Objective To evaluate rat infestation status in Shanghai subway environment, and to explore possible factors related to rat in festation.
Methods According to the Shanghai subway operation time, 12 commercial lines were divided into 4 grades ( < 5 years, 5-years, 10-years, and 15-years), and 8 lines were sampled with at least 50% proportion for those grade less than 10 years operation time and all for those with ≥ 10 years due to small sample size. The rat infestation of selected lines and stations were investigated by rat trace method, food-pulling method, and D2E rat infestation surveillance system in 2013. Information on subway operation time, passenger volume, subway shops, and certification of pest control agencies was collected by designed questionnaire and field in vestigation. The difference of rat infestation among different floors and different functional areas was verified by chi-square test. The correlations of rat infestation with operation time, passenger volume, and proportion of subway shops were evaluated by linear correlation analysis.
Results Rat infestation was most serious in Line 2, and the positive rate of rat trace and the food-pull rate were 12.9% and 20.0%, respectively. Rat infestation levels were significantly different among different floors at the same station (P < 0.01) with the positive rate of rat trace being 71.4% for lower ground floor 3. Rat infestation levels were also different among different functional areas (P < 0.01); specifically, rat infestation was the most serious in water relevant equipment rooms. Rat activity peak appeared from 8 am to 10 am in subway environment. Operation time (r=0.82, P=0.01), passenger volume (r=0.99, P=0.01), subway shop proportion (r=0.81, P=0.03), and pest control certification (χ2=5.61, P < 0.05) were risk factors for rat infestation in subway environment.
Conclusion Rat infestation becomes an important public health problem in Shanghai subway environment, and it is necessary to adapt long-time, continuous, and systematical surveillance and control measures.
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