Dry Dog Food Appears to Be Source of Grain Mites

Dear Dr. Fox:

In June, I took my 5-year-old Yorkie for her annual checkup. Her stool sample revealed hookworm. She was placed on a granular deworming medication for three days. We waited two weeks and took another sample, which again revealed hookworm. She was put on the same medication for five days. Another sample, examined more closely, revealed something our vet of more than 30 years said he had never seen. I looked into the microscope. We both saw something buglike with pincers all around it. The stool was teeming with the creatures. The sample was sent out for further examination; two days later, the results were in.

My Yorkie was infested with grain mites, but she did not have any symptoms. The vet thought they might have come from her dry food. Unknowingly, I had been reinfecting my dog each time I fed her.

I contacted people at Purina, who said this had never been brought to their attention. They agreed to refund me for the two bags of food I had but denied that their product could have been the source of the mites.

As I was cleaning out the cabinet where the food had been stored, I noticed a brown dust coating the bags and surrounding area. After an Internet search, I found that it was "mite dust" and indicated a heavy infestation. Beneful was mentioned as a carrier, as well as Ol' Roy dog food. My vet and the research lab said there is no treatment for grain mites. We hope the dog's immune system will stay strong until her body rids itself of them.

Why are vets not aware of this? Surely dog food manufacturers are aware of it -- several letters were posted on the Internet about dogs with bloody diarrhea and weight loss; a few died. All of the letters I read indicated that the dogs were being fed Beneful or Ol' Roy. None mentioned grain mites as the culprit -- the writers said the vets didn't know what it was and changed their pets' diets.

K.R.K.

Indianapolis