ST. PAUL  — Four more cases of West Nile virus have been reported in Minnesota this past week. But the rate of infection is dropping.

The new illnesses mean that so far this year 65 cases and one death have been attributed to the mosquito-borne virus in Minnesota. Nationwide, there have been more than 3,500 cases and nearly 150 deaths blamed on the disease.

Health officials say hot summer weather across most of the nation is the likely cause for the widespread West Nile outbreak this year. As average temperatures fall, the number of new cases is expected to continue to decline.