PORTLAND, Maine (AP) Avian flu and distemper may be to blame for a rash of seal deaths in Maine, New Hampshire, and Massachusetts.

Southern Maine beaches have been beset with dead harbor seals in recent weeks, with dozens washing up stranded or having perished. The National Oceanic and Atmospheric Administration says Thursday that the first batch of sampled seals have tested preliminarily positive for either avian influenza or phocine distemper virus.

Four seals have tested positive for both viruses.

But NOAA says it’s too soon to determine if either of both of the viruses were the primary cause of the rash of seal deaths.

This month has seen 179 dead harbor seals in Maine. NOAA has said the average for August is 38.4.