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Red maple leaf toxicity warning
things as Newcastle disease and/or infectious bronchitis viruses. Recent advances in our understanding of immune mechanisms involved in viral diseases, together with recent advances in technology allowing for more specific manipulation of viral genetic information are providing new and exciting possibilities for improved immunoprophylaxis for a variety of viral diseases of both humans and animals.(From Ontario Veterinary Report).
RED MAPLE LEAF TOXICITY WARNING Harold W. Tvedten, DVM During the last week of October, 1987, Michigan State University had three horses with a severe hemolytic crisis thought to be due to eating dried Red Maple (Acer rubrum) leaves. The fresh leaves are not toxic but after drying they are toxic at a dose of 3gin/ kg or less. Methemoglobin is produced as in nitrate poisoning so the blood and mucus membranes appear brown. Hemoglobin in the methemoglobin form does not carry oxygen even if an anemia is not present. However, in ponies surviving over 18 hours, a Heinz body hemolytic anemia with hemoglobinuria occurs with a variably severe anemia and hemoglobin nephrosis. Methylene blue in four horses was tried without evidence of improvement. For treatment, Dr. Benjamin Darien at Michigan State University has used blood transfusion, fluids, and other treatments including heparin for secondary disseminated intravascular coagulation. Clients should be advised to remove Red Maple leaves from pastures before the leaves dry and become toxic and horses or ponies eat them. Diagnostic features include hemoglobinuria noted on urinalysis by a strong occult blood, yet few or no intact erythrocytes. This is combined with the presence of a hemolytic anemia. The plasma is quite hemolyzed and icteric. Most human hospital laboratories can perform a methemoglobin determination on a whole blood sample. Methemoglobin in previous cases has been 22-57 percent of the total hemoglobin so compared to the normal of 0 percent is a diagnostic feature. Other causes of Heinz body hemolytic anemias in horses include the ingestion of onions or phenothiazine. (From News and Views, Michigan Veterinary Medical Association).
EQUINE DIARRHEA Lois Roth DVM, PhD Fecal or intestinal culture or immunological techniques are considered by some to be the only way to diagnose the cause of fatal diarrhea in horses. Prolonged antibiotic therapy, improper handling of culture samples or extended post-mortem interval all potentiallyinterfere with the accuracy of culture results. There are, however, characteristic gross lesions of some of the more common causes of fatal diarrhea in horses that permit the prosector to be reasonably certain of the diagnosis at the time of necropsy.
Volume 8, Number 1, 1988
Salmonella spp. is one of the more common causes of diarrhea. Horses may die acutely or following a clinical course of diarrhea of variable length. The major lesion is a segmental, fibrinous enterocolitis. Sheets of yellow green to grey friable material are adherent to the intestinalmucosa. In severe cases there may be solid cores of fibrinous material in the intestinal lumen. The segmental distribution of the lesion means that the fibrinous enterocolitis may be seen only in portions of the small intestine or only in the large intestine. Affected areas of intestine may be separated by areas of normal appearing intestine. The presence of the lesion in the small intestine only does not rule out salmonellosis. Another characteristic of salmonellosis is a distinct"septic tank odor" of the intestine and its contents. Almost every animal that dies with the disease has gross lesions. Animals that are eathanized sometimes do not have gross lesions. Tied off loops of bowel may be submitted for culture. The specimens should be kept cold and it should be specified that Salmonella spp. is suspected since special media is often required to grow the organism. Potomac horse fever (PHF) is another cause of equine diarrhea that has recently received much publicity. Most of the cases of PHF that were first recognized were fatal. Now several years since its description there are relatively fewer fatal cases. PHF is caused by Ehrlichia risticii. It is a "seasonal disease" occurring most frequently in the late spring, summer, and early fall. Affected horses have profuse watery diarrhea that may alternate with periods of normal stool. Horses that die have markedly watery gastrointestinal contents that do not smell bad. There may be some edema of portions of the small and large intestine, bat this is usually pronounced. In spite of a relatively normal appearing cecum and colon there is often a slight to moderate necrotizing thyphlitis and colitis that can be seen histologically. Multiple samples of cecum and colon should be taken and put in formalin for histologic examination. Immunoperoxidase staining may be used to support the diagnosis of PHF. If suspected, blood samples for determinationof E. risticii titers should be taken prior to death. Colitis X or exhaustion colitis is often an overlooked cause of diarrhea in the horse. Horses usually die following a stressful episode. They may have short clinical course of diarrhea or they may die before diarrhea is clinically evident. The major lesion at necropsy is marked edema of the colon. The colon wall may be several centimeters thick due to edema. The mucosal surface may appear normal or slightly dull. A careful, complete necropsy examination is the best way to diagnose colitis X. A specific cause of colitis X has not been determined, although some suspect that it might be a hypersensitivityto different antigens. (From Virginia Veterinary Notes). ANTI-INFLAMMATORY EFFECTS OF AN IMMUNO-MODULATING AGENT Kent Allen Vasko, DVM ~and John McMichael, PhD2 The role of immuno-modulationas a means of enhancing the body defense mechanisms has been the subject of increasing interest among basic scientists and clinicians for a number of Authors'addresses: 1EquineSports Medicine,9170 Hermitage,Chardon, OH 44024; 2ImmunoTherapeutics,P.O. Box 127, Delason,NY 12053.
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RED MAPLE LEAF TOXICITY WARNING Harold W. Tvedten, DVM During the last week of October, 1987, Michigan State University had three horses with a severe hemolytic crisis thought to be due to eating dried Red Maple (Acer rubrum) leaves. The fresh leaves are not toxic but after drying they are toxic at a dose of 3gin/ kg or less. Methemoglobin is produced as in nitrate poisoning so the blood and mucus membranes appear brown. Hemoglobin in the methemoglobin form does not carry oxygen even if an anemia is not present. However, in ponies surviving over 18 hours, a Heinz body hemolytic anemia with hemoglobinuria occurs with a variably severe anemia and hemoglobin nephrosis. Methylene blue in four horses was tried without evidence of improvement. For treatment, Dr. Benjamin Darien at Michigan State University has used blood transfusion, fluids, and other treatments including heparin for secondary disseminated intravascular coagulation. Clients should be advised to remove Red Maple leaves from pastures before the leaves dry and become toxic and horses or ponies eat them. Diagnostic features include hemoglobinuria noted on urinalysis by a strong occult blood, yet few or no intact erythrocytes. This is combined with the presence of a hemolytic anemia. The plasma is quite hemolyzed and icteric. Most human hospital laboratories can perform a methemoglobin determination on a whole blood sample. Methemoglobin in previous cases has been 22-57 percent of the total hemoglobin so compared to the normal of 0 percent is a diagnostic feature. Other causes of Heinz body hemolytic anemias in horses include the ingestion of onions or phenothiazine. (From News and Views, Michigan Veterinary Medical Association).
EQUINE DIARRHEA Lois Roth DVM, PhD Fecal or intestinal culture or immunological techniques are considered by some to be the only way to diagnose the cause of fatal diarrhea in horses. Prolonged antibiotic therapy, improper handling of culture samples or extended post-mortem interval all potentiallyinterfere with the accuracy of culture results. There are, however, characteristic gross lesions of some of the more common causes of fatal diarrhea in horses that permit the prosector to be reasonably certain of the diagnosis at the time of necropsy.
Volume 8, Number 1, 1988
Salmonella spp. is one of the more common causes of diarrhea. Horses may die acutely or following a clinical course of diarrhea of variable length. The major lesion is a segmental, fibrinous enterocolitis. Sheets of yellow green to grey friable material are adherent to the intestinalmucosa. In severe cases there may be solid cores of fibrinous material in the intestinal lumen. The segmental distribution of the lesion means that the fibrinous enterocolitis may be seen only in portions of the small intestine or only in the large intestine. Affected areas of intestine may be separated by areas of normal appearing intestine. The presence of the lesion in the small intestine only does not rule out salmonellosis. Another characteristic of salmonellosis is a distinct"septic tank odor" of the intestine and its contents. Almost every animal that dies with the disease has gross lesions. Animals that are eathanized sometimes do not have gross lesions. Tied off loops of bowel may be submitted for culture. The specimens should be kept cold and it should be specified that Salmonella spp. is suspected since special media is often required to grow the organism. Potomac horse fever (PHF) is another cause of equine diarrhea that has recently received much publicity. Most of the cases of PHF that were first recognized were fatal. Now several years since its description there are relatively fewer fatal cases. PHF is caused by Ehrlichia risticii. It is a "seasonal disease" occurring most frequently in the late spring, summer, and early fall. Affected horses have profuse watery diarrhea that may alternate with periods of normal stool. Horses that die have markedly watery gastrointestinal contents that do not smell bad. There may be some edema of portions of the small and large intestine, bat this is usually pronounced. In spite of a relatively normal appearing cecum and colon there is often a slight to moderate necrotizing thyphlitis and colitis that can be seen histologically. Multiple samples of cecum and colon should be taken and put in formalin for histologic examination. Immunoperoxidase staining may be used to support the diagnosis of PHF. If suspected, blood samples for determinationof E. risticii titers should be taken prior to death. Colitis X or exhaustion colitis is often an overlooked cause of diarrhea in the horse. Horses usually die following a stressful episode. They may have short clinical course of diarrhea or they may die before diarrhea is clinically evident. The major lesion at necropsy is marked edema of the colon. The colon wall may be several centimeters thick due to edema. The mucosal surface may appear normal or slightly dull. A careful, complete necropsy examination is the best way to diagnose colitis X. A specific cause of colitis X has not been determined, although some suspect that it might be a hypersensitivityto different antigens. (From Virginia Veterinary Notes). ANTI-INFLAMMATORY EFFECTS OF AN IMMUNO-MODULATING AGENT Kent Allen Vasko, DVM ~and John McMichael, PhD2 The role of immuno-modulationas a means of enhancing the body defense mechanisms has been the subject of increasing interest among basic scientists and clinicians for a number of Authors'addresses: 1EquineSports Medicine,9170 Hermitage,Chardon, OH 44024; 2ImmunoTherapeutics,P.O. Box 127, Delason,NY 12053.
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