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Parasitology Nov 2023Of the 5 human malarial parasites, and are the most prevalent species globally, while and are less prevalent and typically occur as mixed-infections. , previously... (Review)
Review
Of the 5 human malarial parasites, and are the most prevalent species globally, while and are less prevalent and typically occur as mixed-infections. , previously considered a non-human primate (NHP) infecting species, is now a cause of human malaria in Malaysia. The other NHP species, , , , , and cause malaria in primates, which are mainly reported in southeast Asia and South America. The non- NHP species also emerged and were found to cross-transmit from their natural hosts (NHP) – to human hosts in natural settings. Here we have reviewed and collated data from the literature on the NHPs-to-human-transmitting species. It was observed that the natural transmission of these NHP parasites to humans had been reported from 2010 onwards. This study shows that: (1) the majority of the non- NHP mixed species infecting human cases were from Yala province of Thailand; (2) mono/mixed infections with other human-infecting species were prevalent in Malaysia and Thailand and (3) and were found in Central and South America.
Topics: Animals; Humans; Malaria; Plasmodium knowlesi; Primates; Asia, Southeastern; Plasmodium vivax
PubMed: 37929579
DOI: 10.1017/S003118202300077X -
Genome Medicine Nov 2023Malaria continues to be a major threat to global public health. Whole genome sequencing (WGS) of the underlying Plasmodium parasites has provided insights into the...
BACKGROUND
Malaria continues to be a major threat to global public health. Whole genome sequencing (WGS) of the underlying Plasmodium parasites has provided insights into the genomic epidemiology of malaria. Genome sequencing is rapidly gaining traction as a diagnostic and surveillance tool for clinical settings, where the profiling of co-infections, identification of imported malaria parasites, and detection of drug resistance are crucial for infection control and disease elimination. To support this informatically, we have developed the Malaria-Profiler tool, which rapidly (within minutes) predicts Plasmodium species, geographical source, and resistance to antimalarial drugs directly from WGS data.
RESULTS
The online and command line versions of Malaria-Profiler detect ~ 250 markers from genome sequences covering Plasmodium speciation, likely geographical source, and resistance to chloroquine, sulfadoxine-pyrimethamine (SP), and other anti-malarial drugs for P. falciparum, but also providing mutations for orthologous resistance genes in other species. The predictive performance of the mutation library was assessed using 9321 clinical isolates with WGS and geographical data, with most being single-species infections (P. falciparum 7152/7462, P. vivax 1502/1661, P. knowlesi 143/151, P. malariae 18/18, P. ovale ssp. 5/5), but co-infections were identified (456/9321; 4.8%). The accuracy of the predicted geographical profiles was high to both continental (96.1%) and regional levels (94.6%). For P. falciparum, markers were identified for resistance to chloroquine (49.2%; regional range: 24.5% to 100%), sulfadoxine (83.3%; 35.4- 90.5%), pyrimethamine (85.4%; 80.0-100%) and combined SP (77.4%). Markers associated with the partial resistance of artemisinin were found in WGS from isolates sourced from Southeast Asia (30.6%).
CONCLUSIONS
Malaria-Profiler is a user-friendly tool that can rapidly and accurately predict the geographical regional source and anti-malarial drug resistance profiles across large numbers of samples with WGS data. The software is flexible with modifiable bioinformatic pipelines. For example, it is possible to select the sequencing platform, display specific variants, and customise the format of outputs. With the increasing application of next-generation sequencing platforms on Plasmodium DNA, Malaria-Profiler has the potential to be integrated into point-of-care and surveillance settings, thereby assisting malaria control. Malaria-Profiler is available online (bioinformatics.lshtm.ac.uk/malaria-profiler) and as standalone software ( https://github.com/jodyphelan/malaria-profiler ).
Topics: Humans; Animals; Antimalarials; Parasites; Coinfection; Malaria; Plasmodium; Malaria, Falciparum; Chloroquine; Malaria, Vivax; Drug Resistance; Plasmodium falciparum
PubMed: 37950308
DOI: 10.1186/s13073-023-01247-7 -
Comparative Medicine Jun 2024Malaria is a parasitic disease caused by protozoan species of the genus and transmitted by female mosquitos of the genus and other Culicidae. Most of the parasites of...
Malaria is a parasitic disease caused by protozoan species of the genus and transmitted by female mosquitos of the genus and other Culicidae. Most of the parasites of the genus are highly species specific with more than 200 species described affecting different species of mammals, birds, and reptiles. species strictly affecting humans are , , , and More recently, and other nonhuman primate plasmodia were found to naturally infect humans. Currently, malaria occurs mostly in poor tropical and subtropical areas of the world, and in many of these countries it is the leading cause of illness and death. For more than 100 y, animal models, have played a major role in our understanding of malaria biology. Avian species were the first to be used as models to study human malaria. Malaria parasite biology and immunity were first studied using mainly and . Rodent malarias, particularly and , have been used extensively as models to study malaria in mammals. Several species of from nonhuman primates have been used as surrogate models to study human malaria immunology, pathogenesis, candidate vaccines, and treatments. , , and are important models for studying malaria produced by and , while is used as a model for studying severe malaria. Other nonhuman primate malarias used in research are , , , , and . Very few nonhuman primate species can develop an infection with human malarias. Macaques in general are resistant to infection with , , , and . Only apes and a few species of New World monkeys can support infection with human malarias. Herein we review the most common, and some less common, avian, reptile, and mammal plasmodia species used as models to study human malaria.
PubMed: 38902006
DOI: 10.30802/AALAS-CM-24-000019 -
The American Journal of Tropical... Sep 2023Plasmodium vivax is the second-most common malaria pathogen globally, but is considered very rare in the predominantly Duffy-negative sub-Saharan African population. In...
Plasmodium vivax is the second-most common malaria pathogen globally, but is considered very rare in the predominantly Duffy-negative sub-Saharan African population. In 259 malaria patients from highland southern Rwanda, we assessed Plasmodium species and Duffy blood group status by polymerase chain reaction (PCR). Plasmodium falciparum, P. vivax, Plasmodium malariae, and Plasmodium ovale were seen in 90.7%, 8.1%, 11.6%, and 5.0%, respectively. Plasmodium vivax occurred more frequently as a monoinfection than in combination with P. falciparum. All P. vivax-infected individuals showed heterozygous Duffy positivity, whereas this was the case for only 3.1% of patients with P. falciparum monoinfection and malaria-negative control subjects (P < 0.01). Based on PCR diagnosis, P. vivax is not rare in southern Rwanda. All episodes of P. vivax were observed in heterozygous Duffy-positive patients, whereas elsewhere in Africa, P. vivax is also reported in Duffy-negative individuals. Refined mapping of Plasmodium species is required to establish control and elimination strategies including all malaria species.
Topics: Humans; Malaria, Vivax; Rwanda; Malaria; Plasmodium vivax; Malaria, Falciparum; Plasmodium falciparum; Plasmodium malariae; Duffy Blood-Group System
PubMed: 37549894
DOI: 10.4269/ajtmh.23-0143 -
Scientific Reports Jul 2023Molecular detection methods have revealed higher sensitivity and specificity than conventional microscopy or rapid diagnostic tests for malaria diagnosis. In this study,...
Molecular detection methods have revealed higher sensitivity and specificity than conventional microscopy or rapid diagnostic tests for malaria diagnosis. In this study, we implemented, evaluated and validated according to the ISO 15,189 requirements, a multiplex real-time PCR assay to detect and identify the five human malaria parasites. DNA samples were extracted from whole blood or dried blood spots drawn from patients. Based on the External Quality Assessment (whole blood), this method shows 100% sensitivity and specificity. This PCR detected P. vivax up to 0.25 p/µl, P. falciparum and P. knowlesi up to 0.5 p/µl, P. ovale up to 1 p/µl and P. malariae up to 5 p/µl of blood. From blood spots (extraction from four punches), it detected P. vivax at 5 p/µl, P. falciparum, P. ovale and P. knowlesi at 20 p/µl and P. malariae at 125 p/µl. In conclusion, this quantitative PCR shows excellent performance, is easy to use and DNA saver. It is especially useful to actively screen large population groups and identify the five human malaria parasites in a context of low malaria transmission.
Topics: Humans; Real-Time Polymerase Chain Reaction; Plasmodium; Malaria; Malaria, Vivax; Malaria, Falciparum; Sensitivity and Specificity; Plasmodium vivax; Plasmodium falciparum
PubMed: 37452123
DOI: 10.1038/s41598-023-38621-9 -
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