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Annals of Medicine Dec 2023Microscopy was used to characterize platelet--infected erythrocyte interactions in patients infected with , , or , and to investigate the relationship between...
OBJECTIVE
Microscopy was used to characterize platelet--infected erythrocyte interactions in patients infected with , , or , and to investigate the relationship between platelet-associated parasite killing and parasite clearance.
METHODS
Data from 244 malaria patients admitted to the Fourth People's Hospital of Nanning between 1 January 2011 and 30 September 2022, and 45 healthy controls, were collected prospectively and assessed retrospectively. Characteristics of platelet-erythrocyte interactions were visualized by microscopy, and blood cell count and clinical profiles of these participants were obtained from the electronic medical records. ANOVA, contingency tables and Cox proportional hazards regression models were used to do statistical analysis on the subgroups.
RESULTS
Platelet enlargement and minor pseudopodia development were observed. Platelets were found directly attaching to parasitized erythrocytes by all species studied, especially mature stages, and lysis of parasitized erythrocytes was connected to platelet-mediated cytolysis. Platelet counts were correlated inversely with parasitaemia and duration of parasite clearance. Artemisinin combination therapy was more effective than artemisinin alone in clearing in patients with thrombocytopenia.
CONCLUSIONS
Platelet-parasitized erythrocytes cell-to-cell contacts initiated platelet-associated parasite killing and helped to limit infection in cases of human malaria. The weakening platelet-associated parasite killing effects could be counteracted by artemisinin combination therapy in patients with thrombocytopenia.
Topics: Humans; Animals; Blood Platelets; Parasites; Retrospective Studies; Malaria; Thrombocytopenia; Artemisinins
PubMed: 37310126
DOI: 10.1080/07853890.2023.2221453 -
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 -
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 -
Microorganisms Sep 2023Here, the main goal is to assess natural infections of spp. in anophelines in a forest reserve from the same region where we previously found a surprisingly high rate...
Here, the main goal is to assess natural infections of spp. in anophelines in a forest reserve from the same region where we previously found a surprisingly high rate (5.2%) of plasmodia infections ( = 25) in mosquitoes ( = 480) on the slopes of Serra do Mar, Atlantic Forest, Brazil. The mosquito collection sampling was carried out at the Legado das Águas Forest Reserve using CDC light traps and Shannon traps at night (5-10 pm) in 3-day collections in November 2021 and March, April, May, and November 2022. The captured specimens were morphologically identified at the species level and had their genomic DNA extracted in pools of up to 10 mosquitoes/pool. Each pool was tested using qPCR and nested PCR plus sequencing. A total of 5301 mosquitoes, mostly belonging to the genus (99.7%), were sampled and sorted into 773 pools. Eight pools positive for spp. were identified: four for spp., one for or , one for or , and two for the -like parasite. After Sanger sequencing, two results were further confirmed: or and or . The minimum infection rate for mosquitoes was 0.15% (eight positive pools/5285 mosquitoes). The study reveals a lower-than-expected natural infection rate (expected = 5.2% vs. observed = 0.15%). This low rate relates to the absence of monkeys as the main simian malaria reservoir in the studied region. Their absence was due to a significant population decline following the reemergence of yellow fever virus outbreaks in the Atlantic Forest from 2016 to 2019. However, this also indicates the existence of alternative reservoirs to infect mosquitoes. The found zoonotic species of , including the . -like parasite, may represent a simian malaria risk and thus a challenge for malaria elimination in Brazil.
PubMed: 37894123
DOI: 10.3390/microorganisms11102465 -
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 -
Journal of Vector Borne Diseases 2023Severe malaria is a medical emergency and can lead to severe complications and death if not treated promptly and appropriately. Along with Plasmodium falciparum, P....
BACKGROUND & OBJECTIVES
Severe malaria is a medical emergency and can lead to severe complications and death if not treated promptly and appropriately. Along with Plasmodium falciparum, P. knowlesi is increasingly recognised as a significant cause of fatal and severe malaria.
METHODS
We performed a retrospective review on 54 cases of severe malaria in a district hospital in Kapit, Sarawak, from January 2018 to May 2019. The patients' demographics, clinical features, complications based on organ involvement, and treatment outcomes were examined.
RESULTS
There were 54 cases of severe malaria, with the majority being male (70%) and between the ages of 40 and 49 (26%). All patients with severe malaria were febrile or had a history of pyrexia except for one patient. P. knowlesi (81.5%) was the most common species causing severe malaria in our study, followed by P. falciparum (13%), and P. vivax (5.5%). There were no cases of severe malaria caused by P. ovale or P. malariae. Hyperparasitaemia was present in 76% of patients and the median parasitemia value at hospital admission was 33,944 parasites/μL (interquartile range: 19,920-113,285 parasites/μL). Circulatory shock was observed in 17 patients (31.5%). There were eight patients with acute renal failure and six patients with respiratory distress. One patient died as a result of severe malaria with multiorgan involvement (1.9% fatality rate).
INTERPRETATION & CONCLUSION
P. knowlesi is the most common cause of severe malaria in Kapit, Sarawak, Malaysia. Recognizing symptoms of severe malaria and prompt administration of antimalarial are critical for good clinical outcomes.
Topics: Humans; Male; Adult; Middle Aged; Female; Malaysia; Borneo; Plasmodium knowlesi; Malaria; Antimalarials; Malaria, Vivax; Malaria, Falciparum
PubMed: 38174522
DOI: 10.4103/0972-9062.374238 -
Antimicrobial Agents and Chemotherapy Dec 2023Malaria molecular surveillance remains critical in detecting and tracking emerging parasite resistance to anti-malarial drugs. The current study employed molecular...
Malaria molecular surveillance remains critical in detecting and tracking emerging parasite resistance to anti-malarial drugs. The current study employed molecular techniques to determine species prevalence and characterize the genetic diversity of and molecular markers of sulfadoxine-pyrimethamine resistance in humans and wild mosquito populations in Cameroon. mosquito collections and parasitological survey were conducted in villages to determine species infection, and genomic phenotyping of anti-folate resistance was accomplished by sequencing the dihydrofolate-reductase () and dihydropteroate-synthase () genes of naturally circulating and isolates. The malaria prevalence in Elende was 73.5% with the 5-15 years age group harboring significant (27%) and (19%) infections. The polymorphism breadth of the pyrimethamine-associated marker revealed a near fixation (94%) of the triple-mutant -AI. The backbone mediating sulfadoxine resistance reveals a high frequency of the KAA alleles (20.8%). Similarly, the NKSSFI haplotype (78.4%) was predominantly detected in the asexual blood stage. In contrast, the - occured at 37.2% frequency. The combined quadruple NKSSFI_ KAA (31.9%) was the major circulating haplotype with similar frequency in humans and mosquitoes. This study highlights the increasing frequency of the parasite mostly common in asymptomatic individuals with apparent infection. Interventions directed at reducing malaria transmission such as the scaling-up of SP are favoring the emergence and spread of multiple drug-resistant alleles between the human and mosquito host systems.
Topics: Animals; Humans; Pyrimethamine; Sulfadoxine; Anopheles; Alleles; Cameroon; Antimalarials; Malaria, Falciparum; Drug Combinations; Plasmodium falciparum; Malaria; Drug Resistance; Tetrahydrofolate Dehydrogenase
PubMed: 37947766
DOI: 10.1128/aac.00588-23 -
Infectious Diseases of Poverty Nov 2023Plasmodium malariae was always neglected compared with P. falciparum and P. vivax. In the present study, we aimed to describe the epidemiology of reported cases infected...
BACKGROUND
Plasmodium malariae was always neglected compared with P. falciparum and P. vivax. In the present study, we aimed to describe the epidemiology of reported cases infected with P. malariae in the past decade to raise awareness of the potential threat of this malaria parasite in China.
METHODS
Individual data of malaria cases infected with P. malariae reported in China in the past decade were collected via the China Information System for Disease Control and Prevention and Parasitic Diseases Information Reporting Management System, to explore their epidemiological characteristics. Pearson Chi-square tests or Fisher's Exact Test was used in the statistical analysis.
RESULTS
From 2013 to 2022, a total of 581 P. malariae cases were reported in China, and mainly concentrated in 20-59 years old group (P < 0.001), and there was no significant trend in the number of cases reported per month. Moreover, four kinds of P. malariae cases were classified, including 567 imported cases from 41 countries in 8 regions and distributed in 27 provinces (autonomous regions, municipalities) in China, six indigenous cases in a small outbreak in Hainan, seven recurrent cases in Guangdong and Shanghai, and one induced case in Shanghai, respectively. In addition, only 379 cases (65.2%) were diagnosed as malaria on the first visit (P < 0.001), and 413 cases (71.1%) were further confirmed as P. malariae cases (P = 0.002). Meanwhile, most cases sought healthcare first in the health facilities at the county and prefectural levels, but only 76.7% (161/210) and 73.7% (146/198) cases were diagnosed as malaria, and the accuracy of confirmed diagnosis as malaria cases infected with P. malariae was only 77.2% (156/202) and 69.9% (167/239) in these health facilities respectively.
CONCLUSIONS
Even though malaria cases infected with P. malariae didn't account for a high proportion of reported malaria cases nationwide, the threat posed by widely distributed imported cases, a small number of indigenous cases, recurrent cases and induced case cannot be ignored in China. Therefore, it is necessary to raise awareness and improve the surveillance and response to the non-falciparum species such as P. malariae, and prevent the reestablishment of malaria transmission after elimination.
Topics: Humans; Young Adult; Adult; Middle Aged; Plasmodium malariae; China; Malaria; Malaria, Falciparum; Malaria, Vivax
PubMed: 37986018
DOI: 10.1186/s40249-023-01156-2 -
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 -
Journal of Travel Medicine Apr 2024Malaria continues to pose a significant burden in endemic countries, many of which lack access to molecular surveillance. Insights from malaria cases in travellers...
BACKGROUND
Malaria continues to pose a significant burden in endemic countries, many of which lack access to molecular surveillance. Insights from malaria cases in travellers returning to non-endemic areas can provide valuable data to inform endemic country programmes. To evaluate the potential for novel global insights into malaria, we examined epidemiological and molecular data from imported malaria cases to Australia.
METHODS
We analysed malaria cases reported in Australia from 2012 to 2022 using National Notifiable Disease Surveillance System data. Molecular data on imported malaria cases were obtained from literature searches.
RESULTS
Between 2012 and 2022, 3204 malaria cases were reported in Australia. Most cases (69%) were male and 44% occurred in young adults aged 20-39 years. Incidence rates initially declined between 2012 and 2015, then increased until 2019. During 2012-2019, the incidence in travellers ranged from 1.34 to 7.71 per 100 000 trips. Cases were primarily acquired in Sub-Saharan Africa (n = 1433; 45%), Oceania (n = 569; 18%) and Southern and Central Asia (n = 367; 12%). The most common countries of acquisition were Papua New Guinea (n = 474) and India (n = 277). Plasmodium falciparum accounted for 58% (1871/3204) of cases and was predominantly acquired in Sub-Saharan Africa, and Plasmodium vivax accounted for 32% (1016/3204), predominantly from Oceania and Asia. Molecular studies of imported malaria cases to Australia identified genetic mutations and deletions associated with drug resistance and false-negative rapid diagnostic test results, and led to the establishment of reference genomes for P. vivax and Plasmodium malariae.
CONCLUSIONS
Our analysis highlights the continuing burden of imported malaria into Australia. Molecular studies have offered valuable insights into drug resistance and diagnostic limitations, and established reference genomes. Integrating molecular data into national surveillance systems could provide important infectious disease intelligence to optimize treatment guidelines for returning travellers and support endemic country surveillance programmes.
Topics: Young Adult; Male; Humans; Female; Travel; Malaria; Malaria, Vivax; Plasmodium falciparum; Australia
PubMed: 38127641
DOI: 10.1093/jtm/taad164