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Malaria Journal May 2022During the twentieth century, there was an explosion in understanding of the malaria parasites infecting humans and wild primates. This was built on three main data... (Review)
Review
During the twentieth century, there was an explosion in understanding of the malaria parasites infecting humans and wild primates. This was built on three main data sources: from detailed descriptive morphology, from observational histories of induced infections in captive primates, syphilis patients, prison inmates and volunteers, and from clinical and epidemiological studies in the field. All three were wholly dependent on parasitological information from blood-film microscopy, and The Primate Malarias" by Coatney and colleagues (1971) provides an overview of this knowledge available at that time. Here, 50 years on, a perspective from the third decade of the twenty-first century is presented on two pairs of primate malaria parasite species. Included is a near-exhaustive summary of the recent and current geographical distribution for each of these four species, and of the underlying molecular and genomic evidence for each. The important role of host transitions in the radiation of Plasmodium spp. is discussed, as are any implications for the desired elimination of all malaria species in human populations. Two important questions are posed, requiring further work on these often ignored taxa. Is Plasmodium brasilianum, circulating among wild simian hosts in the Americas, a distinct species from Plasmodium malariae? Can new insights into the genomic differences between Plasmodium ovale curtisi and Plasmodium ovale wallikeri be linked to any important differences in parasite morphology, cell biology or clinical and epidemiological features?
Topics: Animals; Genomics; Humans; Malaria; Parasites; Plasmodium malariae; Plasmodium ovale; Primates
PubMed: 35505317
DOI: 10.1186/s12936-022-04151-4 -
Journal of Microbiology, Immunology,... Oct 2019Plasmodium knowlesi is now regarded as the fifth malaria parasite causing human malaria as it is widely distributed in South-East Asian countries especially east... (Review)
Review
Plasmodium knowlesi is now regarded as the fifth malaria parasite causing human malaria as it is widely distributed in South-East Asian countries especially east Malaysia where two Malaysian states namely Sabah and Sarawak are situated. In 2004, Polymerase Chain Reaction (PCR) was applied for diagnosing knowlesi malaria in the Kapit Division of Sarawak, Malaysia, so that human P. knowlesi infections could be detected correctly while blood film microscopy diagnosed incorrectly as Plasmodium malariae. This parasite is transmitted from simian hosts to humans via Anopheles vectors. Indonesia is the another country in South East Asia where knowlesi malaria is moderately prevalent. In the last decade, Sarawak and Sabah, the two states of east Malaysia became the target of P. knowlesi research due to prevalence of cases with occasional fatal infections. The host species of P. knowlesi are three macaque species namely Macaca fascicularis, Macaca nemestrina and Macaca leonina while the vector species are the Leucosphyrus Complex and the Dirus Complex of the Leucophyrus Group of Anopheles mosquitoes. Rapid diagnostic tests (RDT) are non-existent for knowlesi malaria although timely treatment is necessary for preventing complications, fatality and drug resistance. Development of RDT is essential in dealing with P. knowlesi infections in poor rural healthcare services. Genetic studies of the parasite on possibility of human-to-human transmission of P. knowlesi were recommended for further studies.
Topics: Animals; Anopheles; Asia, Southeastern; Diagnostic Tests, Routine; Humans; Insect Vectors; Macaca fascicularis; Malaria; Malaysia; Monkey Diseases; Plasmodium knowlesi; Polymerase Chain Reaction; Prevalence; Rural Health
PubMed: 31320238
DOI: 10.1016/j.jmii.2019.05.012 -
Malaria Journal Jan 2022In South and Central America, Plasmodium malariae/Plasmodium brasilianum, Plasmodium vivax, Plasmodium simium, and Plasmodium falciparum has been reported in New World...
BACKGROUND
In South and Central America, Plasmodium malariae/Plasmodium brasilianum, Plasmodium vivax, Plasmodium simium, and Plasmodium falciparum has been reported in New World primates (NWP). Specifically in Costa Rica, the presence of monkeys positive to P. malariae/P brasilianum has been identified in both captivity and in the wild. The aim of the present study was to determine the presence of P. brasilianum, P. falciparum, and P. vivax, and the potential distribution of these parasites-infecting NWP from Costa Rica.
METHODS
The locations with PCR (Polymerase Chain Reaction) positive results and bioclimatic predictors were used to construct ecological niche models based on a modelling environment that uses the Maxent algorithm, named kuenm, capable to manage diverse settings to better estimate the potential distributions and uncertainty indices of the potential distribution.
RESULTS
PCR analysis for the Plasmodium presence was conducted in 384 samples of four primates (Howler monkey [n = 130], White-face monkey [n = 132], Squirrel monkey [n = 50], and red spider monkey [n = 72]), from across Costa Rica. Three Plasmodium species were detected in all primate species (P. falciparum, P. malariae/P. brasilianum, and P. vivax). Overall, the infection prevalence was 8.9%, but each Plasmodium species ranged 2.1-3.4%. The niche model approach showed that the Pacific and the Atlantic coastal regions of Costa Rica presented suitable climatic conditions for parasite infections. However, the central pacific coast has a more trustable prediction for malaria in primates.
CONCLUSIONS
The results indicate that the regions with higher suitability for Plasmodium transmission in NWP coincide with regions where most human cases have been reported. These regions were also previously identified as areas with high suitability for vector species, suggesting that enzootic and epizootic cycles occur.
Topics: Alouatta; Animals; Ateles geoffroyi; Cebus capucinus; Costa Rica; Malaria; Monkey Diseases; Plasmodium; Prevalence; Saimiri; Species Specificity
PubMed: 34998402
DOI: 10.1186/s12936-021-04036-y -
Malaria Journal Jun 2022Immunoassay platforms that simultaneously detect malaria antigens including histidine-rich protein 2 (HRP2)/HRP3 and Plasmodium lactate dehydrogenase (pLDH), are useful...
BACKGROUND
Immunoassay platforms that simultaneously detect malaria antigens including histidine-rich protein 2 (HRP2)/HRP3 and Plasmodium lactate dehydrogenase (pLDH), are useful epidemiological tools for rapid diagnostic test evaluation. This study presents the comparative evaluation of two multiplex platforms in identifying Plasmodium falciparum with presence or absence of HRP2/HRP3 expression as being indicative of hrp2/hrp3 deletions and other Plasmodium species. Moreover, correlation between the malaria antigen measurements performed at these platforms is assessed after calibrating with either assay standards or international standards and the cross-reactivity among Plasmodium species is examined.
METHODS
A 77-member panel of specimens composed of the World Health Organization (WHO) international Plasmodium antigen standards, cultured parasites for P. falciparum and Plasmodium knowlesi, and clinical specimens with mono-infections for P. falciparum, Plasmodium vivax, and Plasmodium malariae was generated as both whole blood and dried blood spot (DBS) specimens. Assays for HRP2, P. falciparum-specific pLDH (PfLDH), P. vivax-specific pLDH (PvLDH), and all human Plasmodium species Pan malaria pLDH (PanLDH) on the Human Malaria Array Q-Plex and the xMAP platforms were evaluated with these panels.
RESULTS
The xMAP showed a higher percent positive agreement for identification of hrp2-deleted P. falciparum and Plasmodium species in whole blood and DBS than the Q-Plex. For whole blood samples, there was a highly positive correlation between the two platforms for PfLDH (Pearson r = 0.9926) and PvLDH (r = 0. 9792), moderate positive correlation for HRP2 (r = 0.7432), and poor correlation for PanLDH (r = 0.6139). In Pearson correlation analysis between the two platforms on the DBS, the same assays were r = 0.9828, r = 0.7679, r = 0.6432, and r = 0.8957, respectively. The xMAP HRP2 assay appeared to cross-react with HRP3, while the Q-Plex did not. The Q-Plex PfLDH assay cross-reacted with P. malariae, while the xMAP did not. For both platforms, P. knowlesi was detected on the PvLDH assay. The WHO international standards allowed normalization across both platforms on their HRP2, PfLDH, and PvLDH assays in whole blood and DBS.
CONCLUSIONS
Q-Plex and xMAP show good agreement for identification of P. falciparum mutants with hrp2/hrp3 deletions, and other Plasmodium species. Quantitative results from both platforms, normalized into international units for HRP2, PfLDH, and PvLDH, showed good agreement and should allow comparison and analysis of results generated by either platform.
Topics: Antigens, Protozoan; Diagnostic Tests, Routine; Humans; Immunoassay; L-Lactate Dehydrogenase; Malaria; Malaria, Falciparum; Malaria, Vivax; Plasmodium falciparum; Plasmodium knowlesi; Protozoan Proteins; Sensitivity and Specificity
PubMed: 35672772
DOI: 10.1186/s12936-022-04203-9 -
The Journal of Infectious Diseases Jan 2022Plasmodium falciparum malaria dominates throughout sub-Saharan Africa, but the prevalence of Plasmodium malariae, Plasmodium ovale spp., and Plasmodium vivax...
BACKGROUND
Plasmodium falciparum malaria dominates throughout sub-Saharan Africa, but the prevalence of Plasmodium malariae, Plasmodium ovale spp., and Plasmodium vivax increasingly contribute to infection in countries that control malaria using P. falciparum-specific diagnostic and treatment strategies.
METHODS
We performed quantitative polymerase chain reaction (qPCR) on 2987 dried blood spots from the 2015-2016 Malawi Demographic and Health Survey to identify presence and distribution of nonfalciparum infection. Bivariate models were used to determine species-specific associations with demographic and environmental risk factors.
RESULTS
Nonfalciparum infections had broad spatial distributions. Weighted prevalence was 0.025 (SE, 0.004) for P. malariae, 0.097 (SE, 0.008) for P. ovale spp., and 0.001 (SE, 0.0005) for P. vivax. Most infections (85.6%) had low-density parasitemias ≤ 10 parasites/µL, and 66.7% of P. malariae, 34.6% of P. ovale spp., and 40.0% of P. vivax infections were coinfected with P. falciparum. Risk factors for P. malariae were like those known for P. falciparum; however, there were few risk factors recognized for P. ovale spp. and P. vivax, perhaps due to the potential for relapsing episodes.
CONCLUSIONS
The prevalence of any nonfalciparum infection was 11.7%, with infections distributed across Malawi. Continued monitoring of Plasmodium spp. becomes critical as nonfalciparum infections become important sources of ongoing transmission.
Topics: Adolescent; Adult; Female; Humans; Malaria; Malaria, Vivax; Malawi; Male; Plasmodium malariae; Plasmodium ovale; Plasmodium vivax; Real-Time Polymerase Chain Reaction; Young Adult
PubMed: 34244739
DOI: 10.1093/infdis/jiab353 -
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 -
Current Research in Parasitology &... 2021and are protozoan parasites that can cause malaria in humans. They are genetically indistinguishable from, respectively, and , i.e. parasites infecting New World...
and are protozoan parasites that can cause malaria in humans. They are genetically indistinguishable from, respectively, and , i.e. parasites infecting New World non-human primates in South America. In the tropical rainforests of the Brazilian Atlantic coast, it has long been hypothesized that . and . in platyrrhine primates originated from . and . in humans. A recent hypothesis proposed the inclusion of into the transmission dynamics between humans and non-human primates in the Brazilian Atlantic tropical rainforest. Herein, we assess the occurrence of human malaria in simians and sylvatic anophelines using field-collected samples in the Capivari-Monos Environmental Protection Area from 2015 to 2017. We first tested simian blood and anopheline samples. Two simian () blood samples (18%, = 11) showed DNA sequences, one for . and another for . . From a total of 9,416 anopheline females, we found 17 pools positive for species with a qPCR assay. Only three showed DNA sequence, one for . and the others for rodent malaria species (similar to and ). Based on these results, we tested 25 rodent liver samples for the presence of and obtained . DNA sequence in a rodent ( sp.) liver. The findings of this study indicate complex malaria transmission dynamics composed by parallel spillover-spillback of human malaria parasites, i.e. . , . , and . , in the Brazilian Atlantic forest.
PubMed: 35284897
DOI: 10.1016/j.crpvbd.2021.100032 -
ACS Infectious Diseases Nov 2021and cultivation of has facilitated active research into the malaria parasite toward the quest for basic knowledge and the discovery of effective drug treatments. Such...
and cultivation of has facilitated active research into the malaria parasite toward the quest for basic knowledge and the discovery of effective drug treatments. Such a drug discovery program is currently difficult for simply because of the absence of and cultivation system for its asexual blood stages supporting antimalarial evaluation. Despite availability of artemisinin combination therapies effective on , is being increasingly detected in malaria endemic countries. is responsible for chronic infections and is associated with a high burden of anemia and morbidity. Here, we optimized and adapted conditions under which can be cultured and used for screening antimalarial drugs. Subsequently, this enabled us to test compounds such as artemether, chloroquine, lumefantrine, and quinine for antimalarial activity against .
Topics: Antimalarials; Humans; Lumefantrine; Malaria, Falciparum; Plasmodium falciparum; Plasmodium malariae
PubMed: 34711047
DOI: 10.1021/acsinfecdis.1c00262 -
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 -
The American Journal of Tropical... Dec 2020Although continues to be the main target for malaria elimination, other species persist in Africa. Their clinical diagnosis is uncommon, whereas rapid diagnostic tests...
Although continues to be the main target for malaria elimination, other species persist in Africa. Their clinical diagnosis is uncommon, whereas rapid diagnostic tests (RDTs), the most widely used malaria diagnostic tools, are only able to distinguish between and non- species, the latter as "pan-species." Blood samples from health facilities were collected in southern Nigeria (Lagos and Calabar) in 2017 (October-December) and Calabar only in 2018 (October-November), and analyzed by several methods, namely, microscopy, quantitative real-time PCR (qPCR), and peptide serology targeting candidate antigens ( apical membrane antigen, . lactose dehydrogenase, and . circumsporozoite surface protein). Both microscopy and qPCR diagnostic approaches detected comparable proportions (∼80%) of all RDT-positive samples infected with the dominant malaria parasite. However, higher proportions of non- species were detected by qPCR than microscopy, 10% against 3% infections for and 3% against 0% for , respectively. No infection was detected. Infection rates for varied between age-groups, with the highest rates in individuals aged > 5 years. -specific seroprevalence rates fluctuated in those aged < 10 years but generally reached the peak around 20 years of age for all peptides. The heterogeneity and rates of these non-falciparum species call for increased specific diagnosis and targeting by elimination strategies.
Topics: Adolescent; Antigens, Protozoan; Child; Child, Preschool; Diagnostic Tests, Routine; Female; Humans; Infant; Malaria; Male; Microscopy; Nigeria; Plasmodium; Plasmodium malariae; Plasmodium ovale; Plasmodium vivax; Protozoan Proteins; Real-Time Polymerase Chain Reaction; Seroepidemiologic Studies; Surveys and Questionnaires
PubMed: 33124531
DOI: 10.4269/ajtmh.20-0593