The number of polio cases more than doubled in an impoverished eastern Indian state last year, a rise that could be due to severe monsoon season flooding in the region, health officials said Sunday. There were 133 new polio cases reported in Bihar state last year, up from 61 in 2006, said the state's health secretary, Deepak Kumar. Devastating floods from an unusually heavy monsoon season displaced hundreds of thousands of people across the state and the region in the middle of last year. Stagnant pools left behind by floodwaters and contaminated wells were breeding grounds for disease, and may have contributed to the rise in polio, Kumar said. The polio virus enters the body through the mouth and multiplies in the intestine. It invades the nervous system and can cause permanent paralysis within hours. It can be fatal in some cases.