VPT 421: Veterinary Toxicology (2+0)

Lantana camara and Lippia spp.

LANTANA CAMRA AND LIPPIA SPP.

• Toxic principles are pentacyclic triterpene acids, including lantadene A, B, C and D, reduced lantadene A, dihydrolantadene A, and icterogenin, hepatogenous photosensitizer and gastrointestinal irritants.
• Susceptible species are Lantana camara - sheep, cattle, children and Lippia spp. - Cattle, sheep, goats, horses.

• Foliage and ripe berries of lantana contain toxic substance.
• Green berries have a higher concentration of the toxin.
• Berries may be lethal to children. However, some dark skinned people eat ripe berries without noticing ill effects.
• Poisoning commonly occurs among grazing animals.
• The toxic principles are hepatogenic photosensitizer; hepatotoxic and cause cholestasis.
• The toxins have effects on both hepatocytes and bile canaliculi.
• They decrease in canaliculi ATPase activity and cause collapse of canaliculi.
• Secretory function of hepatocytes is lost; metabolizing function is retained.
• In acute toxicosis the major clinical effect of Lantana toxicosis is photosensitization, the onset of which often takes place in 1 to 2 days after consumption of a toxic dose (1% or more of animal's body weight).
• Jaundice is usually prominent, animals usually become inappetent, and they often exhibit decreased digestive tract motility and constipation.
• Other signs may include: sluggishness, weakness, and transient, sometimes bloody diarrhea. In acute cases, death occurs in 2 to 4 days.
• In subacute and chronic toxicosis the symptoms include subacute poisoning is more common.
• Raw photosensitized surface areas are susceptible to invasions by blow fly maggots and bacteria. In severely affected cattle, lesions may appear at the muzzle, mouth, and nostrils.
• Ulceration may be present in the cheeks, tongue, and gums, while swelling, hardening, peeling of mucous membranes, and deeper tissues occur in the nostrils.
• Death may occur after 1 to 3 weeks of illness and weight loss.
• Lippia spp. toxicity results in emaciation, leg weakness and incoordination.
• Lesions include highly pigmented liver, icterus, general edema and hemorrhages in some organs.
• In sever cases of cattle lesions from muzzle to mouth and nostrils, ulceration of cheeks, tongue, and gums, swelling, hardening, peeling of mucous membranes and deeper tissues in the nostrils.
• Treatment is symptomatic. The animal should be maintained in shade. Itching and pruritus can be controlled with the use of H1 receptor antagonists (classical antihistamincs).
• Use of corticosteroids and fluids is also recommended. Hepatoprotectives are also recommended. Rumenotomy to remove the plant contents from the rumen may be useful.
• Physostigmine may initiate dramatic reversal of some of the signs within minutes. Since the animal will have wound, general measures of wound management including fly repellants, antiseptics and antibacterials is useful.