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Clinica Chimica Acta; International... Jan 2023Blood smear examination through traditional optical microscopy is the gold standard for malaria diagnosis. However, it imposes strict requirements for operational staff...
BACKGROUND
Blood smear examination through traditional optical microscopy is the gold standard for malaria diagnosis. However, it imposes strict requirements for operational staff and its sensitivity cannot perfectly satisfy the needs of clinical requirements. More sensitive and accurate modern technologies should be applied to this field. Digital PCR (dPCR), as an absolute quantification detection method, can serve as an effective tool to facilitate the diagnosis and classification of different malaria species.
OBJECTIVE
We aimed to establish a new multiplex dPCR detection system for four main Plasmodium species: P. vivax, P. falciparum, P. ovale and P. malariae, which can distinguish exact species of malaria by one PCR reaction.
METHODS
A total of 39 patients were identified as malaria-positive by microscopic examination in Huashan Hospital from 2016 to 2021; seventy blood samples from these patients were collected. Additionally, 20 healthy individuals, 20 patients with fever and 6 patients with other types of blood parasites infection were also included in this study. Each blood sample was subjected to examination by both blood smears and dPCR. By optimizing four different fluorescence-labeled probes in one reaction system, dPCR permitted the performance of accurate quantitation and working out the exact number of copies of malaria DNA per microliter in whole blood. Rapid diagnostic tests were also conducted to verify part of the results obtained by dPCR.
RESULTS
The dPCR system was able to make rapid diagnosis and quantification of malaria DNA samples. The analytical sensitivity of multiplex dPCR was as low as 0.557 copies/μL (95% CI 0.521 to 0.607), and it had a sensitivity of 98.0% and a specificity of 100% in clinical samples. Additionally, three multiple malaria co-infection samples have been detected by this dPCR system, including one triple malaria infection case. By testing consecutive daily blood samples of Patient 39, dPCR facilitated monitoring the efficacy of drug treatment. It showed that the DNA concentrations of P. falciparum ranged from 5474 copies/μL to 0 copies/μL, which can reflect the efficacy of antimalarials in real time. This study also found that haemocyte samples (plasma removed) rather than whole blood had higher malaria detection capability and an enhanced positive rate.
CONCLUSION
The multiplex dPCR system newly established here made a substantial contribution in detecting malaria infection at low concentrations. It is suitable for mixed-infection diagnosis and multi-sample continuous monitoring, and presents a promising candidate as an absolute quantitative tool in clinical practice.
Topics: Animals; Humans; Parasites; Sensitivity and Specificity; Malaria; Malaria, Falciparum; Malaria, Vivax; Multiplex Polymerase Chain Reaction; Plasmodium vivax; Plasmodium falciparum
PubMed: 36495929
DOI: 10.1016/j.cca.2022.12.001 -
PLoS Neglected Tropical Diseases Dec 2022Plasmodium ovale curtisi and P. ovale wallikeri are both endemic in sub-Saharan Africa, the Middle East and Southeast Asia. Molecular surveillance data for drug...
Plasmodium ovale curtisi and P. ovale wallikeri are both endemic in sub-Saharan Africa, the Middle East and Southeast Asia. Molecular surveillance data for drug resistance in P. ovale spp. is limited at present. We analysed polymorphisms in the podhfr, pocrt and pocytb genes of P. ovale spp. in 147 samples collected from travelers returning to China from Africa. Two podhfr mutations, S58R and S113N/T were detected in P. ovale curtisi with high/moderate frequencies of 52.17% and 17.39%, respectively. Evidence of positive selection (dN/dS = 2.41) was found for podhfr in P. ovale curtisi and decreased diversity (He) of microsatellite markers flanking the mutant alleles suggests that selective sweeps have occurred for both. Mutations E34G (1.50%) and L43V (1.50%) in pocrt of P. ovale curtisi, and E34G (3.70%), I102M (1.80%) and V111F (1.80%) of P. ovale wallikeri were found at low frequencies. Mutations R66K (6.20%), R75K (11.63%) and R95K (3.88%) of pocytb were found in both P. ovale curtisi and P. ovale wallikeri. These results suggest that the podhfr gene of P. ovale curtisi may be subject to drug selection in Africa, warranting further attention. We observed significant differences in the prevalence and distribution of podhfr mutations between the two P. ovale species, suggestive of fundamental biological differences between them.
Topics: Humans; Plasmodium ovale; Tetrahydrofolate Dehydrogenase; Malaria; Africa; Mutation
PubMed: 36469541
DOI: 10.1371/journal.pntd.0010977 -
BMC Infectious Diseases Dec 2022There are growing reports on the prevalence of non-falciparum species and submicroscopic infections in sub-Saharan African countries but little information is available...
BACKGROUND
There are growing reports on the prevalence of non-falciparum species and submicroscopic infections in sub-Saharan African countries but little information is available from Cameroon.
METHODS
A hospital-based cross-sectional study was carried out in four towns (Douala, Maroua, Mayo-Oulo, and Pette) from three malaria epidemiological strata (Forest, Sahelian, and Soudanian) of Cameroon. Malaria parasites were detected by Giemsa light microscopy and polymerase chain reaction (PCR) assay. Non-falciparum isolates were characterized and their 18S gene sequences were BLASTed for confirmatory diagnosis.
RESULTS
PCR assay detected malaria parasites in 82.4% (98/119) patients, among them 12.2% (12/98) were asymptomatic cases. Three Plasmodium species viz. P. falciparum, P. ovale curtisi and P. vivax, and two co-infection types (P. falciparum + P. vivax and P. falciparum + P. ovale curtisi) were found. The remaining infections were mono-infections with either P. falciparum or P. ovale curtisi. All non-falciparum infections were symptomatic and microscopic. The overall proportion of submicroscopic infections was 11.8% (14/119). Most asymptomatic and submicroscopic infection cases were self-medicated with antimalarial drugs and/or medicinal plants. On analysis, P. ovale curtisi sequences were found to be phylogenetically closer to sequences from India while P. vivax isolates appeared closer to those from Nigeria, India, and Cameroon. No G6PD-d case was found among non-falciparum infections.
CONCLUSIONS
This study confirms our previous work on circulation of P. vivax and P. ovale curtisi and the absence of P. knowlesi in Cameroon. More studies are needed to address non-falciparum malaria along with submicroscopic infections for effective malaria management and control in Cameroon.
Topics: Humans; Cameroon; Cross-Sectional Studies; Malaria; Malaria, Vivax; Antimalarials; Malaria, Falciparum
PubMed: 36460990
DOI: 10.1186/s12879-022-07901-6 -
Frontiers in Pharmacology 2022Clinical trial and individual patient treatment outcomes have produced accumulating evidence that effective primaquine (PQ) treatment of and liver stage hypnozoites is... (Review)
Review
Clinical trial and individual patient treatment outcomes have produced accumulating evidence that effective primaquine (PQ) treatment of and liver stage hypnozoites is associated with genetic variation in the human cytochrome P450 gene, . Successful PQ treatment of individual and population-wide infections by the species that generate these dormant liver stage forms is likely to be necessary to reach elimination of malaria caused by these parasites globally. Optimizing safe and effective PQ treatment will require coordination of efforts between the malaria and pharmacogenomics research communities.
PubMed: 36457706
DOI: 10.3389/fphar.2022.752314 -
Scientific Data Nov 2022Plasmodium cynomolgi causes zoonotic malarial infections in Southeast Asia and this parasite species is important as a model for Plasmodium vivax and Plasmodium ovale....
Plasmodium cynomolgi causes zoonotic malarial infections in Southeast Asia and this parasite species is important as a model for Plasmodium vivax and Plasmodium ovale. Each of these species produces hypnozoites in the liver, which can cause relapsing infections in the blood. Here we present methods and data generated from iterative longitudinal systems biology infection experiments designed and performed by the Malaria Host-Pathogen Interaction Center (MaHPIC) to delve deeper into the biology, pathogenesis, and immune responses of P. cynomolgi in the Macaca mulatta host. Infections were initiated by sporozoite inoculation. Blood and bone marrow samples were collected at defined timepoints for biological and computational experiments and integrative analyses revolving around primary illness, relapse illness, and subsequent disease and immune response patterns. Parasitological, clinical, haematological, immune response, and -omic datasets (transcriptomics, proteomics, metabolomics, and lipidomics) including metadata and computational results have been deposited in public repositories. The scope and depth of these datasets are unprecedented in studies of malaria, and they are projected to be a F.A.I.R., reliable data resource for decades.
Topics: Animals; Host-Pathogen Interactions; Macaca mulatta; Malaria; Plasmodium cynomolgi; Sporozoites; Systems Biology; Zoonoses
PubMed: 36433985
DOI: 10.1038/s41597-022-01755-y -
Cureus Oct 2022Malaria is a global health concern with high morbidity and mortality. It is often attributed to the species, particularly in sub-Saharan Africa, and it normally has an...
Malaria is a global health concern with high morbidity and mortality. It is often attributed to the species, particularly in sub-Saharan Africa, and it normally has an incubation period of seven to 14 days. Dormant disease secondary to and is well-reported, yet only a handful of cases report dormant malaria secondary to . Even though malaria is significantly less common in the United States in comparison to other parts of the world, it is still a growing concern given international travel from endemic regions and a growing immunocompromised population. Here, we present a case of malaria in a patient with systemic lupus erythematosus (SLE) with neuromyelitis optica spectrum disorder (NMOSD) and renal transplant without travel to sub-Saharan Africa in 10 years.
PubMed: 36407205
DOI: 10.7759/cureus.30436 -
Frontiers in Genetics 2022Many standard-textbook population-genetic results apply to a wide range of species. Sometimes, however, population-genetic models and principles need to be tailored to a...
Many standard-textbook population-genetic results apply to a wide range of species. Sometimes, however, population-genetic models and principles need to be tailored to a particular species. This is particularly true for malaria, which next to tuberculosis and HIV/AIDS ranks among the economically most relevant infectious diseases. Importantly, malaria is not one disease-five human-pathogenic species of exist. is not only the most severe form of human malaria, but it also causes the majority of infections. The second most relevant species, , is already considered a neglected disease in several endemic areas. All human-pathogenic species have distinct characteristics that are not only crucial for control and eradication efforts, but also for the population-genetics of the disease. This is particularly true in the context of selection. Namely, fitness is determined by so-called fitness components, which are determined by the parasites live-history, which differs between malaria species. The presence of hypnozoites, i.e., dormant liver-stage parasites, which can cause disease relapses, is a distinct feature of and sp. In inactivated blood-stage parasites can cause a recrudescence years after the infection was clinically cured. To properly describe population-genetic processes, such as the spread of anti-malarial drug resistance, these features must be accounted for appropriately. Here, we introduce and extend a population-genetic framework for the evolutionary dynamics of malaria, which applies to all human-pathogenic malaria species. The model focuses on, but is not limited to, the spread of drug resistance. The framework elucidates how the presence of dormant liver stage or inactivated blood stage parasites that act like seed banks delay evolutionary processes. It is shown that, contrary to standard population-genetic theory, the process of selection and recombination cannot be decoupled in malaria. Furthermore, we discuss the connection between haplotype frequencies, haplotype prevalence, transmission dynamics, and relapses or recrudescence in malaria.
PubMed: 36406132
DOI: 10.3389/fgene.2022.1030463 -
The Canadian Journal of Infectious... 2022Qualified microscopy competency is a key indicator for certification of malaria elimination. To better prepare the country certification and identify the priorities that...
INTRODUCTION
Qualified microscopy competency is a key indicator for certification of malaria elimination. To better prepare the country certification and identify the priorities that need improvement to prevent malaria reestablishment, microscopy competency at different levels were assessed in subnational verification of malaria elimination in China. . Microscopist representatives from centers for disease control and prevention (CDC)/institutes of parasitic diseases (IPD) and medical institutes for malaria diagnosis at the provincial and county levels in the subnational verification were analyzed. Specifically, five provincial microscopist representatives and ten county-level representatives were assessed in each of previously endemic provinces on qualitative identification ( positive or negative) and species identification using standard slides from the National Malaria Diagnosis Reference Laboratory.
RESULTS
A total of 100 provincial-level representatives (60 from 42 CDCs/IPDs and 40 from 34 medical institutes) and 200 county-level representatives (61 from 41 CDCs and 139 from 118 medical institutes) were included. The qualitative accuracy was higher than 90% each ( = 0.137), but slides with low parasite density were easy to be misdiagnosed as negative. Furthermore, the accuracy of species identification was 80.0% and 83.6% in medical institutes and centers for disease control and prevention (CDCs) at the provincial level ( = 0.407) with relatively high misdiagnosis of as in the latter (16.2%) and 82.0% and 85.0% in medical institutes and CDCs at the county level ( = 0.330) for the identification of and non- with higher false-negative in medical institutions ( < 0.001).
CONCLUSIONS
In conclusion, competent microscopy in subnational verification supported the quality in eliminating malaria in China, while the accurate identification of malaria parasites, especially slides with low parasite density still need to be improved through continuous diagnostic platform construction, continuous technological innovation, and targeted training to prevent reestablishment of malaria transmission.
PubMed: 36349187
DOI: 10.1155/2022/8003845 -
Frontiers in Public Health 2022Primaquine, the only licensed antimalarial drug for eradication of and malaria, may cause acute hemolytic anemia in individuals with glucose-6-phosphate dehydrogenase...
Primaquine, the only licensed antimalarial drug for eradication of and malaria, may cause acute hemolytic anemia in individuals with glucose-6-phosphate dehydrogenase deficiency (G6PDd) during treatment. The different prevalence and distribution patterns of G6PDd in Hainan, the ancient malaria-endemic area, are unclear. This study included 5,622 suspected malaria patients between 2009 and 2011 in 11 counties of Hainan. Glucose-6-phosphate dehydrogenase deficiency prevalence was determined using the fluorescent spot test (FST) and malaria patients was confirmed by a positive light microscopy. The G6PDd prevalence for different ethnic groups, genders, and counties were calculated and compared using χ-test. Spatial cluster and Spearman rank correlation of G6PDd prevalence and malaria incidence were analyzed. The overall G6PDd prevalence of study population was 7.45%. The G6PDd prevalence of males, Li ethnic minority, and malaria patients was significantly higher than that of females, Han ethnic majority, and non-malarial patients ( < 0.01), respectively. The spatial cluster of G6PDd and malaria located in south-western and central-southern Hainan, respectively, with no significant correlation. The study provides essential information on G6PDd prevalence in ancient malaria-endemic areas of Hainan Province. We also highlight the need for a better understanding of the mechanisms underlying the relationship between G6PDd prevalence and malaria incidence. These findings provide a reference for the safety of the primaquine-based intervention, even after malaria elimination.
Topics: Humans; Female; Male; Primaquine; Glucosephosphate Dehydrogenase Deficiency; Prevalence; Ethnicity; Minority Groups; Malaria; China
PubMed: 36339224
DOI: 10.3389/fpubh.2022.1010172 -
Scientific Reports Nov 2022The simian parasite Plasmodium knowlesi is the predominant species causing human malaria infection, including hospitalisations for severe disease and death, in Malaysian...
The simian parasite Plasmodium knowlesi is the predominant species causing human malaria infection, including hospitalisations for severe disease and death, in Malaysian Borneo. By contrast, there have been only a few case reports of knowlesi malaria from Indonesian Borneo. This situation seems paradoxical since both regions share the same natural macaque hosts and Anopheles mosquito vectors, and therefore have a similar epidemiologically estimated risk of infection. To determine whether there is a true cross-border disparity in P. knowlesi prevalence, we conducted a community-based malaria screening study using PCR in Kapuas Hulu District, West Kalimantan. Blood samples were taken between April and September 2019 from 1000 people aged 6 months to 85 years attending health care facilities at 27 study sites within or close to jungle areas. There were 16 Plasmodium positive samples by PCR, five human malarias (two Plasmodium vivax, two Plasmodium ovale and one Plasmodium malariae) and 11 in which no species could be definitively identified. These data suggest that, if present, simian malarias including P. knowlesi are rare in the Kapuas Hulu District of West Kalimantan, Indonesian Borneo compared to geographically adjacent areas of Malaysian Borneo. The reason for this discrepancy, if confirmed in other epidemiologically similar regions of Indonesian Borneo, warrants further studies targeting possible cross-border differences in human activities in forested areas, together with more detailed surveys to complement the limited data relating to monkey hosts and Anopheles mosquito vectors in Indonesian Borneo.
Topics: Animals; Humans; Indonesia; Plasmodium knowlesi; Malaria; Anopheles; Mosquito Vectors; Haplorhini; Malaysia
PubMed: 36329096
DOI: 10.1038/s41598-022-21570-0