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1.
Biochem Soc Trans ; 52(2): 593-602, 2024 Apr 24.
Article in English | MEDLINE | ID: mdl-38563493

ABSTRACT

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.


Subject(s)
Cell Division , Malaria , Plasmodium , Protozoan Proteins , Plasmodium/metabolism , Plasmodium/physiology , Animals , Humans , Malaria/parasitology , Malaria/metabolism , Protozoan Proteins/metabolism , Mitosis , Cytokinesis , Meiosis , Protein Processing, Post-Translational , Host-Parasite Interactions
2.
Trends Parasitol ; 39(12): 1074-1086, 2023 12.
Article in English | MEDLINE | ID: mdl-37839913

ABSTRACT

Protozoan pathogens such as Plasmodium spp., Leishmania spp., Toxoplasma gondii, and Trypanosoma spp. are often associated with high-mortality, acute and chronic diseases of global health concern. For transmission and immune evasion, protozoans have evolved diverse strategies to interact with a range of host tissue environments. These interactions are linked to disease pathology, yet our understanding of the association between parasite colonization and host homeostatic disruption is limited. Recently developed techniques for cellular barcoding have the potential to uncover the biology regulating parasite transmission, dissemination, and the stability of infection. Understanding bottlenecks to infection and the in vivo tissue niches that facilitate chronic infection and spread has the potential to reveal new aspects of parasite biology.


Subject(s)
Parasites , Plasmodium , Protozoan Infections , Toxoplasma , Animals , Humans , Host-Parasite Interactions , Protozoan Infections/parasitology , Parasites/physiology , Plasmodium/physiology
3.
Sci Adv ; 9(24): eadf2161, 2023 06 16.
Article in English | MEDLINE | ID: mdl-37327340

ABSTRACT

Critical events in the life cycle of malaria-causing parasites depend on cyclic guanosine monophosphate homeostasis by guanylyl cyclases (GCs) and phosphodiesterases, including merozoite egress or invasion of erythrocytes and gametocyte activation. These processes rely on a single GCα, but in the absence of known signaling receptors, how this pathway integrates distinct triggers is unknown. We show that temperature-dependent epistatic interactions between phosphodiesterases counterbalance GCα basal activity preventing gametocyte activation before mosquito blood feed. GCα interacts with two multipass membrane cofactors in schizonts and gametocytes: UGO (unique GC organizer) and SLF (signaling linking factor). While SLF regulates GCα basal activity, UGO is essential for GCα up-regulation in response to natural signals inducing merozoite egress and gametocyte activation. This work identifies a GC membrane receptor platform that senses signals triggering processes specific to an intracellular parasitic lifestyle, including host cell egress and invasion to ensure intraerythrocytic amplification and transmission to mosquitoes.


Subject(s)
Culicidae , Plasmodium , Animals , Cues , Plasmodium/physiology , Erythrocytes/parasitology , Merozoites/physiology , Life Cycle Stages , Culicidae/parasitology
4.
PLoS Pathog ; 19(3): e1011210, 2023 03.
Article in English | MEDLINE | ID: mdl-36996035

ABSTRACT

Plasmodium parasites have a complex life cycle alternating between a mosquito and a vertebrate host. Following the bite of an Anopheles female mosquito, Plasmodium sporozoites are transmitted from the skin to the liver; their first place of replication within the host. Successfully invaded sporozoites undergo a massive replication and growth involving asynchronous DNA replication and division that results in the generation of tens of thousands or even hundreds of thousands of merozoites depending on the Plasmodium species. The generation of a high number of daughter parasites requires biogenesis and segregation of organelles to finally reach a relatively synchronous cytokinesis event. At the end of liver stage (LS) development, merozoites are packed into merosomes and released into the bloodstream. They are then liberated and infect red blood cells to again produce merozoites by schizogony for the erythrocytic stage of the life cycle. Although parasite LS and asexual blood stage (ABS) differ in many respects, important similarities exist between the two. This review focuses on the cell division of Plasmodium parasite LS in comparison with other life cycle stages especially the parasite blood stage.


Subject(s)
Liver , Plasmodium , Animals , Cytokinesis , Life Cycle Stages , Liver/parasitology , Merozoites , Plasmodium/physiology , Skin , Sporozoites
5.
Mol Biochem Parasitol ; 253: 111543, 2023 02.
Article in English | MEDLINE | ID: mdl-36642385

ABSTRACT

The mosquito gut microbiota is vital to the proper functioning of the host organism. Mosquitoes may benefit from this microbiota in their guts because it promotes factors including blood digestion, fecundity, metamorphosis, and living habitat and inhibits malarial parasites (Plasmodium) growth or transmission. In this overview, we analyzed how mosquitoes acquire their gut microbiota, characterized those bacteria, and discussed the functions they provide. We also investigated the effects of microbiota on malaria vectors, with a focus on the mosquito species Anopheles, as well as the relationship between microbiota and Plasmodium, the aspects in which microbiota influences Plasmodium via immune response, metabolism, and redox mechanisms, and the strategies in which gut bacteria affect the life cycle of malaria vectors and provide the ability to resist insecticides. This article explores the difficulties in studying triadic interactions, such as the interplay between Mosquitoes, Malarial parasite, and the Microbiota that dwell in the mosquitoes' guts, and need additional research for a better understanding of these multiple connections to implement an exact vector control strategies using Gut microbiota in malaria control.


Subject(s)
Anopheles , Malaria , Microbiota , Parasites , Plasmodium , Animals , Humans , Mosquito Vectors/microbiology , Mosquito Vectors/parasitology , Host-Parasite Interactions , Plasmodium/physiology , Malaria/parasitology , Anopheles/parasitology
6.
PLoS One ; 17(9): e0273568, 2022.
Article in English | MEDLINE | ID: mdl-36048823

ABSTRACT

Mosquitoes transmit many pathogens responsible for human diseases, such as malaria which is caused by parasites in the genus Plasmodium. Current strategies to control vector-transmitted diseases are increasingly undermined by mosquito and pathogen resistance, so additional methods of control are required. Paratransgenesis is a method whereby symbiotic bacteria are genetically modified to affect the mosquito's phenotype by engineering them to deliver effector molecules into the midgut to kill parasites. One paratransgenesis candidate is Asaia bogorensis, a Gram-negative bacterium colonizing the midgut, ovaries, and salivary glands of Anopheles sp. mosquitoes. Previously, engineered Asaia strains using native signals to drive the release of the antimicrobial peptide, scorpine, fused to alkaline phosphatase were successful in significantly suppressing the number of oocysts formed after a blood meal containing P. berghei. However, these strains saw high fitness costs associated with the production of the recombinant protein. Here, we report evaluation of five different partner proteins fused to scorpine that were evaluated for effects on the growth and fitness of the transgenic bacteria. Three of the new partner proteins resulted in significant levels of protein released from the Asaia bacterium while also significantly reducing the prevalence of mosquitoes infected with P. berghei. Two partners performed as well as the previously tested Asaia strain that used alkaline phosphatase in the fitness analyses, but neither exceeded it. It may be that there is a maximum level of fitness and parasite inhibition that can be achieved with scorpine being driven constitutively, and that use of a Plasmodium specific effector molecule in place of scorpine would help to mitigate the stress on the symbionts.


Subject(s)
Acetobacteraceae , Biological Control Agents , Mosquito Vectors , Plasmodium , Acetobacteraceae/metabolism , Alkaline Phosphatase/metabolism , Animals , Biological Control Agents/metabolism , Defensins , Malaria/prevention & control , Mosquito Vectors/parasitology , Plasmodium/microbiology , Plasmodium/physiology , Recombinant Proteins/metabolism
7.
Nat Commun ; 13(1): 2949, 2022 05 26.
Article in English | MEDLINE | ID: mdl-35618711

ABSTRACT

In mammals, the serine protease plasmin degrades extracellular proteins during blood clot removal, tissue remodeling, and cell migration. The zymogen plasminogen is activated into plasmin by two serine proteases: tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA), a process regulated by plasminogen activator inhibitor 1 (PAI-1), a serine protease inhibitor that specifically inhibits tPA and uPA. Plasmodium gametes and sporozoites use tPA and uPA to activate plasminogen and parasite-bound plasmin degrades extracellular matrices, facilitating parasite motility in the mosquito and the mammalian host. Furthermore, inhibition of plasminogen activation by PAI-1 strongly blocks infection in both hosts. To block parasite utilization of plasmin, we engineered Anopheles stephensi transgenic mosquitoes constitutively secreting human PAI-1 (huPAI-1) in the midgut lumen, in the saliva, or both. Mosquitoes expressing huPAI-1 strongly reduced rodent and human Plasmodium parasite transmission to mosquitoes, showing that co-opting plasmin for mosquito infection is a conserved mechanism among Plasmodium species. huPAI-1 expression in saliva induced salivary gland deformation which affects sporozoite invasion and P. berghei transmission to mice, resulting in significant levels of protection from malaria. Targeting the interaction of malaria parasites with the fibrinolytic system using genetically engineered mosquitoes could be developed as an intervention to control malaria transmission.


Subject(s)
Anopheles , Malaria , Plasmodium , Animals , Animals, Genetically Modified , Anopheles/parasitology , Fibrinolysin , Humans , Malaria/parasitology , Mammals , Mice , Mosquito Vectors/genetics , Plasminogen , Plasminogen Activator Inhibitor 1/genetics , Plasmodium/physiology , Sporozoites
8.
Malar J ; 21(1): 148, 2022 May 15.
Article in English | MEDLINE | ID: mdl-35570274

ABSTRACT

BACKGROUND: Species of Plasmodium (Haemosporida, Plasmodiidae) are remarkably diverse haemoparasites. Information on genetic diversity of avian malaria pathogens has been accumulating rapidly, however exo-erythrocytic development of these organisms remains insufficiently addressed. This is unfortunate because, contrary to Plasmodium species parasitizing mammals, the avian malaria parasites undergo several cycles of exo-erythrocytic development, often resulting in damage of various organs. Insufficient knowledge on the exo-erythrocytic development in most described Plasmodium species precludes the understanding of mechanisms of virulence during avian malaria. This study extends information on the exo-erythrocytic development of bird malaria parasites. METHODS: A roadkill fieldfare (Turdus pilaris) was sampled in Switzerland and examined using pathologic, cytologic, histologic, molecular and microbiologic methods. Avian malaria was diagnosed, and erythrocytic and exo-erythrocytic stages of the parasite were identified using morphologic characteristics and barcode DNA sequences of the cytochrome b gene. The species-specific characteristics were described, illustrated, and pathologic changes were reported. RESULTS: An infection with Plasmodium matutinum lineage pLINN1 was detected. Parasitaemia was relatively low (0.3%), with all erythrocytic stages (trophozoites, meronts and gametocytes) present in blood films. Most growing erythrocytic meronts were markedly vacuolated, which is a species-specific feature of this parasite's development. Phanerozoites at different stages of maturation were seen in leukocytes, macrophages, and capillary endothelial cells in most organs examined; they were particularly numerous in the brain. Like the erythrocytic meronts, growing phanerozoites were markedly vacuolated. Conspicuous exo-erythrocytic development and maturation in leucocytes suggests that this fieldfare was not adapted to the infection and the parasite was capable to escape from cellular immunity. CONCLUSIONS: This is the first report of exo-erythrocytic development of the malaria parasite lineage pLINN1 during single infection and the first report of this lineage in the fieldfare. The findings of multiple phanerozoites in brain, skeletal muscle, and eye tissue in combination with signs of vascular blockage and thrombus formation strongly suggest an impaired vision and neuromuscular responsiveness as cause of the unexpected collision with a slowly moving car. Further studies on exo-erythrocytic stages of haemosporidian parasites are pivotal to understand the true level of populational damage of avian malaria in wild birds.


Subject(s)
Haemosporida , Malaria, Avian , Plasmodium , Songbirds , Animals , Endothelial Cells , Haemosporida/physiology , Malaria, Avian/parasitology , Mammals , Phylogeny , Plasmodium/physiology , Songbirds/parasitology
9.
PLoS Pathog ; 18(1): e1010223, 2022 01.
Article in English | MEDLINE | ID: mdl-35077503

ABSTRACT

Transmission of malaria-causing parasites to mosquitoes relies on the production of gametocyte stages and their development into gametes. These stages display various microtubule cytoskeletons and the architecture of the corresponding microtubule organisation centres (MTOC) remains elusive. Combining ultrastructure expansion microscopy (U-ExM) with bulk proteome labelling, we first reconstructed in 3D the subpellicular microtubule network which confers cell rigidity to Plasmodium falciparum gametocytes. Upon activation, as the microgametocyte undergoes three rounds of endomitosis, it also assembles axonemes to form eight flagellated microgametes. U-ExM combined with Pan-ExM further revealed the molecular architecture of the bipartite MTOC coordinating mitosis with axoneme formation. This MTOC spans the nuclear membrane linking cytoplasmic basal bodies to intranuclear bodies by proteinaceous filaments. In P. berghei, the eight basal bodies are concomitantly de novo assembled in a SAS6- and SAS4-dependent manner from a deuterosome-like structure, where centrin, γ-tubulin, SAS4 and SAS6 form distinct subdomains. Basal bodies display a fusion of the proximal and central cores where centrin and SAS6 are surrounded by a SAS4-toroid in the lumen of the microtubule wall. Sequential nucleation of axonemes and mitotic spindles is associated with a dynamic movement of γ-tubulin from the basal bodies to the intranuclear bodies. This dynamic architecture relies on two non-canonical regulators, the calcium-dependent protein kinase 4 and the serine/arginine-protein kinase 1. Altogether, these results provide insights into the molecular organisation of a bipartite MTOC that may reflect a functional transition of a basal body to coordinate axoneme assembly with mitosis.


Subject(s)
Axoneme/ultrastructure , Gametogenesis/physiology , Microscopy/methods , Microtubule-Organizing Center/ultrastructure , Mitosis/physiology , Plasmodium/physiology , Animals , Mice , Plasmodium/ultrastructure
10.
Infect Immun ; 90(1): e0031421, 2022 01 25.
Article in English | MEDLINE | ID: mdl-34606368

ABSTRACT

While general mechanisms by which Plasmodium ookinetes invade the mosquito midgut have been studied, details regarding the interface of the ookinete, specifically its barriers to invasion, such as the proteolytic milieu, the chitin-containing, protein cross-linked peritrophic matrix, and the midgut epithelium, remain to be understood. Here, we review our knowledge of Plasmodium chitinases and the mechanisms by which they mediate ookinetes crossing the peritrophic matrix. The integration of new genomic insights into previous findings advances our understanding of Plasmodium evolution. Recently obtained Plasmodium species genomic data enable identification of the conserved residues in the experimentally demonstrated hetero-multimeric, high-molecular-weight complex comprised of a short chitinase covalently linked to binding partners, von Willebrand factor A domain-related protein (WARP) and secreted ookinete adhesive protein (SOAP). Artificial intelligence-based high-resolution structural modeling using the DeepMind AlphaFold algorithm yielded highly informative three-dimensional structures and insights into how short chitinases, WARP, and SOAP may interact at the atomic level to form the ookinete-secreted peritrophic matrix invasion complex. Elucidating the significance of the divergence of ookinete-secreted micronemal proteins among Plasmodium species may lead to a better understanding of the ookinete invasion machinery and the coevolution of Plasmodium-mosquito interactions.


Subject(s)
Chitinases/metabolism , Culicidae/parasitology , Host-Parasite Interactions , Microneme/metabolism , Multiprotein Complexes/metabolism , Plasmodium/physiology , Animals , Biological Evolution , Chitinases/genetics , Digestive System/parasitology , Models, Biological , Models, Molecular , Molecular Weight , Multiprotein Complexes/chemistry , Phylogeny , Plasmodium/classification , Protein Conformation , Species Specificity , Structure-Activity Relationship
11.
Front Immunol ; 12: 770246, 2021.
Article in English | MEDLINE | ID: mdl-34970259

ABSTRACT

Protozoan parasite infection causes severe diseases in humans and animals, leading to tremendous economic and medical pressure. Natural immunity is the first line of defence against parasitic infection. Currently, the role of natural host immunity in combatting parasitic infection is unclear, so further research on natural host immunity against parasites will provide a theoretical basis for the prevention and treatment of related parasitic diseases. Extracellular traps (ETs) are an important natural mechanism of immunity involving resistance to pathogens. When immune cells such as neutrophils and macrophages are stimulated by external pathogens, they release a fibrous network structure, consisting mainly of DNA and protein, that can capture and kill a variety of extracellular pathogenic microorganisms. In this review, we discuss the relevant recently reported data on ET formation induced by protozoan parasite infection, including the molecular mechanisms involved, and discuss the role of ETs in the occurrence and development of parasitic diseases.


Subject(s)
Extracellular Traps/immunology , Immunity, Innate/immunology , Neutrophils/immunology , Protozoan Infections, Animal/immunology , Protozoan Infections/immunology , Signal Transduction/immunology , Animals , Extracellular Traps/parasitology , Host-Parasite Interactions/immunology , Humans , Leishmania/immunology , Leishmania/physiology , Neutrophils/parasitology , Plasmodium/immunology , Plasmodium/physiology , Protozoan Infections/parasitology , Protozoan Infections, Animal/parasitology , Toxoplasma/immunology , Toxoplasma/physiology
12.
PLoS One ; 16(12): e0260785, 2021.
Article in English | MEDLINE | ID: mdl-34855878

ABSTRACT

BACKGROUND: Malaria and anemia remain major public health challenges in Tanzania. Household socioeconomic factors are known to influence these conditions. However, it is not clear how these factors influence malaria transmission and anemia in Masasi and Nanyumbu Districts. This study presents findings on malaria and anemia situation in under-five children and its influencing socioeconomic factors in Masasi and Nanyumbu Districts, surveyed as part of an ongoing seasonal malaria chemoprevention operational study. METHODS: A community-based cross-sectional survey was conducted between August and September 2020. Finger-prick blood samples collected from children aged 3-59 months were used to test for malaria infection using malaria rapid diagnostic test (mRDT), thick smears for determination of asexual and sexual parasitemia, and thin smear for parasite speciation. Hemoglobin concentration was measured using a HemoCue spectrophotometer. A structured questionnaire was used to collect household socioeconomic information from parents/caregivers of screened children. The prevalence of malaria was the primary outcome. Chi-square tests, t-tests, and logistic regression models were used appropriately. RESULTS: Overall mRDT-based malaria prevalence was 15.9% (373/2340), and was significantly higher in Nanyumbu (23.7% (167/705) than Masasi District (12.6% (206/1635), p<0.001. Location (Nanyumbu), no formal education, household number of people, household number of under-fives, not having a bed net, thatched roof, open/partially open eave, sand/soil floor, and low socioeconomic status were major risks for malaria infection. Some 53.9% (1196/2218) children had anemia, and the majority were in Nanyumbu (63.5% (458/705), p<0.001. Location (Nanyumbu), mRDT positive, not owning a bed net, not sleeping under bed net, open/partially open eave, thatched window, sex of the child, and age of the child were major risk factors for anemia. CONCLUSION: Prevalence of malaria and anemia was high and was strongly associated with household socioeconomic factors. Improving household socioeconomic status is expected to reduce the prevalence of the conditions in the area.


Subject(s)
Anemia/epidemiology , Chemoprevention/methods , Health Plan Implementation/methods , Malaria/epidemiology , Plasmodium/physiology , Seasons , Child, Preschool , Cross-Sectional Studies , Female , Humans , Infant , Malaria/parasitology , Malaria/transmission , Male , Prevalence , Risk Factors , Socioeconomic Factors , Tanzania/epidemiology
13.
Malar J ; 20(1): 442, 2021 Nov 20.
Article in English | MEDLINE | ID: mdl-34801056

ABSTRACT

Malaria is a complex parasitic disease, caused by Plasmodium spp. More than a century after the discovery of malaria parasites, this disease continues to pose a global public health problem and the pathogenesis of the severe forms of malaria remains incompletely understood. Extracellular vesicles (EVs), including exosomes and microvesicles, have been increasingly researched in the field of malaria in a bid to fill these knowledge gaps. EVs released from Plasmodium-infected red blood cells and other host cells during malaria infection are now believed to play key roles in disease pathogenesis and are suggested as vital components of the biology of Plasmodium spp. Malaria-derived EVs have been identified as potential disease biomarkers and therapeutic tools. In this review, key findings of malaria EV studies over the last 20 years are summarized and critically analysed. Outstanding areas of research into EV biology are identified. Unexplored EV research foci for the future that will contribute to consolidating the potential for EVs as agents in malaria prevention and control are proposed.


Subject(s)
Extracellular Vesicles/physiology , Malaria/parasitology , Plasmodium/physiology , Humans
14.
Bioorg Chem ; 117: 105359, 2021 12.
Article in English | MEDLINE | ID: mdl-34689083

ABSTRACT

Malaria is a devastating disease caused by Plasmodium parasites. Emerging resistance against current antimalarial therapeutics has engendered the need to develop antimalarials with novel structural classes. We recently described the identification and initial optimization of the 2-anilino quinazoline antimalarial class. Here, we refine the physicochemical properties of this antimalarial class with the aim to improve aqueous solubility and metabolism and to reduce adverse promiscuity. We show the physicochemical properties of this class are intricately balanced with asexual parasite activity and human cell cytotoxicity. Structural modifications we have implemented improved LipE, aqueous solubility and in vitro metabolism while preserving fast acting P. falciparum asexual stage activity. The lead compounds demonstrated equipotent activity against P. knowlesi parasites and were not predisposed to resistance mechanisms of clinically used antimalarials. The optimized compounds exhibited modest activity against early-stage gametocytes, but no activity against pre-erythrocytic liver parasites. Confoundingly, the refined physicochemical properties installed in the compounds did not engender improved oral efficacy in a P. berghei mouse model of malaria compared to earlier studies on the 2-anilino quinazoline class. This study provides the framework for further development of this antimalarial class.


Subject(s)
Aniline Compounds/chemistry , Aniline Compounds/pharmacology , Antimalarials/chemistry , Antimalarials/pharmacology , Malaria/drug therapy , Plasmodium/drug effects , Quinazolines/chemistry , Quinazolines/pharmacology , Amination , Aniline Compounds/therapeutic use , Animals , Antimalarials/therapeutic use , Female , Humans , Malaria/parasitology , Mice , Plasmodium/physiology , Plasmodium falciparum/drug effects , Plasmodium falciparum/physiology , Quinazolines/therapeutic use
15.
Biomed Res Int ; 2021: 3741413, 2021.
Article in English | MEDLINE | ID: mdl-34712731

ABSTRACT

BACKGROUND: Control and prevention activities have brought substantial decline of malaria incidence in the last two decades in Ethiopia. However, lack of local data on the disease transmission and community knowledge, attitude, and practice about malaria are thought to reverse the trend of malaria in certain areas. Therefore, assessment of the prevalence and community awareness towards malaria plays pivotal role for the success of malaria control and prevention. OBJECTIVE: To assess malaria prevalence and knowledge, attitude, and practice about malaria among febrile patients in Bahir Dar Zuria district, Northwest Ethiopia. METHODS: A facility based crosssectional study was conducted from January to March 2020 among 149 febrile patients attending selected health centers in Bahir Dar Zuria district. Data about knowledge, attitude, and practice about malaria were collected using semistructured questionnaire. Blood sample from each participant was tested for Plasmodium species through malaria rapid diagnostic tests and blood film microscopy. Data were analyzed using statistical software for social sciences version 20. RESULTS: Among 149 participants, 22 (14.8%) were positive for Plasmodium infection at least by one diagnostic methods. Prevalence of P. falciparum and P. vivax was 3.4% and 10.1%, respectively, while that of mixed infection was 1.3%. From the total study participants, 29.5% have good knowledge, 77.2% have positive attitude, and 34.9% have good practice towards malaria. Statistically significant associations were observed on knowledge with age group (X 2 = 10.377, P = 0.035), educational level (X 2 = 15.075, P = 0.001), family size (X 2 = 7.601, P = 0.022), attitude level and practice level. Participants with family size < 5 were 6.841 (95% CI: 2.570-18.206, P ≤ 0.001) times more likely to have negative attitude as compared to those with family size ≥ 5. CONCLUSIONS: Prevalence of malaria in the study area was relatively high. Study participants had encouraging attitude; however, their knowledge and practice towards malaria were poor. Therefore, the existing malaria control activities should be supplemented with continuous health educations, aware the community, and ensure participation in the control and prevention activities.


Subject(s)
Health Knowledge, Attitudes, Practice , Malaria/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Chi-Square Distribution , Ethiopia/epidemiology , Humans , Logistic Models , Malaria/parasitology , Malaria/prevention & control , Middle Aged , Multivariate Analysis , Patient Acceptance of Health Care , Plasmodium/physiology , Prevalence , Young Adult
16.
PLoS Negl Trop Dis ; 15(10): e0009912, 2021 10.
Article in English | MEDLINE | ID: mdl-34714824

ABSTRACT

Malaria, a disease caused by Plasmodium parasites, remains a major threat to public health globally. It is the most common disease in patients with sleeping sickness, another parasitic illness, caused by Trypanosoma brucei. We have previously shown that a T. brucei infection impairs a secondary P. berghei liver infection and decreases malaria severity in mice. However, whether this effect requires an active trypanosome infection remained unknown. Here, we show that Plasmodium liver infection can also be inhibited by the serum of a mouse previously infected by T. brucei and by total protein lysates of this kinetoplastid. Biochemical characterisation showed that the anti-Plasmodium activity of the total T. brucei lysates depends on its protein fraction, but is independent of the abundant variant surface glycoprotein. Finally, we found that the protein(s) responsible for the inhibition of Plasmodium infection is/are present within a fraction of ~350 proteins that are excreted to the bloodstream of the host. We conclude that the defence mechanism developed by trypanosomes against Plasmodium relies on protein excretion. This study opens the door to the identification of novel antiplasmodial intervention strategies.


Subject(s)
Coinfection/prevention & control , Liver/parasitology , Malaria/parasitology , Plasmodium/physiology , Protozoan Proteins/blood , Trypanosoma brucei brucei/metabolism , Trypanosomiasis, African/parasitology , Animals , Coinfection/parasitology , Humans , Male , Mice , Mice, Inbred C57BL , Plasmodium/genetics , Protozoan Proteins/genetics , Trypanosoma brucei brucei/genetics , Trypanosomiasis, African/blood
17.
Sci Rep ; 11(1): 15337, 2021 07 28.
Article in English | MEDLINE | ID: mdl-34321525

ABSTRACT

The epidemiology of human malaria differs considerably between and within geographic regions due, in part, to variability in mosquito species behaviours. Recently, the WHO emphasised stratifying interventions using local surveillance data to reduce malaria. The usefulness of vector surveillance is entirely dependent on the biases inherent in the sampling methods deployed to monitor mosquito populations. To understand and interpret mosquito surveillance data, the frequency of use of malaria vector collection methods was analysed from a georeferenced vector dataset (> 10,000 data records), extracted from 875 manuscripts across Africa, the Americas and the Asia-Pacific region. Commonly deployed mosquito collection methods tend to target anticipated vector behaviours in a region to maximise sample size (and by default, ignoring other behaviours). Mosquito collection methods targeting both host-seeking and resting behaviours were seldomly deployed concurrently at the same site. A balanced sampling design using multiple methods would improve the understanding of the range of vector behaviours, leading to improved surveillance and more effective vector control.


Subject(s)
Anopheles/physiology , Behavior, Animal/physiology , Malaria/transmission , Mosquito Vectors/physiology , Africa/epidemiology , Animals , Anopheles/parasitology , Asia/epidemiology , Humans , Malaria/epidemiology , Mosquito Vectors/parasitology , North America/epidemiology , Plasmodium/physiology , South America/epidemiology
18.
Viruses ; 13(7)2021 06 23.
Article in English | MEDLINE | ID: mdl-34201673

ABSTRACT

Humans and wildlife are at risk from certain vector-borne diseases such as malaria, dengue, and West Nile and yellow fevers. Factors linked to global change, including habitat alteration, land-use intensification, the spread of alien species, and climate change, are operating on a global scale and affect both the incidence and distribution of many vector-borne diseases. Hence, understanding the drivers that regulate the transmission of pathogens in the wild is of great importance for ecological, evolutionary, health, and economic reasons. In this literature review, we discuss the ecological factors potentially affecting the transmission of two mosquito-borne pathogens circulating naturally between birds and mosquitoes, namely, West Nile virus (WNV) and the avian malaria parasites of the genus Plasmodium. Traditionally, the study of pathogen transmission has focused only on vectors or hosts and the interactions between them, while the role of landscape has largely been ignored. However, from an ecological point of view, it is essential not only to study the interaction between each of these organisms but also to understand the environmental scenarios in which these processes take place. We describe here some of the similarities and differences in the transmission of these two pathogens and how research into both systems may facilitate a greater understanding of the dynamics of vector-borne pathogens in the wild.


Subject(s)
Culicidae/physiology , Environment , Mosquito Vectors/physiology , Plasmodium/physiology , West Nile virus/physiology , Animals , Culicidae/parasitology , Culicidae/virology , Humans , Malaria, Avian/epidemiology , Malaria, Avian/transmission , Mosquito Vectors/parasitology , Mosquito Vectors/virology , Prevalence , West Nile Fever/epidemiology , West Nile Fever/transmission
19.
Malar J ; 20(1): 297, 2021 Jul 02.
Article in English | MEDLINE | ID: mdl-34215257

ABSTRACT

BACKGROUND: Recent genome wide analysis studies have identified a strong association between single nucleotide variations within the human ATP2B4 gene and susceptibility to severe malaria. The ATP2B4 gene encodes the plasma membrane calcium ATPase 4 (PMCA4), which is responsible for controlling the physiological level of intracellular calcium in many cell types, including red blood cells (RBCs). It is, therefore, postulated that genetic differences in the activity or expression level of PMCA4 alters intracellular Ca2+ levels and affects RBC hydration, modulating the invasion and growth of the Plasmodium parasite within its target host cell. METHODS: In this study the course of three different Plasmodium spp. infections were examined in mice with systemic knockout of Pmca4 expression. RESULTS: Ablation of PMCA4 reduced the size of RBCs and their haemoglobin content but did not affect RBC maturation and reticulocyte count. Surprisingly, knockout of PMCA4 did not significantly alter peripheral parasite burdens or the dynamics of blood stage Plasmodium chabaudi infection or reticulocyte-restricted Plasmodium yoelii infection. Interestingly, although ablation of PMCA4 did not affect peripheral parasite levels during Plasmodium berghei infection, it did promote slight protection against experimental cerebral malaria, associated with a minor reduction in antigen-experienced T cell accumulation in the brain. CONCLUSIONS: The finding suggests that PMCA4 may play a minor role in the development of severe malarial complications, but that this appears independent of direct effects on parasite invasion, growth or survival within RBCs.


Subject(s)
Disease Resistance/genetics , Malaria/genetics , Plasma Membrane Calcium-Transporting ATPases/genetics , Plasmodium/physiology , Animals , Cell Membrane , Malaria/blood , Malaria/parasitology , Malaria, Cerebral/genetics , Malaria, Cerebral/parasitology , Mice , Mice, Knockout , Plasma Membrane Calcium-Transporting ATPases/metabolism , Plasmodium berghei/physiology , Plasmodium chabaudi/physiology , Plasmodium yoelii/physiology
20.
Front Immunol ; 12: 661241, 2021.
Article in English | MEDLINE | ID: mdl-34122419

ABSTRACT

As a relatively successful pathogen, several parasites can establish long-term infection in host. This "harmonious symbiosis" status relies on the "precise" manipulation of host immunity and metabolism, however, the underlying mechanism is still largely elusive. Immunometabolism is an emerging crossed subject in recent years. It mainly discusses the regulatory mechanism of metabolic changes on reprogramming the key transcriptional and post-transcriptional events related to immune cell activation and effect, which provides a novel insight for understanding how parasites regulate the infection and immunity in hosts. The present study reviewed the current research progress on metabolic reprogramming mechanism exploited by parasites to modulate the function in various immune cells, highlighting the future exploitation of key metabolites or metabolic events to clarify the underlying mechanism of anti-parasite immunity and design novel intervention strategies against parasitic infection.


Subject(s)
Dendritic Cells/immunology , Lymphocytes/immunology , Macrophages/immunology , Parasitic Diseases/immunology , Plasmodium/immunology , Schistosoma/immunology , Trypanosoma/immunology , Animals , Dendritic Cells/metabolism , Dendritic Cells/parasitology , Host-Parasite Interactions/immunology , Humans , Lymphocytes/metabolism , Lymphocytes/parasitology , Macrophages/metabolism , Macrophages/parasitology , Parasitic Diseases/metabolism , Parasitic Diseases/parasitology , Plasmodium/physiology , Schistosoma/physiology , Trypanosoma/physiology
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