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Little E, Shenkutie TT, Negash MT, Abagero BR, Abebe A, Popovici J, Feleke SM, Lo E. Prevalence and Characteristics of Plasmodium vivax Gametocytes in Duffy-Positive and Duffy-Negative Populations across Ethiopia. Am J Trop Med Hyg 2024; 110:1091-1099. [PMID: 38626749 PMCID: PMC11154031 DOI: 10.4269/ajtmh.23-0877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/04/2024] [Indexed: 04/18/2024] Open
Abstract
Plasmodium parasites replicate asexually in human hosts. The proportion of infections that carries gametocytes is a proxy for human-to-mosquito transmissibility. It is unclear which proportion of Plasmodium vivax infections in Duffy-negative populations carries gametocytes. We determined the prevalence and characteristics of P. vivax gametocytes in Duffy-positive and -negative populations across broad regions of Ethiopia. Finger-prick blood samples were collected for microscopic and molecular screening of Plasmodium parasites and Duffy status of individuals. Molecular screening of Plasmodium species and Duffy blood group genotyping was done using SYBR green and the Taqman quantitative polymerase chain reaction method. Of the 447 febrile patients who were shown to be P. vivax smear positive, 414 (92.6%) were confirmed by molecular screening as P. vivax and 16 (3.9%) of them were from Duffy-negative individuals. Of these, 5 of 16 (31.3%) Duffy-negative P. vivax-infected samples were detected with gametocytes. Of the 398 Duffy-positive P. vivax-infected samples, 150 (37.7%) were detected with gametocytes, slightly greater than that in Duffy-negative samples. This study highlights the presence of P. vivax gametocytes in Duffy-negative infections, suggestive of human-to-mosquito transmissibility. Although P. vivax infections in Duffy-negative individuals were commonly associated with low parasitemia, some of these infections were shown to have relatively high parasitemia and may represent a prominent erythrocyte invasion capability of P. vivax, and hidden reservoirs that can contribute to transmission. A better understanding of P. vivax transmission biology and gametocyte function particularly in Duffy-negative populations would aid future treatment and management of P. vivax malaria in Africa.
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Affiliation(s)
- Ebony Little
- Department of Biological Sciences, University of North Carolina at Charlotte, North Carolina
| | - Tassew T. Shenkutie
- Department of Microbiology and Immunology, Drexel University, College of Medicine, Philadelphia, Pennsylvania
- Department of Medical Laboratory Sciences, Debre Brehan University, Ethiopia
| | | | - Beka R. Abagero
- Department of Molecular and Cellular Biology and Genetics, Drexel University, College of Medicine, Philadelphia, Pennsylvania
| | - Abnet Abebe
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | | | - Eugenia Lo
- Department of Biological Sciences, University of North Carolina at Charlotte, North Carolina
- Department of Microbiology and Immunology, Drexel University, College of Medicine, Philadelphia, Pennsylvania
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Abebe A, Dieng CC, Dugassa S, Abera D, Shenkutie TT, Assefa A, Menard D, Lo E, Golassa L. Genetic differentiation of Plasmodium vivax duffy binding protein in Ethiopia and comparison with other geographical isolates. Malar J 2024; 23:55. [PMID: 38395885 PMCID: PMC10885561 DOI: 10.1186/s12936-024-04887-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/21/2024] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND Plasmodium vivax Duffy binding protein (PvDBP) is a merozoite surface protein located in the micronemes of P. vivax. The invasion of human reticulocytes by P. vivax merozoites depends on the parasite DBP binding domain engaging Duffy Antigen Receptor for Chemokine (DARC) on these red blood cells (RBCs). PvDBPII shows high genetic diversity which is a major challenge to its use in the development of a vaccine against vivax malaria. METHODS A cross-sectional study was conducted from February 2021 to September 2022 in five study sites across Ethiopia. A total of 58 blood samples confirmed positive for P. vivax by polymerase chain reaction (PCR) were included in the study to determine PvDBPII genetic diversity. PvDBPII were amplified using primers designed from reference sequence of P. vivax Sal I strain. Assembling of sequences was done using Geneious Prime version 2023.2.1. Alignment and phylogenetic tree constructions using MEGA version 10.1.1. Nucleotide diversity and haplotype diversity were analysed using DnaSP version 6.12.03, and haplotype network was generated with PopART version 1.7. RESULTS The mean age of the participants was 25 years, 5 (8.6%) participants were Duffy negatives. From the 58 PvDBPII sequences, seven haplotypes based on nucleotide differences at 8 positions were identified. Nucleotide diversity and haplotype diversity were 0.00267 ± 0.00023 and 0.731 ± 0.036, respectively. Among the five study sites, the highest numbers of haplotypes were identified in Arbaminch with six different haplotypes while only two haplotypes were identified in Gambella. The phylogenetic tree based on PvDBPII revealed that parasites of different study sites shared similar genetic clusters with few exceptions. Globally, a total of 39 haplotypes were identified from 223 PvDBPII sequences representing different geographical isolates obtained from NCBI archive. The nucleotide and haplotype diversity were 0.00373 and 0.845 ± 0.015, respectively. The haplotype prevalence ranged from 0.45% to 27.3%. Two haplotypes were shared among isolates from all geographical areas of the globe. CONCLUSIONS PvDBPII of the Ethiopian P. vivax isolates showed low nucleotide but high haplotype diversity, this pattern of genetic variability suggests that the population may have undergone a recent expansion. Among the Ethiopian P. vivax isolates, almost half of the sequences were identical to the Sal-I reference sequence. However, there were unique haplotypes observed in the Ethiopian isolates, which does not share with isolates from other geographical areas. There were two haplotypes that were common among populations across the globe. Categorizing population haplotype frequency can help to determine common haplotypes for designing an effective blood-stage vaccine which will have a significant role for the control and elimination of P. vivax.
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Affiliation(s)
- Abnet Abebe
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 24756, Addis Ababa, Ethiopia.
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia.
| | - Cheikh Cambel Dieng
- Department of Microbiology and Immunology, College of Medicine, Drexel University, Philadelphia, USA
| | - Sisay Dugassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 24756, Addis Ababa, Ethiopia
| | - Deriba Abera
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 24756, Addis Ababa, Ethiopia
| | - Tassew T Shenkutie
- Department of Microbiology and Immunology, College of Medicine, Drexel University, Philadelphia, USA
| | - Ashenafi Assefa
- Institute of Infectious Disease and Global Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Didier Menard
- Malaria Genetics and Resistance Unit, INSERM U1201, Institut Pasteur, Université Paris Cité, 75015, Paris, France
- Dynamics of Host-Pathogen Interactions, Université de Strasbourg, Institute of Parasitology and Tropical Diseases, 67000, Strasbourg, France
| | - Eugenia Lo
- Department of Microbiology and Immunology, College of Medicine, Drexel University, Philadelphia, USA
| | - Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 24756, Addis Ababa, Ethiopia.
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Kepple D, Ford CT, Williams J, Abagero B, Li S, Popovici J, Yewhalaw D, Lo E. Comparative transcriptomics reveal differential gene expression among Plasmodium vivax geographical isolates and implications on erythrocyte invasion mechanisms. PLoS Negl Trop Dis 2024; 18:e0011926. [PMID: 38285730 PMCID: PMC10901308 DOI: 10.1371/journal.pntd.0011926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 02/28/2024] [Accepted: 01/19/2024] [Indexed: 01/31/2024] Open
Abstract
The documentation of Plasmodium vivax malaria across Africa especially in regions where Duffy negatives are dominant suggests possibly alternative erythrocyte invasion mechanisms. While the transcriptomes of the Southeast Asian and South American P. vivax are well documented, the gene expression profile of P. vivax in Africa is unclear. In this study, we examined the expression of 4,404 gene transcripts belong to 12 functional groups and 43 erythrocyte binding gene candidates in Ethiopian isolates and compared them with the Cambodian and Brazilian P. vivax transcriptomes. Overall, there were 10-26% differences in the gene expression profile amongst geographical isolates, with the Ethiopian and Cambodian P. vivax being most similar. Majority of the gene transcripts involved in protein transportation, housekeeping, and host interaction were highly transcribed in the Ethiopian isolates. Members of the reticulocyte binding protein PvRBP2a and PvRBP3 expressed six-fold higher than Duffy binding protein PvDBP1 and 60-fold higher than PvEBP/DBP2 in the Ethiopian isolates. Other genes including PvMSP3.8, PvMSP3.9, PvTRAG2, PvTRAG14, and PvTRAG22 also showed relatively high expression. Differential expression patterns were observed among geographical isolates, e.g., PvDBP1 and PvEBP/DBP2 were highly expressed in the Cambodian but not the Brazilian and Ethiopian isolates, whereas PvRBP2a and PvRBP2b showed higher expression in the Ethiopian and Cambodian than the Brazilian isolates. Compared to Pvs25, gametocyte genes including PvAP2-G, PvGAP (female gametocytes), and Pvs47 (male gametocytes) were highly expressed across geographical samples.
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Affiliation(s)
- Daniel Kepple
- Biological Sciences, University of North Carolina, Charlotte, North Carolina, United States of America
| | - Colby T. Ford
- Bioinformatics and Genomics, University of North Carolina, Charlotte, North Carolina, United States of America
- School of Data Science, University of North Carolina, Charlotte, North Carolina, United States of America
| | - Jonathan Williams
- Biological Sciences, University of North Carolina, Charlotte, North Carolina, United States of America
| | - Beka Abagero
- Biological Sciences, University of North Carolina, Charlotte, North Carolina, United States of America
| | - Shaoyu Li
- Mathematics and Statistics, University of North Carolina, Charlotte, North Carolina, United States of America
| | - Jean Popovici
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Delenasaw Yewhalaw
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Eugenia Lo
- Biological Sciences, University of North Carolina, Charlotte, North Carolina, United States of America
- Microbiology and Immunology, College of Medicine, Drexel University, Philadelphia, Pennsylvania, United States of America
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Little E, Shenkutie TT, Negash MT, Abagero BR, Abebe A, Popovici J, Mekasha S, Lo E. Prevalence and characteristics of Plasmodium vivax Gametocytes in Duffy-positive and Duffy-negative populations across Ethiopia. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.12.10.23299780. [PMID: 38168152 PMCID: PMC10760292 DOI: 10.1101/2023.12.10.23299780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Plasmodium parasites replicate asexually in the human host. The proportion of infections that carries gametocytes is a proxy for human-to-mosquito transmissibility. It is unclear what proportion of P. vivax infections in Duffy-negatives carries gametocytes. This study aims to determine the prevalence of P. vivax in Duffy-negatives across broad regions of Ethiopia and characterize parasite stages. Finger-prick blood samples were collected for microscopic and molecular screening of Plasmodium parasites and Duffy status of individuals. Molecular screening of plasmodium species and Duffy blood group genotyping was done using SYBR green and Taqman qPCR method. Among the total 447 samples, 414 (92.6%) were P. vivax confirmed and, 16 (3.9%) of them were from Duffy-negatives. Of these, 5/16 (31.3%) Duffy-negative P. vivax-infected samples were detected with gametocytes. Of the 398 Duffy-positive P. vivax-infected samples, 150 (37.7%) were detected with gametocytes, slightly higher than that in Duffy-negatives. This study highlights the presence of P. vivax gametocytes in Duffy-negative infections, suggestive of human-to-mosquito transmissibility. Although P. vivax infections in Duffy-negatives are commonly associated with low parasitemia, some of these infections were shown with relatively high parasitemia and may represent better erythrocyte invasion capability of P. vivax and hidden reservoirs that can contribute to transmission. A better understanding of P. vivax transmission biology and gametocyte function particularly in Duffy-negative populations would aid future treatment and management of vivax malaria in Africa.
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Affiliation(s)
- Ebony Little
- Department of Biological Sciences, University of North Carolina at Charlotte, North Carolina, USA
| | - Tassew T. Shenkutie
- Department of Microbiology and Immunology, Drexel University, College of Medicine, Philadelphia, PA, USA
- Department of Medical Laboratory Sciences, Debre Brehan University, Debre Brehan, Ethiopia
| | | | - Beka R. Abagero
- Department of Molecular and Cellular Biology and Genetics, Drexel University, College of Medicine, Philadelphia, PA, USA
| | - Abnet Abebe
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | - Sindew Mekasha
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Eugenia Lo
- Department of Biological Sciences, University of North Carolina at Charlotte, North Carolina, USA
- Department of Microbiology and Immunology, Drexel University, College of Medicine, Philadelphia, PA, USA
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