Written by Dr Sarah-Jane Molier BVM&S MRCVS BSc (United Kingdom)

1080 poison has been used for pest control in New Zealand since the mid-1950s. Unfortunately, the poison is not selective in its killing. This means that other animals, including dogs and cats, can also be poisoned by 1080, usually resulting in death. Dogs are particularly susceptible to the poison and hundreds of dog deaths have been reported since 1960, with many more likely to have been unreported. So, let’s look at the effects of 1080 poison on dogs and cats.

What is 1080 poison?

1080 poison’s technical name is sodium monofluoroacetate. It consists of a fine white powder with only a very slight taste and odour. It is often mixed with meat or flavoured cereal nuggets to be used as bait. It is the only poison currently allowed in New Zealand’s aerial baiting programmes. These programmes involve dropping poisoned bait from the air over large target areas.

1080 poison is used to control pest species, such as possums, rats, wallabies, stoats, and foxes, in order to protect the rarer indigenous species. Many of the pest species are not native species. They have been introduced to New Zealand, and are upsetting the natural ecosystems, putting native species at risk of declining numbers and extinction. 1080 poison has also been used in the control of tuberculosis (TB), since the common brushtail possum can carry and transmit TB.

What effects does 1080 have on animals?

1080 poison works by disrupting the Krebs cycle, which is also known as the citric acid cycle or TCA (tricarboxylic acid cycle). This is a chemical reaction pathway in the body that breaks down food and turns it into energy. The cells in the tissues and organs of the body use this energy to function.

Disruption to the Krebs cycle means that these cells of the body are starved of energy, including the cells of the heart, lungs, nervous system, and brain. Initially, the body uses up its energy reserves (stores), during which time the central nervous system begins to be affected. Once the energy reserves are used up the lung and heart cells can no longer function, and so the animal dies from respiratory and/or cardiac arrest. Death usually occurs within 6 to 18 hours of eating the poison, but can happen much quicker.

Dogs and cats may be attracted to the poisoned bait itself, and so ingest 1080 directly. The bait can remain poisonous for weeks, even after heavy rainfall. Bait may also be moved around by birds or other wildlife, so may be found in unexpected locations.

More commonly, dogs and cats ingest 1080 by feeding on poisoned carcasses, for example, possums that have eaten 1080 bait. 1080 has been shown to break down very slowly in carcasses, so it can still be present in a carcass months later. This is especially true in colder weather.

Dogs are more commonly affected by 1080 than cats, and usually through eating poisoned carcasses. This is probably because dogs are more likely to scavenge than cats.

There is some evidence, mostly from studies on rats, that long-term, low-level exposure to 1080 can also cause problems for animals. In rats, this long-term contact has been shown to cause damage to the testicles, heart, and growing foetuses, probably because these all require high amounts of energy.

What are the symptoms of 1080 poisoning in dogs and cats?

Symptoms of 1080 poisoning in dogs and cats usually start to show very quickly. They can come on within 20 minutes, or up to 3 hours after ingestion of the poison. Early symptoms include:

• shaking
• behaving in an anxious manner
• frenzied behaviour, such as running around frantically and vocalising
• drooling
• sickness

Later symptoms then progress to:

• seizures (having fits)
• collapse
• coma
• and ultimately death.

1080 poisoning is usually diagnosed from a history of walking in known baited areas, or known scavenging of poisoned bait or carcasses, coupled with the above symptoms.

What is the treatment for 1080 poisoning in dogs and cats?

Sadly, there is no known antidote or cure for 1080 poisoning. If your dog or cat has eaten any amount of 1080 bait or a carcass that may have been poisoned, you must immediately remove them so they cannot ingest any more. If your pet has been sick, you must also remove them from the vomit. Dogs, and sometimes cats, will eat their own vomit, and the poison will still be toxic within the vomit.

You should then call your veterinarian, immediately. Make your way to the nearest veterinary clinic without delay.

If you manage to arrive at a clinic within an hour of the incident, and your pet is fully conscious, then your veterinarian may be able to make your pet sick. This will remove some of the poison that has not yet been absorbed. Your vet may then perform gastric lavage (often known in people as “having your stomach pumped”). This involves placing a stomach tube through the mouth into the stomach and washing out the stomach contents. Your vet may then give activated charcoal, to try to absorb any remaining poison.

The exact treatment will then depend on the symptoms. Treatment often involves anaesthetising the animal until there are signs of recovery, particularly in fitting animals. If the animal is going to recover, this is usually after 12–18 hours under general anaesthetic.

Treatment also involves giving a fluid drip (intravenous fluid therapy or IVFT) to try and help the body to flush out the poison, and to maintain hydration and blood pressure, amongst other things. There is evidence that some medications (sodium bicarbonate or acetamide) given slowly into the vein over time can be effective, alongside the fluid drip.

Can dogs and cats survive 1080 poisoning?

Unfortunately, there is no antidote, or cure, for 1080 poison. The prognosis varies. The chances of survival will depend partly on how much poison has been ingested, how quickly treatment is started, and on individual variation in susceptibility to the poison. The body weight of your pet is also a factor. Sadly, treatment often does not work and so 1080 poisoning has a high mortality (death) rate.

How much 1080 poison would kill a dog or cat?

Most carnivores are very susceptible to 1080, including dogs and cats. Dogs are particularly susceptible, meaning that a lower dose of 1080 poison would kill a dog compared with some other animals.

The amount of poison needed to kill a particular animal can be measured by looking at the LD50. This is the estimated dose of 1080 poison that would be needed to kill half of the population of that species. The lower the LD50, the more susceptible that animal is to 1080, since it means that a lower dose would be fatal.

In dogs, the LD50 is estimated to be 0.06–0.35 milligrams (mg) per kilogram (kg) of body weight. In cats, it is 0.3–0.35 mg per kg of body weight. This means that a small dog could die from eating only half a gram of 1080 bait.

How can I protect my dog from 1080 poisoning?

Since 1080 has a high death rate in dogs, prevention is much better than cure. Be sure to pay attention to any warning signs, which should indicate if 1080 baiting is being used in any given area. Stay away from known 1080 baiting areas where possible. If it is not possible to stay away, then consider keeping your dog on a short lead. Placing a muzzle on your dog is the safest way to prevent ingestion of 1080, since even on a short lead dogs can be quick to scavenge something from the ground!

It is a lot harder to protect cats against 1080 poisoning, especially if they like to roam and hunt.

Final thoughts

The RSPCA has deemed that 1080 poison is not a humane poison. It kills relatively slowly, meanwhile inflicting suffering in the form of distress, pain, or discomfort on the animal. There is no antidote, and treatment is not often successful, so prevention is important. It’s important to consider safety measures such as using muzzles, keeping dogs on leads, and avoiding known baiting areas. Until a suitable, more humane alternative is in use we must do all that we can to protect our pets from 1080 poison.