A 34-year-old man from Lakewood, Colorado died recently after being bitten by one of his pet Gila monsters, which he owned illegally. This incident is particularly notable because, prior to this, there were no confirmed fatalities from Gila monster bites after 1930.
In contrast to our growing knowledge of snake venoms (see here), lizard venoms are poorly understood. Although the subject of ongoing scientific debate, six species of venomous lizards are thought to pose a risk to humans: the Gila monster and its close relative, the beaded lizard (now comprising four distinct species), along with the distantly related Komodo dragon.
Gila monsters are venomous lizards native to the southwestern United States and Mexico, recognizable by their heavy bodies and beadlike scales in black and yellow or pink. They produce venom in glands in their lower jaw, which is introduced to victims through grooves in their teeth during a bite.
Despite myths that Gila monster venom is potent enough to kill just by the lizard’s breath, these bites are known to be very painful but are rarely fatal to humans.
So, How Did The Colorado Man Die?
The man, who had illegally kept two Gila monsters, was bitten by one of them. Following the bite, he immediately exhibited symptoms typical of venom exposure:
- Vomiting
- Losing consciousness
- Ceasing to breathe
Despite being rushed to the hospital, he succumbed to his condition days later. The exact cause of his death remains uncertain, with speculation about whether an allergic reaction to the venom or the venom’s inherent toxicity was the fatal factor.
According to a 2018 case study of a 41-year-old man who fully recovered from a Gila monster envenomation, bites can lead to two types of venom effects: local and systemic. The local effect happens right where you were bitten, causing severe pain, swelling and a tingling sensation. If the venom affects your whole body, which is more serious, you might experience a dangerous drop in blood pressure and swelling in the airways, making it hard to breathe.
A 2021 review based on 22 cases of Gila monster envenomation found that three life-threatening conditions can be at play:
- Angioedema. This is swelling similar to hives, but it occurs under the skin instead of on the surface. It is particularly dangerous when it causes the throat or respiratory pathways to swell, leading to difficulty in breathing or even blocking the airway completely.
- Significant fluid losses. This refers to the body losing a lot of fluid through diarrhea, vomiting and sweating. This can lead to a drop in potassium levels in the blood (hypokalemia) and sometimes a condition called metabolic acidosis, where the body produces too much acid or the kidneys aren’t removing enough acid from the body.
- Atrioventricular conduction disorders. These are problems with the electrical signals in the heart, which can mimic the symptoms of cardiac ischemia (a condition where the heart muscle doesn’t get enough blood). It affects the heart’s ability to pump blood effectively.
Another recent report of a Gila monster envenomation highlights these life-threatening conditions. A 39-year-old man was bitten on the forearm for 7-8 minutes while handling a captive specimen. He was rushed to a hospital, with the systemic conditions described above. Approximately two hours after the bite his respiratory pathway began to swell requiring emergency intubation to help him breath. Soon after, he was transferred to an intensive care unit, where he went into shock with atrial fibrillation (rapid, irregular heartbeat) requiring electrical cardioversion (low-energy shocks to the chest) and medication to restore a normal heartbeat. He eventually made a full recovery but local pain near the bite persisted for two months.
Despite these potentially life-threatening effects, there is no antivenom available.
Does ‘No Antivenom’ Mean These Lizards Are More Dangerous Than Venomous Snakes?
The lack of antivenom for Gila monster bites does not imply that venomous lizards are more dangerous than venomous snakes, for which antivenoms for many species exist. The rarity of Gila monster envenomation and low fatality rate may contribute to the lack of antivenom. Incidents involving Gila monster bites are exceedingly uncommon, especially when compared to snake bites, which are a significant global health issue, killing between 81,000 to 137,000 humans each year.
Other venomous lizards may appear dangerous due to their size and predatory nature. For example, the venom of a Komodo dragon isn’t considered excessively dangerous to humans. One case involved a zookeeper who was bitten by a Komodo dragon. The incident, detailed in a 2023 paper, highlighted that the injuries sustained were managed without the need for antivenom, primarily through local wound care and outpatient antibiotics.
Owning a pet lizard can be a rewarding experience, provided one chooses species that are safe to keep as pets. It’s crucial to research and understand the specific care requirements of any lizard before deciding to bring one into your home. This includes their dietary needs, habitat setup and any legal restrictions on ownership in your area. Some popular lizards to own include bearded dragons, leopard geckos, crested geckos and blue-tongued skinks.