The susceptibility of young chickens, ducks, and turkeys to the photosensitizing effect of Ammi visnaga seeds.

Young chickens, ducks, and turkeys were exposed to sunlight and fed various amounts of Ammi visnaga seeds for 14 days in an attempt to induce photosensitization. In chickens, seeds at 1.25% in the diet had no effect whereas 3% induced mild signs of photosensitization within 6 to 8 days. No visible effects resulted in ducklings from 1.5, 3 and 6% in the diet, or in turkey poults from 3%. These differences appear to be due to differences between these avian species in the metabolism of the photodynamic agent.     

Equine photosensitization

Photosensitization is light-induced dermatitis caused by a heightened sensitivity of the skin to sunlight. Generally heightened sensitivity and reactivity are due to the presence of photodynamic agents or chromophores in the circulation and skin. The clinical signs of photosensitizational dermatitis generally develop within hours after exposure to strong sunlight. Hair and dermal pigments are protective because they absorb light energy before it activates chromophores and damages dermal tissues. Thus, lightly pigmented areas with little hair protection that are exposed to the sun, especially the muzzle, ears, eyelids, face, tail, vulva, and coronary bands are most severely affected. Clinical signs include photophobia and discomfort, which are seen as scratching and rubbing the ears, eyelids, and muzzle. Affected areas develop erythema followed by edema, serous exudation, scab formation, and skin necrosis. Equine photosensitivity is generally caused by plant or fungal products, drugs, chlorophyll metabolites, or other chemicals. The common causes of photosensitization, including primary photosensitization and secondary or hepatogenous photosensitization, are reviewed.     

Primary photosensitization in cattle caused by Froelichia humboldtiana

Three outbreaks of primary photosensitization caused by Froelichia humboldtiana are reported in the semiarid region of the states of Pernambuco and Paraíba, in northeastern Brazil. The disease occurred from March to June 2011, affecting 27 bovines out of a total of 70. The main lesions consisted of dermatitis of the white skin, with edema and necrosis. All the bovines recovered after removal from the areas invaded by F. humboldtiana. To produce the disease experimentally, one bovine with white skin was placed for 14days into an area with F. humboldtiana as the sole forage. This bovine presented photodermatitis on the third day of consumption. The serum concentrations of total, indirect, and conjugated bilirubin and the serum activities of gamma-glutamyl transferase (GGT) and aspartate-aminotransferase (AST) in the spontaneously affected cattle and in the experimental cattle remained within normal ranges. It is concluded that F. humboldtiana causes primary photosensitization in cattle in northeastern Brazil.     

Narthecium ossifragum Associated Photosensitization in Sheep in The Faroe Islands

Hepatogenous photosensitization in sheep is an important problem in various parts of the world. Most photosensitization diseases are associated with ingestion of plant or fungal toxins. The lily, Narthecium ossifragum, has long been associated with photosensitization in lambs in western Norway (Ender 1955, Flåøyen 1993) and in the northern regions of the British Isles (Ford 1964).     

Photosensitizaton: A literature review

Photosensitization is a skin disease caused by activation of a photodynamic agent by ligth energy (280–790 nm). Various drugs, chemicals and plants cause photosensitization in domestic animals; with skin erythema and swelling leading to necrosis and skin sloughing in advanced cases. Three types of photosensitization occur-primary (type I), aberrant pigment synthesis (type II), and hepatogenous (type III)-depending on the source of the photodynamic agent. Some of the common photosensitizations are Hypericism (type I), pink tooth (type II), Geeldikkop (type III), and facial eczema (type III). All produce identical skin lesions. Factors such as diet, climate, and health of the animal must be considered in determining the disease etiology.     

Photosenitization of sheep on kleingrass pasture

The clinical appearance and serum gamma-glutamyl transpeptidase (GGT) activity were studied in 5 groups of sheep (12 per group) on kleingrass (Panicum coloratum) pasture plots and in 1 group of sheep (10 animals) on native buffalograss (Buchlo? dactyloides) pasture. Eleven sheep (at least 1 from each group on kleingrass pasture plots) had elevated serum GGT activity. Seven of 11 sheep with elevated serum GGT activity developed signs of photosensitization. None of the sheep on buffalograss pasture developed signs of photosensitization or elevated GGT activity. The pathologic findings were similar in the sheep that had signs of photosensitization. Grossly, there was icterus and subcutaneous edema. The livers had tapeworms (Thysanosoma actinioides) in the bile ducts, were slightly swollen, and varied in color from yellow to ochre in severe cases of biliary system derangements. Microscopically, there was cholangitis.     

Hepatogenous photosensitization associated with liver copper accumulation in buffalos

Four 1.5-year-old, male, Murrah buffalos were maintained during eight months without direct solar exposure during a study of copper toxicosis. Four days after solar exposure, all buffalos presented clinical manifestations consistent with acute photosensitization, including anorexia, apathy, loss of body weight, and generalized cutaneous lesions. Gross lesions were characterized by severe erythema, localized edema, fissures, tissue necrosis, gangrene and crust formation with serous exudation. Liver copper concentration was evaluated, and cutaneous biopsies were taken when clinical signs were evident. The liver copper concentration before solar exposure was increased in all animals. Histopathologic examination of the skin revealed hepatogenous photosensitization characterized by parakeratotic hyperkeratosis, acantholysis, degeneration of squamous epithelial cells, epidermal necrosis with atrophy of sweat glands, and multifocal superficial and deep dermal edema. These findings suggest that asymptomatic accumulation of copper within the liver might have induced hepatic insufficiency thereby resulting in secondary photosensitization when these buffalos were exposed to sunlight.     

Photosensitivity in South Africa. VI. The experimental induction of geeldikkop in sheep with crude steroidal saponins from Tribulus terrestris

Geeldikkop was induced in sheep by the oral administration of crude steroidal saponins from Tribulus terrestris. Two of the sheep developed typical lesions of geeldikkop, including birefringent crystalloid material in bile ducts and concentric periductal lamellar fibrosis. The clinical pathological changes in these sheep were also consistent with those of geeldikkop: aspartate transaminase and gamma-glutamyl transferase activities in the sera of both were elevated, and one had bilirubinaemia. A third sheep became photosensitive without typical lesions of geeldikkop in the liver or changes in the activities of liver enzymes before euthanasia. The findings of these trials are consistent with reports from abroad that ovine hepatogenous photosensitization, caused by Agave lechuguilla and Narthecium ossifragum, can be induced with crude saponins from the respective plants.     

Chronic lesions in geese photosensitized by Ammi majus.

Chronic lesions of the beak, footweb, and eye of geese photosensitized by the comsumption of Ammi majus (L.) are described, 7 weeks after the acute symptoms commenced. Sixty-four (48%) of the 133 birds in the flock showed various degrees of abnormality. All affected birds had stunting of the upper beak and cicatrization and thickening of the footweb. Eighty-nine percent of the affected birds showed ocular involvement, comprising chemosis, blepharoconjunctivitis, keratitis, symblepharon, ankyloblepharon, cicatricial ectropium, and mydriasis.     

Kleingrass (Panicum coloratum L.) poisoning in sheep

Twenty-four lambs grazing pastures of Panicum coloratum developed photosensitization secondary to hepatic dysfunction. Lesions were necrosis of scattered hepatocytes, obstruction of small bile ducts and bile canaliculi by small aggregates of birefringent crystals, and accumulation of birefringent crystals in phagocytes within sinusoids. The number of crystals in livers of affected sheep varied, depending on the amount of time of exposure to toxic plants and severity of hepatic abnormalities. Crystals in the liver were soluble in acidified ethyl alcohol, acetic acid, pyridine, chloral hydrate, and methanol, but not in xylene, petroleum ether, diethyl ether, acetone, water, or cold ethyl alcohol. Crystals were not stained by oil red O. There was necrosis of epithelial cells in renal distal convoluted tubules, papillary muscles of the heart, and the adrenal cortex. Lesions of Panicum coloratum-associated disease are similar to those associated with photosensitization induced by Tribulus terrestris, Agave lecheguilla, and Nolina texana.     

Glycogen accumulation and histological changes in the livers of lambs with alveld and experimental sporidesmin intoxication

Alveld is a hepatogenous photosensitization disease seen in lambs grazing Narthecium ossifragum pastures in Norway. Mycotoxins, possibly sporidesmin, have been suspected to cause the liver damage in alveld as in facial eczema. The histological changes in the liver of alveld cases and in lambs photosensitized after experimental sporidesmin intoxication were compared. The liver damage characterized by necrosis in single centrilobular hepatocytes, was of the same type in both conditions. Minor to moderate portal fibroplasia and bile duct proliferation were almost always present. Accumulated glycogen was seen in hepatocytes in the centrilobular areas. This was significantly correlated to the enzymatically measured glycogen content and there was good correlation between parenchymal damage and glycogen accumulation. The glucose-6-phosphatase and glycogen phosphorylase activities were normal. These findings indicate that parenchymal damage, rather than obstruction of the bile ducts, caused the retention of phylloerythrin both in alveld cases and in experimentally sporidesmin-intoxicated lambs. The accumulation of glycogen could not be explained.Abbreviations HE haematoxylin and eoson - PAS periodic acid Schiff - EDTA ethylene diamine tetracetic acid     

Experimental Photosensitization and Toxicity in Sheep Produced by Tetradymia glabrata

Factors affecting the phototoxic response of sheep to Tetradymia glabrata were investigated. Photosensitization, which occurs regularly in the field situation, was unpredictable and difficult to produce experimentally. In attempting to understand this unpredictability we concluded that the plant does not lose its toxicity after field collection either through volatility of the toxin, plant enzymatic degradation of the toxin or dehydration. The chlorophyll source, from which the suspected phototoxic agent phylloerythrin is derived, did not appear to be important. The single case of photosensitization produced gave no clues as to why it occurred. Some predisposing factors important to the production of tetradymia related photosensitization in sheep are unknown.

In disagreement with previous reports the hepatotoxic response of sheep to Tetradymia glabrata was extremely variable. Also plants in comparable stages of growth, but from different locations, varied in their toxicity to sheep. Young budding plants are most toxic, however, toxicity of the plant remains through maturity.

     

Nonrespiratory diseases of stocker cattle.

Bovine respiratory disease is the most common health issue affecting stocker cattle. There are several nonrespiratory diseases that affect stockers. The more common diseases include rumen tympany, infectious bovine keratoconjunctivitis, coccidiosis, photosensitization, and foot rot. Accurate diagnosis, early treatment, and incorporating appropriate preventive measures can assist cattle production.     

Acute and chronic manifestations of Ammi majus induced photosensitisation in ducks.

The acute and chronic symptoms seen in ducks following Ammi majus induced photosensitisation are described. The acute changes were inflammatory in nature whereas the chronic changes included severe deformities of the beak and footwebs, mydriasis and eccentric location of the pupil.     

Congenital erythropoietic protoporphyria in a Limousin calf

Bovine congenital erythropoietic protoporphyria is an uncommon genetic defect in Limousin and Blonde d'Aquitaine cattle that is characterized by severe photosensitization. Clinical signs include intense pruritus and exudative dermatitis involving the face, pinnae, and dorsal aspect of the thorax. Affected cattle have hematologic and serum biochemical values within reference ranges, and their teeth are normochromic. Definitive diagnosis of bovine congenital erythropoietic protoporphyria is accomplished by genetic testing. Affected cattle should be sent to a terminal market.     

Case report: photosensitization followed by chronic exungulation in cattle

Isolated cases of photosensitization in grazing cattle are observed in a greenland district of North West Germany close to the North Sea. With adequate treatment the disease usually takes a benign course. Sometimes, however, also the claws are involved in the disease process with the consequence that the photodermatitis later on is followed by chronic exungulation. Details of a respective case are described and documented by pictures: A non-pregnant heifer (age 2 years) was falling sick with acute photodermatitis and Pododermatitis/-dermatosis coronaria aseptica in late autumn (November). After treatment and housing of the patient the acute symptoms (dermatitis, lameness) subsided. About 3 months later deep horizontal circular fissures of the horn wall about 2 cm beneath the coronary band could be observed in all 8 claws - the beginning of chronic exungulation. Subsequently the distally growing "old" horn-capsulars became progressively smaller and movable. The patient, being again on pasture (on soft ground) in the next grazing season, showed recurring lameness. The lameness could be improved by repeated cutting of the horn-wall at the tip of the claws. The "new horn-shoes" had normal conformation and full weightbearing capacity. The heifer calved in September; her milkproduction was in the average of 3 years 9.428 kg. The cause of the photosensitization could not be identified.     

Mini review on photosensitization by plants in grazing herbivores

Photosensitization is severe dermatitis or oxidative/chemical changes in the epidermal tissues activated by the light-induced excitation of molecules within the tissue. It is a series of reactions mediated through light receptors and is more common when the plant-produced metabolites are heterocyclic/polyphenols in nature. The areas affected are exposed body parts and mostly non-pigmented areas with least ultraviolet protection. Similarly, cellular alteration also occurs in the affected animal’s dermal tissues and body parts and grazing animals by the accumulation and activation of photodynamic molecules. Photo-oxidation can also occur within the plant due to the generation of reactive oxygen species causing damage and degradation in the form of free radicals and DNA. During the last few decades, many new tropical grass species have been introduced in the grazing lands which are genetically modified, and the animals grazing on them are facing various forms of toxicity including photosensitization. The plant’s secondary metabolites/drugs may cause toxicity when bacteria, viral agents, fungi (Pithomyces chartarum), or neoplasia injures the liver and prevents the phylloerythrin excretion. All these may disturb the liver enzymes and blood profile causing a decrease in weight and production (wool and milk etc.) with severe dermal, digestive, and nervous problems. Recent advancements in OMICS (cellomics, ethomics, metabolomics, metabonomics, and glycomics) have enabled us to detect and identify the plants’ secondary metabolites and changes in the animal’s physiology and histopathology as a causative of photosensitivity. The review focuses on types of photosensitization, reasons, secondary metabolic compounds, chemistry, and environmental effect on plants.     

Photosensitization of cattle in southeast Texas: identification of phototoxic activity associated with Cooperia pedunculata

A microbiological assay (Candida albicans) was used to screen plants in southeast Texas where bovine photosensitization (PS) of unknown cause was a recurring problem. Phototoxic activity was identified associated with dead leaf tips of Cooperia pedunculata, a native, perennial forb of the Amaryllis family (Amaryllidaceae) from central, southeast, and south Texas and parts of Mexico. A syndrome compatible with naturally occurring PS in cattle was induced in laboratory mice after oral administration of dead leaf material from C pedunculata. Availability and phototoxic activity of dead leaf material of C pedunculata corresponded with occurrence of PS in cattle. Seemingly, C pedunculata was involved in recurring PS.     

Parenchymal injury and biliary obstruction in relation to photosensitization in sporidesmin-intoxicated lambs

The hepatic changes were compared in lambs photosensitized or not photosensitized after exposure to sporidesmin. Injury to both the parenchyma and the biliary system was more severe in the photosensitized than in the non-photosensitized lambs. The activities of -glutamyltransferase and glutamate dehydrogenase, and the total, conjugated and unconjugated bilirubin concentrations were significantly higher in sera from the photosensitized than from the non-photosensitized lambs. Hepatic glycogen levels were decreased in both the photosensitized and the non-photosensitized lambs, but were significantly lower in the former. Hence it is possible that lesions in hepatocytes contribute to retention of phylloerythrin and so to photosensitization.