The U.S. Food and Drug Administration (FDA) is continuing to investigate thousands of complaints about pet illnesses it has received since 2007 — mainly in dogs but also in some cats — and which may be associated with the consumption of pet jerky treats from China. So far, more than 1,000 canine deaths have been reported, FDA stated in its May 16 update on the situation. However, the agency has still not identified a specific cause. According to the recent update, “As of May 1, 2014, FDA has received approximately 4,800 reports of pet illnesses which may be related to consumption of the jerky treats. (These include 1,800 complaints received since FDA’s last update in October 2013.) Most of the reports involve jerky products sourced from China.” The update continues, “The majority of the complaints involve dogs, but cats also have been affected. The reports involve more than 5,600 dogs, 24 cats, three people and include more than 1,000 canine deaths. There does not appear to be a geographic pattern to the case reports.” Of the illness reports, FDA stated that “about 60 percent are for gastrointestinal illness (with or without elevated liver enzymes) and about 30 percent relate to kidney or urinary signs. The remaining 10 percent of cases involve a variety of other signs, including convulsions, tremors, hives, and skin irritation.” The jerky treats are “commonly chicken or duck or jerky-wrapped treats, mostly imported from China,” FDA stated, adding that, “Pet owners should be aware that manufacturers do not need to list the country of origin for each ingredient used in their products, so packages that do not state on the label that they are made in another country may still contain ingredients sourced from China or other countries that export to the U.S.” FDA stated that 26 necropsies (animal autopsies) were performed on dogs, revealing that half of them died from something else probably unrelated to consumption of jerky treats and that the deaths of the other half may have been linked to the treats. The Chinese jerky pet treats have been tested for various contaminants, FDA stated, and the human antiviral drug amantadine was found in some of the chicken-flavored products. Agency officials don’t believe amantadine has a connection with the pet illnesses since the side effects of that drug do not relate to other symptoms in the illness cases. Other contaminants for which FDA has tested the jerky treats include: 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 other chemicals and poisonous compounds. Tests for toxic and heavy metals were negative, FDA stated. While the agency has not announced the brand names of the jerky treats being tested, internal documents obtained by msnbc.com earlier this year indicate that they include the following: Waggin’ Train or Canyon Creek Ranch jerky treats or tenders, both produced by Nestle Purina PetCare Co., and Milo’s Kitchen Home-style Dog Treats, produced by the Del Monte Corp. Anyone with a complaint relating to Chinese jerky pet treats, or any other other illness associated with pet foods, may report the case to the FDA Consumer Complaint Coordinator in their state, or electronically through the Safety Reporting Portal. More information regarding “How to Report a Pet Food Complaint” to FDA can be found here.