Islamabad, September 19 Fighting between the Pakistani Army and Islamist militants as well as hostility towards vaccinating teams has led to a sharp increase in polio cases in Pakistan this year, health workers said on Friday. Pakistan is one of the few countries where the deadly, crippling disease still exists. Polio, spreads through poor hygiene, and is also endemic in Nigeria, India and Afghanistan. Pakistan has had 55 polio cases this year compared with 32 last year and 39 in 2006. Pakistani forces have been battling militants in the northwest of the country, in areas on the Afghan border, disrupting efforts to make sure every child gets vaccination drops. Parts of Swat and parts of FATA, we haven