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The American Journal of Tropical... Jun 2010The merozoite surface protein 1 (MSP1) is the principal surface antigen of the blood stage form of the Plasmodium parasite. Antibodies recognizing MSP1 are frequently...
The merozoite surface protein 1 (MSP1) is the principal surface antigen of the blood stage form of the Plasmodium parasite. Antibodies recognizing MSP1 are frequently detected following Plasmodium infection, making this protein a significant component of malaria vaccines and diagnostic tests. Although the MSP1 gene sequence has been reported for Plasmodium falciparum and Plasmodium vivax, this gene has not been identified for the other two major human-infectious species, Plasmodium malariae and Plasmodium ovale. MSP1 genes from these two species were isolated from Cameroon blood donor samples. The genes are similar in size to known MSP1 genes and encode proteins with interspecies conserved domains homologous to those identified in other Plasmodium species. Sequence and phylogenetic analysis of all available Plasmodium MSP1 amino acid sequences clearly shows that the Po and Pm MSP1 sequences are truly unique within the Plasmodium genus and not simply Pf or Pv variants.
Topics: Amino Acid Sequence; Animals; Blood Donors; Gene Expression Regulation; Humans; Merozoite Surface Protein 1; Molecular Sequence Data; Phylogeny; Plasmodium malariae; Plasmodium ovale
PubMed: 20519591
DOI: 10.4269/ajtmh.2010.09-0022 -
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 -
Malaria Journal Nov 2014Artemisinin combination therapy (ACT) is recommended as first-line treatment for uncomplicated Plasmodium falciparum malaria, whereas chloroquine is still commonly used... (Review)
Review
BACKGROUND
Artemisinin combination therapy (ACT) is recommended as first-line treatment for uncomplicated Plasmodium falciparum malaria, whereas chloroquine is still commonly used for the treatment of non-falciparum species (Plasmodium vivax, Plasmodium ovale and Plasmodium malariae). A more simplified, more uniform treatment approach across all malaria species is worthwhile to be considered both in endemic areas and for malaria as an imported condition alike.
METHODS
A PROSPERO-registered systematic review to determine the efficacy and safety of ACT for the treatment of non-falciparum malaria was conducted, following PRISMA guidelines. Without language restrictions, Medline/PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, LILACS, Biosis Previews and the African Index Medicus were searched for studies published up to November 2014.
RESULTS
The literature search identified 986 reports; 40 publications were found eligible for inclusion, all of them on non-falciparum malaria in endemic areas. Most evidence was available for P. vivax (n = 35). Five clinical trials in total were identified evaluating ACT for P. ovale, P. malariae and Plasmodium knowlesi. Most ACT presentations have high efficacy against P. vivax parasites; artemisinin-based combinations have shorter parasite and fever clearance times compared to chloroquine. ACT is as effective as chloroquine in preventing recurrent parasitaemia before day 28. Artemisinin-based combinations with long half-lives show significantly fewer recurrent parasitaemia up to day 63. The limited evidence available supports both the use of chloroquine and an ACT for P. ovale and P. malariae. ACT seems to be preferable for optimal treatment of P. knowlesi.
CONCLUSION
ACT is at least equivalent to chloroquine in effectively treating non-falciparum malaria. These findings may facilitate development of simplified protocols for treating all forms of malaria with ACT, including returning travellers. Obtaining comprehensive efficacy and safety data on ACT use for non-falciparum species particularly for P. ovale, P. malariae and P. knowlesi should be a research priority.
TRIAL REGISTRATION
CRD42014009103.
Topics: Antimalarials; Artemisinins; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Humans; Malaria; Treatment Outcome
PubMed: 25428624
DOI: 10.1186/1475-2875-13-463 -
Parasites & Vectors Nov 2021Merozoite surface protein 1 (MSP1) plays an essential role in erythrocyte invasion by malaria parasites. The C-terminal 19-kDa region of MSP1 has long been considered...
BACKGROUND
Merozoite surface protein 1 (MSP1) plays an essential role in erythrocyte invasion by malaria parasites. The C-terminal 19-kDa region of MSP1 has long been considered one of the major candidate antigens for a malaria blood-stage vaccine against Plasmodium falciparum. However, there is limited information on the C-terminal 19-kDa region of Plasmodium ovale MSP1 (PoMSP1). This study aims to analyze the genetic diversity and immunogenicity of PoMSP1.
METHODS
A total of 37 clinical Plasmodium ovale isolates including Plasmodium ovale curtisi and Plasmodium ovale wallikeri imported from Africa into China and collected during the period 2012-2016 were used. Genomic DNA was used to amplify P. ovale curtisi (poc) msp1 (pocmsp1) and P. ovale wallikeri (pow) msp1 (powmsp1) genes by polymerase chain reaction. The genetic diversity of pomsp1 was analyzed using the GeneDoc version 6 programs. Recombinant PoMSP1 (rPoMSP1)-glutathione S-transferase (GST) proteins were expressed in an Escherichia coli expression system and analyzed by western blot. Immune responses in BALB/c mice immunized with rPoMSP1-GST were determined using enzyme-linked immunosorbent assay. In addition, antigen-specific T cell responses were assessed by lymphocyte proliferation assays. A total of 49 serum samples from healthy individuals and individuals infected with P. ovale were used for the evaluation of natural immune responses by using protein microarrays.
RESULTS
Sequences of pomsp1 were found to be thoroughly conserved in all the clinical isolates. rPoMSP1 proteins were efficiently expressed and purified as ~ 37-kDa proteins. High antibody responses in mice immunized with rPoMSP1-GST were observed. rPoMSP1-GST induced high avidity indexes, with an average of 92.57% and 85.32% for rPocMSP1 and rPowMSP1, respectively. Cross-reactivity between rPocMSP1 and rPowMSP1 was observed. Cellular immune responses to rPocMSP1 (69.51%) and rPowMSP1 (52.17%) induced in rPocMSP1- and rPowMSP1-immunized mice were found in the splenocyte proliferation assays. The sensitivity and specificity of rPoMSP1-GST proteins for the detection of natural immune responses in patients infected with P. ovale were 89.96% and 75%, respectively.
CONCLUSIONS
This study revealed highly conserved gene sequences of pomsp1. In addition, naturally acquired humoral immune responses against rPoMSP1 were observed in P. ovale infections, and high immunogenicity of rPoMSP1 in mice was also identified. These instructive findings should encourage further testing of PoMSP1 for rational vaccine design.
Topics: Animals; Antibodies, Protozoan; Antigens, Protozoan; Humans; Immunogenicity, Vaccine; Malaria Vaccines; Merozoite Surface Protein 1; Mice; Mice, Inbred BALB C; Plasmodium ovale; Polymorphism, Genetic; Protozoan Proteins; Vaccine Development
PubMed: 34819151
DOI: 10.1186/s13071-021-05086-6 -
International Journal of Gynaecology... Jun 2021COVID‐19 and malaria may have a similar presentation in pregnancy.
COVID‐19 and malaria may have a similar presentation in pregnancy.
PubMed: 33713432
DOI: 10.1002/ijgo.13670 -
Hematology, Transfusion and Cell Therapy Apr 2024
PubMed: 38614930
DOI: 10.1016/j.htct.2023.11.017 -
Tropical Diseases, Travel Medicine and... 2017Malaria poses an exceptionally complex problem for providers of travel medicine services. Perceived high risk of exposure during travel typically prompts prescribing...
Malaria poses an exceptionally complex problem for providers of travel medicine services. Perceived high risk of exposure during travel typically prompts prescribing protective antimalarial drugs. Suppressive chemoprophylactic agents have dominated strategy for that practice for over 70 years. This broad class of therapeutic agents kills parasites after they emerge from the liver and attempt development in red blood cells. The dominance of suppressive chemoprophylaxis in travel medicine stems largely from the view of as the utmost threat to the patient - these drugs are poorly suited to preventing and due to inactivity against the latent liver stages of these species not produced by . Those hypnozoites awaken to cause multiple clinical attacks called relapses in the months following infection. Causal prophylactic agents kill parasites as they attempt development in hepatic cells. The only drug proven effective for causal prophylaxis against is primaquine. That drug is not widely recommended for primary prophylaxis for travelers despite preventing both primary attacks of all the plasmodia and relapses of . The long-held perception of as causing a benign malaria in part explains the dominance of suppressive chemoprophylaxis strategies poorly suited to its prevention. Recent evidence from both travelers and patients hospitalized in endemic areas reveals as a pernicious clinical threat capable of progression to severe disease syndromes associated with fatal outcomes. Effective prevention of clinical attacks of vivax malaria following exposure during travel requires primary causal prophylaxis or post-travel presumptive anti-relapse therapy following suppressive prophylaxis.
PubMed: 28883977
DOI: 10.1186/s40794-017-0049-x -
Journal of Korean Medical Science Jan 2019Mixed-species malaria infections are often unrecognized or underestimated. We hereby report the first described case of mixed infection with and malaria in a returned...
Mixed-species malaria infections are often unrecognized or underestimated. We hereby report the first described case of mixed infection with and malaria in a returned traveller in Korea. In August 2016, a 25-year-old returned traveller from Cameroon and Democratic Republic of Congo presented with fever. He was diagnosed as malaria and successfully treated with artesunate. And 5 weeks after the completion of treatment, he presented with fever and diagnosed as infection. infection is a rare cause of malaria and often shows delayed presentation due to its dormant liver stage as hypnozoites. At re-presentation, the immunochromatographic test and microscopic examinations of our patient did not reveal , which was only detected via polymerase chain reaction (PCR) assay. This case highlights the importance of considering malaria infection even in persons who have previously received malaria treatment. It also shows the usefulness of PCR testing for diagnosing infections, which often present with a low level of parasitaemia.
Topics: Adult; Antimalarials; Chloroquine; DNA, Protozoan; Humans; Malaria; Male; Plasmodium falciparum; Plasmodium ovale; Primaquine
PubMed: 30662388
DOI: 10.3346/jkms.2019.34.e23 -
Parasites & Vectors Jun 2022Although Plasmodium falciparum infection is largely documented and this parasite is the main target for malaria eradication, other Plasmodium species persist, and these...
BACKGROUND
Although Plasmodium falciparum infection is largely documented and this parasite is the main target for malaria eradication, other Plasmodium species persist, and these require more attention in Africa. Information on the epidemiological situation of non-P. falciparum species infections is scarce in many countries, including in the Democratic Republic of the Congo (hereafter Republic of the Congo) where malaria is highly endemic. The aim of this study was to determine the prevalence and distribution of non-P. falciparum species infections in the region south of Brazzaville.
METHODS
A cross-sectional survey was conducted in volunteers living in rural and urban settings during the dry and rainy seasons in 2021. Socio-demographic and clinical parameters were recorded. Plasmodium infection in blood samples was detected by microscopic analysis and nested PCR (sub-microscopic analysis).
RESULTS
Of the 773 participants enrolled in the study, 93.7% were from the rural area, of whom 97% were afebrile. The prevalence of microscopic and sub-microscopic Plasmodium spp. infection was 31.2% and 63.7%, respectively. Microscopic Plasmodium malariae infection was found in 1.3% of participants, while sub-microscopic studies detected a prevalence of 14.9% for P. malariae and 5.3% for Plasmodium ovale. The rate of co-infection of P. malariae or P. ovale with P. falciparum was 8.3% and 2.6%, respectively. Higher rates of sub-microscopic infection were reported for the urban area without seasonal fluctuation. In contrast, non-P. falciparum species infection was more pronounced in the rural area, with the associated risk of the prevalence of sub-microscopic P. malariae infection increasing during the dry season.
CONCLUSION
There is a need to include non-P. falciparum species in malaria control programs, surveillance measures and eradication strategies in the Republic of the Congo.
Topics: Congo; Cross-Sectional Studies; Humans; Malaria; Malaria, Falciparum; Plasmodium falciparum; Prevalence
PubMed: 35706053
DOI: 10.1186/s13071-022-05312-9 -
BMC Medicine Nov 2018Plasmodium ovale spp. and P. malariae cause illness in endemic regions and returning travellers. Far less is known about these species than P. falciparum and P. vivax.
BACKGROUND
Plasmodium ovale spp. and P. malariae cause illness in endemic regions and returning travellers. Far less is known about these species than P. falciparum and P. vivax.
METHODS
The UK national surveillance data, collected 1987 to 2015, were collated with the International Passenger Survey and climatic data to determine geographical, temporal and seasonal trends of imported P. ovale spp. and P. malariae infection.
RESULTS
Of 52,242 notified cases of malaria, 6.04% (3157) were caused by P. ovale spp. and 1.61% (841) by P. malariae; mortality was 0.03% (1) and 0.12% (1), respectively. Almost all travellers acquired infection in West or East Africa. Infection rate per travel episode fell fivefold during the study period. The median latency of P. malariae and P. ovale spp. was 18 and 76 days, respectively; delayed presentation occurred with both species. The latency of P. ovale spp. infection imported from West Africa was significantly shorter in those arriving in the UK during the West African peak malarial season compared to those arriving outside it (44 days vs 94 days, p < 0.0001), implying that relapse synchronises with the period of high malarial transmission. This trend was not seen in P. ovale spp. imported from East Africa nor in P. malariae.
CONCLUSION
In West Africa, where malaria transmission is highly seasonal, P. ovale spp. may have evolved to relapse during the malarial high transmission season. This has public health implications. Deaths are very rare, supporting current guidelines emphasising outpatient treatment. However, late presentations do occur.
Topics: Chronic Disease; Female; Humans; Malaria; Male; Plasmodium malariae; Plasmodium ovale; Travel; United Kingdom
PubMed: 30477484
DOI: 10.1186/s12916-018-1204-6