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Journal of Microbiology, Immunology,... Oct 2017Plasmodium ovale is widely distributed in tropical countries, whereas it has not been reported in the Americas. It is not a problem globally because it is rarely... (Review)
Review
Plasmodium ovale is widely distributed in tropical countries, whereas it has not been reported in the Americas. It is not a problem globally because it is rarely detected by microscopy owing to low parasite density, which is a feature of clinical ovale malaria. P.o. curtisi and P.o. wallikeri are widespread in both Africa and Asia, and were known to be sympatric in many African countries and in southeast Asian countries. Small subunit ribosomal RNA (SSUrRNA) gene, cytochrome b (cytb) gene, and merozoite surface protein-1 (msp-1) gene were initially studied for molecular discrimination of P.o. curtisi and P.o. wallikeri using polymerase chain reaction (PCR) and DNA sequencing. DNA sequences of other genes from P. ovale in Southeast Asia and the southwestern Pacific regions were also targeted to differentiate the two sympatric types. In terms of clinical manifestations, P.o. wallikeri tended to produce higher parasitemia levels and more severe symptoms. To date, there have been a few studies that used the quantitative PCR method for discrimination of the two distinct P. ovale types. Conventional PCR with consequent DNA sequencing is the common method used to differentiate these two types. It is necessary to identify these two types because relapse periodicity, drug susceptibility, and mosquito species preference need to be studied to reduce ovale malaria. In this article, an easier method of molecular-level discrimination of P.o. curtisi and P.o. wallikeri is proposed.
Topics: Animals; Cytochromes b; DNA, Protozoan; Genes, Protozoan; Genes, rRNA; Humans; Malaria; Merozoite Surface Protein 1; Plasmodium ovale; Polymerase Chain Reaction; Protozoan Proteins; Sequence Analysis, DNA
PubMed: 28065415
DOI: 10.1016/j.jmii.2016.08.004 -
Trends in Parasitology Apr 2021The phenomenon of relapsing malaria has been recognised for centuries. It is caused in humans by the parasite species Plasmodium vivax and Plasmodium ovale, which can... (Review)
Review
The phenomenon of relapsing malaria has been recognised for centuries. It is caused in humans by the parasite species Plasmodium vivax and Plasmodium ovale, which can arrest growth at an early, asymptomatic stage as hypnozoites inside liver cells. These dormant parasites can remain quiescent for months or years, then reactivate causing symptomatic malaria. The dynamics of hypnozoite dormancy and reactivation are well documented but the molecular basis remains a complete mystery. Here, I observe that the process has striking parallels with plant vernalisation, whereby plants remain dormant through the winter before flowering in spring. Vernalisation is thoroughly studied in several plant species and its mechanisms are known in exquisite detail. Vernalisation may thus provide a useful framework for interrogating hypnozoite biology.
Topics: Animals; Humans; Life Cycle Stages; Malaria; Plant Dormancy; Plasmodium ovale; Plasmodium vivax
PubMed: 33257270
DOI: 10.1016/j.pt.2020.11.001 -
Emerging Topics in Life Sciences Dec 2017Plasmodium falciparum is a protozoan parasite that causes the most severe form of human malaria. Five other Plasmodium species can also infect humans - P. vivax, P....
Plasmodium falciparum is a protozoan parasite that causes the most severe form of human malaria. Five other Plasmodium species can also infect humans - P. vivax, P. malariae, P. ovale curtisi, P. ovale wallikeri and P. knowlesi - but P. falciparum is the most prevalent Plasmodium species in the African region, where 90% of all malaria occurs, and it is this species that causes the great majority of malaria deaths. These were reported by the WHO at 438 000 in 2015 from an estimated 214 million cases; importantly, however, figures for the global burden of malaria tend to have wide margins of error due to poor and inaccurate reporting. In this Perspective, features of P. falciparum that are unique among human malaria parasites are highlighted, and current issues surrounding the control and treatment of this major human pathogen are discussed.
PubMed: 33525841
DOI: 10.1042/ETLS20170099 -
Journal of Tropical Medicine 2021Although China is moving toward the eradication of malaria and no indigenous malaria has been reported in most Chinese provinces for several years, recent evaluations... (Review)
Review
Although China is moving toward the eradication of malaria and no indigenous malaria has been reported in most Chinese provinces for several years, recent evaluations have revealed that imported cases remain a major challenge to eliminating malaria, with the number of transfusion-transmitted malaria (TTM) cases increasing over time. Here, we review several TTM case reports published after the implementation of the National Malaria Elimination Program in 2010. A total of 12 TTM cases were reported in China between 2013 and 2018. All recipients and donors were diagnosed using rapid diagnosis test and peripheral blood smears. species in donors with low-density parasites were identified using PCR. Nine (75.0%) were identified as , two (16.7%) were identified as , and one (8.3%) was identified as . All were imported from malaria-endemic areas. New action plans designed to meet the challenges of TTM are necessary to ensure the elimination of malaria in China. Paying more attention to the frequency of TTM could help to enhance blood safety in China.
PubMed: 34306101
DOI: 10.1155/2021/3970370 -
Acta Medica Indonesiana Jan 2023Plasmodium ovale consists of two subspecies - P. ovale wallikeri and P. ovale curtisi. Increased reports of imported malaria ovale in non-endemic regions and mixed...
Plasmodium ovale consists of two subspecies - P. ovale wallikeri and P. ovale curtisi. Increased reports of imported malaria ovale in non-endemic regions and mixed infection of P. ovale with other Plasmodium species suggest that P. ovale might be under-detected during routine surveillance. Areas endemic with P. ovale have mostly been reported in African and Western Pacific countries. A recent case report in Indonesia indicated that regions with P. ovale endemicity are not only distributed in Lesser Sunda and Papua, but also in North Sumatra.
Topics: Humans; Plasmodium ovale; Indonesia; Malaria; Coinfection
PubMed: 36999258
DOI: No ID Found -
Diagnostics (Basel, Switzerland) Oct 2021Nowadays, is divided into two non-recombinant sympatric species: and . In this mini review, we summarize the available knowledge on the clinical/biological aspects of... (Review)
Review
Nowadays, is divided into two non-recombinant sympatric species: and . In this mini review, we summarize the available knowledge on the clinical/biological aspects of spp. malaria and current techniques for the diagnosis/characterisation of and . infections are characterized by a deeper thrombocytopenia and shorter latency compared to infections, indicating that is more pathogenic than . Rapid diagnosis for effective management is difficult for spp., since specific rapid diagnostic tests are not available and microscopic diagnosis, which is recognized as the gold standard, requires expert microscopists to differentiate spp. from other species. Neglect in addressing these issues in the prevalence of spp. represents the existing gap in the fight against malaria.
PubMed: 34679597
DOI: 10.3390/diagnostics11101900 -
Scientific Reports Mar 2021Malaria caused by Plasmodium ovale species is considered a neglected tropical disease with limited information about its characteristics. It also remains unclear whether... (Comparative Study)
Comparative Study Meta-Analysis
Malaria caused by Plasmodium ovale species is considered a neglected tropical disease with limited information about its characteristics. It also remains unclear whether the two distinct species P. ovale curtisi and P. ovale wallikeri exhibit differences in their prevalence, geographic distribution, clinical characteristics, or laboratory parameters. Therefore, this study was conducted to clarify these differences to support global malaria control and eradication programs. Studies reporting the occurrence of P. ovale curtisi and P. ovale wallikeri were explored in databases. Differences in proportion, clinical data, and laboratory parameters between the two species were estimated using a random-effects model and expressed as pooled odds ratios (ORs), mean difference (MD), or standardized MD depending on the types of extracted data. The difference in geographical distribution was visualized by mapping the origin of the two species. A total of 1453 P. ovale cases extracted from 35 studies were included in the meta-analysis. The p-value in the meta-analyses provided evidence favoring a real difference between P. ovale curtisi malaria cases (809/1453, 55.7%) and P. ovale wallikeri malaria cases (644/1453, 44.3%) (p: 0.01, OR 1.61, 95% CI 0.71-3.63, I: 77%). Subgroup analyses established evidence favoring a real difference between P. ovale curtisi and P. ovale wallikeri malaria cases among the imported cases (p: 0.02, 1135 cases). The p value in the meta-analyses provided evidence favoring a real difference in the mean latency period between P. ovale curtisi (289 cases) and P. ovale wallikeri malaria (266 cases) (p: 0.03, MD: 27.59, 95% CI 1.99-53.2, I: 94%), total leukocyte count (p < 0.0001, MD: 840, 95% CI 610-1070, I: 0%, two studies) and platelet count (p < 0.0001, MD: 44,750, 95% CI 2900-60,500, I: 32%, three studies). Four continents were found to have reports of P. ovale spp., among which Africa had the highest number of reports for both P. ovale spp. in its 37 countries, with a global proportion of 94.46%, and an almost equal distribution of both P. ovale spp., where P. ovale curtisi and P. ovale wallikeri reflected 53.09% and 46.90% of the continent's proportion, respectively. This is the first systematic review and meta-analysis to demonstrate the differences in the characteristics of the two distinct P. ovale species. Malaria caused by P. ovale curtisi was found in higher proportions among imported cases and had longer latency periods, higher platelet counts, and higher total leukocyte counts than malaria caused by P. ovale wallikeri. Further studies with a larger sample size are required to confirm the differences or similarities between these two species to promote malaria control and effective eradication programs.
Topics: Adolescent; Adult; Africa; Asia; Australia; Child; Child, Preschool; Communicable Diseases, Imported; Europe; Female; Genes, Protozoan; Humans; Malaria; Male; Middle Aged; Neglected Diseases; Plasmodium ovale; Polymerase Chain Reaction; Prevalence; RNA, Protozoan; Young Adult
PubMed: 33742015
DOI: 10.1038/s41598-021-85398-w -
The Journal of Infectious Diseases Apr 2024
Topics: Humans; Plasmodium ovale; Plasmodium malariae; Malaria; Plasmodium
PubMed: 38243611
DOI: 10.1093/infdis/jiae015 -
The American Journal of Tropical... Dec 2014Splenic infarction is a rare complication of malaria. We report two recent cases of splenic infarction after Plasmodium vivax infection. No systematic review of...
Splenic infarction is a rare complication of malaria. We report two recent cases of splenic infarction after Plasmodium vivax infection. No systematic review of malaria-induced splenic infarction was available, therefore we conducted a systematic review of the English, French, and Spanish literature in PubMed and KoreaMed for reports of malaria-associated splenic infarction from 1960 to 2012. Of the 40 cases collected on splenic infarction by Plasmodium species, 23 involved P. vivax, 11 Plasmodium falciparum, one Plasmodium ovale, and five a mixed infection of P. vivax and P. falciparum. Of the 40 cases, 2 (5.0%) involved splenectomy and 5 (12.5%) were accompanied by splenic rupture. The median time from symptom onset to diagnosis was 8.5 days (range, 3-90 days). Improved findings after treatment were observed in 8 (88.9%) of 9 patients with splenic infarction on follow-up by computed tomography or ultrasonography. All patients survived after treatment with the exception of one patient with cerebral malaria. Clinicians should consider the possibility of splenic infarction when malaria-infected patients have left upper quadrant pain.
Topics: Adult; Female; Humans; Malaria; Male; Middle Aged; Splenic Infarction; Tomography, X-Ray Computed
PubMed: 25294615
DOI: 10.4269/ajtmh.14-0190