Simian malaria: a narrative review on emergence, epidemiology and threat to global malaria elimination

Fornace, Kimberly; Laporta, Gabriel Zorello; Vythilingham, Indra; Chua, Tock Hing; Ahmed, Kamruddin; Jeyaprakasam, Nantha Kumar; Duarte, Ana Maria Ribeiro de Castro; Amir, Amirah; Phang, Wei Kit; Drakeley, Chris; Sallum, Maria Anice Mureb; Lau, Yee Ling

doi:10.1016/s1473-3099(23)00298-0

Cited by 8 publications

(7 citation statements)

References 166 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…knowlesi was ‘negligible’, i.e. below some low threshold of annual incidence [ 60 , 66 ]–a requirement that has already prevented Malaysia from receiving elimination certification [ 67 ]. Given this requirement, continued surveillance and mitigation of P .…”

Section: Discussionmentioning

confidence: 99%

Updating estimates of Plasmodium knowlesi malaria risk in response to changing land use patterns across Southeast Asia

Tobin,

Harrison,

Tully

et al. 2024

PLoS Negl Trop Dis

View full text Add to dashboard Cite

Background Plasmodium knowlesi is a zoonotic parasite that causes malaria in humans. The pathogen has a natural host reservoir in certain macaque species and is transmitted to humans via mosquitoes of the Anopheles Leucosphyrus Group. The risk of human P. knowlesi infection varies across Southeast Asia and is dependent upon environmental factors. Understanding this geographic variation in risk is important both for enabling appropriate diagnosis and treatment of the disease and for improving the planning and evaluation of malaria elimination. However, the data available on P. knowlesi occurrence are biased towards regions with greater surveillance and sampling effort. Predicting the spatial variation in risk of P. knowlesi malaria requires methods that can both incorporate environmental risk factors and account for spatial bias in detection. Methods & results We extend and apply an environmental niche modelling framework as implemented by a previous mapping study of P. knowlesi transmission risk which included data up to 2015. We reviewed the literature from October 2015 through to March 2020 and identified 264 new records of P. knowlesi, with a total of 524 occurrences included in the current study following consolidation with the 2015 study. The modelling framework used in the 2015 study was extended, with changes including the addition of new covariates to capture the effect of deforestation and urbanisation on P. knowlesi transmission. Discussion Our map of P. knowlesi relative transmission suitability estimates that the risk posed by the pathogen is highest in Malaysia and Indonesia, with localised areas of high risk also predicted in the Greater Mekong Subregion, The Philippines and Northeast India. These results highlight areas of priority for P. knowlesi surveillance and prospective sampling to address the challenge the disease poses to malaria elimination planning.

show abstract

Section: Discussionmentioning

confidence: 99%

Updating estimates of Plasmodium knowlesi malaria risk in response to changing land use patterns across Southeast Asia

Tobin,

Harrison,

Tully

et al. 2024

PLoS Negl Trop Dis

View full text Add to dashboard Cite

show abstract

“…However, deforestation and the spread of plantations have transformed the ecology and increased human exposure to zoonotic malaria [ 2 – 5 ]. Despite relatively large numbers of Plasmodium knowlesi infections in humans, Malaysia has almost eliminated ‘human’ malaria parasite species as the last indigenous human malaria case was reported in 2017 [ 6 ], and is currently progressing towards receiving E-2020 malaria elimination certification [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

The public health response to a Plasmodium malariae outbreak in Penampang district, Sabah during a COVID-19 movement control order

Naserrudin,

Jiee,

Habil

et al. 2023

Malar J

Self Cite

View full text Add to dashboard Cite

Background Since 2018, no indigenous human malaria cases has been reported in Malaysia. However, during the recent COVID-19 pandemic the World Health Organization is concerned that the pandemic might erode the success of malaria control as there are reports of increase malaria cases in resource limited countries. Little is known how the COVID-19 pandemic has impacted malaria in middle-income countries like Malaysia. Here the public health response to a Plasmodium malariae outbreak occurred in a village in Sabah state, Malaysia, during a COVID-19 movement control order is reported. Methods An outbreak was declared following the detection of P. malariae in July 2020 and active case detection for malaria was performed by collecting blood samples from residents residing within 2 km radius of Moyog village. Vector prevalence and the efficacy of residual insecticides were determined. Health awareness programmes were implemented to prevent future outbreaks. A survey was conducted among villagers to understand risk behaviour and beliefs concerning malaria. Results A total of 5254 blood samples collected from 19 villages. Among them, 19 P. malariae cases were identified, including the index case, which originated from a man who returned from Indonesia. His return from Indonesia and healthcare facilities visit coincided with the movement control order during COVID-19 pandemic when the healthcare facilities stretched its capacity and only serious cases were given priority. Despite the index case being a returnee from a malaria endemic area presenting with mild fever, no malaria test was performed at local healthcare facilities. All cases were symptomatic and uncomplicated except for a pregnant woman with severe malaria. There were no deaths; all patients recovered following treatment with artemether-lumefantrine combination therapy. Anopheles balabacensis and Anopheles barbirostris were detected in ponds, puddles and riverbeds. The survey revealed that fishing and hunting during night, and self-treatment for mild symptoms contributed to the outbreak. Despite the index case being a returnee from a malaria-endemic area presenting with mild fever, no malaria test was performed at local healthcare facilities. Conclusion The outbreak occurred during a COVID-19 movement control order, which strained healthcare facilities, prioritizing only serious cases. Healthcare workers need to be more aware of the risk of malaria from individuals who return from malaria endemic areas. To achieve malaria elimination and prevention of disease reintroduction, new strategies that include multisectoral agencies and active community participation are essential for a more sustainable malaria control programme.

show abstract

“…Of the five major Plasmodium species that cause malaria in humans, Pk is the only one with zoonotic transmission and is known as a simian malaria parasite [15,16]. The predominant natural hosts of Pk are M. fascicularis and M. nemestrina (pig-tailed macaque) (Figure 2B) [17,18]. Macaque-mosquito-macaque transmission and macaque-mosquito-human transmission occur naturally by Anopheles of the Leucosphyrus Group, which are exophagic (bite outdoors) [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

“…balabacensis, while An. latens is the main vector in parts of Sarawak [18,26]. Experimental human-mosquito-human transmission has been demonstrated by An.…”

Section: Introductionmentioning

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

View full text Add to dashboard Cite

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.

show abstract

Simian malaria: a narrative review on emergence, epidemiology and threat to global malaria elimination

Cited by 8 publications

References 166 publications

Updating estimates of Plasmodium knowlesi malaria risk in response to changing land use patterns across Southeast Asia

Updating estimates of Plasmodium knowlesi malaria risk in response to changing land use patterns across Southeast Asia

The public health response to a Plasmodium malariae outbreak in Penampang district, Sabah during a COVID-19 movement control order

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

Contact Info

Product

Resources

About