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1.
Acta Trop ; 255: 107249, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38740319

RESUMEN

BACKGROUND: Natural human infections by Plasmodium cynomolgi and P. inui have been reported recently and gain the substantial attention from Southeast Asian countries. Zoonotic transmission of non-human malaria parasites to humans from macaque monkeys occurred through the bites of the infected mosquitoes. The objective of this study is to establish real-time fluorescence loop-mediated isothermal amplification (LAMP) assays for the detection of zoonotic malaria parasites by combining real-time fluorescent technology with the isothermal amplification technique. METHODS: By using 18S rRNA as the target gene, the primers for P. cynomolgi, P. coatneyi and P. inui were newly designed in the present study. Four novel real-time fluorescence LAMP assays were developed for the detection of P. cynomolgi, P. coatneyi, P. inui and P. knowlesi. The entire amplification process was completed in 60 min, with the assays performed at 65 °C. By using SYTO-9 as the nucleic acid intercalating dye, the reaction was monitored via real-time fluorescence signal. RESULTS: There was no observed cross-reactivity among the primers from different species. All 70 field-collected monkey samples were successfully amplified by real-time fluorescence LAMP assays. The detection limit for P. cynomolgi, P. coatneyi and P. knowlesi was 5 × 109 copies/µL. Meanwhile, the detection limit of P. inui was 5 × 1010 copies/µL. CONCLUSION: This is the first report of the detection of four zoonotic malaria parasites by real-time fluorescence LAMP approaches. It is an effective, rapid and simple-to-use technique. This presented platform exhibits considerable potential as an alternative detection for zoonotic malaria parasites.


Asunto(s)
Malaria , Técnicas de Diagnóstico Molecular , Técnicas de Amplificación de Ácido Nucleico , Plasmodium , ARN Ribosómico 18S , Sensibilidad y Especificidad , Zoonosis , Animales , Técnicas de Amplificación de Ácido Nucleico/métodos , Malaria/diagnóstico , Malaria/parasitología , Malaria/veterinaria , ARN Ribosómico 18S/genética , Técnicas de Diagnóstico Molecular/métodos , Plasmodium/genética , Plasmodium/aislamiento & purificación , Plasmodium/clasificación , Zoonosis/parasitología , Zoonosis/diagnóstico , Humanos , Cartilla de ADN/genética , Fluorescencia , Macaca/parasitología , Enfermedades de los Monos/parasitología , Enfermedades de los Monos/diagnóstico
2.
Science ; 384(6695): 513-514, 2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38696584

RESUMEN

Natural infections are distinct from those of laboratory-or zombie-strains.


Asunto(s)
Malaria , Plasmodium , Animales , Humanos , Malaria/parasitología , Plasmodium/genética , Plasmodium/crecimiento & desarrollo
3.
Anal Chem ; 96(19): 7524-7531, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38695755

RESUMEN

Asymptomatic infections of Plasmodium parasites are major obstacles to malaria control and elimination. A sensitive, specific, and user-friendly method is urgently needed for point-of-care (POC) Plasmodium diagnostics in asymptomatic malaria, especially in resource-limited settings. In this work, we present a POC method (termed Cas13a-SDT) based on the cascade sequence recognition and signal amplification of dual Cas13a trans-cleavage and strand displacement-triggered transcription (SDT). Cas13a-SDT not only achieves exceptional specificity in discriminating the target RNA from nontarget RNAs with any cross-interaction but also meets the sensitivity criterion set by the World Health Organization (WHO) for effective malaria detection. Remarkably, this novel method was successfully applied to screen malaria in asymptomatic infections from clinical samples. The proposed method provides a user-friendly and visually interpretable output mode while maintaining high accuracy and reliability comparable to RT-PCR. These excellent features demonstrate the significant potential of Cas13a-SDT for POC diagnosis of Plasmodium infections, laying a vital foundation for advancing malaria control and elimination efforts.


Asunto(s)
Sistemas CRISPR-Cas , Malaria , Sistemas de Atención de Punto , Malaria/diagnóstico , Malaria/parasitología , Humanos , Sistemas CRISPR-Cas/genética , Plasmodium/genética , Plasmodium/aislamiento & purificación , Transcripción Genética
4.
Parasitol Int ; 101: 102892, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38565335

RESUMEN

Reducing Plasmodium parasite transmission via the mosquito vector is a promising strategy for malaria control and elimination in endemic regions. In the mosquito midgut after the ingestion of an infected blood meal, malaria parasite gametes egress from erythrocytes and fertilize to develop into motile ookinetes that traverse midgut epithelial cells and transform into oocysts adjacent the basal lamina. Plasmodium ookinetes and young oocysts possess a unique organelle called the crystalloid; which has a honeycomb-like matrix structure and is indicated to be involved in sporozoite formation and maturation. In this study, we identified a novel crystalloid protein, PY17X_1113800, that is exclusively expressed in developing ookinetes. The protein possesses a signal peptide sequence, but lacks a transmembrane domain or GPI anchor signal sequence, as well as predicted adhesive domains which are characterisitic of many crystalloid proteins. The protein is highly conserved across the phylum Apicomplexa and within the greater clade Alveolata, such as Vitrella and the ciliates Paramecium and Tetrahymena, but is absent in cryptosporidia.


Asunto(s)
Proteínas Protozoarias , Proteínas Protozoarias/metabolismo , Proteínas Protozoarias/genética , Animales , Plasmodium , Oocistos , Orgánulos , Mosquitos Vectores/parasitología , Anopheles/parasitología
5.
Rev Alerg Mex ; 71(1): 54, 2024 Feb 01.
Artículo en Español | MEDLINE | ID: mdl-38683072

RESUMEN

OBJECTIVE: Analyze the molecular mimicry between Plasmodium spp. and autoantigens associated with GBS, identifying possible antigenic epitopes. METHODS: PSI-Blast, Praline, Emboss, Protein Data Bank, Swiss Model Server, AlphaFold 2, Ellipro and PyMol 2.3 were used to search for homologies, perform alignments, obtain protein structures, and predict epitopes. RESULTS: 17 autoantigens and seven immunological targets of the peripheral nervous system were included, identifying 72 possible epitopes associated with GBS. From the proteome of Plasmodium spp. (298 proteins), only two showed similarities close to 30% with TRIM21 and BACE1, generating seven possible epitopes. CONCLUSION: No significant homologies were observed between the proteome of GBS and Plasmodium spp. The exploration of other mechanisms such as immune-mediated capillary damage, Epitope Spreading or Bystander Activation is suggested to explain the mentioned association. These findings underscore the need to clarify the etiology of autoimmune diseases and the role of pathogens. The need for experimental studies to validate these results is emphasized.


OBJETIVO: Analizar el mimetismo molecular entre Plasmodium spp. y autoantígenos asociados al SGB, identificando posibles epítopos antigénicos. MÉTODOS: Se emplearon PSI-Blast, Praline, Emboss, Protein Data Bank, Swiss Model Server, AlphaFold 2, Ellipro y PyMol 2.3 para buscar homologías, realizar alineamientos, obtener estructuras proteicas y predecir epítopos. RESULTADOS: Se incluyeron 17 autoantígenos y siete objetivos inmunológicos del sistema nervioso periférico, identificándose 72 posibles epítopos asociados al SGB. Del proteoma de Plasmodium spp. (298 proteínas), solo dos mostraron similitud cercana al 30% con TRIM21 y BACE1, generando siete posibles epítopos. CONCLUSIÓN: No se observaron homologías significativas entre el proteoma de SGB y Plasmodium spp. Se sugiere la exploración de otros mecanismos como el daño capilar inmunomediado, Epitope Spreading o Bystander Activation para explicar la asociación mencionada. Estos hallazgos subrayan la necesidad de aclarar la etiología de las enfermedades autoinmunes y el papel de los patógenos. Se enfatiza la necesidad de estudios experimentales para validar estos resultados.


Asunto(s)
Síndrome de Guillain-Barré , Imitación Molecular , Imitación Molecular/inmunología , Síndrome de Guillain-Barré/inmunología , Humanos , Plasmodium/inmunología , Autoantígenos/inmunología , Epítopos/inmunología
7.
Theor Popul Biol ; 157: 118-128, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38626854

RESUMEN

Infectious disease agents can influence each other's dynamics in shared host populations. We consider such influence for two mosquito-borne infections where one pathogen is endemic at the time that a second pathogen invades. We regard a setting where the vector has a bias towards biting host individuals infected with the endemic pathogen and where there is a cost to co-infected hosts. As a motivating case study, we regard Plasmodium spp., that cause avian malaria, as the endemic pathogen, and Usutu virus (USUV) as the invading pathogen. Hosts with malaria attract more mosquitoes compared to susceptible hosts, a phenomenon named vector bias. The possible trade-off between the vector-bias effect and the co-infection mortality is studied using a compartmental epidemic model. We focus first on the basic reproduction number R0 for Usutu virus invading into a malaria-endemic population, and then explore the long-term dynamics of both pathogens once Usutu virus has become established. We find that the vector bias facilitates the introduction of malaria into a susceptible population, as well as the introduction of Usutu in a malaria-endemic population. In the long term, however, both a vector bias and co-infection mortality lead to a decrease in the number of individuals infected with either pathogen, suggesting that avian malaria is unlikely to be a promoter of Usutu invasion. This proposed approach is general and allows for new insights into other negative associations between endemic and invading vector-borne pathogens.


Asunto(s)
Aves , Flavivirus , Plasmodium , Animales , Aves/virología , Aves/parasitología , Plasmodium/patogenicidad , Flavivirus/patogenicidad , Coinfección/virología , Malaria Aviar , Enfermedades Endémicas , Infecciones por Flavivirus/virología , Mosquitos Vectores/virología , Mosquitos Vectores/parasitología , Malaria
8.
Biochem Soc Trans ; 52(2): 593-602, 2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38563493

RESUMEN

Malaria, a vector borne disease, is a major global health and socioeconomic problem caused by the apicomplexan protozoan parasite Plasmodium. The parasite alternates between mosquito vector and vertebrate host, with meiosis in the mosquito and proliferative mitotic cell division in both hosts. In the canonical eukaryotic model, cell division is either by open or closed mitosis and karyokinesis is followed by cytokinesis; whereas in Plasmodium closed mitosis is not directly accompanied by concomitant cell division. Key molecular players and regulatory mechanisms of this process have been identified, but the pivotal role of certain protein complexes and the post-translational modifications that modulate their actions are still to be deciphered. Here, we discuss recent evidence for the function of known proteins in Plasmodium cell division and processes that are potential novel targets for therapeutic intervention. We also identify key questions to open new and exciting research to understand divergent Plasmodium cell division.


Asunto(s)
División Celular , Malaria , Plasmodium , Proteínas Protozoarias , Plasmodium/metabolismo , Plasmodium/fisiología , Animales , Humanos , Malaria/parasitología , Malaria/metabolismo , Proteínas Protozoarias/metabolismo , Mitosis , Citocinesis , Meiosis , Procesamiento Proteico-Postraduccional , Interacciones Huésped-Parásitos
9.
Sci Rep ; 14(1): 9871, 2024 04 30.
Artículo en Inglés | MEDLINE | ID: mdl-38684775

RESUMEN

The Plasmodium is responsible for malaria which poses a major health threat, globally. This study is based on the estimation of the relative abundance of mosquitoes, and finding out the correlations of meteorological parameters (temperature, humidity and rainfall) with the abundance of mosquitoes. In addition, this study also focused on the use of nested PCR (species-specific nucleotide sequences of 18S rRNA genes) to explore the Plasmodium spp. in female Anopheles. In the current study, the percentage relative abundance of Culex mosquitoes was 57.65% and Anopheles 42.34% among the study areas. In addition, the highest number of mosquitoes was found in March in district Mandi Bahauddin at 21 °C (Tmax = 27, Tmin = 15) average temperature, 69% average relative humidity and 131 mm rainfall, and these climatic factors were found to affect the abundance of the mosquitoes, directly or indirectly. Molecular analysis showed that overall, 41.3% of the female Anopheles pools were positive for genus Plasmodium. Among species, the prevalence of Plasmodium (P.) vivax (78.1%) was significantly higher than P. falciparum (21.9%). This study will be helpful in the estimation of future risk of mosquito-borne diseases along with population dynamic of mosquitoes to enhance the effectiveness of vector surveillance and control programs.


Asunto(s)
Anopheles , Malaria , Mosquitos Vectores , Plasmodium , Reacción en Cadena de la Polimerasa , Animales , Anopheles/parasitología , Anopheles/genética , Mosquitos Vectores/parasitología , Mosquitos Vectores/genética , Reacción en Cadena de la Polimerasa/métodos , Femenino , Plasmodium/genética , Plasmodium/aislamiento & purificación , Malaria/epidemiología , Malaria/parasitología , Malaria/transmisión , ARN Ribosómico 18S/genética , Culex/parasitología , Culex/genética , Humanos , Plasmodium falciparum/genética , Plasmodium falciparum/aislamiento & purificación , Plasmodium vivax/genética
10.
PeerJ ; 12: e16361, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38563018

RESUMEN

Parasite transmission is a heterogenous process in host-parasite interactions. This heterogeneity is particularly apparent in vector-borne parasite transmission where the vector adds an additional level of complexity. Haemosporidian parasites, a widespread protist, cause a malaria-like disease in birds globally, but we still have much to learn about the consequences of infection to hosts' health. In the Caribbean, where malarial parasites are endemic, studying host-parasites interactions may give us important insights about energetic trade-offs involved in malarial parasites infections in birds. In this study, we tested the consequences of Haemoproteus infection on the Bananaquit, a resident species of Puerto Rico. We also tested for potential sources of individual heterogeneity in the consequences of infection such as host age and sex. To quantify the consequences of infection to hosts' health we compared three complementary body condition indices between infected and uninfected individuals. Our results showed that Bananaquits infected by Haemoproteus had higher body condition than uninfected individuals. This result was consistent among the three body condition indices. Still, we found no clear evidence that this effect was mediated by host age or sex. We discuss a set of non-mutually exclusive hypotheses that may explain this pattern including metabolic syndrome, immunological responses leading to host tolerance or resistance to infection, and potential changes in consumption rates. Overall, our results suggest that other mechanisms, may drive the consequences of avian malarial infection.


Asunto(s)
Enfermedades de las Aves , Haemosporida , Parásitos , Passeriformes , Plasmodium , Humanos , Animales , Enfermedades de las Aves/epidemiología , Passeriformes/parasitología , Puerto Rico
11.
Parasit Vectors ; 17(1): 184, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38600596

RESUMEN

Human malaria, an ancient tropical disease, is caused by infection with protozoan parasites belonging to the genus Plasmodium and is transmitted by female mosquitoes of the genus Anopheles. Our understanding of human malaria parasites began officially in 1880 with their discovery in the blood of malaria patients by Charles Louis Alphonse Lavéran (1845-1922), a French army officer working in Algeria. A claim for priority was made by Philipp Friedrich Hermann Klencke (1813-1881) in 1843, who wrote a chapter entitled: "Marvellous parallelism between the manifestations of vertigo and the presence of animalcule vacuoles in living blood." We should not lose sight of this old controversy, which is rarely mentioned in historical reviews on malaria.


Asunto(s)
Anopheles , Malaria , Parásitos , Plasmodium , Animales , Humanos , Femenino , Malaria/parasitología , Argelia/epidemiología
12.
Mol Biol Rep ; 51(1): 555, 2024 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-38642192

RESUMEN

The eradication of Plasmodium parasites, responsible for malaria, is a daunting global public health task. It requires a comprehensive approach that addresses symptomatic, asymptomatic, and submicroscopic cases. Overcoming this challenge relies on harnessing the power of molecular diagnostic tools, as traditional methods like microscopy and rapid diagnostic tests fall short in detecting low parasitaemia, contributing to the persistence of malaria transmission. By precisely identifying patients of all types and effectively characterizing malaria parasites, molecular tools may emerge as indispensable allies in the pursuit of malaria elimination. Furthermore, molecular tools can also provide valuable insights into parasite diversity, drug resistance patterns, and transmission dynamics, aiding in the implementation of targeted interventions and surveillance strategies. In this review, we explore the significance of molecular tools in the pursuit of malaria elimination, shedding light on their key contributions and potential impact on public health.


Asunto(s)
Malaria , Parásitos , Plasmodium , Animales , Humanos , Malaria/epidemiología , Malaria/prevención & control , Salud Pública , Microscopía/métodos
13.
Malar J ; 23(1): 112, 2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38641572

RESUMEN

BACKGROUND: In malaria endemic regions of the Peruvian Amazon, rainfall together with river level and breeding site availability drive fluctuating vector mosquito abundance and human malaria cases, leading to temporal heterogeneity. The main variables influencing spatial transmission include location of communities, mosquito behaviour, land use/land cover, and human ecology/behaviour. The main objective was to evaluate seasonal and microgeographic biting behaviour of the malaria vector Nyssorhynchus (or Anopheles) darlingi in Amazonian Peru and to investigate effects of seasonality on malaria transmission. METHODS: We captured mosquitoes from 18:00 to 06:00 h using Human Landing Catch in two riverine (Lupuna, Santa Emilia) and two highway (El Triunfo, Nuevo Horizonte) communities indoors and outdoors from 8 houses per community, during the dry and rainy seasons from February 2016 to January 2017. We then estimated parity rate, daily survival and age of a portion of each collection of Ny. darlingi. All collected specimens of Ny. darlingi were tested for the presence of Plasmodium vivax or Plasmodium falciparum sporozoites using real-time PCR targeting the small subunit of the 18S rRNA. RESULTS: Abundance of Ny. darlingi varied across village, season, and biting behaviour (indoor vs outdoor), and was highly significant between rainy and dry seasons (p < 0.0001). Biting patterns differed, although not significantly, and persisted regardless of season, with peaks in highway communities at ~ 20:00 h in contrast to biting throughout the night (i.e., 18:00-06:00) in riverine communities. Of 3721 Ny. darlingi tested for Plasmodium, 23 (0.62%) were infected. We detected Plasmodium-infected Ny. darlingi in both community types and most (20/23) were captured outdoors during the rainy season; 17/23 before midnight. Seventeen Ny. darlingi were infected with P. vivax, and 6 with P. falciparum. No infected Ny. darlingi were captured during the dry season. Significantly higher rates of parity were detected in Ny. darlingi during the rainy season (average 64.69%) versus the dry season (average 36.91%) and by community, Lupuna, a riverine village, had the highest proportion of parous to nulliparous females during the rainy season. CONCLUSIONS: These data add a seasonal dimension to malaria transmission in peri-Iquitos, providing more evidence that, at least locally, the greatest risk of malaria transmission is outdoors during the rainy season mainly before midnight, irrespective of whether the community was located adjacent to the highway or along the river.


Asunto(s)
Anopheles , Mordeduras y Picaduras , Malaria Falciparum , Malaria Vivax , Malaria , Plasmodium , Animales , Femenino , Humanos , Anopheles/genética , Malaria/epidemiología , Perú/epidemiología , Mosquitos Vectores , Malaria Vivax/epidemiología , Estaciones del Año
14.
Front Cell Infect Microbiol ; 14: 1304839, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38572319

RESUMEN

Background: Chemotherapies for malaria and babesiosis frequently succumb to the emergence of pathogen-related drug-resistance. Host-targeted therapies are thought to be less susceptible to resistance but are seldom considered for treatment of these diseases. Methods: Our overall objective was to systematically assess small molecules for host cell-targeting activity to restrict proliferation of intracellular parasites. We carried out a literature survey to identify small molecules annotated for host factors implicated in Plasmodium falciparum infection. Alongside P. falciparum, we implemented in vitro parasite susceptibility assays also in the zoonotic parasite Plasmodium knowlesi and the veterinary parasite Babesia divergens. We additionally carried out assays to test directly for action on RBCs apart from the parasites. To distinguish specific host-targeting antiparasitic activity from erythrotoxicity, we measured phosphatidylserine exposure and hemolysis stimulated by small molecules in uninfected RBCs. Results: We identified diverse RBC target-annotated inhibitors with Plasmodium-specific, Babesia-specific, and broad-spectrum antiparasitic activity. The anticancer MEK-targeting drug trametinib is shown here to act with submicromolar activity to block proliferation of Plasmodium spp. in RBCs. Some inhibitors exhibit antimalarial activity with transient exposure to RBCs prior to infection with parasites, providing evidence for host-targeting activity distinct from direct inhibition of the parasite. Conclusions: We report here characterization of small molecules for antiproliferative and host cell-targeting activity for malaria and babesiosis parasites. This resource is relevant for assessment of physiological RBC-parasite interactions and may inform drug development and repurposing efforts.


Asunto(s)
Antimaláricos , Babesia , Babesiosis , Malaria Falciparum , Malaria , Parásitos , Plasmodium , Animales , Humanos , Babesiosis/tratamiento farmacológico , Malaria/parasitología , Eritrocitos/parasitología , Antimaláricos/farmacología , Plasmodium falciparum
15.
Artículo en Inglés | MEDLINE | ID: mdl-38426407

RESUMEN

Malaria, caused by different species of protists of the genus Plasmodium, remains among the most common causes of death due to parasitic diseases worldwide, mainly for children aged under 5. One of the main obstacles to malaria eradication is the speed with which the pathogen evolves resistance to the drug schemes developed against it. For this reason, it remains urgent to find innovative therapeutic strategies offering sufficient specificity against the parasite to minimize resistance evolution and drug side effects. In this context, nanotechnology-based approaches are now being explored for their use as antimalarial drug delivery platforms due to the wide range of advantages and tuneable properties that they offer. However, major challenges remain to be addressed to provide a cost-efficient and targeted therapeutic strategy contributing to malaria eradication. The present work contains a systematic review of nanotechnology-based antimalarial drug delivery systems generated during the last 10 years. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.


Asunto(s)
Antimaláricos , Malaria , Nanomedicina , Humanos , Antimaláricos/uso terapéutico , Antimaláricos/farmacología , Sistemas de Liberación de Medicamentos , Malaria/tratamiento farmacológico , Modelos Teóricos , Plasmodium
16.
Malar J ; 23(1): 84, 2024 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-38500090

RESUMEN

BACKGROUND: Malaria is an infectious malady caused by Plasmodium parasites, cerebral malaria standing out as one of its most severe complications. Clinical manifestation include elevated body temperature, loss of consciousness, and seizures. However, reports of cerebral malaria presenting as nonconvulsive status epilepticus are extremely rare. The case presented involves psychiatric symptoms, with the electroencephalogram indicated nonconvulsive status epilepticus associated with cerebral malaria. CASE PRESENTATION: A 53-year-old male, was urgently admitted, due to confusion and abnormal behaviour for 10 h. The patient returned to China after developing a fever while working in Tanzania two months ago. The blood smear revealed Plasmodium vivax and Plasmodium falciparum, and he was diagnosed with malaria. He recovered following anti-malarial treatment. After admission, the patient was confused, unable to communicate normally, and unwilling to cooperate with the physical examination. Plasmodium was not found in the blood smear, but the DNA sequence of P. falciparum was discovered using metagenomic next-generation sequencing of cerebrospinal fluid. Brain MRI revealed no significant abnormalities. Continuous electroencephalogram monitoring revealed that the patient had non-convulsive status epilepticus, which was treated with diazepam and levetiracetam. The patient had normal consciousness and behaviour. He received anti-malarial treatment for two weeks and fully recovered. CONCLUSIONS: This case demonstrates that nonconvulsive status epilepticus can be a manifestation of cerebral malaria. It is imperative for attending physicians to heighten vigilance when encountering patients with a history of travel to malaria-endemic regions or a prior malaria infection, especially in the presence of unusual clinical presentations.


Asunto(s)
Antimaláricos , Malaria Cerebral , Malaria Falciparum , Plasmodium , Estado Epiléptico , Masculino , Humanos , Persona de Mediana Edad , Malaria Cerebral/complicaciones , Malaria Cerebral/diagnóstico , Malaria Cerebral/tratamiento farmacológico , Antimaláricos/uso terapéutico , Malaria Falciparum/complicaciones , Malaria Falciparum/diagnóstico , Malaria Falciparum/tratamiento farmacológico , Estado Epiléptico/diagnóstico , Estado Epiléptico/tratamiento farmacológico , Estado Epiléptico/etiología
17.
Malar J ; 23(1): 70, 2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-38459560

RESUMEN

BACKGROUND: Birds chronically infected with avian malaria parasites often show relapses of parasitaemia after latent stages marked by absence of parasites in the peripheral circulation. These relapses are assumed to result from the activation of dormant exo-erythrocytic stages produced during secondary (post-erythrocytic) merogony of avian Plasmodium spp. Yet, there is no morphological proof of persistent or dormant tissue stages in the avian host during latent infections. This study investigated persistence of Plasmodium relictum pSGS1 in birds with latent infections during winter, with the goal to detect presumed persisting tissue stages using a highly sensitive RNAscope® in situ hybridization technology. METHODS: Fourteen domestic canaries were infected with P. relictum pSGS1 by blood-inoculation in spring, and blood films examined during the first 4 months post infection, and during winter and spring of the following year. After parasitaemia was no longer detectable, half of the birds were dissected, and tissue samples investigated for persisting tissue stages using RNAscope ISH and histology. The remaining birds were blood-checked and dissected after re-appearance of parasitaemia, and their tissues equally examined. RESULTS: Systematic examination of tissues showed no exo-erythrocytic stages in birds exhibiting latent infections by blood-film microscopy, indicating absence of dormant tissue stages in P. relictum pSGS1-infected canaries. Instead, RNAscope ISH revealed rare P. relictum blood stages in capillaries of various tissues and organs, demonstrating persistence of the parasites in the microvasculature. Birds examined after re-appearance of parasitemia showed higher numbers of P. relictum blood stages in both capillaries and larger blood vessels, indicating replication during early spring and re-appearance in the peripheral circulation. CONCLUSIONS: The findings suggest that persistence of P. relictum pSGS1 during latent infection is mediated by continuous low-level erythrocytic merogony and possibly tissue sequestration of infected blood cells. Re-appearance of parasitaemia in spring seems to result from increased erythrocytic merogony, therefore representing recrudescence and not relapse in blood-inoculated canaries. Further, the study highlights strengths and limitations of the RNAscope ISH technology for the detection of rare parasite stages in tissues, providing directions for future research on persistence and tissue sequestration of avian malaria and related haemosporidian parasites.


Asunto(s)
Infección Latente , Malaria Aviar , Plasmodium , Animales , Canarios/parasitología , Malaria Aviar/parasitología , Plasmodium/genética , Aves , Hibridación in Situ , Parasitemia/parasitología , Recurrencia
18.
Front Cell Infect Microbiol ; 14: 1354880, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38465236

RESUMEN

Plasmodium vivax, the most widespread human malaria parasite, and P. knowlesi, an emerging Plasmodium that infects humans, are the phylogenetically closest malarial species that infect humans, which may induce cross-species reactivity across most co-endemic areas in Southeast Asia. The thrombospondin-related anonymous protein (TRAP) family is indispensable for motility and host cell invasion in the growth and development of Plasmodium parasites. The merozoite-specific TRAP (MTRAP), expressed in blood-stage merozoites, is supposed to be essential for human erythrocyte invasion. We aimed to characterize MTRAPs in blood-stage P. vivax and P. knowlesi parasites and ascertain their cross-species immunoreactivity. Recombinant P. vivax and P. knowlesi MTRAPs of full-length ectodomains were expressed in a mammalian expression system. The MTRAP-specific immunoglobulin G, obtained from immune animals, was used in an immunofluorescence assay for subcellular localization and invasion inhibitory activity in blood-stage parasites was determined. The cross-species humoral immune responses were analyzed in the sera of patients with P. vivax or P. knowlesi infections. The MTRAPs of P. vivax (PvMTRAP) and P. knowlesi (PkMTRAP) were localized on the rhoptry body of merozoites in blood-stage parasites. Both anti-PvMTRAP and anti-PkMTRAP antibodies inhibited erythrocyte invasion of blood-stage P. knowlesi parasites. The humoral immune response to PvMTRAP showed high immunogenicity, longevity, and cross-species immunoreactivity with P. knowlesi. MTRAPs are promising candidates for development of vaccines and therapeutics against vivax and knowlesi malaria.


Asunto(s)
Malaria Vivax , Malaria , Parásitos , Plasmodium , Animales , Humanos , Plasmodium vivax/genética , Parásitos/metabolismo , Merozoítos , Trombospondinas/metabolismo , Plasmodium/metabolismo , Malaria/parasitología , Malaria Vivax/parasitología , Proteínas Protozoarias/metabolismo , Mamíferos/metabolismo
19.
Nat Commun ; 15(1): 2104, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38453916

RESUMEN

Malaria-causing Plasmodium parasites first replicate as liver stages (LS), which then seed symptomatic blood stage (BS) infection. Emerging evidence suggests that these stages impact each other via perturbation of host responses, and this influences the outcome of natural infection. We sought to understand whether the parasite stage interplay would affect live-attenuated whole parasite vaccination, since the efficacy of whole parasite vaccines strongly correlates with their extend of development in the liver. We thus investigated the impact of BS infection on LS development of genetically attenuated and wildtype parasites in female rodent malaria models and observed that for both, LS infection suffered severe suppression during concurrent BS infection. Strikingly and in contrast to previously published studies, we find that the BS-induced iron-regulating hormone hepcidin is not mediating suppression of LS development. Instead, we demonstrate that BS-induced host interferons are the main mediators of LS developmental suppression. The type of interferon involved depended on the BS-causing parasite species. Our study provides important mechanistic insights into the BS-mediated suppression of LS development. This has direct implications for understanding the outcomes of live-attenuated Plasmodium parasite vaccination in malaria-endemic areas and might impact the epidemiology of natural malaria infection.


Asunto(s)
Hepatopatías , Vacunas contra la Malaria , Malaria , Plasmodium , Femenino , Humanos , Hepcidinas , Malaria/parasitología , Hígado
20.
BMC Public Health ; 24(1): 918, 2024 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-38549091

RESUMEN

BACKGROUND: In Chad, malaria remains a significant public health concern, particularly among nomadic populations. Geographical factors and the mobility of human populations have shown to be associated with the diversity of Plasmodium species. The study aims to describe the malaria prevalence among nomadic children and to investigate its associated factors. METHODS: A cross-sectional study was conducted in February and October 2021 among nomadic communities in Chad. Blood sample were collected and tested from 187 Arab, Fulani and Dazagada nomadic children aged 3-59 months using malaria rapid diagnostic test (RDT). A structured electronic questionnaire was administered to their parents to collect information about the socio­economic data. Malaria testing results were categorized according to the SD BIOLINE Malaria Ag Pf/Pan RDT procedures. Logistic regression analysis was used to determine key risk factors explaining the prevalence of malaria. STATA version IC 13 was used for statistical analysis. RESULTS: The overall malaria prevalence in nomadic children was 24.60%, with 65.20% being Plasmodium falciparum species and 34.8% mixed species. Boys were twice as likely (COR = 1.83; 95% CI, 0.92-3.62; p = 0.083) to have malaria than girls. Children whose parents used to seek traditional drugs were five times more likely (AOR = 5.59; 95% CI, 1.40-22.30, p = 0.015) to have malaria than children whose parents used to seek health facilities. Children whose parents reported spending the last night under a mosquito net were one-fifth as likely (AOR = 0.17; 95% CI, 0.03-0.90, p = 0.037) to have malaria compared to children whose parents did not used a mosquito net. Furthermore, Daza children were seventeen times (1/0.06) less likely (AOR = 0.06; 95% CI, 0.01-0.70, p = 0.024) to have malaria than Fulani children and children from households piped water as the main source were seven times more likely (AOR = 7.05; 95% CI, 1.69-29.45; p = 0.007) to have malaria than those using surface water. CONCLUSIONS: Malaria remains a significant public health issue in the nomadic communities of Chad. Community education and sensitization programs within nomad communities are recommended to raise awareness about malaria transmission and control methods, particularly among those living in remote rural areas. The National Malaria Control Program (NMCP) should increase both the coverage and use of long-lasting insecticidal nets (LLINs) and seasonal malaria chemoprevention (SMC) in addition to promoting treatment-seeking behaviors in nomadic communities.


Asunto(s)
Mosquiteros Tratados con Insecticida , Malaria , Plasmodium , Niño , Masculino , Femenino , Humanos , Chad , Estudios Transversales , Malaria/diagnóstico , Malaria/epidemiología , Malaria/prevención & control , Agua
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