Lizards often spark curiosity, leading to questions about their potential danger to humans. While most species are generally harmless, certain situations or types of lizards can pose risks. These risks typically stem from venom, physical bites and scratches, or disease transmission. Understanding these dangers and how to mitigate them is important for safe interaction with these reptiles.
Lizards That Use Venom
Only a small number of lizard species worldwide produce venom that can affect humans. The most recognized are the Gila monster (Heloderma suspectum) and the Mexican beaded lizard (Heloderma horridum). These reptiles are native to the southwestern United States, Mexico, and Guatemala. Unlike snakes, these lizards deliver venom by chewing, allowing it to flow from glands in their lower jaw along grooves in their teeth into the wound as they bite and hold on.
The venom of Gila monsters and Mexican beaded lizards contains a complex mixture of compounds, including neurotoxins and hemotoxins. A bite causes immediate and excruciating pain, often described as intense burning, which may last for hours or days. Other common symptoms include significant swelling at the bite site, nausea, vomiting, dizziness, weakness, and a rapid drop in blood pressure. While their venom is potent and can cause severe discomfort, bites are rarely fatal to healthy adult humans. Bites from these lizards are defensive, occurring when they feel threatened or are provoked.
Physical Threats From Larger Lizards
Beyond venom, larger lizard species can pose physical threats through their bites and powerful claws. Monitor lizards, such as the Komodo dragon (Varanus komodoensis), are notable examples. These animals possess sharp, serrated teeth and strong jaws, capable of inflicting deep lacerations and significant tissue damage.
The bite force of a Komodo dragon, combined with a tearing motion, can cause severe wounds and substantial blood loss. Their sharp claws also contribute to serious injuries requiring medical attention. Large iguanas, often kept as pets or encountered in warmer climates, also possess sharp teeth and claws. An iguana bite can result in painful, jagged cuts, and they may latch on and thrash their heads, causing further damage. Scratches from their powerful claws can also be deep and carry a risk of infection.
Disease Risks Associated with Lizards
Lizards, like many reptiles, can carry bacteria that pose a risk to human health, even if the lizards themselves appear healthy. A primary concern is Salmonella bacteria, which commonly resides in the intestinal tracts of many lizard species without causing illness in the reptiles. These bacteria are shed in their feces.
Humans can become infected with Salmonella through direct or indirect contact with contaminated surfaces, feces, or the lizard itself, especially if hands are not washed thoroughly afterward. Symptoms of Salmonella infection in humans include diarrhea, abdominal cramps, and fever, usually appearing 12 to 72 hours after exposure. While most infections are mild and resolve within a few days, severe cases can lead to dehydration and may require medical intervention, particularly for young children or individuals with compromised immune systems.
Safe Practices Around Lizards
Interacting safely with lizards, whether in the wild or as pets, involves a few practical measures. When encountering wild lizards, observe them from a distance. Provoking or attempting to handle them can lead to defensive bites or scratches, as lizards generally prefer to avoid confrontation and flee if approached.
Maintaining good hygiene is important after any potential contact with lizards or their environments. Thoroughly washing hands with soap and water after handling a reptile or its enclosure is recommended. This practice is particularly important for children and immunocompromised individuals, who are more susceptible to infections like Salmonella. Also, avoid allowing pet lizards to roam in areas where food is prepared or consumed.