Exploring the Relationship between Melioidosis Morbidity Rate and Local Environmental Indicators Using Remotely Sensed Data (original) (raw)
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Geospatial Health
Melioidosis, a bacterial, infectious disease contracted from contaminated soil or water, is a public health problem identified in tropical regions and endemic several regions of Thailand. Surveillance and prevention are important for determining its distribution patterns and mapping its risk, which have been analysed in the present study. Case reports in Thailand were collected from 1 January 2016 to 31 December 2020. Spatial autocorrelation was analyzed using Moran’s I and univariate local Moran’s I. Spatial point data of melioidosis incidence were calculated, with riskmapping interpolation performed by Kriging. It was highest in 2016, at 32.37 cases per 100,000 people, and lowest in 2020, at 10.83 cases per 100,000 people. General observations revealed that its incidence decreased slightly from 2016 to 2018 and drastically in 2019 and 2020. The Moran’s I values for melioidosis incidence exhibited a random spatial pattern in 2016 and clustered distribution from 2017 to 2020. The ri...
Chiang Mai University Journal of Natural Sciences, 2021
Melioidosis is a public health problem in the tropical regions, occurring to meteorological variability. For 10 years of melioidosis outbreaks, we create probability maps of melioidosis distribution during 2009–2018 and determine the association with meteorological factors. The monthly average rainfall and incidence of melioidosis were high from July to September but they not significantly associated (P = 0.576). However, the monthly maximum and minimum temperature were significantly associated with melioidosis incidence (P = 0.002 and P = 0.029, respectively). We estimated the spatial distribution of rainfall and maximum and minimum temperature using the Co-Kriging interpolation method which found that the spatial distribution of the melioidosis incidence was significantly associated with rainfall in 2009, 2010, and 2015; with the maximum temperature in 2009, 2010, 2011, 2013, and 2015; and with the minimum temperature in 2010, 2011, and 2015. Our finding approach may support infor...
Socio-epidemiological and land cover risk factors for melioidosis in Kedah, Northern Malaysia
PLOS Neglected Tropical Diseases, 2019
Background Melioidosis, a fatal infectious disease caused by Burkholderia pseudomallei, is increasingly diagnosed in tropical regions. However, data on risk factors and the geographic epidemiology of the disease are still limited. Previous studies have also largely been based on the analysis of case series data. Here, we undertook a more definitive hospital-based matched case-control study coupled with spatial analysis to identify demographic, socioeconomic and landscape risk factors for bacteremic melioidosis in the Kedah region of northern Malaysia.
Climatic drivers of melioidosis in Laos and Cambodia: a 16-year case series analysis
The Lancet. Planetary health, 2018
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. 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. 870 patients were diagnosed with melioidosis in Laos and 173 patients were diagnosed...
Environmental Monitoring and Assessment, 2017
In our analysis of 136 water samples from wetland environments (rice paddies, natural wetland sites, man-made water bodies) in rural areas of NorthEast Thailand, Burkholderia pseudomallei was most prevalent in rice paddies (15 of the 30 positive sites). The high prevalence in the water of rice fields is indicative of the inherent vulnerability of farmers in rural agricultural areas in this area of Thailand and likely other locations in the tropics. Nearly all B. pseudomallei-positive sites were found within the vicinity of a large wetland associated with the Chi River, in the month of July 2014. Positive samples were found in water ranging in pH from 5.9 to 8.7, salinity ranging from 0.04 to 1.58 ppt, nitrate ranging from 0 to 10.8 ppm, and iron ranging from 0.003 to 1.519 ppm. Of these variables, only iron content was statistically higher in B. pseudomallei-positive versus B. pseudomallei-negative sites, suggesting that increasing concentrations of iron may encourage the growth of this bacterium, which is responsible for melioidosis. Our results, when combined with data from other published studies, support the notion that B. pseudomallei can exist in a wide range of environmental conditions. Thus, we argue that health safety education is a more appropriate means of addressing farmer vulnerability than chemical or physical alterations to fields at large scales. Further, it may be important to investigate melioidosis through transdisciplinary approaches that consider the complex social and ecological contexts in which the disease occurs.
Geospatial Health
This study statistically identified the association of remotely sensed environmental factors, such as Land Surface Temperature (LST), Night Time Light (NTL), rainfall, the Normalised Difference Vegetation Index (NDVI) and elevation with the incidence of leptospirosis in Thailand based on the nationwide 7,495 confirmed cases reported during 2013–2015. This work also established prediction models based on empirical findings. Panel regression models with random-effect and fixed-effect specifications were used to investigate the association between the remotely sensed environmental factors and the leptospirosis incidence. The Local Indicators of Spatial Association (LISA) statistics were also applied to detect the spatial patterns of leptospirosis and similar results were found (the R2 values of the random-effect and fixed-effect models were 0.3686 and 0.3684, respectively). The outcome thus indicates that remotely sensed environmental factors possess statistically significant contribut...
The Journal of infection, 2016
Melioidosis is an often fatal disease in humans and animals and endemic in Southeast Asia and northern Australia. It is caused by the environmental bacterium Burkholderia pseudomallei. We analysed weather and climate factors preceding new melioidosis cases in Darwin and compared the time between weather event and admission to hospital for severe and average wet season rainfall. In a time-series analysis from 1990 to 2013 we applied a boosted regression tree and a negative binomial model to investigate the association between melioidosis cases and weather events. Fitted Fourier terms controlled for long-term seasonal trends. We found a rise in the dew point, cloud cover, rainfall, maximum temperature and groundwater to be associated with an increased risk to acquire melioidosis. A shorter 'putative' incubation period was evident after severe rainfall events. Rainfall occurring early in the wet season was linked to more cases as was an increase in the local sea surface tempera...
International Journal of Environmental Research and Public Health, 2013
Hand, Foot and Mouth Disease (HFMD) is an emerging viral disease, and at present, there are no antiviral drugs or vaccines available to control it. Outbreaks have persisted for the past 10 years, particularly in northern Thailand. This study aimed to elucidate the phenomenon of HFMD outbreaks from 2003 to 2012 using general statistics and spatial-temporal analysis employing a GIS-based method. The spatial analysis examined data at the village level to create a map representing the distribution pattern, mean center, standard deviation ellipse and hotspots for each outbreak. A temporal analysis was used to analyze the correlation between monthly case data and meteorological factors. The results indicate that the disease can occur at any time of the year, but appears to peak in the rainy and cold seasons. The distribution of outbreaks exhibited a clustered pattern. Most mean centers and standard deviation ellipses occurred in similar areas. The linear directional mean values of the outbreaks were oriented toward the south. When separated by season, it was found that there was a significant correlation with the direction of the southwest monsoon at the same time. An autocorrelation analysis revealed that hotspots tended to increase even when patient cases subsided. In particular, a new hotspot was found in the recent year in Mae Hong Son province.
Spatial analysis of melioidosis distribution in a suburban area
Epidemiology and Infection, 2010
SUMMARYBurkholderia pseudomallei, the causative agent of melioidosis is associated with soil. This study used a geographic information system (GIS) to determine the spatial distribution of clinical cases of melioidosis in the endemic suburban region of Townsville in Australia. A total of 65 cases over the period 1996–2008 were plotted using residential address. Two distinct groupings were found. One was around the base of a hill in the city centre and the other followed the old course of a major waterway in the region. Both groups (accounting for 43 of the 65 cases examined) are in areas expected to have particularly wet topsoils following intense rainfall, due to soil type or landscape position.
Background Leptospirosis is a zoonotic disease caused by spirochete bacteria in the genus Leptospira, and it has become a significant public health challenge in Malaysia. Environmental survival and persistence of this pathogen are highly dependent on environmental conditions such as moisture content, pH and temperature. These conditions are further adapted by the natural climate system including precipitation and humidity which is highly heterogeneous at a geographical scale. This paper described the spatial and temporal distribution of leptospirosis incidence with climate factors using Geographical Information System and stratified the climate factors based on their association with the disease incidence rate. Methods Leptospirosis surveillance data from 2012-2016 were integrated into this study along with seven geo-spatial climate variables for the state of Sarawak, Malaysia. High and low clustering of incidence rate was explored by Getis Ord Gi* statistics. Geographical Weighted ...