Monday Medical Holiday Toxins: Mistletoe

Mistletoe in a hackberry tree on my sister's land in Texas

About this time last year I was in a van, driving through west Texas back country with a camera crew.  Suddenly, I saw something very familiar to me. Since we were on our way to film a Christmas special, it seemed all too appropriate.

"Look! Mistletoe!" I pointed out the window of the van.
No one believed me.

But having grown up with the stuff dripping from the oak trees on my parents' land in central Texas, I knew what I was talking about. It was mistletoe, and I won the Trivia round that day with the crew.

Oddly for a wintertime holiday plant, a large number of mistletoe varieties are tropical or sub-tropical. Mistletoe is also a partial parasite, and it grows in clumps in trees like oak, walnut and hackberry.

And since mistletoe is a known toxin to both humans and pets, it makes a good Medical Monday topic for December.

One of the earliest mentions of mistletoe is in Greek mythology around the first century BCE, in Virgil's The Aeneid. It also makes an appearance in thirteenth century Norse mythology. Mistletoe didn't really become a part of Christmas tradition until the 18th century.

1900's postcard, public domain

Back in the first century, mistletoe was actually considered to be an antidote to poisons. That's sadly ironic, since mistletoe is toxic to humans and pets alike.

It was also considered to be a cure for infertility in animals. Pliny the Elder documented a Celtic ritual in his "Natural History" series where mistletoe was mixed in a drink and served to animals to increase fertility. One wonders how many farm animals survived this practice.

There are two main species of mistletoe, the European variety and the American variety. The European variety is considered the more poisonous of the two. Both varieties are harvested commercially for Christmas decorations.

If you suspect your pet may have turned your décor into a menu item, look for symptoms to begin to show up in 2 to 24 hours. As with all toxins, the symptoms may vary with the amount ingested.

If you think it was just a berry or two that got eaten, or maybe a few leaves nibbled on, then look for things that might indicate you have inflammation in the stomach or intestines – stuff like drooling, abdominal pain, diarrhea and vomiting.

If your mistletoe is completely gone and you suspect Fido might have chowed down on it, that’s a bit more dangerous. In large doses, mistletoe can affect the cardiovascular system – especially if it’s of the Eurpopean variety.

You risk low blood pressure, abnormal heart rate, seizures, or a condition known as ataxia (or “walking drunk”). This can even be fatal, so seek medical help immediately.

And remember, if you ever suspect your pet may have eaten something he shouldn’t, call your veterinarian immediately. There is also a Global Crisis Solution Center that has a poison emergency page that includes animals. On it you can find a link to Poison Control Center phone lines in over 70 countries.

Wishing you a safe and enjoyable holiday season - for you and your pets!
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Sources:

Images of American & Eurpoean Mistletoe
Mistletoe species are partial parasites
If your pets eat mistletoe, what should you expect? FDA.gov
Pet Poison Helpline
Mistletoe commentary by Pliny the Elder