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MedRxiv : the Preprint Server For... Oct 2023spp. infections are endemic across multiple African countries and are caused by two distinct non-recombining species, () and (). These species are thought to differ...
BACKGROUND
spp. infections are endemic across multiple African countries and are caused by two distinct non-recombining species, () and (). These species are thought to differ in clinical symptomatology and latency, but existing diagnostic assays have limited ability to detect and distinguish them. In this study, we developed a new duplex assay for the detection and differentiation of and that can be used to improve our understanding of these parasites.
METHODS
Repetitive sequence motifs were identified in available and genomes and used for assay development and validation. We evaluated the analytical sensitivity and specificity of the best-performing assay using a panel of samples from Tanzania and the Democratic Republic of the Congo (DRC), then validated its performance using 55 spp. samples and 40 non-ovale samples from the DRC. and prevalence among symptomatic individuals sampled across three provinces of the DRC were estimated.
RESULTS
The best-performing and targets had 9 and 8 copies within the reference genomes, respectively. Our duplex assay had 100% specificity and 95% confidence lower limits of detection of 4.2 and 41.2 parasite genome equivalents/μl for and , respectively. Species was determined in 80% of all spp.-positive field samples and 100% of those with >10 parasites/μl. Most spp. field samples from the DRC were found to be infections.
CONCLUSIONS
We identified promising multi-copy targets for molecular detection and differentiation of and and used them to develop a new duplex real-time PCR assay that performed well when applied to diverse field samples. Though low-density infections are not reliably detected, the assay is highly specific and can be used for high-throughput studies of spp. epidemiology among symptomatic cases in malaria-endemic countries like the DRC.
PubMed: 37961397
DOI: 10.1101/2023.10.31.23297819 -
MedRxiv : the Preprint Server For... Dec 2023Recent studies point to the need to incorporate non-falciparum species detection into malaria surveillance activities in sub-Saharan Africa, where 95% of malaria cases...
Recent studies point to the need to incorporate non-falciparum species detection into malaria surveillance activities in sub-Saharan Africa, where 95% of malaria cases occur. Although infection is typically more severe, diagnosis, treatment, and control for , spp., and may be more challenging. The prevalence of these species throughout sub-Saharan Africa is poorly defined. Tanzania has geographically heterogeneous transmission levels but an overall high malaria burden. In order to estimate the prevalence of malaria species in Mainland Tanzania, 1,428 samples were randomly selected from 6,005 asymptomatic isolates collected in cross-sectional community surveys across four regions and analyzed via qPCR to detect each species. was most prevalent, with and spp. detected at lower prevalence (<5%) in all four regions. was not detected. Malaria elimination efforts in Tanzania will need to account for these non-falciparum species.
PubMed: 38234751
DOI: 10.1101/2023.12.28.23300584 -
Genome Biology and Evolution Aug 2023Ubiquitin is an extraordinarily highly conserved 76 amino acid protein encoded by three different types of gene, where the primary translation products are fusions...
Ubiquitin is an extraordinarily highly conserved 76 amino acid protein encoded by three different types of gene, where the primary translation products are fusions either of ubiquitin with one of two ribosomal proteins (RPs) or of multiple ubiquitin monomers from head to tail. Here, we investigate the evolution of ubiquitin genes in mammalian malaria parasites (Plasmodium species). The ubiquitin encoded by the RPS27a fusion gene is highly divergent, as previously found in a variety of protists. However, we also find that two other forms of divergent ubiquitin sequence, each previously thought to be extremely rare, have arisen recently during the divergence of Plasmodium subgenera. On two occasions, in two distinct lineages, the ubiquitin encoded by the RPL40 fusion gene has rapidly diverged. In addition, in one of these lineages, the polyubiquitin genes have undergone a single codon insertion, previously considered a unique feature of Rhizaria. There has been disagreement whether the multiple ubiquitin coding repeats within a genome exhibit concerted evolution or undergo a birth-and-death process; the Plasmodium ubiquitin genes show clear signs of concerted evolution, including the spread of this codon insertion to multiple repeats within the polyubiquitin gene.
Topics: Animals; Ubiquitin; Polyubiquitin; Ribosomal Proteins; Magnoliopsida; Plasmodium; Mammals
PubMed: 37481258
DOI: 10.1093/gbe/evad137 -
Malaria Journal Jul 2023Malaria is a major public health problem, particularly in the tropical regions of America, Africa and Asia. Plasmodium falciparum is not only the most widespread but...
BACKGROUND
Malaria is a major public health problem, particularly in the tropical regions of America, Africa and Asia. Plasmodium falciparum is not only the most widespread but also the most deadly species. The share of Plasmodium infections caused by the other species (Plasmodium ovale and Plasmodium malariae) is clearly underestimated. The objective of the study was to determine the molecular epidemiology of plasmodial infection due to P. malariae and P. ovale in Côte d'Ivoire.
METHODS
The study was cross-sectional. The study participants were recruited from Abengourou, San Pedro and Grand-Bassam. Sample collection took place from May 2015 to April 2016. Questionnaires were administered and filter paper blood samples were collected for parasite DNA extraction. The molecular analysis was carried out from February to March 2021. A nested PCR was used for species diagnosis. The data was presented in frequencies and proportions.
RESULTS
A total of 360 patients were recruited, including 179 men (49,7%) for 181 women (50,3%). The overall Plasmodium positive rate was 72.5% (261/360). The specific index was 77.4% and 1.5% for P. falciparum and P. malariae in mono-infection, respectively. There was also 15% P. falciparum and P. malariae co-infection, 3.4% P. falciparum and P. ovale co-infection and 2.3% P. falciparum, P. malariae and P. ovale triple-infection. Typing of P. ovale subspecies showed a significant predominance of P. ovale curtisi (81.2% of cases).
CONCLUSION
Plasmodium falciparum remains the most prevalent malaria species in Côte d'Ivoire, but P. malariae and P. ovale are also endemic mostly in co-infection. Malaria elimination requires a better understanding of the specific epidemiological characteristics of P. malariae and P. ovale with a particular emphasis on the identification of asymptomatic carriers.
Topics: Male; Humans; Female; Plasmodium falciparum; Cote d'Ivoire; Molecular Epidemiology; Coinfection; Cross-Sectional Studies; Prevalence; Malaria, Falciparum; Malaria; Plasmodium ovale; Plasmodium malariae
PubMed: 37468917
DOI: 10.1186/s12936-023-04639-7 -
MedRxiv : the Preprint Server For... Sep 2023Recent data indicate that non- species may be more prevalent than previously realized in sub-Saharan Africa, the region where 95% of the world's malaria cases occur....
Recent data indicate that non- species may be more prevalent than previously realized in sub-Saharan Africa, the region where 95% of the world's malaria cases occur. Although spp., and are generally less severe than , treatment and control are more challenging, and their geographic distributions are not well characterized. In order to characterize the distribution of malaria species in Mainland Tanzania (which has a high burden and geographically heterogeneous transmission levels), we randomly selected 3,284 samples from 12,845 samples to determine presence and parasitemia of different malaria species. The samples were collected from cross-sectional surveys in 100 health facilities across ten regions and analyzed via quantitative real-time PCR to characterize regional positivity rates for each species. was most prevalent, but and were found in all regions except Dar es Salaam, with high levels (>5%) of in seven regions (70%). The highest positivity rate of was 4.5% in Mara region and eight regions (80%) had positivity rates ≥1%. We also detected three infections in the very low-transmission Kilimanjaro region. While most samples that tested positive for non-falciparum malaria were co-infected with , 23.6% (n = 13/55) of and 14.7% (n = 24/163) of spp. samples were mono-infections. remains by far the largest threat, but our data indicate that malaria elimination efforts in Tanzania will require increased surveillance and improved understanding of the biology of non-falciparum species.
PubMed: 37790396
DOI: 10.1101/2023.09.19.23295562 -
Comparative Medicine Jun 2024Malaria is a parasitic disease caused by protozoan species of the genus and transmitted by female mosquitos of the genus and other Culicidae. Most of the parasites of...
Malaria is a parasitic disease caused by protozoan species of the genus and transmitted by female mosquitos of the genus and other Culicidae. Most of the parasites of the genus are highly species specific with more than 200 species described affecting different species of mammals, birds, and reptiles. species strictly affecting humans are , , , and More recently, and other nonhuman primate plasmodia were found to naturally infect humans. Currently, malaria occurs mostly in poor tropical and subtropical areas of the world, and in many of these countries it is the leading cause of illness and death. For more than 100 y, animal models, have played a major role in our understanding of malaria biology. Avian species were the first to be used as models to study human malaria. Malaria parasite biology and immunity were first studied using mainly and . Rodent malarias, particularly and , have been used extensively as models to study malaria in mammals. Several species of from nonhuman primates have been used as surrogate models to study human malaria immunology, pathogenesis, candidate vaccines, and treatments. , , and are important models for studying malaria produced by and , while is used as a model for studying severe malaria. Other nonhuman primate malarias used in research are , , , , and . Very few nonhuman primate species can develop an infection with human malarias. Macaques in general are resistant to infection with , , , and . Only apes and a few species of New World monkeys can support infection with human malarias. Herein we review the most common, and some less common, avian, reptile, and mammal plasmodia species used as models to study human malaria.
PubMed: 38902006
DOI: 10.30802/AALAS-CM-24-000019 -
Scientific Reports Feb 2024Despite Plasmodium ovale curtisi (Poc) and wallikeri (Pow) being important human-infecting malaria parasites that are widespread across Africa and Asia, little is known...
Despite Plasmodium ovale curtisi (Poc) and wallikeri (Pow) being important human-infecting malaria parasites that are widespread across Africa and Asia, little is known about their genome diversity. Morphologically identical, Poc and Pow are indistinguishable and commonly misidentified. Recent rises in the incidence of Poc/Pow infections have renewed efforts to address fundamental knowledge gaps in their biology, and to develop diagnostic tools to understand their epidemiological dynamics and malaria burden. A major roadblock has been the incompleteness of available reference assemblies (PocGH01, PowCR01; ~ 33.5 Mbp). Here, we applied multiple sequencing platforms and advanced bioinformatics tools to generate new reference genomes, Poc221 (South Sudan; 36.0 Mbp) and Pow222 (Nigeria; 34.3 Mbp), with improved nuclear genome contiguity (> 4.2 Mbp), annotation and completeness (> 99% Plasmodium spp., single copy orthologs). Subsequent sequencing of 6 Poc and 15 Pow isolates from Africa revealed a total of 22,517 and 43,855 high-quality core genome SNPs, respectively. Genome-wide levels of nucleotide diversity were determined to be 2.98 × 10 (Poc) and 3.43 × 10 (Pow), comparable to estimates for other Plasmodium species. Overall, the new reference genomes provide a robust foundation for dissecting the biology of Poc/Pow, their population structure and evolution, and will contribute to uncovering the recombination barrier separating these species.
Topics: Animals; Humans; Plasmodium ovale; Parasites; Sequence Analysis, DNA; Malaria; Nigeria
PubMed: 38360879
DOI: 10.1038/s41598-024-54382-5 -
Transfusion Jan 2024Malaria is caused by protozoa of the genus Plasmodium and transmitted by Anopheles mosquitos. In the US, blood donors are assessed for malaria risk, including donor...
BACKGROUND
Malaria is caused by protozoa of the genus Plasmodium and transmitted by Anopheles mosquitos. In the US, blood donors are assessed for malaria risk, including donor travel or previous residence in endemic areas and history of malaria by questionnaire and deferred for three months or three years, respectively.
METHODS
The Procleix Plasmodium Assay is a qualitative nucleic acid test based on transcription-mediated amplification (TMA) for the detection of 18S ribosomal RNA of P. falciparum, P. ovale, P. vivax, P. malariae, and P. knowlesi for use on the Procleix Panther system. Analytical sensitivity was evaluated with in vitro transcripts and infected red blood cells. For clinical specificity, 12,800 individual donations and 283 pools of 16 samples from routine US donors were screened. Malaria risk was evaluated by testing 862 donors deferred for 3 years. Reactive results were confirmed with in-house real-time TMA assay and serology.
RESULTS
Assay sensitivity was 8.47-11.89 RNA copies/mL and 2.10-6.82 infected red cells/mL. Specificity was 99.99% in 12,800 individual donations and 100% in 283 pools of 16. Of 862 tested deferred donor samples, one donor (0.12%) confirmed positive individually and in pools; he remained confirmed positive for 13 months. The infected donor was a prior resident of a malaria-endemic area in West Africa.
CONCLUSIONS
The Procleix Plasmodium Assay showed high sensitivity and specificity and detected Plasmodium RNA in an asymptomatic presenting donor. This assay may prove helpful as a screening test versus the use of risk questions to reduce the number of donors deferred for malaria risk.
Topics: Animals; Humans; Male; Blood Transfusion; Malaria; Malaria, Falciparum; Plasmodium; RNA
PubMed: 38018462
DOI: 10.1111/trf.17612 -
Micromachines Oct 2023Malaria is listed as one of the three most hazardous infectious diseases worldwide. Travelers and migrants passing through exit and entry ports are important sources of...
Malaria is listed as one of the three most hazardous infectious diseases worldwide. Travelers and migrants passing through exit and entry ports are important sources of malaria pandemics globally. Developing accurate and rapid detection technology for malaria is important. Here, a novel hairpin-mediated amplification (HMA) technique was proposed for the detection of four Plasmodium species, including , , , and . Based on the conserved nucleotide sequence of Plasmodium, specific primers and probes were designed for the HMA process, and the amplicon can be detected using lateral flow detection (LFD); the results can be read visually without specialized equipment. The specificity of HMA-LFD was evaluated using nucleic acids extracted from four different Plasmodium species and two virus species. The sensitivity of HMA-LFD was valued using 10× serial dilutions of plasmid containing the template sequence. Moreover, 78 blood samples were collected to compare HMA-LFD and qPCR. The HMA-LFD results were all positive for four different Plasmodium species and negative for the other two virus species. The sensitivity of HMA-LFD was tested to be near five copies/μL. The analysis of clinical samples indicated that the consistency of HMA-LFD and qPCR was approximately 96.15%. Based on these results, the HMA-LFD assay was demonstrated to be a rapid, sensitive, and specific technique for the detection of Plasmodium and has great advantages for on-site detection in low-resource areas and exit and entry ports.
PubMed: 37893354
DOI: 10.3390/mi14101917 -
Trends in Parasitology Mar 2024
Topics: Plasmodium ovale
PubMed: 38160179
DOI: 10.1016/j.pt.2023.12.010