Tianjin In Water Main Pathogens Distribution Law

Legionella is one of Gram-negative bacilli that distribute widely in the water and soil of natural and artificial environment. They can be inhaled by means of aerosol contaminated with the bacilli, resulting in infection and Legionnaire's disease in humans. There are 42 species and 64 serum-type of legionella. Nineteen of them are related to human disease. Legionella pneumophila, the major pathogen of Legionnaire's disease has 15 serum-type. It is the second important pathogen of serious social acquired pneumonia. Statistic data indicated that more than 80% Legionnaire's disease cases were caused by Legionella pneumophila. Legionella pneumophila could pollute the water in community, such as tap water, cooling-tower water, well water, bathe water. There are no reports about the distribution of legionella in water mass of nature and live environment.With develop of economy and standard of living, more and more centre air-conditioner systems were installed in tall buildings. Center air-conditioner and close environment in tall buildings could lead to the breakout of Legionnaire's disease and do harm to the health of people who live in tall building. Otherwise, legionella in environment probably pollute fountain and condensed water in fission air-conditioner. Therefore, it's very imperative to develop a rapid, accurate, simple method to detect legionella in water bodies so that we could investigate the time and space distribution of legionella.Several molecular marker techniques were applied in identification of legionella, such as optimization of general bacteria incubation, optimization of general PCR, D-RAPD, AFLP, and MPD. The advantages and disadvantages of above methods were compared and analyzed. The large scale investigation of legionella in environment requires the detection method with the characteristic of handy, low-expense, high sensitivity and high specificity. Therefore, the selected procedure for detection and identification of legionella were described as following: the water samples were incubated with GVP culture medium at first. If the positive legionella clones were found, the second incubation was done with BYCE culture medium. If the candidate clones still grow after second incubation, PCR and serologic test were applied to identify legionella. This series of tests could avoid cross contamination and false positive farthest.We collected every kind of water samples in Tianjin to determine the distribution of Legionella pneumophila in all kinds of water sources and provide scientific evidence for preventing and controlling water-borne transmission of legionella.Twenty-eight representative water samples from the 126 sampling sites were tested positive for Legionella. In the yearly surveillance, 36 samples of the 430 samples collected over a year were positive for legionella, of which 23 samples were Lp positive. Therefore, the legionella positive rates for the ambient and recreational water bodies were 32.1% and 22.2%, respectively, and Lp positive rates were 21.4% and 16.7%, respectively. Overall, the positive rates were higher in the summer and autumn seasons as well as in air-conditioner cooling tower water, shower water, and lake water in public parks.Lps are widely distributed in all kinds of ambient and recreational water sources. The ambient temperature appeared to be an important factor for Lp's contamination, because the summer and autumn are the seasons with high detectable rates of Legionella contamination and Legionellosis spread. However, Lps could also be found in the spring and winter seasons. People who have a close contact with the contaminated water, such as park water, air-conditioner cooling tower water, shower water etc., are at high risks of legionella and legionellosis infection and transmission. Necessary measures should be taken promptly to protect the public from health hazard of Lps in water supplies. Luan River-diverted channel became the drinking water source of Tianjin City in 1983. This project changed the quality of drinking water in Tianjin completely. With the development of industry and agriculture and the improvement of people life, living sewage and industry waste water were poured into Luan River-diverted channel through leakage and sluice by enterprise that located along Luan River-diverted waterway. The water quality of Luan River-diverted got worse and worse. For example, waste water was discharged into uncovered ditch because of the damage of floodpipe at Woutou River in Baodi County since Dec. 1995 to Jan. 1996. The leakage incident occurred at Qinzhuangzi pump station since Dec. 1998 to Jan. 1999.The results of routine water quality monitor indicated that the biological pollution status was very serious at the 26 km-longth Luan River-diverted waterway from Erwangzhuang reservoir to Yixingfu pump station in the recent 20 years. Total coliform is over 238000 cfu/L that exceed the first grade standard depend on "Life drinking water source standard" (CJ3020-93). In this study the sample dots were selected according to pollution status, crossing of waterway and distribution of floodgates. Pathogenys in water sample were detected (including Total bacteria count, total coliform, fecal coliform, pathogenic bacteria, f₂ phage, cryptosporidium). The distribution and wave law were studies either. The safeguards were determined according to the above data. The results as following:Major pollution source for the waterway for Yuqiao reservoir to Erwangzhuang reservoir (uncovered ditchs) were industrial waste water, sewage and leakage of floodgate.Total bacteria count, total coliform, fecal coliform and f₂ phage were detected frequently in summer and autumn. Cryptosporidium oocysts were detected from April to December.Biological contamination was detected from Yuqiao reservoir to Erwangzhuang reservoir. The contamination status was rather serious at Yinliu Bridge and Jiuwangzhuang Gate and rather slight at Erwangzhuang reservoir and Yixingfu Pumping Station.This study provided the available control strategy for safegjuard to prevention of the source water diverted from Luan River. Some suggestions come into effect already. These suggestions will bring huge social benefit, potential economic benefit and definite academic influence.