Pennsylvania environmental officials are warning people to be on guard against the West Nile virus.

The recent rains and rising temperatures create the perfect conditions for mosquito breeding, said officials, adding that last year was a record season for the virus in Pennsylvania.

More than 3,400 mosquito samples tested positive for the virus in 2012, officials said. The virus was detected in 52 counties, including Berks.

So far, officials said two mosquito samples have tested positive for the virus. They also said a sample from a bird has tested positive.