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.

METHODS: From January to October 2022, a study using qualitative methods was conducted in four rural villages in Kudat district of Sabah, Malaysia. A total of nine in-depth interviews were conducted with community and faith leaders, after the completion of twelve focus group discussions with 26 photovoice participants. The interviews were conducted using the Sabah Malay dialect, audio-recorded, transcribed, and translated into English. The research team led the discussion and analysis, which was approved by participants through member checking at the community level.

RESULTS: Participants identified disparity in health as a key issue affecting their health and livelihoods. Injustice in the social environment was also identified as a significant challenge, including the importance of listening to the voices of affected communities in disentangling the social and economic phenomena that can impact malaria control. Specific concerns included inadequate access to health-related resources and degradation of the environment. Participants recommended improving access to water and other necessities, increasing the availability of malaria control commodities in healthcare facilities, and developing sustainable programs to reduce socioeconomic disparities.

METHODS: Vector data from various sources were used to create distribution maps from 1957 to 2021. A predictive statistical model utilizing logistic regression was developed using significant environmental factors. Interpolation maps were created using the inverse distance weighted (IDW) method and overlaid with the corresponding environmental variables.

RESULTS: Based on the IDW analysis, high vector abundances were found in the southwestern part of Sarawak, the northern region of Pahang and the northwestern part of Sabah. However, most parts of Johor, Sabah, Perlis, Penang, Kelantan and Terengganu had low vector abundance. The accuracy test indicated that the model predicted sampling and non-sampling areas with 75.3% overall accuracy. The selected environmental variables were entered into the regression model based on their significant values. In addition to the presence of water bodies, elevation, temperature, forest loss and forest cover were included in the final model since these were significantly correlated. Anopheles mosquitoes were mainly distributed in Peninsular Malaysia (Titiwangsa range, central and northern parts), Sabah (Kudat, West Coast, Interior and Tawau division) and Sarawak (Kapit, Miri, and Limbang). The predicted Anopheles mosquito density was lower in the southern part of Peninsular Malaysia, the Sandakan Division of Sabah and the western region of Sarawak.

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.

METHODS: From January through June 2022, 26 participants were recruited from four villages in Kudat, Sabah, using purposive sampling. Participants were male and female villagers, aged > 18 years old. After photovoice training in the villages, participants documented facilitators of and barriers related to avoiding mosquito bites using their own smartphone cameras, and provided narratives for their photos. Twelve Focus Group Discussions (FGDs) sessions in three rounds were held to share and discuss the photos, and to address challenges to the avoidance of mosquito bites. All discussions were conducted in the Sabah Malay dialect, and were video and audio recorded, transcribed, and analyzed using reflexive thematic analysis. The Ideation Model, a meta-theoretical model of behaviour change, underpinned this study.

RESULTS: The most common types of barriers identified by participants included (I) intrapersonal factors such as low perceived threat of malaria, (II) livelihood and lifestyle activities consisting of the local economy and socio-cultural activities, and (III) physical and social environment. The facilitators were categorized into (I) intrapersonal reasons, including having the opportunity to stay indoors, especially women who are housewives, (II) social support by the households, neaighbours and healthcare workers, and (III) support from healthcare services and malaria awareness program. Participants emphasized the importance of stakeholder's support in implementing feasible and affordable approaches to P. knowlesi malaria control.

METHODS: Imported malaria cases reported in Sarawak from 2011 to 2019 were collected from Sarawak State Health Department and analysed in this longitudinal retrospective study.

RESULTS: A total of 2058 imported malaria cases were registered in all districts in Sarawak. Highest number of cases were reported in Kapit (n = 559; 27.16%), followed by Sibu (n = 424; 20.6%), and Miri (n = 166; 8.07%). Based on the demographic profile, most of the patients constituted of either male sex (98.49%), age group of 40-49 years (39.6%), Iban ethnic (57.92%), worked in logging industry (88.58%), Malaysian nationals (91.84%), contracted malaria in Papua New Guinea (46.11%), uncomplicated disease (77.89%), or hospitalised cases (97.86%). The most prominent Plasmodium species diagnosed were P. vivax (52.67%) and P. falciparum (35.81%).

METHODS: From January to June 2022, a photovoice study was conducted with rural communities in Matunggong subdistrict, Malaysia, to explore their experiences with and local knowledge of non-human primate malaria and prevention practices. The study included (1) an introductory phase in which participants were introduced to the photovoice method; (2) a documentation phase in which participants captured and narrated photos from their communities; (3) a discussion phase in which participants discussed photos and relevant topics through a series of three focus group discussions (FGDs) per village; and (4) a dissemination phase where selected photos were shared with key stakeholders through a photo exhibition. A purposively selected sample of 26 participants (adults > 18 years old, male, and female) from four villages participated in all phases of the study. The study activities were conducted in Sabah Malay dialect. Participants and the research team contributed to data review and analyses.

RESULTS: Rural communities in Sabah, Malaysia possess local knowledge that attributes non-human primate malaria to natural factors related to the presence of mosquitoes that bite humans and which carry "kuman-malaria" or malaria parasite. Participants revealed various preventive practises ranging from traditional practises, including burning dried leaves and using plants that produce foul odours, to non-traditional approaches such as aerosols and mosquito repellents. By engaging with researchers and policymakers, the participants or termed as co-researchers in this study, showcased their ability to learn and appreciate new knowledge and perspectives and valued the opportunity to share their voices with policymakers. The study successfully fostered a balance of power dynamics between the co-researchers, research team members and policymakers.

METHOD: To examine potential factors that influence malaria-prevention behaviour in communities exposed to P. knowlesi malaria, 12 malaria experts participated in a modified Delphi study; every participant maintained their anonymity throughout the study. Three Delphi rounds were conducted via different online platforms between 15 November 2021 and 26 February 2022, and consensus was achieved when 70% of the participants agreed on a particular point with a 4-5 median. The results from the open-ended questions were then subjected to thematic analysis, and the dataset generated by this study was analysed using a deductive and inductive approach.

RESULTS: After a systematic, iterative process, knowledge and belief, social support, cognitive and environmental factors, past experience as a malaria patient, and the affordability and feasibility of a given intervention were critical contributors to malaria-prevention behaviour.

METHODS: Using parasite clearance data from 714 patients with knowlesi malaria and enrolled in three trials, the Worldwide Antimalarial Resistance Network (WWARN) Parasite Clearance Estimator (PCE) standard two-stage approach and Bayesian hierarchical modelling were compared. Both methods estimate the parasite clearance rate from a model that incorporates a lag phase, slope, and tail phase for the parasitaemia profiles.

RESULTS: The standard two-stage approach successfully estimated the parasite clearance rate for 678 patients, with 36 (5%) patients excluded due to an insufficient number of available parasitaemia measurements. The Bayesian hierarchical estimation method was applied to the parasitaemia data of all 714 patients. Overall, the Bayesian method estimated a faster population mean parasite clearance (0.36/h, 95% credible interval [0.18, 0.65]) compared to the standard two-stage method (0.26/h, 95% confidence interval [0.11, 0.46]), with better model fits (compared visually). Artemisinin-based combination therapy (ACT) is more effective in treating P. knowlesi than chloroquine, as confirmed by both methods, with a mean estimated parasite clearance half-life of 2.5 and 3.6 h, respectively using the standard two-stage method, and 1.8 and 2.9 h using the Bayesian method.

METHODS: We performed a retrospective review on 54 cases of severe malaria in a district hospital in Kapit, Sarawak, from January 2018 to May 2019. The patients' demographics, clinical features, complications based on organ involvement, and treatment outcomes were examined.

RESULTS: There were 54 cases of severe malaria, with the majority being male (70%) and between the ages of 40 and 49 (26%). All patients with severe malaria were febrile or had a history of pyrexia except for one patient. P. knowlesi (81.5%) was the most common species causing severe malaria in our study, followed by P. falciparum (13%), and P. vivax (5.5%). There were no cases of severe malaria caused by P. ovale or P. malariae. Hyperparasitaemia was present in 76% of patients and the median parasitemia value at hospital admission was 33,944 parasites/μL (interquartile range: 19,920-113,285 parasites/μL). Circulatory shock was observed in 17 patients (31.5%). There were eight patients with acute renal failure and six patients with respiratory distress. One patient died as a result of severe malaria with multiorgan involvement (1.9% fatality rate).

METHODS: Pubmed, Scopus and the Web of Science databases for literature describing asymptomatic P. knowlesi malaria published between 2010 and 2020 were searched. A systematic literature review was conducted to identify studies reporting the prevalence and incidence of laboratory confirmed asymptomatic P. knowlesi cases in humans, their clinical and demographic characteristics, and methods used to diagnose these cases.

RESULTS: By analysing over 102 papers, thirteen were eligible for this review. Asymptomatic P. knowlesi infections have been detected in 0.03%-4.0% of the population depending on region, and infections have been described in children as young as 2 years old. Various different diagnostic methods were used to detect P. knowlesi cases and there were differing definitions of asymptomatic cases in these studies. The literature indicates that regionally-differing immune-related mechanisms may play a part on the prevalence of asymptomatic P. knowlesi.

METHODS: Between 1 November 2021 and 28 February 2022, we conducted a study in Kudat district, Sabah, using a multi-method design. All participants consented to the study, which included health care workers (HCWs) (n = 5), community leaders (n = 8), and faith leaders (n = 1). We conducted interviews, transect walks, and observations with gatekeepers to ensure data trustworthiness. All interviews were conducted in the Sabah Malay dialect. The sessions were audio- and video-recorded, transcribed into English and analyzed using thematic analysis.

RESULTS: Between 2017 and 2021, the number of cases of P. knowlesi malaria detected in humans ranged from 35 to 87 in villages under the care of the Lotong primary health care clinic. The challenges in controlling malaria include social norms, lifestyles, socioeconomic factors, environmental factors, and limitations of basic resources. Critical discussions regarding participation with the gatekeepers identified that face-to-face interviews were preferable to online discussions, and influenced willingness to participate in future research.

METHODS: Individuals of An. balabacensis were collected in the field in Ranau district, Sabah to establish a laboratory colony. Induced mating was used, and the life history parameters of the progeny were recorded. The age-stage, two-sex life table approach was used in the analysis. The culture conditions in the laboratory were 9 h light:15 h dark, mean temperature 25.7 °C ± 0.05 and relative humidity 75.8% ± 0.31.

RESULTS: The eggs hatched within 2 days, and the larval stage lasted for 10.5 days in total, with duration of instar stages I, II, III and IV of 2.3, 3.7, 2.3, 2.2 days, respectively. The maximum total fecundity was 729 for one particular female, while the maximum female age-specific mean fecundity (mx) was 142 at age 59 days. The gross reproductive rate or number of offspring per individual was about 102. On average, each female laid 1.81 ± 0.19 (range 1-7) batches of eggs, with 63% of the females producing only one batch; only one female laid six batches, while one other laid seven. Each batch comprised 159 ± 17.1 eggs (range 5-224) and the female ratio of offspring was 0.28 ± 0.06. The intrinsic rate of increase, finite rate of increase, net reproductive rate, mean generation time and doubling time were, respectively, 0.12 ± 0.01 day-1, 1.12 ± 0.01 day-1, 46.2 ± 14.97, 33.02 ± 1.85 and 5.97 days.