Lantana camara

Abstract

DISTRIBUTION: Originally from Central and South America, it is now a serious invading plant. More commonly found in the moist eastern parts of the country. Often cultivated as a garden subject.

BOTANICAL DESCRIPTION: General: A bushy shrub or untidy scrambler. The branches are ridged or four- angled and generally covered with short stiff hairs and recurved prickles. Leaves: The dark green leaves have toothed margins, are rough to the touch on the upper surface and slightly hairy beneath. They smell strongly when crushed. Flowers: Compact flower heads with tubular flowers coloured from red, orange, mauve to white. Usually a mixture of 2 or more of these colours. September - April. Fruit: Round, black berries in a cluster, ±5 mm in diameter, containing a stone with two seeds.

TOXIC PRINCIPLE: • Very similar to that of Lippia rehmannii • Pentacyclic, triterpene acids such as lantadene. Mechanism of action: • Alters permeability of liver cell membranes and leads to intrahepatic cholestasis with relatively little damage to liver cells. • Also paralyses smooth muscle of gall bladder - can’t contract - bile accumulation may cause erosion. • Phylloerythrin concentration increases in circulation.

SYNDROMES: Hepatogenous photosensitivity primarily due to liver parenchymal damage.

SYSTEMS AFFECTED: Liver.

CLINICAL SIGNS: • Mainly a cattle problem. • Goats may eat it. • Sheep are also susceptible, but seldom eat it. • Secondary photosensitivity - unpigmented areas, hairless areas, i.e. muzzle, and perineal area. • Marked icterus.• Rumen stasis, constipation - may have diarrhea.

NECROPSY: Macroscopical findings: • Secondary photosensitivity skin lesions• Yellow to orange brown liver with enormously enlarged gall bladder with oedematous wall containing straw-coloured to dark green bile. • Nephrosis • Impaction of caecum and colon.

HISTOPATHOLOGY: Cellular degeneration and necrosis in liver and kidney.

TREATMENT: • Can try choleretics, i.e. clanobutin. • Antihistamines • Antibiotics • Place in shade • Dose activated charcoal • Diet low in chlorophyll (good quality hay) • Skin protectant creams.

PREVENTION AND ERADICATION: • Avoid infected veld at danger periods. • Eradication difficult - spread by birds. • Herbicides: “Round-up” (glyphosate), “Tordon” (picloram) effective, but expensive.