Challenges in diagnosis of Plasmodium knowlesi infections

Jeremiah, SS; Janagond, Anand; Parija, Subhash Chandra

doi:10.4103/2229-5070.129156

Cited by 20 publications

(7 citation statements)

References 39 publications

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“…Plasmodium knowlesi contains proteins referred to as NBPXa and NBPXb (normocyte binding-like proteins-NBPs) which have been found essential for the invasion of human erythrocytes [144, 145]. The parasite’s short multiplication time (quotidian cycle) and its ability to infect both immature and mature erythrocytes results in hyper-parasitaemia developing quickly (within several days) if the disease goes undetected [146–148]. Respiratory distress along with jaundice, hypotension, acute renal failure, and organ dysfunction are typical of the severe complications manifested, with thrombocytopaenia nearly universal in cases of infection [146, 149, 150].…”

Section: Introductionmentioning

confidence: 99%

Defining the ecological and evolutionary drivers of Plasmodium knowlesi transmission within a multi-scale framework

Davidson

Chua

Cook

et al. 2019

Malar J

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Plasmodium knowlesi is a zoonotic malaria parasite normally residing in long-tailed and pig-tailed macaques ( Macaca fascicularis and Macaca nemestrina, respectively) found throughout Southeast Asia. Recently, knowlesi malaria has become the predominant malaria affecting humans in Malaysian Borneo, being responsible for approximately 70% of reported cases. Largely as a result of anthropogenic land use changes in Borneo, vectors which transmit the parasite, along with macaque hosts, are both now frequently found in disturbed forest habitats, or at the forest fringes, thus having more frequent contact with humans. Having access to human hosts provides the parasite with the opportunity to further its adaption to the human immune system. The ecological drivers of the transmission and spread of P. knowlesi are operating over many different spatial (and, therefore, temporal) scales, from the molecular to the continental. Strategies to prevent and manage zoonoses, such as P. knowlesi malaria require interdisciplinary research exploring the impact of land use change and biodiversity loss on the evolving relationship between parasite, reservoir hosts, vectors, and humans over multiple spatial scales.

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Section: Introductionmentioning

confidence: 99%

Defining the ecological and evolutionary drivers of Plasmodium knowlesi transmission within a multi-scale framework

Davidson

Chua

Cook

et al. 2019

Malar J

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“…In such cases, the sequencing step of this assay will still allow species discrimination. It may also allow the detection of Plasmodium species previously unknown to infect humans similar to the recent discovery of P. knowlesi as a human pathogen (5,6).…”

Section: Discussionmentioning

confidence: 96%

“…Rapid antigen-based diagnostic tests have aided diagnosis of malaria, particularly in resourcepoor settings (9), but these tests have limited capability for species discrimination, as they cannot distinguish among non-falciparum Plasmodium species (10). More recently, various molecular assays have emerged for malaria species identification (5). These assays have increased specificity compared to microscopy and are superior for detecting mixed infections (11), which can account for Ͼ5% of malarial infections (12).…”

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confidence: 99%

Simple Real-Time PCR and Amplicon Sequencing Method for Identification of Plasmodium Species in Human Whole Blood

et al. 2015

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Malaria is the leading identifiable cause of fever in returning travelers. Accurate Plasmodium species identification has therapy implications for P. vivax and P. ovale, which have dormant liver stages requiring primaquine. Compared to microscopy, nucleic acid tests have improved specificity for species identification and higher sensitivity for mixed infections. Here, we describe a SYBR green-based real-time PCR assay for Plasmodium species identification from whole blood, which uses a panel of reactions to detect species-specific non-18S rRNA gene targets. A pan-Plasmodium 18S rRNA target is also amplified to allow species identification or confirmation by sequencing if necessary. An evaluation of assay accuracy, performed on 76 clinical samples (56 positives using thin smear microscopy as the reference method and 20 negatives), demonstrated clinical sensitivities of 95.2% for P. falciparum (20/21 positives detected) and 100% for the Plasmodium genus (52/52), P. vivax (20/20), P. ovale (9/9), and P. malariae (6/6). The sensitivity of the P. knowlesi-specific PCR was evaluated using spiked whole blood samples (100% [10/10 detected]). The specificities of the real-time PCR primers were 94.2% for P. vivax (49/52) and 100% for P. falciparum (51/51), P. ovale (62/62), P. malariae (69/69), and P. knowlesi (52/52). Thirty-three specimens were used to test species identification by sequencing the pan-Plasmodium 18S rRNA PCR product, with correct identification in all cases. The real-time PCR assay also identified two samples with mixed P. falciparum and P. ovale infection, which was confirmed by sequencing. The assay described here can be integrated into a malaria testing algorithm in low-prevalence areas, allowing definitive Plasmodium species identification shortly after malaria diagnosis by microscopy.M alaria infections are a major cause of morbidity and mortality throughout the world, with 198 million cases and 584,000 deaths globally in 2013 and with the heaviest burden of disease seen in developing countries (1). Malaria is also the single most common etiologic agent of febrile illness in travelers returning to areas where malaria is not endemic (2). In a recent GeoSentinel surveillance study, Plasmodium infections accounted for 21% of 6,957 patients with fever in a cohort of 24,920 ill returned travelers (3). Malaria was most frequently diagnosed in febrile persons returning from areas where malaria is endemic such as Sub-Saharan Africa, South and Central Asia, and Latin America (3). Additionally, 33% of mortality among febrile travelers was attributed to malaria (3). Thus, the ability to promptly identify and treat malaria in nonendemic areas is critical. Furthermore, identification of the infecting species is essential for effective treatment of P. vivax and P. ovale. These Plasmodium species possess a dormant hypnozoite stage in the liver that can reactivate and cause disease months to years after the initial infection (4). Primaquine is the only antimalarial drug that can eradicate the hypnozoites and is, t...

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“…Detection of P. knowlesi using RDTs has demonstrated low sensitivity [ 20 ]. PCR, on the other hand, can detect and diagnose P. knowlesi with high sensitivity and specificity; however, it is expensive and requires specialized equipment and highly trained personnel [ 21 ].…”

Section: Discussionmentioning

confidence: 99%

Malaria elimination in Malaysia and the rising threat of Plasmodium knowlesi

Chin

Maluda

Jelip

et al. 2020

J Physiol Anthropol

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Background Malaria is a major public-health problem, with over 40% of the world’s population (more than 3.3 billion people) at risk from the disease. Malaysia has committed to eliminate indigenous human malaria transmission by 2020. The objective of this descriptive study is to understand the epidemiology of malaria in Malaysia from 2000 through 2018 and to highlight the threat posed by zoonotic malaria to the National Malaria Elimination Strategic Plan. Methods Malaria is a notifiable infection in Malaysia. The data used in this study were extracted from the Disease Control Division, Ministry of Health Malaysia, contributed by the hospitals and health clinics throughout Malaysia. The population data used in this study was extracted from the Department of Statistics Malaysia. Data analyses were performed using Microsoft Excel. Data used for mapping are available at EPSG:4326 WGS84 CRS (Coordinate Reference System). Shapefile was obtained from igismap. Mapping and plotting of the map were performed using QGIS. Results Between 2000 and 2007, human malaria contributed 100% of reported malaria and 18–46 deaths per year in Malaysia. Between 2008 and 2017, indigenous malaria cases decreased from 6071 to 85 (98.6% reduction), while during the same period, zoonotic Plasmodium knowlesi cases increased from 376 to 3614 cases (an 861% increase). The year 2018 marked the first year that Malaysia did not report any indigenous cases of malaria caused by human malaria parasites. However, there was an increasing trend of P. knowlesi cases, with a total of 4131 cases reported in that year. Although the increased incidence of P. knowlesi cases can be attributed to various factors including improved diagnostic capacity, reduction in human malaria cases, and increase in awareness of P. knowlesi, more than 50% of P. knowlesi cases were associated with agriculture and plantation activities, with a large remainder proportion linked to forest-related activities. Conclusions Malaysia has entered the elimination phase of malaria control. Zoonotic malaria, however, is increasing exponentially and becoming a significant public health problem. Improved inter-sectoral collaboration is required in order to develop a more integrated effort to control zoonotic malaria. Local political commitment and the provision of technical support from the World Health Organization will help to create focused and concerted efforts towards ensuring the success of the National Malaria Elimination Strategic Plan.

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Challenges in diagnosis of Plasmodium knowlesi infections

Cited by 20 publications

References 39 publications

Defining the ecological and evolutionary drivers of Plasmodium knowlesi transmission within a multi-scale framework

Defining the ecological and evolutionary drivers of Plasmodium knowlesi transmission within a multi-scale framework

Simple Real-Time PCR and Amplicon Sequencing Method for Identification of Plasmodium Species in Human Whole Blood

Malaria elimination in Malaysia and the rising threat of Plasmodium knowlesi

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