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Toxics Feb 2023Primaquine (PQ) is the only antimalarial medication used to eradicate many species of gametocytes and prevent relapse in vivax and ovale malarias. PQ metabolites induce...
Primaquine (PQ) is the only antimalarial medication used to eradicate many species of gametocytes and prevent relapse in vivax and ovale malarias. PQ metabolites induce oxidative stress and impair parasitic mitochondria, leading to protozoal growth retardation and death. Collateral damage is also presented in mammalian host cells, particularly erythrocytes, resulting in hemolysis and tissue destruction. However, the underlying mechanisms of these complications, particularly the mitochondria-mediated cell death of the host, are poorly understood. In the present study, toxicopathological studies were conducted on a rat model to determine the effect of PQ on affected tissues and mitochondrial toxicity. The results indicated that the LD for PQ is 200 mg/kg. A high dose of PQ induced hemolytic anemia, elevated a hepatic enzyme (SGPT), and induced proximal tubular degeneration, ventricular cardiomyopathy, and mitochondrial dysregulation. In addition, PQ induced the upregulation of apoptosis-related proteins Drp-1 and caspase-3, with a positive correlation, as well as the pro-apoptotic mitochondrial gene expression of , reflecting the toxic effect of high doses of PQ on cellular damage and mitochondrial apoptosis in terms of hepatotoxicity, nephrotoxicity, and cardiotoxicity. Regarding the risk/benefit ratio of drug administration, our research provides caution for the use of PQ in the treatment of malaria based on its toxicopathological effects.
PubMed: 36851021
DOI: 10.3390/toxics11020146 -
Frontiers in Veterinary Science 2023The imminent risk of zoonoses of non-human malaria parasites is not far from reality in India, as has been observed in the case of Plasmodium knowlesi (Pk), and so is...
INTRODUCTION
The imminent risk of zoonoses of non-human malaria parasites is not far from reality in India, as has been observed in the case of Plasmodium knowlesi (Pk), and so is possible with (Pc), already reported from South East Asian countries. Therefore, a novel multiplex qPCR assay was developed and evaluated for detection of non-human malaria parasites- Pk and Pc in populations at risk.
METHODS
The qPCR primers were designed in-house with fluorescence labeled probes (HEX for Pk and FAM for Pc). DNA samples of Pk and Pc were used as templates and further the qPCR assay was evaluated in 250 symptomatic and asymptomatic suspected human blood samples from malaria endemic areas of North Eastern states of India.
RESULTS
The qPCR assay successfully amplified the target 18S rRNA gene segment from Pk and Pc and was highly specific for Pk and Pc parasites only, as no cross reactivity was observed with (Pf), (Pv), (Pm), and (Po). Standard curves were generated to estimate the limit of detection (LOD) of Pk and Pc parasites DNA (0.00275 & 0.075 ng/μl, respectively). Due to COVID-19 pandemic situation during 2020-21, the sample accessibility was difficult, however, we managed to collect 250 samples. The samples were tested for Pf and Pv using conventional PCR- 14 Pf and 11 Pv infections were observed, but no Pk and Pc infections were detected. For Pk infections, previously reported conventional PCR was also performed, but no Pk infection was detected.
DISCUSSION
The multiplex qPCR assay was observed to be robust, quick, cost-effective and highly sensitive as compared to the currently available conventional PCR methods. Further validation of the multiplex qPCR assay in field setting is desirable, especially from the high-risk populations. We anticipate that the multiplex qPCR assay would prove to be a useful tool in mass screening and surveillance programs for detection of non-human malaria parasites toward the control and elimination of malaria from India by 2030.
PubMed: 36777671
DOI: 10.3389/fvets.2023.1127273 -
Journal of Vector Borne Diseases 2022India's target of malaria elimination by 2030 may not be achieved solely by detecting Plasmodium falciparum and P. vivax, the two common Plasmodium species causing...
India's target of malaria elimination by 2030 may not be achieved solely by detecting Plasmodium falciparum and P. vivax, the two common Plasmodium species causing infections in humans. Sporadic reports have been documented on other Plasmodium species in the country, associated mostly with travel history. A febrile patient of Indian origin (Non-resident Indian (NRI)) was diagnosed with an infection of Plasmodium ovale curtisi malaria on his arrival from Sudan. A case report from Kerala was published in December 2020 and this is second report. Due to the inaccessibility of molecular techniques for routine diagnosis, this neglected non-falciparum malaria goes undetected. For an accurate diagnosis, suspected malaria cases should be tested using PCR and other advanced methods.
Topics: Humans; Plasmodium ovale; Malaria; Plasmodium; Malaria, Vivax; India
PubMed: 36751769
DOI: 10.4103/0972-9062.369243 -
The American Journal of Tropical... Mar 2023Malaria remains an important public health problem despite efforts to control it. Besides active transmission, relapsing malaria caused by dormant liver stages of...
Malaria remains an important public health problem despite efforts to control it. Besides active transmission, relapsing malaria caused by dormant liver stages of Plasmodium vivax and Plasmodium ovale hypnozoites is a major hurdle in malaria control and elimination programs. Primaquine (PQ) is the most widely used drug for radical cure of malaria. Due to its anti-hypnozoite and gametocidal activity, PQ plays a key role in malaria relapse and transmission. The human enzyme glucose-6-phosphate dehydrogenase (G6PD) is crucial in determining the safety of PQ because G6PD-deficient individuals are prone to hemolysis if treated with PQ. Therefore, there is a need to study the prevalence of G6PD-deficient genetic variants in endemic populations to assess the risk of PQ treatment and the necessity to develop alternative treatments. In this work, we discuss the common G6PD variants, their varying enzymatic activity, and their distribution on the three-dimensional structure of G6PD. Our work highlights the important G6PD variants and the need for large-scale G6PD gene polymorphism studies to predict populations at risk of PQ-induced toxicity.
Topics: Humans; Primaquine; Antimalarials; Glucosephosphate Dehydrogenase; Polymorphism, Single Nucleotide; Malaria; Glucosephosphate Dehydrogenase Deficiency; Malaria, Vivax
PubMed: 36746659
DOI: 10.4269/ajtmh.22-0468 -
Scientific Reports Jan 2023With global progress towards malaria reduction stalling, further analysis of epidemiology is required, particularly in countries with the highest burden. National...
With global progress towards malaria reduction stalling, further analysis of epidemiology is required, particularly in countries with the highest burden. National surveys have mostly analysed infection prevalence, while large-scale data on parasite density and different developmental forms rarely available. In Nigeria, the country with the largest burden globally, blood slide microscopy of children up to 5 years of age was conducted in the 2018 National Demographic and Health Survey, and parasite prevalence previously reported. In the current study, malaria parasite density measurements are reported and analysed for 7783 of the children sampled across the 36 states within the six geopolitical zones of the country. Asexual and sexual stages, and infections with different malaria parasite species are analysed. Across all states of Nigeria, there was a positive correlation between mean asexual parasite density within infected individuals and prevalence of infection in the community (Spearman's rho = 0.39, P = 0.02). Asexual parasite densities were highest in the northern geopolitical zones (geometric means > 2000 μL), extending the evidence of exceptionally high infection burden in many areas. Sexual parasite prevalence in each state was highly correlated with asexual parasite prevalence (Spearman's rho = 0.70, P < 0.001), although sexual parasite densities were low (geometric means < 100 μL in all zones). Infants had lower parasite densities than children above 1 year of age, but there were no differences between male and female children. Most infections were of P. falciparum, which had higher asexual densities but lower sexual parasite densities than P. malariae or P. ovale mono-infections. However, mixed species infections had the highest asexual parasite densities. It is recommended that future large surveys in high burden countries measure parasite densities as well as developmental stages and species, to improve the quality of malaria epidemiology and tracking of future changes.
Topics: Child; Infant; Animals; Humans; Male; Female; Parasites; Microscopy; Nigeria; Malaria; Malaria, Falciparum; Prevalence; Coinfection; Plasmodium falciparum
PubMed: 36709336
DOI: 10.1038/s41598-023-27535-1 -
Parasites & Vectors Jan 2023Malaria control efforts are highly skewed towards Plasmodium falciparum while overlooking other Plasmodium species such as P. malariae. A better understanding of the...
BACKGROUND
Malaria control efforts are highly skewed towards Plasmodium falciparum while overlooking other Plasmodium species such as P. malariae. A better understanding of the role of Plasmodium species other than P. falciparum is needed to strengthen malaria elimination initiatives. The aim of the present study was to elucidate the contribution of P. malariae to malaria transmission in Cameroon.
METHODS
The study was conducted in the Ngatti Health District, a forest-savannah transition area in the Adamawa Region, Cameroon. A total of 497 individuals aged from 1 to 85 years were diagnosed with malaria in November 2020 using a rapid diagnostic test (RDT) and microscopy. Adult mosquitoes were collected between September 2019 and March 2020 by indoor aspiration and identified morphologically and molecularly. The infection status of Plasmodium spp. was also determined by quantitative PCR, and dried blood spots were collected from 156 participants with the aim to detect different Plasmodium species by nested PCR.
RESULTS
The overall Plasmodium prevalence was 50.3%, 51.8% and 64.7%, as detected by microscopy, the RDT and PCR, respectively. Based on the PCR results, P. falciparum was the most prevalent species (43%); followed by co-infections P. falciparum/P. malariae (17%), P. falciparum/P. ovale (1.3%), P. falciparum/P. ovale/P. malariae (1.3%); and then by P. malariae mono-infection (2.5%). The same trend was observed using microscopy, with 35% of participants infected with P. falciparum, 11% co-infected with P. falciparum/P. malariae and 4% infected with P. malariae. The prevalence and parasite density of malaria infection varied significantly with age group (P < 0.05), with the highest prevalence rate observed in children aged 6-10 years (P = 0.0001) while the density of Plasmodium infection increased significantly in children aged < 5 years compared to the other age groups (P = 10). Among the 757 Anopheles mosquitoes collected, 737 (97.35%) were An. funestus sensu stricto, 15 (1.9%) were An. gambiae and 5 (0.6%) were An. hancocki. The Plasmodium species recorded at the head/thorax level were P. falciparum and P. malariae, with a sporozoite infection rate of 8.4%; the highest sporozoite infection rate was recorded at Mibellon village (13.6%).
CONCLUSION
The results of this study reveal the significant contribution of P. malariae, in addition to P. falciparum, to the high malaria transmission rate in this region. These findings highlight the need to deploy initiatives to also tackle this Plasmodium species to eliminate malaria in the region.
Topics: Child; Adult; Animals; Humans; Infant; Child, Preschool; Adolescent; Young Adult; Middle Aged; Aged; Aged, 80 and over; Plasmodium malariae; Cameroon; Malaria; Malaria, Falciparum; Plasmodium falciparum; Anopheles; Prevalence; Forests
PubMed: 36698132
DOI: 10.1186/s13071-022-05635-7 -
PLoS Neglected Tropical Diseases Jan 2023Plasmodium parasites caused 241 million cases of malaria and over 600,000 deaths in 2020. Both P. falciparum and P. ovale are endemic to Mali and cause clinical malaria,...
Plasmodium parasites caused 241 million cases of malaria and over 600,000 deaths in 2020. Both P. falciparum and P. ovale are endemic to Mali and cause clinical malaria, with P. falciparum infections typically being more severe. Here, we sequenced RNA from nine pediatric blood samples collected during infections with either P. falciparum or P. ovale, and characterized the host and parasite gene expression profiles. We found that human gene expression varies more between individuals than according to the parasite species causing the infection, while parasite gene expression profiles cluster by species. Additionally, we characterized DNA polymorphisms of the parasites directly from the RNA-seq reads and found comparable levels of genetic diversity in both species, despite dramatic differences in prevalence. Our results provide unique insights into host-pathogen interactions during malaria infections and their variations according to the infecting Plasmodium species, which will be critical to develop better elimination strategies against all human Plasmodium parasites.
Topics: Child; Humans; Malaria; Malaria, Falciparum; Plasmodium falciparum; Plasmodium ovale; Transcriptome
PubMed: 36696438
DOI: 10.1371/journal.pntd.0010802 -
Malaria Journal Dec 2022Asymptomatic malaria infections are important parasite reservoirs and could sustain transmission in the population, but they are often unreported. A community-based...
BACKGROUND
Asymptomatic malaria infections are important parasite reservoirs and could sustain transmission in the population, but they are often unreported. A community-based survey was conducted to investigate the prevalence and factors associated with asymptomatic malaria infections in a historically high transmission setting in northern Uganda.
METHODS
Using a cross-sectional design, 288 children aged 2-15 years were enrolled and tested for the presence of malaria parasites using rapid diagnostic tests (RDTs) and blood smear microscopy between January to May 2022. Statistical analysis was performed using the exact binomial and Fisher's exact test with p ≤ 0.05 indicating significance. The logistic regression was used to explore factors associated with asymptomatic malaria infections.
RESULTS
Overall, the prevalence of asymptomatic infection was 34.7% (95% CI 29.2-40.5) with the highest observed in children 5-10 years 45.9% (95% CI 35.0-57.0). Gweri village accounted for 39.1% (95% CI 27.6-51.6) of malaria infections. Median parasite density was 1500 parasites/µl of blood. Plasmodium falciparum was the dominant species (86%) followed by Plasmodium malariae (5%). Factors associated with asymptomatic malaria infection were sleeping under mosquito net (Adjusted Odds Ratio (aOR) 0.27; 95% CI 0.13-0.56), p = 0.001 and presence of village health teams (VHTs) (aOR 0.02; 95% CI 0.01-0.45), p = 0.001. Sensitivity and specificity were higher for the P. falciparum/pLDH RDTs compared to HRP2-only RDTs, 90% (95% CI 86.5-93.5) and 95.2% (95% CI 92.8-97.7), p = 0.001, respectively.
CONCLUSION
Asymptomatic malaria infections were present in the study population and this varied with place and person in the different age groups. Plasmodium falciparum was the dominant parasite species however the presence of P. malariae and Plasmodium ovale was observed, which may have implication for the choice and deployment of diagnostic tools. Individuals who slept under mosquito net or had presence of functional VHTs were less likely to have asymptomatic malaria infection. P.f/pLDH RDTs performed better than the routinely used HRP2 RDTs. In view of these findings, investigation and reporting of asymptomatic malaria reservoirs through community surveys is recommended for accurate disease burden estimate and better targeting of control.
Topics: Child; Humans; Malaria, Falciparum; Antigens, Protozoan; Uganda; Asymptomatic Infections; Cross-Sectional Studies; Diagnostic Tests, Routine; Plasmodium falciparum; Malaria; Sensitivity and Specificity
PubMed: 36550492
DOI: 10.1186/s12936-022-04421-1 -
The American Journal of Tropical... Jan 2023The five major Plasmodium spp. that cause human malaria appear similar under light microscopy, which raises the possibility that misdiagnosis could routinely occur in... (Meta-Analysis)
Meta-Analysis
The five major Plasmodium spp. that cause human malaria appear similar under light microscopy, which raises the possibility that misdiagnosis could routinely occur in clinical settings. Assessing the extent of misdiagnosis is of particular importance for monitoring P. knowlesi, which cocirculates with the other Plasmodium spp. We performed a systematic review and meta-analysis of studies comparing the performance of microscopy and polymerase chain reaction (PCR) for diagnosing malaria in settings with co-circulation of the five Plasmodium spp. We assessed the extent to which co-circulation of Plasmodium parasites affects diagnostic outcomes. We fit a Bayesian hierarchical latent class model to estimate variation in microscopy sensitivity and specificity measured against PCR as the gold standard. Mean sensitivity of microscopy was low, yet highly variable across Plasmodium spp., ranging from 65.7% (95% confidence interval: 48.1-80.3%) for P. falciparum to 0.525% (95% confidence interval 0.0210-3.11%) for P. ovale. Observed PCR prevalence was positively correlated with estimated microscopic sensitivity and negatively correlated with estimated microscopic specificity, though the strength of the associations varied by species. Our analysis suggests that cocirculation of Plasmodium spp. undermines the accuracy of microscopy. Sensitivity was considerably lower for P. knowlesi, P. malariae, and P. ovale. The negative association between specificity and prevalence imply that less frequently encountered species may be misdiagnosed as more frequently encountered species. Together, these results suggest that the burden of P. knowlesi, P. malariae, and P. ovale may be underappreciated in a clinical setting.
Topics: Humans; Bayes Theorem; Malaria; Malaria, Falciparum; Microscopy; Plasmodium knowlesi; Polymerase Chain Reaction; Communicable Diseases, Emerging; Coinfection; Diagnostic Errors; Plasmodium ovale; Plasmodium malariae
PubMed: 36509046
DOI: 10.4269/ajtmh.21-1155 -
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