In an update on its investigation of pet illnesses linked to jerky treats made in China, the U.S. Food and Drug Administration (FDA) says it has expanded testing to include irradiation byproducts and is consulting with the National Aeronautics and Space Administration (NASA) experts on the issue.

It says the deaths of more than 360 dogs and one cat in the past 18 months reported from all 50 states and 6 Canadian provinces continues to confound scientists and investigators.

Most of the FDA complaints involved chicken jerky (treats, tenders and strips), but others include duck, sweet potato, and treats where chicken or duck jerky is wrapped around dried fruits, sweet potatoes, or yams.

Most of the dogs who were reported ill or died had gastrointestinal symptoms, including vomiting and diarrhea, sometimes with blood and/or mucus, and some showed severe signs such as pancreatitis or gastrointestinal bleeding, according to the FDA. Some animals also developed kidney problems, including frequent urination, increased urine, severe thirst, kidney failure and some cases resemble a rare kidney related illness called Fanconi's syndrome.

So far, the FDA says product samples have been tested for Salmonella, metals, furans, pesticides, antibiotics, mycotoxins, rodenticides, nephrotoxins (such as aristolochic acid, maleic acid, paraquat, ethylene glycol, diethylene glycol, toxic hydrocarbons, melamine, and related triazines) and were screened for other chemicals and poisonous compounds.

None of the test results have revealed the cause of the illnesses, it says.

The FDA says it inspected five plants in China earlier this year. It also verified the DNA in the samples to confirm the treats contained chicken, and tests for heavy metals have been negative.

The FDA advises pet owners who continue to feed their pets jerky treats to watch closely for any decrease in appetite or activity; vomiting; diarrhea, sometimes with blood; increased water consumption and/or increased urination. It recommends owners consult their veterinarian if signs are severe or persist for more than 24 hours.

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