Earth, wind, rain, and melioidosis
Authors: Louis Yi Ann Chai, Dale Fisher
Journal: The Lancet Planetary Health (2018)

The earliest report of melioidosis is accredited to Whitmore and Krishnaswami1Whitmore A Krishnaswami CS A hitherto undescribed infective disease in Rangoon.Ind Med Gaz. 1912; 47: 262-267PubMed Google Scholar in Myanmar in 1912, in which they described a series of 38 patients presenting with a variant glanders-like disease. Autopsy showed "peculiar cheesy consolidation" of the lungs, subcutaneous or splenic abscesses with "non-Gram-staining-[Burkholderia mallei]-like bacilli". The infection, identified later in the Federated Malay States, was coined melioidosis in 1921. Indeed, naming the condition has been somewhat whimsical through the 20th century, with names given by those working with the organism to describe its key features, such as the clinical presentation (pseudoglanders), its latency (Vietnamese time bomb), or those at risk (morphia injector's septicaemia, Nightcliff gardener's disease and paddy-field disease). Mass underdiagnosis of melioidosis is evident across the tropics, and this is probably due in part to the lack of specific identifying features. The varied and quirky nicknames highlight that there is no simple way to describe this condition in lay terms. Melioidosis can incubate for 1 day or for decades, and it can be an acute fulminant condition or very slow mild disease (indeed, it can be asymptomatic). Although inoculation is typically cutaneous or inhalational, several other routes of transmission have been described, such as ingestion2Currie BJ Melioidosis: evolving concepts in epidemiology, pathogenesis, and treatment.Semin Respir Crit Care Med. 2015; 36: 111-125Crossref PubMed Scopus (170) Google Scholar and even sexual and mother-to-child transmission.3McCormick JB Sexton DJ McMurray JG Carey E Hayes P Feldman RA Human-to-human transmission of Pseudomonas pseudomallei.Ann Intern Med. 1975; 83: 512-513Crossref PubMed Scopus (75) Google Scholar A state of altered immunity influences the presentation and outcomes, but deaths of healthy military servicemen in Singapore have been described.4Lim MK Tan EH Soh CS Chang TL Burkholderia pseudomallei infection in the Singapore Armed Forces from 1987 to 1994—an epidemiological review.Ann Acad Med Singapore. 1997; 26: 13-17PubMed Google Scholar Melioidosis is relatively unknown to the public and is unidentified by health workers in most countries where it is endemic, except for perhaps Australia, Singapore, and Brunei.5Limmathurotsakul D Golding N Dance DA et al.Predicted global distribution of Burkholderia pseudomallei and burden of melioidosis.Nat Microbiol. 2016; 1: 15008Crossref Scopus (426) Google Scholar Stories of melioidosis feature routinely in the Australian Northern Territory's lay press.6NT NewsDarwin melioidosis warning following monsoonal rains.https://www.ntnews.com.au/news/darwin-melioidosis-warning-following-monsoonal-rains/news-story/c0ed87f63607314f4ea4f55a0b5faf9fDate: Jan 30, 2018Date accessed: July 11, 2018Google Scholar By contrast, in Thailand there is little public knowledge.7Chansrichavala P Wongsuwan N Suddee S et al.Public awareness of melioidosis in Thailand and potential use of video clips as educational tools.PloS One. 2015; 10: e0121311Crossref PubMed Scopus (13) Google Scholar Why is melioidosis so underdiagnosed? Being a disease of the tropics, it is endemic in many countries with less sophisticated health systems. Melioidosis requires a laboratory diagnosis because the clinical features and presentations are so variable and non-specific. Laboratory systems are even less accessible in rural areas, where most cases present. In this issue of The Lancet Planetary Health, Philip Bulterys and colleagues8Bulterys PL Bulterys MA Phommasone K et al.Climatic drivers of melioidosis in Laos and Cambodia: a 16-year case series analysis.Lancet Planet Health. 2018; 2: e334-e343Summary Full Text Full Text PDF PubMed Scopus (11) Google Scholar report findings from their study of melioidosis in Laos and Cambodia, where the incidence of the disease has not been previously well described. The authors identified humidity, visibility, rainfall, and wind speed as independent predictors of melioidosis, thus adding to the pool of data from Thailand, Singapore, and northern Australia that links weather with the incidence of disease.9Liu X Pang L Sim SH et al.Association of melioidosis incidence with rainfall and humidity, Singapore, 2003–2012.Emerg Infect Dis. 2015; 21: 159-162Crossref PubMed Scopus (35) Google Scholar There is a clear seasonal pattern of increased melioidosis incidence during the monsoon season, which sweeps through Asia bringing heavy rainfall.9Liu X Pang L Sim SH et al.Association of melioidosis incidence with rainfall and humidity, Singapore, 2003–2012.Emerg Infect Dis. 2015; 21: 159-162Crossref PubMed Scopus (35) Google Scholar Additionally, extreme weather events can precede melioidosis clusters. Tropical, unpredictable wet weather, especially with occurrence of the La Niña phenomenon, can create flooding in rural and highly urbanised areas alike. Precipitation and humidity optimise conditions for Burkholderia pseudomallei. Bulterys and colleagues, and others,10Limmathurotsakul D Kanoksil M Wuthiekanun V et al.Activities of daily living associated with acquisition of melioidosis in northeast Thailand: a matched case-control study.PLoS Negl Trop Dis. 2013; 7: e2072Crossref PubMed Scopus (92) Google Scholar have made a strong case for water exposure being central to transmission of disease. This theory, together with the significant invocation of wind speed, substantiates the current perception that inhalation of aerosolised B pseudomallei is a major method of acquisition and, in particular, predisposing people to fulminant pneumonia. The pathogen is small and devoid of advanced homoeostatic or thermostatic mechanisms. As such, humidity and temperature changes have a bearing on B pseudomallei growth characteristics, including survival and incubation times. Indeed, B pseudomallei exhibits enhanced growth, motility, and tolerance to environmental stress at hotter, tropical temperatures.11Paksanont S Sintiprungrat K Yimthin T Pumirat P Peacock SJ Chantratita N Effect of temperature on Burkholderia pseudomallei growth, proteomic changes, motility and resistance to stress environments.Sci Rep. 2018; 8: 9167Crossref PubMed Scopus (9) Google Scholar Unique geographical or local characteristics also facilitate prevalence of the disease. Melioidosis is common in the Asia-Pacific region, where agriculture and farming are prominent. Anthrosol and acrisol soil, encountered in irrigated agriculture in this geographical region, favour B pseudomallei.10Limmathurotsakul D Kanoksil M Wuthiekanun V et al.Activities of daily living associated with acquisition of melioidosis in northeast Thailand: a matched case-control study.PLoS Negl Trop Dis. 2013; 7: e2072Crossref PubMed Scopus (92) Google Scholar Agricultural practices, including residual crop burning that results in depletion of soil nutrients, further support B pseudomallei. Rice-field workers and others exposed to soil or the ingestion of contaminated water have high risks of melioidosis.2Currie BJ Melioidosis: evolving concepts in epidemiology, pathogenesis, and treatment.Semin Respir Crit Care Med. 2015; 36: 111-125Crossref PubMed Scopus (170) Google Scholar, 10Limmathurotsakul D Kanoksil M Wuthiekanun V et al.Activities of daily living associated with acquisition of melioidosis in northeast Thailand: a matched case-control study.PLoS Negl Trop Dis. 2013; 7: e2072Crossref PubMed Scopus (92) Google Scholar Concerns about the effect of climate change on infectious diseases are understated. Global warming and extreme weather, together with soil changes and unplanned urbanisation, may cause an increase in the incidence and the geographical spread of melioidosis. Improved understanding of climatic factors that facilitate transmission could allow for improved awareness by the public and health workers. However, this understanding needs to translate to improved surveillance, diagnostics, and interventions for prevention and case management. Linking these efforts to weather conditions could provide the best value for countries with many competing health priorities. This online publication has been corrected. The corrected version first appeared at thelancet.com/planetaryhealth on February 20, 2019 This online publication has been corrected. The corrected version first appeared at thelancet.com/planetaryhealth on February 20, 2019 LYAC is supported by the Clinician Scientist Award, Individual Research Grant, Bedside & Bench Grants, Centre Grant, and the Training Fellowship Award from the National Medical Research Council, Singapore. LYAC. also acknowledges the Aspiration Grant & Summit Research Program and Bench to Bedside Grant from the National University Health System, as well as the Synthetic Biology Research & Development Program of the National Research Foundation, Singapore. DF declares no competing interests. Climatic drivers of melioidosis in Laos and Cambodia: a 16-year case series analysisThe results of this study demonstrate a significant seasonal burden of melioidosis among adults and children in Laos and Cambodia. Our findings highlight the risks of infection during highly humid and windy conditions, and suggest a need for increased awareness among at-risk individuals, such as children. Full-Text PDF Open AccessCorrection to Lancet Planet Health 2018; 2: e329–30Chai LYA, Fisher D. Earth, wind, rain, and melioidosis. Lancet Planet Health 2018; 2: e329–30—The reference to the linked Article by Philip Bulterys and colleagues has been corrected. This correction has been made to the online version as of Feb 20, 2010, and the printed version is correct. Full-Text PDF Open Access