Limits...
Airborne Transmission of Melioidosis to Humans from Environmental Aerosols Contaminated with B. pseudomallei.

Chen PS, Chen YS, Lin HH, Liu PJ, Ni WF, Hsueh PT, Liang SH, Chen C, Chen YL - PLoS Negl Trop Dis (2015)

Bottom Line: Aerosols that contained B. pseudomallei-specific TTSS (type III secretion system) ORF2 DNA were well distributed in the endemic area but were rare in the surrounding areas during the rainy season.Moreover, the isolation rate in the superficial layers of the contaminated cropped field in the northwest was correlated with PCR positivity for aerosols collected from the southeast over a 2-year period.According to pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) analyses, PFGE Type Ia (ST58) was the predominant pattern linking the molecular association among soil, aerosol and human isolates.

View Article: PubMed Central - PubMed

Affiliation: Department of Public Health, Kaohsiung Medical University, Kaohsiung, Taiwan.

ABSTRACT
Melioidosis results from an infection with the soil-borne pathogen Burkholderia pseudomallei, and cases of melioidosis usually cluster after rains or a typhoon. In an endemic area of Taiwan, B. pseudomallei is primarily geographically distributed in cropped fields in the northwest of this area, whereas melioidosis cases are distributed in a densely populated district in the southeast. We hypothesized that contaminated cropped fields generated aerosols contaminated with B. pseudomallei, which were carried by a northwesterly wind to the densely populated southeastern district. We collected soil and aerosol samples from a 72 km2 area of land, including the melioidosis-clustered area and its surroundings. Aerosols that contained B. pseudomallei-specific TTSS (type III secretion system) ORF2 DNA were well distributed in the endemic area but were rare in the surrounding areas during the rainy season. The concentration of this specific DNA in aerosols was positively correlated with the incidence of melioidosis and the appearance of a northwesterly wind. Moreover, the isolation rate in the superficial layers of the contaminated cropped field in the northwest was correlated with PCR positivity for aerosols collected from the southeast over a 2-year period. According to pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) analyses, PFGE Type Ia (ST58) was the predominant pattern linking the molecular association among soil, aerosol and human isolates. Thus, the airborne transmission of melioidosis moves from the contaminated soil to aerosols and/or to humans in this endemic area.

No MeSH data available.


Related in: MedlinePlus

The distribution of melioidosis cases and sampling sites.Using a random sampling strategy, the locations of sampling sites of the cropped field, wetted but non-cropped field, urban ground or urban green area are shown (legends on left of the figure). The positive isolation sites of the sampling sites are labeled with hollow or solid red stars. The solid red star indicates a site that was sampled using the fixed-interval strategy. The melioidosis locations are indicated by different symbols representing the number of melioidosis cases (see left on the figure). The circle on the map indicates the endemic areas of melioidosis (n = 75, defined in a previous study [21]). An ellipse on the map indicates the core region of melioidosis cases (n = 68, defined by this study). The hypothesis is that aerosols contaminated with B. pseudomallei are carried by wind (wind direction indicated by dotted lined with a directional arrow) from the northwestern contaminated cropped field (red star) and envelop the endemic area, particularly the core region, during the rainy (typhoon) season.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4462588&req=5

pntd.0003834.g001: The distribution of melioidosis cases and sampling sites.Using a random sampling strategy, the locations of sampling sites of the cropped field, wetted but non-cropped field, urban ground or urban green area are shown (legends on left of the figure). The positive isolation sites of the sampling sites are labeled with hollow or solid red stars. The solid red star indicates a site that was sampled using the fixed-interval strategy. The melioidosis locations are indicated by different symbols representing the number of melioidosis cases (see left on the figure). The circle on the map indicates the endemic areas of melioidosis (n = 75, defined in a previous study [21]). An ellipse on the map indicates the core region of melioidosis cases (n = 68, defined by this study). The hypothesis is that aerosols contaminated with B. pseudomallei are carried by wind (wind direction indicated by dotted lined with a directional arrow) from the northwestern contaminated cropped field (red star) and envelop the endemic area, particularly the core region, during the rainy (typhoon) season.

Mentions: The study areas were approximately 72 km2, including an endemic area and its surroundings (Fig 1). Using a Moran I analysis, which consisted of a spatial autocorrelation measurement, we previously observed that the melioidosis incidence was higher in the endemic area than in the neighboring areas [21]. As shown in Fig 1, the topographies of rivers, lakes and hills were mapped (MapInfo, v. 7.0) using GPS coordinates from Google Earth. The land north of the Dian-Bao River is utilized to grow rice, pineapple, sugarcane and vegetables, while a densely populated district is located south of the river. The neighborhood-level locations of the melioidosis cases from 2008–2013 were retrieved from the melioidosis databases at the Centers for Disease Control (CDC) in Taiwan. This database only showed weekly incidences after 2011. The Central Weather Bureau (Taiwan) collected the rainfall (mm), wind speed (m/sec) and wind direction (60° interval) per hour data at a recording station in the endemic area. According to the monthly data, which indicated that rainfall (>200 mm) first appeared in the month of the last typhoon alarm, the rainy season was defined as July to September of 2012 and July to October of 2013 (S1 Fig).


Airborne Transmission of Melioidosis to Humans from Environmental Aerosols Contaminated with B. pseudomallei.

Chen PS, Chen YS, Lin HH, Liu PJ, Ni WF, Hsueh PT, Liang SH, Chen C, Chen YL - PLoS Negl Trop Dis (2015)

The distribution of melioidosis cases and sampling sites.Using a random sampling strategy, the locations of sampling sites of the cropped field, wetted but non-cropped field, urban ground or urban green area are shown (legends on left of the figure). The positive isolation sites of the sampling sites are labeled with hollow or solid red stars. The solid red star indicates a site that was sampled using the fixed-interval strategy. The melioidosis locations are indicated by different symbols representing the number of melioidosis cases (see left on the figure). The circle on the map indicates the endemic areas of melioidosis (n = 75, defined in a previous study [21]). An ellipse on the map indicates the core region of melioidosis cases (n = 68, defined by this study). The hypothesis is that aerosols contaminated with B. pseudomallei are carried by wind (wind direction indicated by dotted lined with a directional arrow) from the northwestern contaminated cropped field (red star) and envelop the endemic area, particularly the core region, during the rainy (typhoon) season.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4462588&req=5

pntd.0003834.g001: The distribution of melioidosis cases and sampling sites.Using a random sampling strategy, the locations of sampling sites of the cropped field, wetted but non-cropped field, urban ground or urban green area are shown (legends on left of the figure). The positive isolation sites of the sampling sites are labeled with hollow or solid red stars. The solid red star indicates a site that was sampled using the fixed-interval strategy. The melioidosis locations are indicated by different symbols representing the number of melioidosis cases (see left on the figure). The circle on the map indicates the endemic areas of melioidosis (n = 75, defined in a previous study [21]). An ellipse on the map indicates the core region of melioidosis cases (n = 68, defined by this study). The hypothesis is that aerosols contaminated with B. pseudomallei are carried by wind (wind direction indicated by dotted lined with a directional arrow) from the northwestern contaminated cropped field (red star) and envelop the endemic area, particularly the core region, during the rainy (typhoon) season.
Mentions: The study areas were approximately 72 km2, including an endemic area and its surroundings (Fig 1). Using a Moran I analysis, which consisted of a spatial autocorrelation measurement, we previously observed that the melioidosis incidence was higher in the endemic area than in the neighboring areas [21]. As shown in Fig 1, the topographies of rivers, lakes and hills were mapped (MapInfo, v. 7.0) using GPS coordinates from Google Earth. The land north of the Dian-Bao River is utilized to grow rice, pineapple, sugarcane and vegetables, while a densely populated district is located south of the river. The neighborhood-level locations of the melioidosis cases from 2008–2013 were retrieved from the melioidosis databases at the Centers for Disease Control (CDC) in Taiwan. This database only showed weekly incidences after 2011. The Central Weather Bureau (Taiwan) collected the rainfall (mm), wind speed (m/sec) and wind direction (60° interval) per hour data at a recording station in the endemic area. According to the monthly data, which indicated that rainfall (>200 mm) first appeared in the month of the last typhoon alarm, the rainy season was defined as July to September of 2012 and July to October of 2013 (S1 Fig).

Bottom Line: Aerosols that contained B. pseudomallei-specific TTSS (type III secretion system) ORF2 DNA were well distributed in the endemic area but were rare in the surrounding areas during the rainy season.Moreover, the isolation rate in the superficial layers of the contaminated cropped field in the northwest was correlated with PCR positivity for aerosols collected from the southeast over a 2-year period.According to pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) analyses, PFGE Type Ia (ST58) was the predominant pattern linking the molecular association among soil, aerosol and human isolates.

View Article: PubMed Central - PubMed

Affiliation: Department of Public Health, Kaohsiung Medical University, Kaohsiung, Taiwan.

ABSTRACT
Melioidosis results from an infection with the soil-borne pathogen Burkholderia pseudomallei, and cases of melioidosis usually cluster after rains or a typhoon. In an endemic area of Taiwan, B. pseudomallei is primarily geographically distributed in cropped fields in the northwest of this area, whereas melioidosis cases are distributed in a densely populated district in the southeast. We hypothesized that contaminated cropped fields generated aerosols contaminated with B. pseudomallei, which were carried by a northwesterly wind to the densely populated southeastern district. We collected soil and aerosol samples from a 72 km2 area of land, including the melioidosis-clustered area and its surroundings. Aerosols that contained B. pseudomallei-specific TTSS (type III secretion system) ORF2 DNA were well distributed in the endemic area but were rare in the surrounding areas during the rainy season. The concentration of this specific DNA in aerosols was positively correlated with the incidence of melioidosis and the appearance of a northwesterly wind. Moreover, the isolation rate in the superficial layers of the contaminated cropped field in the northwest was correlated with PCR positivity for aerosols collected from the southeast over a 2-year period. According to pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) analyses, PFGE Type Ia (ST58) was the predominant pattern linking the molecular association among soil, aerosol and human isolates. Thus, the airborne transmission of melioidosis moves from the contaminated soil to aerosols and/or to humans in this endemic area.

No MeSH data available.


Related in: MedlinePlus