Poster Presentation First Malaria World Congress 2018

Spatial epidemiology of malaria in Tak Province, Thailand, 2012-2015 (#347)

Chris Erwin G Mercado 1 2 , Saranath Lawpoolsri 2 3 , Prayuth Sudathip 4 , Jaranit Kaewkungwal 2 3 , Amnat Khamsiriwatchara 3 , Wirichada Pan-ngum 1 2 , Surapon Yimsamran 2 , Siam Lawawirojwong 5 , Nattwut Ekapirat 1 , Jacher Wiladphaingern 1 6 , Rapeephan R Maude 1 7 , Nicholas PJ Day 1 8 , Arjen M. Dondorp 1 8 , Richard J Maude 1 8 9
  1. Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
  2. Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
  3. Center of Excellence for Biomedical and Public Health Informatics (BIOPHICS), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
  4. Department of Disease Control, Ministry of Public Health (MoPH), Nonthaburi, Thailand
  5. Geo-Informatics and Space Technology Development Agency (GISTDA), Bangkok, Thailand
  6. Shoklo Malaria Research Unit (SMRU), Mae Sot, Thailand
  7. Mahachai Hospital, Samut Sakhon, Thailand
  8. Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
  9. Harvard TH Chan School of Public Health, Harvard University, Boston, USA

Thailand has made significant progress towards its aim to eliminate malaria by 2024, reducing its reported cases by 84% between 2000 and 2016. While successful disease control efforts have led to this decline, 19% of the Thai population remain at risk for malaria, particularly those living in areas along the borders with surrounding countries. Tak Province in Thailand shares its borders with eastern Myanmar, and is a crucial target to achieving nationwide malaria elimination. Analysis of routine incidence data was conducted to examine the spatial and temporal epidemiology of malaria in this province. Malaria passive surveillance data on clinical cases from 2012 to 2015 were obtained from the Thai Ministry of Public Health and analysed at subdistrict level. Relationships between trends in incidence and other factors such as climate and forest cover were explored. There were 36,536 confirmed malaria cases reported from 2012 to 2015. Most cases were men (63%), adults (56% aged ≥15 years) and comprised of both Burmese (56%) and Thai (39%) populations. There was an overall decline in total number of confirmed cases in Tak Province, from 37% (2012) to 21% (2015) of the national total. Annual ratio of Plasmodium falciparum to vivax cases were 0.64 (2012), 0.67 (2013), 0.44 (2014) and 0.44 (2015). Annual risk maps indicate a spatial pattern of reduction over time for both major species, starting from the northeastern areas, with the remaining high-risk areas observed in Tha Song Yang and Umphang Districts along the Thailand-Myanmar border. Significant malaria clusters were confirmed using hotspot analysis. Factors that had significant correlation with monthly risk of malaria include total rainfall (p-value=0.0136), average temperature at 1-month (p-value=0.0077) and 2-month lags (p-value=0.0010). Findings from this study aim to support the national malaria control programme in its vision of a malaria-free Thailand.

  1. WHO. World malaria report 2017. Geneva: World Health Organization; 2017.