe ◽  
Sam L. Nsobya ◽  
Ann Nanteza ◽  
...  

ABSTRACT Mutations that mediate resistance of Plasmodium falciparum to aminoquinoline antimalarials are selected by prior drug use and may alter parasite fitness, but associations with clinical presentations are uncertain. We evaluated genotypes in samples from a case-control study of determinants of severe malaria in Ugandan children 4 months to 10 years of age. We studied 274 cases with severe malaria matched by age and geography to 275 uncomplicated malaria controls and 179 asymptomatic parasitemic controls. The overall prevalence of mutations of interest (considering mixed results as mutant) was 67.0% for PfCRT K76T, 8.5% for PfMDR1 N86Y, 71.5% for PfMDR1 Y184F, and 14.7% for PfMDR1 D1246Y. Compared to asymptomatic controls, the odds of mutant PfCRT 76T were lower for uncomplicated (odds ratio, 0.42 [95% confidence interval, 0.24 to 0.72]; P < 0.001) or severe (0.56 [0.32 to 0.97]; P = 0.031) malaria; the odds of mutant PfMDR1 86Y were lower for uncomplicated (0.33 [0.16 to 0.65]; P < 0.001) or severe (0.21 [0.09 to 0.45]; P < 0.001) malaria; and the odds of mutant PfMDR1 1246Y were higher for uncomplicated (1.83 [0.90 to 3.98]; P = 0.076) or severe (2.06 [1.01 to 4.55]; P = 0.033) malaria. The odds of mutant PfMDR1 184F were lower in severe than asymptomatic (0.59 [0.37 to 0.92]; P = 0.016) or uncomplicated (0.61 [0.41 to 0.90]; P = 0.009) malaria. Overall, the PfCRT 76T and PfMDR1 86Y mutations were associated with decreased risk of symptomatic malaria, PfMDR1 1246Y was associated with increased risk of symptomatic malaria, and PfMDR1 184F was associated with decreased risk of severe malaria. These results offer insights into parasite genotypes in children with different presentations, although the basis for the identified associations is likely complex.


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