A peer-reviewed open access journal published by the National Institute of Environmental Health Sciences

The consumption of alcohol, tobacco and betel quid has been found to be an important contributor to esophageal squamous cell carcinoma (ESCC) in Taiwan. The genotoxic effect of the ADH1B and ALDH2 genes modulating an individual's alcohol‐metabolizing capacity on ESCC may be linked to drinking behavior, intake pattern and other exogenous factors. To investigate the interplay of these genetic and environmental factors in determining the risk of ESCC, a multicenter case‐control study was conducted. Here, 406 patients with pathology‐proven ESCC, as well as 656 gender, age and study hospital matched controls were recruited. Genetic polymorphisms of ADH1B and ALDH2 appeared to correlate with the abstinence of alcohol, though not with tobacco and betel quid. Within the same levels of alcohol consumption, carcinoma risks increased along with an increase in the numbers of ADH1B*1 and ALDH2*2 alleles. The inactive ALDH2*1/*2 genotype was found to multiplicatively interact with a low‐to‐moderate (0.1–30 g/day) and a heavy (>30 g/day) ethanol intake to increase the ESCC risk (the joint aOR = 14.5 and 102.6, respectively). Among low‐to‐moderate drinkers, a smoking‐dependent carcinogenetic effect for the ADH1B*1/*1 and ALDH2*1/*2+*2/*2 genotypes was recognized, with significant risks found in smokers, but not in nonsmokers. Further, a supra‐multiplicative combined risk of ESCC for alcohol and tobacco use was identified among carriers of the ADH1B*1/*1 genotype (p for interaction = 0.042). In conclusion, the interplay of the ADH1B and ALDH2 genotypes, in conjunction with a behaved drinking habit and a practiced drinking pattern, along with continued tobacco consumption, plays an important pathogenic role in modulating ESCC risk.

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. Cases of melioidosis, an emerging disease, are usually clustered after rains or typhoons. In Taiwan, the endemic area includes rural cropped fields contaminated with B. pseudomallei in the northwest and a densely populated district in the southeast, where melioidosis-cluster is distributed. We hypothesized that contaminated cropped fields generated aerosols contaminated with B. pseudomallei, which were carried by a northwesterly wind and enveloped the southeastern densely populated district. In a prospective study, aerosols that contained B. pseudomallei-specific DNA were well distributed in the densely populated districts but were rarely found in their surrounding areas. The concentration of specific DNA in aerosols correlated with the melioidosis incidence and the northwesterly wind in this endemic area. The isolation rate in the superficial layers of the contaminated cropped field in the northwest correlated with the PCR positivity of aerosols collected from the southeastern district over a 2-year period. We used genetic typing to identify a molecular association among the soil, aerosols and human isolates. We suggest that melioidosis is airborne and is transmitted from the contaminated soils to aerosols and/or to humans in this area.

In spring, windblown dust storms originating in the deserts of Mongolia and China travel to Taipei city. These occurrences are known as Asian dust storm (ADS) events. The objective of this study was to assess the possible associations of constituents of ADS with hospital pneumonia admissions of residents in Taipei, Taiwan, during the period 1996–2001. Fifty-four dust storm episodes were identified and were classified as index days. Daily pneumonia admissions on the index days were compared with admissions on comparison days. Two comparison days for each index day, 7 d before the index days and 7 d after the index days, were selected. The study results indicated a statistically significant association between ADS events and daily pneumonia admissions 1 d after the event. It is worthwhile to pay more attention to ADS events and health in the future based on the findings in this investigation.