DALLAS, Aug 24: The number of West Nile virus infections in the United States has jumped more than 60 per cent in the past week in what federal officials say is one of the country’s biggest-ever outbreaks of the disease. The US Centers for Disease Control said on Wednesday that 1,118 cases and 41 deaths had been reported so far this year, up from fewer than 700 cases and 26 deaths just one week ago. (agencies)