Moldy Food (Mycotoxins) Poisoning in Dogs

Mycotoxins are poisonous substances produced by fungi and molds that grow on spoiled food. These substances are toxic to dogs as well as humans and can pose a problem for pets that like to eat food out of the trash. There are many different kinds of mycotoxins which are divided into several families. The most common group are tremorgenic, meaning that they contain a neurotoxin which causes tremors or seizures in dogs. 

Tremorgenic mycotoxins are produced by various Penicillium species of bacteria, with penitrem-A being the substance that most frequently causes poisoning in dogs. Penitrem-A is found on many types of spoiled food, including, bread, dairy products, and nuts. This type of poisoning is relatively common in dogs, with immediate symptoms of vomiting, tremors, and fever. Without treatment, high doses can cause fatal seizures.

Other toxic mycotoxins can also be present including aflatoxins produced by aspergillus fungi. These mycotoxins are metabolized in the liver and may cause hepatocellular necrosis (liver cell death) which will affect liver function giving dogs a yellowish, jaundiced appearance. Fusarium mold containing trichothecene mycotoxins can also sometimes be found on old or contaminated pet food. This will cause vomiting, diarrhea and abdominal pain. Severe mycotoxin poisoning can result in death and even non-fatal doses may be symptomatic for up to five days. Veterinary treatment can reduce the symptoms and help to eliminate the toxins faster, greatly increasing the dog’s chances of recovery.

Moldy food can contain mycotoxins that are poisonous to your dog. If ingested, the syndrome that can occur is called mycotoxin intoxication or mycotoxin toxicosis. Seizures and tremors are the most common symptoms. Severe cases can be fatal without treatment.

These symptoms could indicate mycotoxin poisoning.

• Vomiting
• Diarrhea
• Restlessness
• Disorientation
• Tremors
• Seizures
• High fever (hyperthermia)
• Jaundiced appearance (icterus)
• Abdominal pain

Types

These are some of the mycotoxins found frequently in moldy food.

Penitrem-A

• The most common type of tremorgenic mycotoxin associated with poisoning in dogs, frequently found in mold growing on bread, nuts, cheese and other spoiled products

Aflatoxins

• Produced by aspergillus fungi this can also be a component in many types of mold
• In dogs, it can affect liver function and may cause icterus (jaundice)

Vomitoxin

• A trichothecene mycotoxin produced by Fusarium mold that grows on grains such as those found in bread or dog food
• This is an infrequent cause of poisoning in dogs that is mainly caused by contaminated dog food

Roquefortine

• Another tremorgenic mycotoxin frequently found with penitrem-A

These are some of the causes and risk factors for mycotoxin poisoning.

• Spoiled food left in an open trashcan
• Compost heap
• Feeding spoiled food to a dog

A history of moldy food ingestion is the easiest way of identifying a likely mycotoxin poisoning in your dog. Whenever possible, you should bring a sample of the suspected substance with you so the veterinarian will be able to better identify the mycotoxin that is causing the problem. If aflatoxins are present, a blood test will show reduced liver function, but other mycotoxins rarely have obvious diagnostic markers. 

Lab testing of the spoiled food or the contents of your dog’s stomach will be necessary to definitively diagnose mycotoxin toxicosis and identify the substance that is causing your dog’s symptoms. The veterinarian will also need to test for alternative causes since ingestion of other toxic substances like ethylene glycol, hydrocarbons or amphetamines could cause similar symptoms. A history of your dog’s recent activities may be helpful, especially if you didn’t see the incident.

Initial treatment will focus on eliminating the toxic substance. Vomiting may be induced or gastric lavage may be done under anesthesia. Activated charcoal may be given to reduce absorption in the stomach as well as a cathartic medication to initiate bowel movements. Intravenous fluids usually form part of the therapy too.

More advanced cases will require medication to control symptoms. Diazepam is often prescribed to control seizures with tremorgenic mycotoxins. Intravenous methocarbamol may be necessary with very severe seizures. For aflatoxin poisoning, intravenous fluids and electrolytes will be necessary to support liver function and blood transfusions might be required in severe cases. Corticosteroids may be prescribed if your dog is in shock as well as other medications to regulate body temperature.

Most dogs will survive mycotoxin poisoning with aggressive treatment. It is important to get treatment however, since this type of toxicity can be fatal. Finding and removing the cause of poisoning will be necessary to prevent a recurrence. You should buy fresh dog food and throw away the old food in a sealed container or a dog-proof garbage can. Buying dog food in smaller quantities can reduce the risk of contamination. 

Spoiled food should be disposed of in a garbage disposal whenever possible. Rinse out old milk cartons or bottles before recycling them. Keep sealed lids on all your garbage cans and try to train your dog not to go through trash; teaching a 'leave it' command can come in very useful, especially when out and about. Avoid feeding any spoiled food to your dog. Food that is not fit for human consumption will likely be toxic for your dog also.

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