Climatic drivers of melioidosis in Laos and Cambodia: a 16-year case series analysis

Philip L Bulterys; Michelle A Bulterys; Koukeo Phommasone; Manophab Luangraj; Mayfong Mayxay; Sabine Kloprogge; Thyl Miliya; Manivanh Vongsouvath; Paul N Newton; Rattanaphone Phetsouvanh; Christopher T French; Jeff F Miller; Paul Turner; David A B Dance

doi:10.1016/S2542-5196(18)30172-4

Climatic drivers of melioidosis in Laos and Cambodia: a 16-year case series analysis

Lancet Planet Health. 2018 Aug;2(8):e334-e343. doi: 10.1016/S2542-5196(18)30172-4.

Affiliations

¹ UCLA-Caltech Medical Scientist Training Program, David Geffen School of Medicine, Los Angeles, CA, USA; Molecular Biology Institute, Los Angeles, CA, USA; Department of Microbiology, Immunology, and Molecular Genetics, Los Angeles, CA, USA. Electronic address: pbulterys@mednet.ucla.edu.
² School of Public Health, University of Washington, Seattle, WA, USA.
³ Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos.
⁴ Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Faculty of Postgraduate Studies, University of Health Sciences, Ministry of Health, Vientiane, Laos.
⁵ Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia.
⁶ Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
⁷ Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
⁸ Department of Microbiology, Immunology, and Molecular Genetics, Los Angeles, CA, USA; California NanoSystems Institute UCLA, Los Angeles, CA, USA.
⁹ Molecular Biology Institute, Los Angeles, CA, USA; Department of Microbiology, Immunology, and Molecular Genetics, Los Angeles, CA, USA; California NanoSystems Institute UCLA, Los Angeles, CA, USA.
¹⁰ Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia.

Abstract

Background: Burkholderia pseudomallei is the cause of melioidosis, a serious and difficult to treat infection that is endemic throughout the tropics. Melioidosis incidence is highly seasonal. We aimed to identify the climatic drivers of infection and to shed light on modes of transmission and potential preventive strategies.

Methods: We examined the records of patients diagnosed with melioidosis at the Microbiology Laboratory of Mahosot Hospital in Vientiane, Laos, between October, 1999, and August, 2015, and all patients with culture-confirmed melioidosis presenting to the Angkor Hospital for Children in Siem Reap, Cambodia, between February, 2009, and December, 2013. We also examined local temperature, humidity, precipitation, visibility, and wind data for the corresponding time periods. We estimated the B pseudomallei incubation period by examining profile likelihoods for hypothetical exposure-to-presentation delays.

Findings: 870 patients were diagnosed with melioidosis in Laos and 173 patients were diagnosed with melioidosis in Cambodia during the study periods. Melioidosis cases were significantly associated with humidity (p<0·0001), low visibility (p<0·0001), and maximum wind speeds (p<0·0001) in Laos, and humidity (p=0·010), rainy days (p=0·015), and maximum wind speed (p=0·0070) in Cambodia. Compared with adults, children were at significantly higher odds of infection during highly humid months (odds ratio 2·79, 95% CI 1·83-4·26). Lung and disseminated infections were more common during windy months. The maximum likelihood estimate of the incubation period was 1 week (95% CI 0-2).

Interpretation: The 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.

Funding: Wellcome Trust.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Adult
Aged
Aged, 80 and over
Burkholderia pseudomallei / physiology*
Cambodia / epidemiology
Child
Child, Preschool
Climate*
Cohort Studies
Female
Humans
Incidence
Laos / epidemiology
Likelihood Functions
Male
Melioidosis / epidemiology*
Melioidosis / microbiology
Middle Aged
Weather*
Young Adult

Climatic drivers of melioidosis in Laos and Cambodia: a 16-year case series analysis

Authors

Affiliations

Abstract

Publication types

MeSH terms

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