Over the course of March in Sedona, the chance of a day with only rain decreases from 17% to 12%, the chance of a day with mixed snow and rain remains an essentially constant 1% throughout, and the chance of a day with only snow remains an essentially constant 0% throughout.
Testing. 1  All dogs should be tested annually for heartworm infection. 2  Dogs should be tested for heartworm if they are going to be switched from one preventive to another. 3  Puppies under seven months of age can be started on heartworm preventives without first being tested.
Even after treatment and health clearance, in rare cases some former heartworm patients can still test. positive for the heartworm antigen for four to six months after treatment, which is why the dog should. be reâtested in four months and again six months later while being kept on the monthly preventative.