The vibrant flowering shrub Lantana camara, native to tropical regions, is a popular ornamental plant found in many gardens worldwide. Despite its beauty, it contains chemical compounds that render it toxic to both humans and animals. The plant’s danger lies primarily in ingestion rather than simple physical contact. Understanding the distinction between a minor dermal reaction and a severe systemic reaction helps assess the risk posed by this species.
Answering the Contact Question: Dermal Reactions
Direct physical contact with Lantana camara is not acutely dangerous. The leaves and stems are covered in fine hairs that can cause mild mechanical irritation upon handling, which may manifest as contact dermatitis. People with sensitive skin or existing allergies may be more susceptible to this minor reaction.
The plant’s toxins are not absorbed through the skin in quantities large enough to cause systemic harm. In rare instances, contact followed by sun exposure can lead to phytophotodermatitis, making the skin temporarily sensitive to ultraviolet light. Wearing gloves when handling the plant prevents these localized skin issues.
The Primary Danger: Systemic Toxicity from Ingestion
Ingestion of Lantana camara plant material leads to systemic toxicity affecting internal organs. This poisoning is caused by potent compounds known as pentacyclic triterpenoids, specifically lantadene A and lantadene B. These toxins are absorbed in the digestive tract and primarily target the liver, making them hepatotoxic.
The mechanism involves lantadenes causing intrahepatic cholestasis, which suppresses bile flow from the liver. This impairment leads to an accumulation of breakdown products in the bloodstream, resulting in jaundice. Early symptoms of ingestion include gastrointestinal distress, such as vomiting, nausea, abdominal pain, and diarrhea.
In livestock, the poisoning causes photosensitivity, making the skin prone to blistering when exposed to sunlight. Ingestion of sufficient quantities can ultimately lead to liver failure, respiratory depression, and death in animals and, rarely, in humans.
High-Risk Groups and Toxic Plant Parts
Young children and grazing animals are the populations most vulnerable to Lantana poisoning, as they are the most likely to ingest parts of the plant. Children are often attracted to the plant’s berries, which change color as they ripen. Livestock, including cattle, sheep, and goats, are frequently poisoned when forced to consume the foliage due to a lack of other available feed.
All parts of the plant are considered toxic, but the concentration of lantadenes varies depending on the part and its maturity. The unripe, green berries contain the highest concentration of toxins and represent the greatest danger for human ingestion. The leaves and stems also contain substantial amounts of the toxic triterpenoids. Ripe, dark berries and flowers are less concentrated but still pose a risk, especially if consumed in quantity.
Immediate Steps Following Exposure
If skin irritation occurs after contact, the exposed area should be washed thoroughly with soap and water. For persistent redness or itching, over-the-counter treatments like calamine lotion or hydrocortisone cream may provide relief. Avoid direct sun exposure on the affected skin to prevent photosensitive reactions.
If ingestion of any part of the Lantana camara plant is suspected, immediate action is necessary. For a person, contact a regional Poison Control Center for guidance based on the estimated amount consumed. For a pet or livestock animal, call a veterinarian or an animal poison control center immediately. Professional intervention is necessary for ingestion cases, and inducing vomiting should only be done if specifically instructed by a medical professional.