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The American Journal of Tropical... Aug 2021Plasmodium malariae infections are often asymptomatic and long-lasting. Mixed infections are often underdetected in areas where P. malariae, P. vivax, and P. falciparum...
Plasmodium malariae infections are often asymptomatic and long-lasting. Mixed infections are often underdetected in areas where P. malariae, P. vivax, and P. falciparum are coendemic. In this study, we described the occurrence of these species circulating as single or mixed infections in Pará state, Brazil, in the Amazon region, with the purpose of clarifying the impact of misidentification of parasite species based only on morphological description using thick blood smear. By using real-time polymerase chain reaction based on the amplification of the mitochondrial DNA, we detected a prevalence of 46% (58/126) mixed infections with 33.3% P. malariae/P. vivax which were read as P. vivax monoinfections by microscopy detection. Our findings confirmed the high circulation of P. malariae in a malaria endemic area in the Brazilian Amazon region.
Topics: Brazil; Coinfection; Endemic Diseases; Humans; Malaria; Plasmodium falciparum; Plasmodium malariae; Plasmodium vivax; Prevalence
PubMed: 34370704
DOI: 10.4269/ajtmh.21-0296 -
Parasitology International Apr 2022Information about Plasmodium malariae is scanty worldwide due to its "benign" nature and low infection rates. Consequently, studies on the genetic polymorphisms of P....
Information about Plasmodium malariae is scanty worldwide due to its "benign" nature and low infection rates. Consequently, studies on the genetic polymorphisms of P. malariae are lacking. Here, we report genetic polymorphisms of 28 P. malariae circumsporozoite protein (Pmcsp) isolates from Malaysia which were compared with those in other regions in Asia as well as those from Africa. Phylogenetic analysis revealed that most Malaysian P. malariae isolates clustered together but independently from other Asian isolates. Low nucleotide diversity was observed in Pmcsp non-repeat regions in contrast to high nucleotide diversity observed in non-repeat regions of Plasmodium knowlesi CSP gene, the current major cause of malaria in Malaysia. This study contributes to the characterisation of naturally occurring polymorphisms in the P. malariae CSP gene.
Topics: Amino Acid Sequence; Malaria; Malaysia; Nucleotides; Phylogeny; Plasmodium knowlesi; Plasmodium malariae; Polymorphism, Genetic; Protozoan Proteins
PubMed: 34800724
DOI: 10.1016/j.parint.2021.102519 -
Malaria Journal Apr 2021Plasmodium knowlesi is recognized as the fifth Plasmodium species causing malaria in humans. It is morphologically similar to the human malaria parasite Plasmodium...
BACKGROUND
Plasmodium knowlesi is recognized as the fifth Plasmodium species causing malaria in humans. It is morphologically similar to the human malaria parasite Plasmodium malariae, so molecular detection should be used to clearly discriminate between these Plasmodium species. This study aimed to quantify the rate at which P. knowlesi is misidentified as P. malariae by microscopy in endemic and non-endemic areas.
METHODS
The protocol of this systematic review was registered in the PROSPERO International Prospective Register of Systematic Reviews (ID = CRD42020204770). Studies reporting the misidentification of P. knowlesi as P. malariae by microscopy and confirmation of this by molecular methods in MEDLINE, Web of Science and Scopus were reviewed. The risk of bias in the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS). The pooled prevalence and 95% confidence interval (CI) of the misidentification of P. knowlesi as P. malariae by microscopy were estimated using a random effects model. Subgroup analysis of the study sites was performed to demonstrate any differences in the misidentification rates in different areas. Heterogeneity across the included studies was assessed and quantified using Cochran's Q and I statistics, respectively. Publication bias in the included studies was assessed using the funnel plot, Egger's test and contour-enhanced funnel plot.
RESULTS
Among 375 reviewed studies, 11 studies with a total of 1569 confirmed P. knowlesi cases in humans were included. Overall, the pooled prevalence of the misidentification of P. knowlesi as P. malariae by microscopy was estimated at 57% (95% CI 37-77%, I: 99.3%). Subgroup analysis demonstrated the highest rate of misidentification in Sawarak, Malaysia (87%, 95% CI 83-90%, I: 95%), followed by Sabah, Malaysia (85%, 95% CI 79-92%, I: 85.1%), Indonesia (16%, 95% CI 6-38%), and then Thailand (4%, 95% CI 2-9%, I: 95%).
CONCLUSION
Although the World Health Organization (WHO) recommends that all P. malariae-positive diagnoses made by microscopy in P. knowlesi endemic areas be reported as P. malariae/P. knowlesi malaria, the possibility of microscopists misidentifying P. knowlesi as P. malariae is a diagnostic challenge. The use of molecular techniques in cases with malariae-like Plasmodium with high parasite density as determined by microscopy could help identify human P. knowlesi cases in non-endemic countries.
Topics: Humans; Malaria; Microscopy; Plasmodium knowlesi; Plasmodium malariae; Prevalence
PubMed: 33836773
DOI: 10.1186/s12936-021-03714-1 -
Nature Communications Apr 2022The human parasite Plasmodium malariae has relatives infecting African apes (Plasmodium rodhaini) and New World monkeys (Plasmodium brasilianum), but its origins remain...
The human parasite Plasmodium malariae has relatives infecting African apes (Plasmodium rodhaini) and New World monkeys (Plasmodium brasilianum), but its origins remain unknown. Using a novel approach to characterise P. malariae-related sequences in wild and captive African apes, we found that this group comprises three distinct lineages, one of which represents a previously unknown, highly divergent species infecting chimpanzees, bonobos and gorillas across central Africa. A second ape-derived lineage is much more closely related to the third, human-infective lineage P. malariae, but exhibits little evidence of genetic exchange with it, and so likely represents a separate species. Moreover, the levels and nature of genetic polymorphisms in P. malariae indicate that it resulted from the zoonotic transmission of an African ape parasite, reminiscent of the origin of P. falciparum. In contrast, P. brasilianum falls within the radiation of human P. malariae, and thus reflects a recent anthroponosis.
Topics: Animals; Hominidae; Humans; Malaria; Malaria, Falciparum; Phylogeny; Plasmodium; Plasmodium malariae
PubMed: 35387986
DOI: 10.1038/s41467-022-29306-4 -
Malaria Journal Aug 2021Plasmodium malariae is the cause of the rare but severe form of malaria that sometimes affects individuals travelling to malaria-endemic regions. This report presents...
BACKGROUND
Plasmodium malariae is the cause of the rare but severe form of malaria that sometimes affects individuals travelling to malaria-endemic regions. This report presents the unique case of a patient exhibiting severe malaria symptoms caused by P. malariae with no record of recent travel to any malaria-endemic areas.
CASE PRESENTATION
An 81-year-old French woman was admitted to the emergency department with sustained fever and severe weakness for the past 5 days. She suffered from anaemia, thrombocytopenia, confusion, somnolence, pulmonary complications, and hypoxaemia. In the absence of any concrete aetiology that could explain the fever together with thrombocytopenia, physicians suspected malaria as a probable diagnosis. The LAMP-PCR and lateral flow test confirmed the presence of malaria parasite, Plasmodium sp. Microscopic examination (May-Grünwald Giemsa-stained thin blood smear) revealed the presence of trophozoites, schizonts, and gametocytes with 0.93 % parasitaemia. Conventional PCR amplification targeting 510 bp DNA fragment of small subunit ribosomal RNA (ssrRNA) and bidirectional sequencing identified the parasite as Plasmodium malariae. The travel history of this patient revealed her visits to several countries in Europe (Greece), North Africa (Tunisia and Morocco), and the West Indies (Dominican Republic). Of these, the latter was the only country known to be endemic for malaria at the time (three malaria parasite species were prevalent: Plasmodium falciparum, Plasmodium vivax, and P. malariae). The patient had most likely got infected when she visited the Dominican Republic in the summer of 2002. This time interval between the initial parasite infection (2002) till the onset of symptoms and its subsequent diagnosis (2020) is a reminder of the ability of P. malariae to persist in the human host for many years.
CONCLUSIONS
This report highlights the persistent nature and ability of P. malariae to cause severe infection in the host even after a prolonged time interval.
Topics: Aged, 80 and over; Dominican Republic; Female; France; Humans; Malaria; Plasmodium malariae; Time Factors; Travel
PubMed: 34353333
DOI: 10.1186/s12936-021-03870-4 -
Parasite (Paris, France) 2020Microsatellites can be utilized to explore genotypes, population structure, and other genomic features of eukaryotes. Systematic characterization of microsatellites has...
Microsatellites can be utilized to explore genotypes, population structure, and other genomic features of eukaryotes. Systematic characterization of microsatellites has not been a focus for several species of Plasmodium, including P. malariae and P. ovale, as the majority of malaria elimination programs are focused on P. falciparum and to a lesser extent P. vivax. Here, five human malaria species (P. falciparum, P. vivax, P. malariae, P. ovale curtisi, and P. knowlesi) were investigated with the aim of conducting in-depth categorization of microsatellites for P. malariae and P. ovale curtisi. Investigation of reference genomes for microsatellites with unit motifs of 1-10 base pairs indicates high diversity among the five Plasmodium species. Plasmodium malariae, with the largest genome size, displays the second highest microsatellite density (1421 No./Mbp; 5% coverage) next to P. falciparum (3634 No./Mbp; 12% coverage). The lowest microsatellite density was observed in P. vivax (773 No./Mbp; 2% coverage). A, AT, and AAT are the most commonly repeated motifs in the Plasmodium species. For P. malariae and P. ovale curtisi, microsatellite-related sequences are observed in approximately 18-29% of coding sequences (CDS). Lysine, asparagine, and glutamic acids are most frequently coded by microsatellite-related CDS. The majority of these CDS could be related to the gene ontology terms "cell parts," "binding," "developmental processes," and "metabolic processes." The present study provides a comprehensive overview of microsatellite distribution and can assist in the planning and development of potentially useful genetic tools for further investigation of P. malariae and P. ovale curtisi epidemiology.
Topics: Gene Ontology; Genome, Protozoan; Genotype; Microsatellite Repeats; Plasmodium; Plasmodium malariae; Plasmodium ovale; Tandem Repeat Sequences
PubMed: 32410726
DOI: 10.1051/parasite/2020034 -
Journal of Clinical Microbiology Dec 2004There have been reports of increasing numbers of cases of malaria among migrants and travelers. Although microscopic examination of blood smears remains the "gold... (Comparative Study)
Comparative Study
There have been reports of increasing numbers of cases of malaria among migrants and travelers. Although microscopic examination of blood smears remains the "gold standard" in diagnosis, this method suffers from insufficient sensitivity and requires considerable expertise. To improve diagnosis, a multiplex real-time PCR was developed. One set of generic primers targeting a highly conserved region of the 18S rRNA gene of the genus Plasmodium was designed; the primer set was polymorphic enough internally to design four species-specific probes for P. falciparum, P. vivax, P. malarie, and P. ovale. Real-time PCR with species-specific probes detected one plasmid copy of P. falciparum, P. vivax, P. malariae, and P. ovale specifically. The same sensitivity was achieved for all species with real-time PCR with the 18S screening probe. Ninety-seven blood samples were investigated. For 66 of them (60 patients), microscopy and real-time PCR results were compared and had a crude agreement of 86% for the detection of plasmodia. Discordant results were reevaluated with clinical, molecular, and sequencing data to resolve them. All nine discordances between 18S screening PCR and microscopy were resolved in favor of the molecular method, as were eight of nine discordances at the species level for the species-specific PCR among the 31 samples positive by both methods. The other 31 blood samples were tested to monitor the antimalaria treatment in seven patients. The number of parasites measured by real-time PCR fell rapidly for six out of seven patients in parallel to parasitemia determined microscopically. This suggests a role of quantitative PCR for the monitoring of patients receiving antimalaria therapy.
Topics: Animals; DNA, Protozoan; Humans; Malaria; Plasmodium; Plasmodium falciparum; Plasmodium malariae; Plasmodium ovale; Plasmodium vivax; Polymerase Chain Reaction; RNA, Ribosomal, 18S; Sensitivity and Specificity; Species Specificity
PubMed: 15583293
DOI: 10.1128/JCM.42.12.5636-5643.2004 -
Transactions of the Royal Society of... Jan 2010We describe a 32-year-old Bangladeshi male presenting with severe malaria caused by a mono-infection with Plasmodium malariae. Rosetting of infected and uninfected...
We describe a 32-year-old Bangladeshi male presenting with severe malaria caused by a mono-infection with Plasmodium malariae. Rosetting of infected and uninfected erythrocytes, a putative virulence factor in falciparum malaria, was observed in the blood slide. Severe disease caused by P. malariae is extremely rare. The patient made a rapid recovery with intravenous quinine treatment.
Topics: Adult; Antimalarials; Bangladesh; Humans; Malaria; Male; Plasmodium malariae; Polymerase Chain Reaction; Quinine; Rosette Formation; Treatment Outcome
PubMed: 19818463
DOI: 10.1016/j.trstmh.2009.06.014 -
Parasitology International Feb 2018The gold standard for malaria diagnosis is the microscopic examination of Giemsa stained thick blood smears though microscopy mostly may not detect the presence of...
The gold standard for malaria diagnosis is the microscopic examination of Giemsa stained thick blood smears though microscopy mostly may not detect the presence of Plasmodium species infections in asymptomatic samples. In the reported study, we used two diagnostic methods viz. the conventional microscopic examination and polymerase chain reaction (PCR) assay to analyse the asymptomatic malaria samples. PCR assay amplifying 18S small-subunit ribosomal RNA (SSU rRNA) gene of Plasmodium in 122 samples confirmed 68% of isolates as asymptomatic P. falciparum infections; with 87.9% mono-infections. We observed that the P. malariae positive samples were not diagnosed in microscopic examination of the blood smears but the PCR based diagnostic method revealed the presence of 12% P. malariae infections in asymptomatic samples from Yaoundé region of Cameroon where no official cases of P. malariae have been reported for over a decade. The sequence analysis further confirmed the presence of 12% P. malariae in malaria positive samples with three base pair deletions and five substitutions in the SSU rRNA gene.
Topics: Adolescent; Asymptomatic Infections; Base Sequence; Cameroon; Child; Child, Preschool; DNA, Protozoan; Female; Humans; Malaria; Male; Microscopy; Plasmodium malariae; Polymerase Chain Reaction; RNA, Ribosomal, 18S; Sequence Alignment
PubMed: 28263883
DOI: 10.1016/j.parint.2017.02.009 -
International Journal of Infectious... May 2014Since the initial discovery of Plasmodium knowlesi in Malaysia, cases have been reported from several neighbouring countries. Tourism has also resulted in an increasing... (Review)
Review
OBJECTIVES
Since the initial discovery of Plasmodium knowlesi in Malaysia, cases have been reported from several neighbouring countries. Tourism has also resulted in an increasing number of cases diagnosed in Europe, America, and Oceania. In this review we focus on the risk of the travel-associated acquisition of P. knowlesi malaria.
METHODS
A search of the literature in PubMed was carried out to identify articles and literature on the distribution of P. knowlesi infections in Southeast Asia and details of its acquisition and importation by travellers to other continents. The cut-off date for the search was December 1, 2013. Search words used were: "Plasmodium knowlesi", "Plasmodium knowlesi infections", "Plasmodium knowlesi travellers", "Plasmodium knowlesi prevalence", "Plasmodium knowlesi host", "Plasmodium knowlesi vector" "Plasmodium knowlesi RDT", and "Plasmodium knowlesi Malaysia". Traveller numbers to Malaysia were obtained from the Tourism Malaysia website.
RESULTS
A total of 103 articles were found. Using a selection of these and others identified from the reference lists of the papers, we based our review on a total of 66 articles.
RESULTS
P. knowlesi malaria appears to be the most common malaria species in Malaysian Borneo and is also widely distributed on the Malaysian mainland. Furthermore, locally transmitted cases of P. knowlesi malaria have been reported in Thailand, the Philippines, Vietnam, Singapore, Myanmar, Indonesian Borneo, and Cambodia. Two cases have been reported from non-endemic countries in Asia (Japan and Taiwan) in people with a history of travel to Malaysia and the Philippines. Twelve cases were imported to their home countries by travellers from other continents: two from the USA, two from the Netherlands, two from Germany, and one each from Spain, France, Sweden, Finland, Australia, and New Zealand. In most cases, the infection was associated with a trip to or near forested areas. The symptoms were fever (n=12), headache (n=6), chills (n=6), nausea (n=4), myalgia (n=3), back pain (n=3), abdominal problems (n=1), anorexia (n=2), fatigue (n=2), malaise (n=1), arthralgia (n=1), sore throat (n=1) vomiting (n=2), and jaundice (n=1). All patients were treated successfully with currently available antimalaria treatments. The identification of the pathogen by microscopy can be problematic due to the morphological similarity of P. knowlesi to Plasmodium malariae.
CONCLUSION
P. knowlesi appears to be a threat not only to the local population in Malaysia, but also to the estimated 25 million annual tourists and occupational travellers to Malaysia, especially those who visit rural, forested areas of the country. The P. knowlesi risk is not limited to Malaysia, and travellers from Southeast Asia presenting with possible malaria should be considered for a diagnostic work-up that includes P. knowlesi.
Topics: Adult; Animals; Antimalarials; Asia, Southeastern; Child; Diagnosis, Differential; Female; Humans; Macaca fascicularis; Malaria; Male; Plasmodium knowlesi; Plasmodium malariae; Travel
PubMed: 24631521
DOI: 10.1016/j.ijid.2013.12.016