Threats to malaria elimination in the Himalayas
Authors: Shiva Raj Mishra, Meghnath Dhimal, Renzo R Guinto, Bipin Adhikari, Cordia Chu
Journal: The Lancet Global Health (2016)

Kinley Wangdi and colleagues (May, 2016)1Wangdi K Banwell C Gatton ML Kelly GC Namgay R Clements AC Malaria burden and costs of intensified control in Bhutan, 2006–14: an observational study and situation analysis.Lancet Glob Health. 2016; 4: e336-e343Summary Full Text Full Text PDF Scopus (11) Google Scholar warn of the importation of malaria from other countries as one of the potential threats to ongoing elimination efforts in Bhutan. We identified two additional challenges to malaria elimination in Bhutan and other Himalayan countries that are worthy of consideration. First, temperature, precipitation, and vegetation phenology have changed rapidly in the Himalayas as part of global climate change. The average annual mean temperature in the region has increased by 1·5°C and precipitation by 163 mm in the past 25 years.2Shrestha UB Gautam S Bawa KS Widespread climate change in the Himalayas and associated changes in local ecosystems.PLoS One. 2012; 7: e36741Crossref Scopus (369) Google Scholar A surge in temperature can lead to vector species spreading into new breeding habitats in high elevations3Chen IC Hill JK Ohlemuller R Roy DB Thomas CD Rapid range shifts of species associated with high levels of climate warming.Science. 2011; 333: 1024-1026Crossref PubMed Scopus (3070) Google Scholar and extend the transmission season for the disease. One study has shown that an increase in average temperature of 1°C is associated with a 25% rise in malaria incidence in the region.4Dhimal M O'Hara RB Karki R Thakur GD Kuch U Ahrens B Spatio-temporal distribution of malaria and its association with climatic factors and vector-control interventions in two high-risk districts of Nepal.Malar J. 2014; 13: 457Crossref PubMed Scopus (46) Google Scholar In Bhutan, malaria has been reported in seven of 20 dzongkhags (districts) in the southern plains, which comprised roughly 42% of the country's population (753 947 people) in 2013. The remaining districts in the highlands also have an increased risk of transmission due to the changing climate.1Wangdi K Banwell C Gatton ML Kelly GC Namgay R Clements AC Malaria burden and costs of intensified control in Bhutan, 2006–14: an observational study and situation analysis.Lancet Glob Health. 2016; 4: e336-e343Summary Full Text Full Text PDF Scopus (11) Google Scholar Second, the growing population, which was traditionally dependent on millet, barley, and maize as staples in their diet, has developed an unsustainable appetite for rice, which puts pressure on rice production. As a result, growing numbers of dams are being constructed in rivers in the Himalayas to support irrigation and hydropower generation. In India's mountainous north, 100 new dams have already been constructed. Ten additional dams are being built in neighbouring Bhutan. Another 400 dams are proposed for construction in India, Nepal, Bhutan, and Pakistan in the next two decades.5Grumbine RE Pandit MK Ecology. Threats from India's Himalaya dams.Science. 2013; 339: 36-37Crossref Scopus (161) Google Scholar Ongoing construction of dams to support the ongoing dietary transition and rising energy demand is likely to increase the transmission of malaria, as seen in Africa.6Kibret S Lautze J McCartney M Wilson GG Nhamo L Malaria impact of large dams in sub-Saharan Africa: maps, estimates and predictions.Malar J. 2015; 14: 339Crossref Scopus (35) Google Scholar In view of these additional threats, not just in Bhutan, but in the Himalayas in general, malaria elimination activities should be streamlined with climate adaptation and mitigation efforts. Identification of potential hotspots and addressing the environmental drivers of malaria transmission is crucial. To accomplish these aims, closer collaboration between the health and environmental sectors is needed. A systematic approach that focuses not only on the pathogen or the vector, but also on the broader physical and social environments that affect health and disease is urgently needed. We declare no competing interests.