Duffy antigen receptor for chemokines gene polymorphisms and malaria in Mangaluru, India

Relationship between Duffy Genotype/Phenotype and Prevalence of Plasmodium vivax Infection: A Systematic Review

The Duffy protein, a transmembrane molecule, functions as a receptor for various chemokines and facilitates attachment between the reticulocyte and the Plasmodium Duffy antigen-binding protein. Duffy expression correlates with the Duffy receptor gene for the chemokine, located on chromosome 1, and exhibits geographical variability worldwide. Traditionally, researchers have described the Duffy negative genotype as a protective factor against Plasmodium vivax infection. However, recent studies suggest that this microorganism's evolution could potentially diminish this protective effect. Nevertheless, there is currently insufficient global data to demonstrate this phenomenon. This study aimed to evaluate the relationship between the Duffy genotype/phenotype and the prevalence of P. vivax infection. The protocol for the systematic review was registered in PROSPERO as CRD42022353427 and involved reviewing published studies from 2012 to 2022. The Medline/PubMed, Web of Science, Scopus, and SciELO databases were consulted. Assessments of study quality were conducted using the STROBE and GRADE tools. A total of 34 studies were included, with Africa accounting for the majority of recorded studies. The results varied significantly regarding the relationship between the Duffy genotype/phenotype and P. vivax invasion. Some studies predominantly featured the negative Duffy genotype yet reported no malaria cases. Other studies identified minor percentages of infections. Conversely, certain studies observed a higher prevalence (99%) of Duffy-negative individuals infected with P. vivax. In conclusion, this systematic review found that the homozygous Duffy genotype positive for the A allele (FY*A/*A) is associated with a higher incidence of P. vivax infection. Furthermore, the negative Duffy genotype does not confer protection against vivax malaria.

Evolution of Plasmodium vivax and resistance patterns for infection based on Duffy genotype and phenotype

The Duffy protein, a transmembrane molecule, acts as a receptor for various chemokines and facilitates binding between reticulocytes and the Plasmodium Duffy antigen binding protein. Duffy expression is associated with the Duffy chemokine receptor antigen genotype on chromosome 1 and exhibits variation across different geographic regions. Traditionally, the Duffy negative genotype and phenotype have been described to confer a certain level of protection against infection and symptom development. However, recent data suggest a shift in this behavior, with significantly higher prevalence observed in individuals with Duffy negative genotype or phenotype. Given that malaria is an endemic vector-borne disease in regions of Asia, Africa, and Latin America, posing a substantial global burden of disease and prioritizing public and global health, identifying evolutionary changes in infection and resistance patterns holds great importance for the design of strategies and reevaluation of conventional interventions. Hence, the aim of this review was to analyze the evolution of Plasmodium vivax and infection resistance patterns based on Duffy genotype and phenotype. The distribution of genotypes, phenotypes, and polymorphisms of P. vivax ligands and erythrocyte receptors varies geographically, notably resistance patterns of this microorganism in individuals with Duffy negative genotype and phenotype have significantly changed compared to studies conducted 30 years ago. The prevalence of vivax malaria in individuals with a Duffy negative status can reach up to 100%. Consequently, prioritizing research on this topic is essential for public health.

The highest Duffy (FYX) allele frequency ever reported for Scottish population: A cross-sectional study

Background and Aim

The Duffy (FY) blood group system has six known antigens among which the Fy^a and Fy^b are known as major antigens. Fy^x phenotype forms as a result of two point mutations in the FYB allele leading to instability of Duffy protein and so reduction of Duffy antigen expression in the cells. This study aimed to investigate the FYX allele frequency in the Scottish population.

Methods

The Duffy blood group system was serologically and molecularly investigated in 222 samples collected from donors of Aberdeen Regional Blood Transfusion Center (BTC). The haemagglutination and BeadChip microarray chemistry methods were used for phenotyping and genotyping. Confirmatory tests were also used to check the discrepant results.

Results

In this study, the frequency of Duffy blood group phenotypes including Fy^a+, Fy^a+b+, and Fy^b+ were 17.57%, 42.79%, and 39.64%, respectively. Furthermore, the frequency of FYA/FYA, FYA/FYB, and FYB/FYB genotypes was estimated to be 14.41%, 45.95%, and 39.64%, respectively, using the Bioarray method. In the present study, based on Duffy DNA sequencing results, 12 samples (5.41%) had just one FYX allele.

Conclusion

The frequency of the FYX allele in this study was estimated to be 0.0270% which is more than the results reported so far.

Postpartum anemia and its determinant factors among postnatal women in two selected health institutes in Gondar, Northwest Ethiopia: A facility-based, cross-sectional study

Background

Anemia is highly prevalent globally and disproportionately affects postnatal women. It is a significant cause of maternal mortality and morbidity globally.

Objective

The main aim of this study was to determine the extent of postpartum anemia and associated factors among postnatal women in two selected health facilities in Gondar, Northwest Ethiopia.

Methods

A facility-based, cross-sectional study was conducted among 282 postnatal women from March to May 2021. A systematic sampling technique was used to recruit study participants from each institute. Sociodemographic, obstetric, and clinical data were collected through a semi-structured questionnaire. A venous blood sample was collected to determine the red blood cell parameters. A thin blood smear preparation was performed to examine blood morphology. In addition, direct wet mount and formalin-ether sedimentation techniques were used for stool examination to identify intestinal parasites. Data were entered into EpiData and exported to Stata 14 for statistical analysis. Descriptive statistics were presented in text, tables, and figures. A binary logistic regression model was used to identify factors associated with postpartum anemia. A p-value <0.05 was considered statistically significant.

Results

The proportion of postpartum anemia was 47.16%; 95% CI; 41.30-53.03 with moderate, mild, and severe anemia accounting for 45.11, 42.86, and 12.03%, respectively. The majority of the anemia (94%) was of the normocytic normochromic type. It was associated with postpartum hemorrhage (AOR = 2.23; 95% CI: 1.24-4.01), cesarean section (AOR = 4.10; 95% CI: 2.11-7.78), lack of iron and folate supplementation during pregnancy (AOR = 2.12; 95% CI: 1.17-4.02), and low diet diversity level (AOR = 1.83; 95% CI: 1.05-3.18).

Conclusion

The prevalence of anemia was found to be a major public health concern. Iron and folate supplementation during pregnancy, improved management of PPH, an effective cesarean section with post-operative care, and taking a diversified diet will reduce the burden. Therefore, identified factors should be considered to prevent and control postpartum anemia.

Vivax malaria in Duffy-negative patients shows invariably low asexual parasitaemia: implication towards malaria control in Ethiopia

BACKGROUND

The increase in detections of Plasmodium vivax infection in Duffy-negative individuals in Africa has challenged the dogma establishing the unique P. vivax Duffy Binding Protein-Duffy antigen receptor for chemokines (PvDBP-DARC) pathway used by P. vivax merozoites to invade reticulocytes. Information on the impact of Duffy antigen polymorphisms on the epidemiology of P. vivax malaria remains elusive. The objective of this study was to determine the distribution of asexual parasitaemia of P. vivax according to the Duffy antigen polymorphisms in Ethiopia.

METHODS

DNA was extracted from dried blood spots (DBS) collected from prospectively recruited 138 P. vivax-infected patients from health centres. The identification and estimation of P. vivax asexual parasitaemia were performed by microscopic examination and quantitative real-time polymerase chain reaction (PCR). Duffy genotyping was conducted by DNA sequencing in a total of 138 P.vivax infected samples.

RESULTS

The proportion of Duffy-negatives (FY*BES/FY*BES) in P. vivax infected patients was 2.9% (4/138). Duffy genotype FY*B/FY*BES (48.6%) was the most common, followed by FY*A/FY*BES genotype (25.4%). In one patient, the FY*02 W.01/FY*02 N.01 genotype conferring a weak expression of the Fyb antigen was observed. All P.vivax infected Duffy-negative patients showed low asexual parasitaemia (≤ 110 parasites/µL). The median P. vivax parasitaemia in Duffy-negative patients (53 parasites/µL) was significantly lower than those found in homozygous and heterozygous individuals (P < 0.0001).

CONCLUSION

Plasmodium vivax in Duffy-negative patients shows invariably low asexual parasitaemia. This finding suggests that the pathway used by P. vivax to invade Duffy-negative reticulocytes is much less efficient than that used in Duffy-positives. Moreover, the low asexual parasitaemia observed in Duffy-negative individuals could constitute an 'undetected silent reservoir', thus likely delaying the elimination of vivax malaria in Ethiopia.

Malaria Elimination in India: Bridging the Gap Between Control and Elimination

India observed a significant reduction in malaria cases in the previous year, reaffirming our trust and efficiency of the existing tools to achieve malaria elimination. On 25 April, 2019, countries around the world marked World Malaria Day under the theme “Zero malaria starts with me”. This provides an opportunity to rejoice the success and re-evaluate ongoing challenges in the fight against this preventable and treatable parasitic disease. We highlight the potential gaps in the malaria elimination program, and underscore potential solutions and strategies to implement, improve and intensify the success of the national goal of malaria elimination by 2030.

MiRNA-146a Polymorphism Was Not Associated with Malaria in Southern India

Micro-RNAs (miRNAs) play a crucial role in immune regulation, and a common miRNA-146a polymorphism (rs2910164) increased the odds of falciparum malaria in pregnant African women. Here, we examined whether this association holds true in a different population, that is, 449 mainly male and adult malaria patients and 666 community controls in southwestern India. Plasmodium vivax malaria (67%) predominated over falciparum malaria (11%) and mixed species infections (22%). Overall, 59% of the study participants carried the miRNA-146a polymorphism. However, it was not associated with the odds of malaria, irrespective of parasite species. This underlines the importance of considering the complexities of clinical manifestations of malaria, genetic background, and parasite species when disentangling the role of human genetic variation, including those of miRNAs in malaria.