Rosane M.T. Medeiros

Plantas tóxicas para ruminantes e eqüídeos no Seridó Ocidental e Oriental do Rio Grande do Norte

To determine the occurrence of plant poisoning in the Western and Eastern Serido regions of the state of Rio Grande do Norte, 82 persons including farmers, agronomists and veterinarians were interviewed. The two more important toxic plants are Ipomoea asarifolia, which causes nervous signs in sheep, goats and cattle, and Aspidosperma pyrifolium, leading to abortion in goats, sheep and cattle. The abortive properties of this plant had been demonstrated experimentally in goats, but not in sheep and cattle. Some farmers mentioned the poisoning by A. pyrifolium as a cause of nervous signs in equidae and cattle. Poisoning by cyanogenic plants including Manihot spp, Anadenanthera colubrina var. cebil (=Piptadenia macrocarpa), Sorghum bicolor and Sorghum halepense are important in the region. Important is also poisoning by Prosopis juliflora in cattle and with less frequency in goats, poisoning by Crotalaria retusa in horses, sheep and cattle, and by Mascagnia rigida in cattle. Poisoning by Brachiaria decumbens and Enterolobium contortisiliquum is sporadic. Other less important toxic plants in the region are Indigofera suffruticosa, Ipomoea carnea, and Ricinus communis. Some farmers reported poisoning by Marsdenia sp affecting sheep and cattle, and also a group of swine fed with the roots of the plant; the leaves and the roots are experimentally toxic to ruminants causing nervous signs, without histologic lesions. Another poisoning demonstrated experimentally is caused by Tephrosia cinerea and results in ascitis with hepatic fibrosis in sheep. Six farmers reported poisoning by Nerium oleander, always in cattle that had access to the shrub after been cut, mixed or not with other plants. Farmers mentioned also poisoning by other plants with unknown toxicity, including Paullinia sp, Passiflora sp, Dalechampia sp, Portulaca oleracea, Luffa acutangula, Cereus sp, Leersia hexandra, and Stemodia maritima. Echinochloa polystachya and Pennisetum purpureum, which cause nitrite poisoning were mentioned by some farmers as cause of cattle mortalities. One farmer mentioned an outbreak of poisoning in cattle and goats by Dieffenbachia picta which had been cut and left to the animals.

Outbreaks of Pythiosis in Two Flocks of Sheep in Northeastern Brazil

Two outbreaks of cutaneous pythiosis caused by Pythium insidiosum were diagnosed in two herds of crossbred hair wool sheep of different ages in the semiarid region of Northeastern Brazil. In one herd of 120 sheep, 40 were affected. The other outbreak affected six sheep out of 80. Local swellings with ulcerative lesions were observed in the limbs and abdominal and prescapular regions. Three sheep were necropsied. Two of them had lung metastasis characterized by multifocal nodules measuring 0.5–2 cm. In one animal, the prescapular lymph node was also affected. In another, the cutaneous lesion extended to the sesamoid bone. Microscopically, there were multifocal granulomas with intralesional P. insidiosum hyphae and Splendore-Hoeppli material surrounding the hyphae. The diagnosis was based on the histologic lesions, immunohisto-chemical identification, and culture of the etiologic agent. One sheep treated with potassium iodide recovered. Standing in swampy water for long periods in a warm aquatic environment seems to be the reason for the high prevalence of the disease.

Mimosa tenuiflora as a Cause of Malformations in Ruminants in the Northeastern Brazilian Semiarid Rangelands

Craniofacial anomalies, eye malformations, and permanent flexures of the forelimbs are common malformations seen in ruminants grazing semiarid rangelands of Northeastern Brazil. To investigate the cause of these malformations, we fed 2 suspected plants, Mimosa tenuiflora or Prosopis juliflora, to groups of 4 pregnant goats each. Fresh green M. tenuiflora was collected daily and fed ad libitum to 4 goats in group 1 throughout pregnancy. This treatment group also received a supplemental feed concentrate equivalent to 1% body weight. Four goats in group 2 received a ration with 70% of P. juliflora pods and 30% hay throughout pregnancy. Four control goats were fed supplemental feed concentrate (1% body weight) and hay ad libitum throughout pregnancy. Goats treated with P. juliflora pods and the control goats delivered 9 normal kids. The four goats that were fed M. tenuiflora during pregnancy delivered 4 kids, 3 of which had abnormalities similar to those observed in field cases, including cleft lip, unilateral corneal opacity, ocular bilateral dermoids, buphthalmos with a cloudy brownish appearance of the anterior chamber due to an iridal cyst, and segmental stenosis of the colon. Malformations induced experimentally by M. tenuiflora were similar to those observed in field cases, suggesting that M. tenuiflora is a cause of the field cases observed in the Brazilian semiarid rangelands.

Doenças do sistema nervoso central em caprinos e ovinos no semi-árido

The knowledge of the diseases of domestic animals in the different Brazilian regions is important to determine measures for their control and prevention. The objective of this paper is to report the epidemiology, clinical signs and pathology of the diseases of the central nervous system (CNS) of goats and sheep in the Brazilian semiarid, mainly in the state of Paraiba, diagnosed at the Veterinary Hospital of the Federal University of Campina Grande, from January 2000 to May 2006. During the period, 365 cases or outbreaks were diagnosed in goats and 270 in sheep. From these, 63 (9.92%) were of diseases of the CNS, being 34 (9.31%) in goats and 29 (10.7%) in sheep. The main diseases were abscesses (19.04%), tetanus (15.9%), rabies (9.52%) poisoning by Ipomoea asarifolia (7.93%), listeriosis (6.34%), traumatism (6.34%), polioencephalo-malacia (4.77%), pregnancy toxemia (3.17%), enzootic ataxia (3.17%), and meningitis (3.17%). Other diseases diagnosed in only one opportunity (1.59%) were intoxications by Crotalaria retusa, Ipomoea carnea, Ipomoea sericophylla and Prosopis juliflora, otitis with encephalitis, malformation, lymphoblastic lymphosarcoma, medulloblastoma, and focal symmetric necrosis. In 6.34% of the cases diagnosis was unknown.

Tremorgenic syndrome in goats caused by Ipomoea asarifolia in Northeastern Brazil.

Green leaves of Ipomoea asarifolia were dosed to 10 goats. Nine goats ingesting 5-37 g/kg bw daily had clinical signs in 4-38 days. One goat ingesting 2.5 g/kg bw daily during 125 days and two control goats had no clinical signs. Clinical signs were characteristic for a tremorgenic syndrome. Five goats recovered in 4-9 days after the withdrawal of the plant. Two goats died spontaneously and three were euthanased for histologic and ultrastructural studies. No significant lesions were observed at necropsies or on the histologic and ultrastructural studies. Samples of the plant analyzed for enzymatic inhibitors were negative for calystegines and contained an almost undetectable amount of swainsonine (less than 0.001%). It is concluded that I. asarifolia causes a tremorgenic syndrome due to an unknown tremorgenic phytotoxins or mycotoxins.

Poisoning of sheep by seeds of Crotalaria retusa: Acquired resistance by continuous administration of low doses

Seeds of Crotalaria retusa containing 6.84% (dry weight) of monocrotaline (MCT) were administered experimentally to sheep. Three sheep that received 136.8mg MCT/kg bw daily for 70 days had no clinical signs. Five out of six sheep ingesting single doses of 205.2 and 273.6mg MCT/kg bw died with acute (three sheep) or chronic intoxication (two sheep). Acute intoxicated sheep had periacinar liver necrosis and chronic intoxicated sheep liver fibrosis and megalocytosis. Another three sheep had no clinical signs after the ingestion of 20 daily doses of 136.8mg MCT/kg, followed by seven doses of 273.6mg MCT/kg, and one single dose of 342mg MCT/kg. These experiments demonstrated that sheep are susceptible to acute intoxication by MCT being intoxicated by a single oral dose of approximately 205.2mg/kg. In contrast, they develop strong resistance to MCT after the daily ingestion of non lethal doses (136.8mg/kg). It is suggested that chronic poisoning does not occur by the repeated ingestion of non acutely toxic doses, but probably by the ingestion of single toxic doses. It is also suggested that sheep do not become intoxicated with the ingestion of C. retusa in the vegetative non-seeding stage.

Importância econômica, epidemiologia e controle das intoxicações por plantas no Brasil

A importância economica, epidemiologia e controle das intoxicacoes por plantas em animais domesticos no Brasil sao revisadas. Com os dados dos laboratorios de diagnostico de diferentes regioes do pais, as perdas anuais por mortes de animais foram estimadas em 820.761 a 1.755.763 bovinos, 399.800 a 445.309 ovinos, 52.675 a 63.292 caprinos e 38.559 equinos. No Brasil, atualmente, o numero de plantas toxicas e de 131 especies e 79 generos e aumenta permanentemente. No entanto, a maioria das perdas sao causadas por poucas plantas, incluindo Palicourea marcgravii, Amorimia spp., Senecio spp., Pteridium aquilinum, Ateleia glazioviana e Cestrum laevigatum em bovinos, Brachiaria spp em bovinos e ovinos, Nierembergia veitchii, Mimosa tenuiflora e Ipomoea asarifolia em ovinos, plantas que contem swainsonina (Ipomoea carnea, Turbina cordata e Sida carpinifolia) em caprinos e Brachiaria humidicola e Crotalaria retusa em equinos. Os principais fatores epidemiologicos relacionados as intoxicacoes por plantas incluem palatabilidade, fome, sede, facilitacao social, desconhecimento da planta, acesso a plantas toxicas, dose toxica, periodo de ingestao, variacoes de toxicidade e resistencia/susceptibilidade dos animais as intoxicacoes. Quanto aos metodos de controle e profilaxia descrevem-se os resultados obtidos no Brasil com metodos recentemente desenvolvidos, incluindo controle biologico, aversao alimentar condicionada, utilizacao de variedades nao toxicas de forrageiras, utilizacao de animais resistentes as intoxicacoes e tecnicas de inducao de resistencia.

Mycotoxicoses of ruminants and horses

In the current study, mycotoxicoses of ruminants and horses are reviewed, with an emphasis on the occurrence of these diseases in South America. The main mycotoxicoses observed in grazing cattle include intoxications by indole-diterpenoid mycotoxins (Paspalum spp. contaminated by Claviceps paspali, Lolium perenne infected by Neotyphodium lolii, Cynodon dactylon infected by Claviceps cynodontis, and Poa huecu), gangrenous ergotism and dysthermic syndrome (hyperthermia) caused by Festuca arundinacea (syn. Festuca elatior) infected by Neotyphodium coenophialum (syn. Acremonium coenophialum), and photosensitization in pastures contaminated by toxigenic Pithomyces chartarum. Other mycotoxicoses in grazing cattle include slaframine toxicity in clover pastures infected by Rhizoctonia leguminicola and diplodiosis in cattle grazing in corn stubbles. The mycotoxicoses caused by contaminated concentrated food or byproducts in cattle include poisoning by toxins of Aspergillus clavatus, which contaminate barley or sugar beetroot by-products, gangrenous ergotism or dysthermic syndrome caused by wheat bran or wheat screenings contaminated with Claviceps purpurea, and acute respiratory distress caused by damaged sweet potatoes (Ipomoea batatas). The main mycotoxicosis of horses is leukoencephalomalacia caused by the fumonisins B1 and B2 produced by Fusarium spp. Poisoning by C. purpurea and F. elatior infected by N. coenophialum has also been reported as a cause of agalactia and neonatal mortality in mares. Slaframine toxicosis caused by the ingestion of alfalfa hay contaminated by R. leguminicola has also been reported in horses.

Neurohistologic and Ultrastructural Lesions in Cattle Experimentally Intoxicated with the Plant Prosopis juliflora

Intoxication by pods of Prosopis juliflora (mesquite beans) causes an impairment of cranial nerve function in cattle and goats. In goats, vacuolation of neurons in the trigeminal motor nuclei has been reported. To study the lesions in cattle caused by consumption of P. juliflora pods and dry ground pods, eight 6- to 12-month-old male cattle were divided into 4 groups: group 1 was fed a ration containing 50% of pods; groups 2 and 3 received a ration containing 50 and 75% of dry ground pods, respectively; group 4 was the control. After 200 days, all cattle were killed and sampled for histologic evaluation. Samples of the trigeminal motor nucleus were examined by electron microscopy. All cattle from groups 1, 2, and 3 showed clinical signs resulting from impaired function of cranial nerves V, IX, X, and XII, starting 45-75 days after consumption of the plant. The main histologic lesions were vacuolation and loss of neurons in trigeminal motor nuclei and other motor cranial nerve nuclei with Wallerian-like degeneration in the cranial nerves. Mild denervation atrophy was observed in the masseter and other masticatory muscles. On electron microscopy, neurons of the trigeminal nuclei had markedly swollen mitochondria, with the mitochondrial cristae displaced peripherally, disoriented and disintegrating. Intoxication by P. juliflora seems to have a novel pathogenesis, characterized by a selective, primary, chronic, and progressive injury to mitochondria of neurons of the trigeminal and other cranial nerve nuclei. Cranial nerve degeneration and denervation atrophy of the muscles occurs as a consequence of the neuronal lesion.

Malformações congênitas em ruminantes no semiárido do Nordeste Brasileiro

Congenital malformations caused by the ingestion of Mimosa tenuiflora have been reported in ruminants in the semiarid of the Brazilian Northeast. This paper reports malformations diagnosed in ruminants, from 2000 to 2008, by the Veterinary Pathology Laboratory of the Federal University of Campina Grande, Patos, PB, in municipalities of the states of Paraiba, Pernambuco and Rio Grande do Norte. During the period, 47 (3.48%) out of 1.347 ascensions were reported as malformations. Based in the type of malformation and in the origin of the animals, malformations were divided in: 1) caused by the ingestion of M. tenuiflora, and 2) sporadic malformations of unknown causes. In sheep, 21 out of 418 ascensions were malformations, being 18 (4.3%) of malformations caused by M. tenuiflora and 3 (0.71%) of sporadic malformations. In cattle, 14 out of 434 ascensions were malformations, from these 8 (1.84%) were caused by M. tenuiflora and 6 (1.38%) were sporadic malformations. In goats, 12 out of 495 ascensions were malformations, being 9 (1.81%) malformations related with the ingestion of M. tenuiflora and 3 (0.6%) sporadic malformations. More frequent malformations caused by M. tenuiflora were arthrogryposis, micrognatia, palatoschisis, microphtalmia and unilateral or bilateral hypoplasia or aplasia of the incisive bones. Sporadic malformations were acephaly and hermaphrodite, dicephaly and malformations of mesenteric vessel in sheep; atresia ani in three goats; and hydranencephaly, atresia ani, ribs malformation with eventracion, cerebellar hypoplasia with hydrocephalus, pulmonary choristoma and meningocele, and siamese twins in cattle. A case of cerebellar hypoplasia with hydrocephalus was negative on immunohistochemistry to bovine viral diarrhea virus. Malformations caused by M. tenuiflora occurred during the whole year. The highest frequency in sheep seems to be associated with the consumption of the plant by ewes after first rains, in the first two months of gestation, when they are supplemented with concentrates, and M. tenuiflora is the main green forage available. Malformations occur mainly in degraded areas of native forest (caatinga) invaded by M. tenuiflora, with lesser variety of other species.Congenital malformations caused by the ingestion of Mimosa tenuiflora have been reported in ruminants in the semiarid of the Brazilian Northeast. This paper reports malformations diagnosed in ruminants, from 2000 to 2008, by the Veterinary Pathology Laboratory of the Federal University of Campina Grande, Patos, PB, in municipalities of the states of Paraiba, Pernambuco and Rio Grande do Norte. During the period, 47 (3.48%) out of 1.347 ascensions were reported as malformations. Based in the type of malformation and in the origin of the animals, malformations were divided in: 1) caused by the ingestion of M. tenuiflora, and 2) sporadic malformations of unknown causes. In sheep, 21 out of 418 ascensions were malformations, being 18 (4.3%) of malformations caused by M. tenuiflora and 3 (0.71%) of sporadic malformations. In cattle, 14 out of 434 ascensions were malformations, from these 8 (1.84%) were caused by M. tenuiflora and 6 (1.38%) were sporadic malformations. In goats, 12 out of 495 ascensions were malformations, being 9 (1.81%) malformations related with the ingestion of M. tenuiflora and 3 (0.6%) sporadic malformations. More frequent malformations caused by M. tenuiflora were arthrogryposis, micrognatia, palatoschisis, microphtalmia and unilateral or bilateral hypoplasia or aplasia of the incisive bones. Sporadic malformations were acephaly and hermaphrodite, dicephaly and malformations of mesenteric vessel in sheep; atresia ani in three goats; and hydranencephaly, atresia ani, ribs malformation with eventracion, cerebellar hypoplasia with hydrocephalus, pulmonary choristoma and meningocele, and siamese twins in cattle. A case of cerebellar hypoplasia with hydrocephalus was negative on immunohistochemistry to bovine viral diarrhea virus. Malformations caused by M. tenuiflora occurred during the whole year. The highest frequency in sheep seems to be associated with the consumption of the plant by ewes after first rains, in the first two months of gestation, when they are supplemented with concentrates, and M. tenuiflora is the main green forage available. Malformations occur mainly in degraded areas of native forest (caatinga) invaded by M. tenuiflora, with lesser variety of other species.