State and city health officials have identified a 69-year old man as the city's first case of West Nile Virus this year. While no other human cases have been reported, experts are recommending that people take precautions to prevent being bitten by an infected mosquito. The Centers for Disease Control and Prevention advise purchasing federally approved repellent, such as those with DEET. "Most of what you'll buy in a store will contain DEET, and some have pretty high concentrations. Those are the ones that will be the most effective in preventing mosquito bites," said Thomas Fekete, chair of the department of infectious diseases at Temple's School of Medicine.