World Health Organization, 2019. World Malaria Report 2019. Geneva, Switzerland: WHO.
Hussin N, Lim YAL, Goh PP, William T, Jelip J, Mudin RN, 2020. Updates on malaria incidence and profile in Malaysia from 2013 to 2017. Malar J 19: 55.
Singh B, Lee KS, Matusop A, Radhakrishnan A, Shamsul SS, Cox-Singh J, Thomas A, Conway DJ, 2004. A large focus of naturally acquired Plasmodium knowlesi infections in human beings. Lancet 363: 1017–1024.
Lee KS, Vythilingam I, 2013. Plasmodium knowlesi: Emergent human malaria in Southeast Asia. Lim YAL, Vythilingam I, eds. Parasites and Their Vectors. Vienna, Austria: Springer, 5–31.
Vythilingam I, Tan CH, Asmad M, Chan ST, Lee KS, Singh B, 2006. Natural transmission of Plasmodium knowlesi to humans by Anopheles latens in Sarawak, Malaysia. Trans R Soc Trop Med Hyg 100: 1087–1088.
Tan CH, Vythilingam I, Matusop A, Chan ST, Singh B, 2008. Bionomics of Anopheles latens in Kapit, Sarawak, Malaysian Borneo in relation to the transmission of zoonotic simian malaria parasite Plasmodium knowlesi. Malar J 7: 52.
Millar SB, Cox-Singh J, 2015. Human infections with Plasmodium knowlesi-zoonotic malaria. Clin Microbiol Infect 21: 640–648.
Rejeki DSS, Fuad A, Widartono BS, Murhandarwati EEH, Kusnanto H, 2019. Spatiotemporal patterns of malaria at cross-boundaries area in Menoreh Hills, Java, Indonesia. Malar J 18: 80.
Phang WK, Hamid MHA, Jelip J, Mudin RN, Chuang TW, Lau YL, Fong MY, 2020. Spatial and temporal analysis of Plasmodium knowlesi infection in Peninsular Malaysia, 2011 to 2018. Int J Environ Res Public Health 17: 9271.
Brown R, Chua TH, Fornace K, Drakeley C, Vythilingam I, Ferguson HM, 2020. Human exposure to zoonotic malaria vectors in village, farm and forest habitats in Sabah, Malaysian Borneo. PLoS Negl Trop Dis 14: e0008617.
Fornace KM et al. 2019. Local human movement patterns and land use impact exposure to zoonotic malaria in Malaysian Borneo. Elife 8: e47602.
Brooker S, Clarke S, Njagi JK, Polack S, Mugo B, Estambale B, Muchiri E, Magnussen P, Cox J, 2004. Spatial clustering of malaria and associated risk factors during an epidemic in a highland area of western Kenya. Trop Med Int Health 9: 757–766.
Gaudart J et al. 2006. Space-time clustering of childhood malaria at the household level: a dynamic cohort in a Mali village. BMC Public Health 6: 286.
Stresman G, Bousema T, Cook J, 2019. Malaria hotspots: is there epidemiological evidence for fine-scale spatial targeting of interventions? Trends Parasitol 35: 822–834.
Sarawak Government, 2020. The Geography of Sarawak. Available at: https://www.sarawak.gov.my/web/home/article_view/159/176/. Accessed March 31, 2020.
Department of Statistics Malaysia, 2020. Malaysia @ a Glance. Available at: https://www.dosm.gov.my/v1/index.php?r=column/cone&menu_id=clJnWTlTbWFHdmUwbmtSTE1EQStFZz09. Accessed March 31, 2020.
Forestry Department Peninsular Malaysia, 2019. Forestry Statistics. Available at: https://www.forestry.gov.my/en/2016-06-07-02-53-46/2016-06-07-03-12-29. Accessed December 21, 2019.
Ooi CH, Bujang MA, Tg Abu Bakar Sidik TMI, Ngui R, Lim YA, 2017. Over two decades of Plasmodium knowlesi infections in Sarawak: trend and forecast. Acta Trop 176: 83–90.
Singh B, Daneshvar C, 2013. Human infections and detection of Plasmodium knowlesi. Clin Microbiol Rev 26: 165–184.
Department of Statistics Malaysia, 2011. Population Distribution and Basic Demographic Characteristics 2010. Putrajaya, Malaysia: Department of Statistics Malaysia.
Cleveland R, Cleveland WS, McRae J, Terpenning IJ, 1990. STL: a seasonal-trend decomposition procedure based on loess. J Off Stat 6: 3–33.
Kulldorff M, 1997. A spatial scan statistic. Commun Stat Theory Methods 26: 1481–1496.
Jawahir M, Ikhwan R, Mutalip H, Hasim H, Che Dom N, 2019. Spatio-temporal distribution of malaria in Betong, Sarawak, Malaysia: a five years study. Serangga 24: 104–118.
Brock PM, Fornace KM, Grigg MJ, Anstey NM, William T, Cox J, Drakeley CJ, Ferguson HM, Kao RR, 2019. Predictive analysis across spatial scales links zoonotic malaria to deforestation. Proc Biol Sci 286: 20182351.
Fornace KM, Abidin TR, Alexander N, Brock P, Grigg MJ, Murphy A, William T, Menon J, Drakeley CJ, Cox J, 2016. Association between landscape factors and spatial patterns of Plasmodium knowlesi infections in Sabah, Malaysia. Emerg Infect Dis 22: 201–208.
Cooper DJ et al. 2020. Plasmodium knowlesi malaria in Sabah, Malaysia, 2015–2017: ongoing increase in incidence despite near-elimination of the human-only Plasmodium species. Clin Infect Dis 70: 361–367.
Solomon T, Loha E, Deressa W, Gari T, Lindtjorn B, 2019. Spatiotemporal clustering of malaria in southern-central Ethiopia: a community-based cohort study. PLoS One 14: e0222986.
Grigg MJ et al. 2017. Individual-level factors associated with the risk of acquiring human Plasmodium knowlesi malaria in Malaysia: a case-control study. Lancet Planet Health 1: e97–e104.
Canelas T, Castillo-Salgado C, Ribeiro H, 2018. Analyzing the local epidemiological profile of malaria transmission in the Brazilian Amazon between 2010 and 2015. PLoS Curr 10: ecurrents.outbreaks.8f23fe5f0c2052bfaaa648e6931e4e1a.
Divis PCS, Hu TH, Kadir KA, Mohammad DSA, Hii KC, Daneshvar C, Conway DJ, Singh B, 2020. Efficient surveillance of Plasmodium knowlesi genetic subpopulations, Malaysian Borneo, 2000–2018. Emerg Infect Dis 26: 1392–1398.
Ang XDJ, Kadir KA, Mohamad DSA, Matusop AA, Divis PCS, Yaman K, Singh B, 2020. New vectors in northern Sarawak, Malaysian Borneo, for the zoonotic malaria parasite, Plasmodium knowlesi. Parasites Vectors 13: 472.
Davidson G, Chua TH, Cook A, Speldewinde P, Weinstein P, 2019. Defining the ecological and evolutionary drivers of Plasmodium knowlesi transmission within a multi-scale framework. Malar J 18: 66.
Shearer FM et al. 2016. Estimating geographical variation in the risk of zoonotic Plasmodium knowlesi infection in countries eliminating malaria. PLoS Negl Trop Dis 10: e0004915.
Herdiana H et al. 2016. Malaria risk factor assessment using active and passive surveillance data from Aceh Besar, Indonesia, a low endemic, malaria elimination setting with Plasmodium knowlesi, Plasmodium vivax, and Plasmodium falciparum. Malar J 15: 468.
Mercado CEG et al. 2019. Spatiotemporal epidemiology, environmental correlates, and demography of malaria in Tak Province, Thailand (2012–2015). Malar J 18: 240.
Fornace KM, Nuin NA, Betson M, Grigg MJ, William T, Anstey NM, Yeo TW, Cox J, Ying LT, Drakeley CJ, 2016. Asymptomatic and submicroscopic carriage of Plasmodium knowlesi malaria in household and community members of clinical cases in Sabah, Malaysia. J Infect Dis 213: 784–787.
Jiram AI, Ooi CH, Rubio JM, Hisam S, Karnan G, Sukor NM, Artic MM, Ismail NP, Alias NW, 2019. Evidence of asymptomatic submicroscopic malaria in low transmission areas in Belaga district, Kapit division, Sarawak, Malaysia. Malar J 18: 156.
Siner A, Liew ST, Kadir KA, Mohamad DSA, Thomas FK, Zulkarnaen M, Singh B, 2017. Absence of Plasmodium inui and Plasmodium cynomolgi, but detection of Plasmodium knowlesi and Plasmodium vivax infections in asymptomatic humans in the Betong division of Sarawak, Malaysian Borneo. Malar J 16: 417.
Imwong M et al. 2019. Asymptomatic natural human infections with the simian malaria parasites Plasmodium cynomolgi and Plasmodium knowlesi. J Infect Dis 219: 695–702.
Van den Eede P, Vythilingam I, Ngo DT, Nguyen VH, Le XH, D’Alessandro U, Erhart A, 2010. Plasmodium knowlesi malaria in Vietnam: some clarifications. Malar J 9: 20.
Lubis IND, Wijaya H, Lubis M, Lubis CP, Divis PCS, Beshir KB, Sutherland CJ, 2017. Contribution of Plasmodium knowlesi to multispecies human malaria infections in North Sumatera, Indonesia. J Infect Dis 215: 1148–1155.
Herdiana H et al. 2018. Two clusters of Plasmodium knowlesi cases in a malaria elimination area, Sabang Municipality, Aceh, Indonesia. Malar J 17: 186.
Okell LC, Bousema T, Griffin JT, Ouedraogo AL, Ghani AC, Drakeley CJ, 2012. Factors determining the occurrence of submicroscopic malaria infections and their relevance for control. Nat Commun 3: 1237.
Ouedraogo M, Samadoulougou S, Rouamba T, Hien H, Sawadogo JEM, Tinto H, Alegana VA, Speybroeck N, Kirakoya-Samadoulougou F, 2018. Spatial distribution and determinants of asymptomatic malaria risk among children under 5 years in 24 districts in Burkina Faso. Malar J 17: 460.
Raja TN, Hu TH, Kadir KA, Mohamad DSA, Rosli N, Wong LL, Hii KC, Simon Divis PC, Singh B, 2020. Naturally acquired human Plasmodium cynomolgi and P. knowlesi infections, Malaysian Borneo. Emerg Infect Dis 26: 1801–1809.
Grignard L, Shah S, Chua TH, William T, Drakeley CJ, Fornace KM, 2019. Natural human infections with Plasmodium cynomolgi and other malaria species in an elimination setting in Sabah, Malaysia. J Infect Dis 220: 1946–1949.
Ta TH, Hisam S, Lanza M, Jiram AI, Ismail N, Rubio JM, 2014. First case of a naturally acquired human infection with Plasmodium cynomolgi. Malar J 13: 68.
DePina AJ, Andrade AJB, Dia AK, Moreira AL, Furtado UD, Baptista H, Faye O, Seck I, Niang EHA, 2019. Spatiotemporal characterisation and risk factor analysis of malaria outbreak in Cabo Verde in 2017. Trop Med Health 47: 3.
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Zoonotic knowlesi malaria has replaced human malaria as the most prevalent malaria disease in Malaysia. The persistence of knowlesi malaria in high-risk transmission areas or hotspots can be discouraging to existing malaria elimination efforts. In this study, retrospective data of laboratory-confirmed knowlesi malaria cases were obtained from the Sarawak Health Department to investigate the spatiotemporal patterns and clustering of knowlesi malaria in the state of Sarawak from 2008 to 2017. Purely spatial, purely temporal, and spatiotemporal analyses were performed using SaTScan software to define clustering of knowlesi malaria incidence. Purely spatial and spatiotemporal analyses indicated most likely clusters of knowlesi malaria in the northern region of Sarawak, along the Sarawak–Kalimantan border, and the inner central region of Sarawak between 2008 and 2017. Temporal cluster was detected between September 2016 and December 2017. This study provides evidence of the existence of statistically significant Plasmodium knowlesi malaria clusters in Sarawak, Malaysia. The analysis approach applied in this study showed potential in establishing surveillance and risk management system for knowlesi malaria control as Malaysia approaches human malaria elimination.
Financial support: Wei Kit Phang was supported by graduate research assistantship funded by the Ministry of Higher Education Malaysia Long Term Research Grant Scheme (LR002D-2018).
Authors’ addresses: Choo Huck Ooi, Vector Borne Disease Section, Sarawak Health Department, Ministry of Health Malaysia, Kuching, Malaysia, E-mail: firstname.lastname@example.org. Wei Kit Phang, Jonathan Wee Kent Liew, and Yee Ling Lau, Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia, E-mails: email@example.com, firstname.lastname@example.org, email@example.com.