Narrative Review of the Control and Prevention of Knowlesi Malaria

Mohammad, Ahmad Hazim; Naserrudin, Nurul Athirah; Rahim, Syed Sharizman Syed Abdul; Jelip, Jenarun; Atil, Azman; Sazali, Mohd Fazeli; Muyou, Adora J.; Kunasagran, Priya Dharishini; Kamarudin, Nornazirah Ahmad; Azhar, Zahir Izuan; Dapari, Rahmat; Jeffree, Mohammad Saffree; Hassan, Mohd Rohaizat

doi:10.3390/tropicalmed7080178

Cited by 4 publications

(4 citation statements)

References 84 publications

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“…From the zoonotic malaria control perspective, it is important to address the interdependence between humans, animals, and their environmental variations. The involvement of macaques as the natural hosts of P. knowlesi complicates the elimination and subsequent eradication of malaria and requires intervention strategies designed to specifically address zoonotic pathways, which is different from the strategy for tackling human malaria ( Vythilingam et al, 2018 ; Mohammad et al, 2022 ). Thus, a unifying approach converging transdisciplinary and multisectoral efforts is essential to combat the transmission of P. knowlesi , as advocated in the “One Health” concept.…”

Section: Discussionmentioning

confidence: 99%

“…For instance, the localities of the population at risk can be identified and effective interventions can be adapted to target populations. In this case, personal-level protective equipment such as insecticide-treated outdoor clothing, topical repellent, chemoprophylaxis, and spatial repellent shall be distributed more frequently to agricultural and logging workers, military personnel, as well as people living in high-risk areas ( Vythilingam et al, 2021 ; Mohammad et al, 2022 ). Regular screening as well as awareness programs shall be conducted for communities in these areas.…”

Section: Discussionmentioning

confidence: 99%

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Predicting Plasmodium knowlesi transmission risk across Peninsular Malaysia using machine learning-based ecological niche modeling approaches

Phang

Hamid²,

Jelip³

et al. 2023

Front. Microbiol.

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The emergence of potentially life-threatening zoonotic malaria caused by Plasmodium knowlesi nearly two decades ago has continued to challenge Malaysia healthcare. With a total of 376 P. knowlesi infections notified in 2008, the number increased to 2,609 cases in 2020 nationwide. Numerous studies have been conducted in Malaysian Borneo to determine the association between environmental factors and knowlesi malaria transmission. However, there is still a lack of understanding of the environmental influence on knowlesi malaria transmission in Peninsular Malaysia. Therefore, our study aimed to investigate the ecological distribution of human P. knowlesi malaria in relation to environmental factors in Peninsular Malaysia. A total of 2,873 records of human P. knowlesi infections in Peninsular Malaysia from 1st January 2011 to 31st December 2019 were collated from the Ministry of Health Malaysia and geolocated. Three machine learning-based models, maximum entropy (MaxEnt), extreme gradient boosting (XGBoost), and ensemble modeling approach, were applied to predict the spatial variation of P. knowlesi disease risk. Multiple environmental parameters including climate factors, landscape characteristics, and anthropogenic factors were included as predictors in both predictive models. Subsequently, an ensemble model was developed based on the output of both MaxEnt and XGBoost. Comparison between models indicated that the XGBoost has higher performance as compared to MaxEnt and ensemble model, with AUCROC values of 0.933 ± 0.002 and 0.854 ± 0.007 for train and test datasets, respectively. Key environmental covariates affecting human P. knowlesi occurrence were distance to the coastline, elevation, tree cover, annual precipitation, tree loss, and distance to the forest. Our models indicated that the disease risk areas were mainly distributed in low elevation (75–345 m above mean sea level) areas along the Titiwangsa mountain range and inland central-northern region of Peninsular Malaysia. The high-resolution risk map of human knowlesi malaria constructed in this study can be further utilized for multi-pronged interventions targeting community at-risk, macaque populations, and mosquito vectors.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Predicting Plasmodium knowlesi transmission risk across Peninsular Malaysia using machine learning-based ecological niche modeling approaches

Phang

Hamid²,

Jelip³

et al. 2023

Front. Microbiol.

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“…Fortunately, PCR and molecular testing, the gold-standard for diagnosis, are becoming more accessible in Malaysia and other countries [23,120]. Rapid Pk testing can also be performed using loop-mediated isothermal amplification (LAMP), a point-of-care test that is related to PCR, but amplifies nucleic acids at a constant temperature [8,23].…”

Section: Molecular Testingmentioning

confidence: 99%

Plasmodium knowlesi (Pk) Malaria: A Review & Proposal of Therapeutically Rational Exchange (T-REX) of Pk-Resistant Red Blood Cells

Jajosky,

Wu,

Jajosky

et al. 2023

TropicalMed

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Plasmodium knowlesi (Pk) causes zoonotic malaria and is known as the “fifth human malaria parasite”. Pk malaria is an emerging threat because infections are increasing and can be fatal. While most infections are in Southeast Asia (SEA), especially Malaysia, travelers frequently visit this region and can present with Pk malaria around the world. So, clinicians need to know (1) patients who present with fever after recent travel to SEA might be infected with Pk and (2) Pk is often misdiagnosed as P. malariae (which typically causes less severe malaria). Here we review the history, pathophysiology, clinical features, diagnosis, and treatment of Pk malaria. Severe disease is most common in adults. Signs and symptoms can include fever, abdominal pain, jaundice, acute kidney injury, acute respiratory distress syndrome, hyponatremia, hyperparasitemia, and thrombocytopenia. Dengue is one of the diseases to be considered in the differential. Regarding pathophysiologic mechanisms, when Pk parasites invade mature red blood cells (RBCs, i.e., normocytes) and reticulocytes, changes in the red blood cell (RBC) surface can result in life-threatening cytoadherence, sequestration, and reduced RBC deformability. Since molecular mechanisms involving the erythrocytic stage are responsible for onset of severe disease and lethal outcomes, it is biologically plausible that manual exchange transfusion (ET) or automated RBC exchange (RBCX) could be highly beneficial by replacing “sticky” parasitized RBCs with uninfected, deformable, healthy donor RBCs. Here we suggest use of special Pk-resistant donor RBCs to optimize adjunctive manual ET/RBCX for malaria. “Therapeutically-rational exchange transfusion” (T-REX) is proposed in which Pk-resistant RBCs are transfused (instead of disease-promoting RBCs). Because expression of the Duffy antigen on the surface of human RBCs is essential for parasite invasion, T-REX of Duffy-negative RBCs—also known as Fy(a-b-) RBCs—could replace the majority of the patient’s circulating normocytes with Pk invasion-resistant RBCs (in a single procedure lasting about 2 h). When sequestered or non-sequestered iRBCs rupture—in a 24 h Pk asexual life cycle—the released merozoites cannot invade Fy(a-b-) RBCs. When Fy(a-b-) RBC units are scarce (e.g., in Malaysia), clinicians can consider the risks and benefits of transfusing plausibly Pk-resistant RBCs, such as glucose-6-phosphate dehydrogenase deficient (G6PDd) RBCs and Southeast Asian ovalocytes (SAO). Patients typically require a very short recovery time (<1 h) after the procedure. Fy(a-b-) RBCs should have a normal lifespan, while SAO and G6PDd RBCs may have mildly reduced half-lives. Because SAO and G6PDd RBCs come from screened blood donors who are healthy and not anemic, these RBCs have a low-risk for hemolysis and do not need to be removed after the patient recovers from malaria. T-REX could be especially useful if (1) antimalarial medications are not readily available, (2) patients are likely to progress to severe disease, or (3) drug-resistant strains emerge. In conclusion, T-REX is a proposed optimization of manual ET/RBCX that has not yet been utilized but can be considered by physicians to treat Pk malaria patients.

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“…As seen for Pk , control of Pcy malaria could pose a problem in the absence of strategies for controlling the mainly forest-dwelling mosquito vectors and primate reservoir of Pcy parasites [ 86 ]. Repellents, odor-based mosquito traps, and insecticide-treated clothes have been proposed, but evidences for their effectiveness are still lacking [ 97 ]. Thus, there is need for more studies on Pcy especially on development, evaluation, and implementation of integrated intervention measures (vector control, personal level protection and community engagement, environment control) to curb the chain of transmission of simian parasites from animals to humans [ 97 , 98 ].…”

Section: Knowledge Gaps and Future Directionsmentioning

confidence: 99%

Plasmodium cynomolgi in humans: current knowledge and future directions of an emerging zoonotic malaria parasite

et al. 2022

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Plasmodium cynomolgi ( Pcy ), a simian malaria parasite, is a recent perfect example of emerging zoonotic transfer in human. This review summarizes the current knowledge on the epidemiology of natural Pcy infections in humans, mosquitoes and monkeys, along with its biological, clinical and drug sensitivity patterns. Knowledge gaps and further studies on Pcy in humans are also discussed. This parasite currently seems to be geographically limited in South-East Asia (SEA) with a global prevalence in human ranging from 0 to 1.4%. The Pcy infections were reported in local SEA populations and European travelers, and range from asymptomatic carriage to mild/moderate attacks with no evidence of pathognomonic clinical and laboratory patterns but with Pcy strain-shaped clinical differences. Geographical distribution and competence of suitable mosquito vectors and non-primate hosts, globalization, climate change, and increased intrusion of humans into the habitat of monkeys are key determinants to emergence of Pcy parasites in humans, along with its expansion outside SEA. Sensitization/information campaigns coupled with training and assessment sessions of microscopists and clinicians on Pcy are greatly needed to improve data on the epidemiology and management of human Pcy infection. There is a need for development of sensitive and specific molecular tools for individual diagnosis and epidemiological studies. The development of safe and efficient anti-hypnozoite drugs is the main therapeutic challenge for controlling human relapsing malaria parasites. Experience gained from P. knowlesi malaria, development of integrated measures and strategies—ideally with components related to human, monkeys, mosquito vectors, and environment—could be very helpful to prevent emergence of Pcy malaria in humans through disruption of transmission chain from monkeys to humans and ultimately contain its expansion in SEA and potential outbreaks in a context of malaria elimination. Supplementary Information The online version contains supplementary material available at 10.1007/s15010-022-01952-2.

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Narrative Review of the Control and Prevention of Knowlesi Malaria

Cited by 4 publications

References 84 publications

Predicting Plasmodium knowlesi transmission risk across Peninsular Malaysia using machine learning-based ecological niche modeling approaches

Predicting Plasmodium knowlesi transmission risk across Peninsular Malaysia using machine learning-based ecological niche modeling approaches

Plasmodium knowlesi (Pk) Malaria: A Review & Proposal of Therapeutically Rational Exchange (T-REX) of Pk-Resistant Red Blood Cells

Plasmodium cynomolgi in humans: current knowledge and future directions of an emerging zoonotic malaria parasite

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