Diego M. Oliveira

Plantas tóxicas para ruminantes e eqüídeos no Norte Piauiense

The objective of this study was to survey toxic plants for ruminants and equidae in northern Piaui. Seventy one persons were interviewed, including farmers, veterinary practitioners, agronomists, and agrarian technicians from 16 municipalities, performing at least four interviews in each municipality. The most common plant mentioned as a cause of poisoning was Ipomoea asarifolia, which is a well known cause of tremogenic disease in ruminants. Stryphnodendron coriaceum which causes digestive signs was referred as a common cause of death, and is probably the plant that causes most cattle deaths in the region. Enterolobium contortisiliquum was also mentioned as a frequent cause of digestive signs, abortion and photosensitization in cattle. Outbreaks of nephrosis caused by Thiloa glaucocarpa are frequent at the beginning of the raining season. Poisoning by the cyanogenic plants Manihot spp. e Piptadenia macrocarpa are a cause of peracute deaths. Other plants mentioned as toxic were Buchenavia tomentosa, Caesalpinia sp., Brunfelsia sp., Luetzelburgia sp., Hybantus ipecaconha, Phisalys angulata, and Spondias luta. Farmers report that goats are poisoned by the ingestion of the pods of Luetzelburgia sp., which causes digestive signs and death. The ingestion of the fruits of Buchenavia tomentosa is associated with digestive signs and and abortion in ruminants. Brunfelsia sp. is mentioned as a cause of nervous signs at the start of the raining season and donkeys are apparently more affected. The consumption of the fruits of Spondias luta are associated with diarrhea in goats. Recent unpublished experiments demonstrated the toxicity of Brunfelsia sp. as a cause of nervous signs and of Luetzelburgia sp. as a cause of digestive signs in goats. Experiments with other plants are necessary to confirm their toxicity.

High mortality and lesions of the central nervous system in trypanosomosis by Trypanosoma vivax in Brazilian hair sheep.

Here, we report an outbreak of Trypanosoma vivax-induced trypanosomosis in Brazilian hair sheep on a farm in Paraíba state, a non-endemic region in northeastern Brazilian. Of 306 total sheep, 240 showed clinical signs and 216 died. Clinical signs included anorexia, lethargy, anemia, rough hair coat, weight loss, submandibular edema, abortion, and in some cases, neurological signs such as head pressing, lateral recumbence, paddling movements and muscle tremors. T. vivax was identified by blood smear analysis and polymerase chain reaction (PCR). At necropsy, animals exhibited watery blood, pale tissue coloring, and the presence of liquid in the peritoneal cavity and pericardial sac. Histologically, nonsuppurative myocarditis and meningoencephalitis with areas of malacia were observed. After treatment, no parasites were detected by blood smear analysis or PCR. Cattle and buffalo that remained in the same pasture were also infected but presented with asymptomatic infections. Epidemiological data suggest that T. vivax was introduced to the farm and the susceptible flock by buffalos that were asymptomatic carriers of the infection; T. vivax was most likely transmitted by Tabanus spp. bites and also iatrogenically.

Intoxicação por Mascagnia rigida (Malpighiaceae) em ovinos e caprinos

Mascagnia rigida is the most important toxic plant for cattle in the Northeastern region of Brazil, causing sudden death during exercise. The objectives of this research were to report three outbreaks of poisoning by M. rigida in sheep and one in goats in the semiarid of the state of Paraiba, to reproduce experimentally the disease, and to determine if the active principle of the plant is eliminated through the milk. The outbreaks occurred at beginning of the raining season, when the plant sprouts ahead other forages, or after the end of the raining season, when M. rigida stayed green and other forages had dried. In the experimental reproduction of the poisoning doses of 10 and 20g of M. rigida per kg body weight from two different regions were lethal to 3 goats and 3 sheep. One goat that ingested 20g/kg and a sheep that ingested 10g/kg recovered. Two sheep and two goats that ingested 5g/kg had mild clinical signs and recovered. Clinical signs of experimental and spontaneous cases were ingurgitation of the jugular veins, reluctance to move, sternal recumbence, incoordination, respiratory distress, depression, instability, and muscular tremors. Death occurred after a clinical manifestation period of about 4 min to 27h40min. The main lesions were pulmonary edema and vacuolization and necrosis of epithelial cells in some renal tubules. To test if the active principle of M. rigida causes sudden deaths in newborn lambs and kids, 2g/kg of the plant were given daily to two goats and five sheep in the 15 days previous to parturition. One sheep aborted two lambs, 5 days before parturition. The four lambs of the other four sheep ingested the colostrum without problems. The kid from one goat ingested the colostrum and died suddenly 5 minutes after. The kid from the other goat died immediately after parturition before ingestion of colostrum. These results suggest that the active principle of M. rigida was eliminated through the milk at toxic doses for the kids. Management measures to prevent the poisoning are recommended.

Intoxicação experimental por Ipomoea asarifolia (Convolvulaceae) em caprinos e ovinos

Ipomoea asarifolia causes a tremogenic syndrome in sheep, goats, cattle and buffaloes. The objectives of the experiments were (1) to determine the toxicity to goats of fresh I. asarifolia collected during the raining and the dry season, and the toxicity of the dried plant, and (2) to determine the toxicity of the plant to sheep, and if the active principle is eliminated through the milk. In the first experiment the plant collected in the dry season and in the raining season was fed to 16 goats. The plant collected during the dry season caused clinical signs at the daily doses of 5g and 10g/kg body weight. The plant collected during the raining season was toxic at daily doses of 20g and 30g/kg, indicating that the plant is more toxic during the dry season. The plant collected in the dry season and dried was fed to 9 goats at doses of 1.7g, 2.0g, 3.4g, and 5.1g per kg. Daily doses of 3.0g, 4.0g and 5.1g/kg caused clinical signs, showing that the plant maintains its toxicity after being dried. In the second experiment the fresh plant collected in the dry and in the raining season was fed to 10 sheep. The plant collected in the dry season was toxic at the dose of 5g/kg, and the plant collected in the raining season was toxic at the doses of 10g and 20g/kg. The experimental results suggest that sheep are more susceptible to the poisoning than goats. As some farmers mentioned that suckling non-grazing lambs are poisoned by milk ingestion, I. asarifolia was fed at daily doses of 2.5g, 5.0g and 10g/kg for variable periods to 5 sheep from the day of parturition (2 sheep), after the last day of pregnancy (1 sheep) and 60 days before parturition (2 sheep). The sheep but not the lambs showed clinical signs of intoxication suggesting that the active principle is not eliminated through the milk at doses toxic for the lambs. In one euthanized sheep no gross or histologic lesions were detected. The main ultra-structural findings were found in Purkinje cell dendrites and included swelling, decrease or absence of dendritic spines, decrease or absence of neurotubules and neurofilaments and vacuolation of the dendroplasm. Swelling of the smooth endoplasmic reticulum and granular eletrondense inclusions in dendroplasm was observed. Swelling of astrocyte foot processes was conspicuous. It is suggested that these alterations are a result of continuous tremors induced by the plant with liberation of glutamate causing excitotoxicity, which probably constitutes a neuronal mechanism of defense.

Doenças do sistema nervoso central de equídeos no semi-árido

Diseases of the central nervous system (CNS) in equidae are important in these species, and their knowledge in the different Brazilian regions is necessary to determine efficient control and preventive measures. This paper reports epidemiologic aspects, clinical signs and pathology of diseases of the CNS in equidae diagnosed by the Veterinary Pathology Laboratory at the Federal University of Campina Grande in the city of Patos, state of Paraiba, northeastern Brazil, during 2002-2008. During the period, 159 cases or outbreaks of those diseases were studied, 49 (30.8%) affecting the CNS. Hepatic encephalopathy caused by Crotalaria retusa poisoning, with 14 cases (28.5%), was the main disease observed. Tetanus was diagnosed in 13 (26.5%) cases and rabies in 11 (22.4%). In seven (14.2%) cases the death or euthanasia was due to traumatic lesions of the CNS. Also were diagnosed 1 case of leucoencephalomalacia, 1 case of encephalitis by equine herpesvirus-1, 1 case of intracarotid artery injection, 1 outbreak of Eastern equine encephalitis, 1 of Turbina cordata poisoning, and 1 of a tremogenic disease of unknown cause. In 5 cases the diagnosis was inconclusive. This paper indicates the importance of diagnostic veterinary laboratories, in the different Brazilian regions, for the knowledge of livestock diseases.

Paratuberculose em caprinos e ovinos no Brasil

This paper reports paratuberculosis in sheep and goats for the first time in Brazil. On Farm 1 in a flock of 33 goats and 13 sheep, one adult female goat presented progressive weight loss during about one year, and soft feces during one month before death. All the animals from the flock were submitted to the comparative tuberculin test. One sheep was positive to the avian tuberculin (2.2%) and in two the results were inconclusive. On Farm 2, in a flock of 200 sheep and 80 goats, one adult ewe presented progressive weight loss during about one year, and soft feces during 20 days before death. All sheep older than four months of age and 23 goats were submitted to tuberculin test with avian tuberculin; 47 (25.4%) sheep were positive, 115 (61.5%) had inconclusive results, and 25 (13.4%) were negative. No positive tuberculin test were observed in the goats, but in 11 (47.8%) the test was inconclusive and in 12 (52.2%) was negative. At necropsy both affected animals had enlarged mesenteric lymph nodes. In the affected sheep, the gut wall was thickened and corrugated, mainly in the ileum and ileocecal valve. Histologically, granulomas with mainly foamy macrophages were observed in the lamina propria and submucosa of the gut, in mesenteric lymph nodes, and in the goat also in the liver. One tuberculin positive sheep and one tuberculin negative goat from Farm 1 were euthanized and necropsied. A mild thickened of the intestinal wall was observed grossly in both animals. Inflammatory infiltrate with mainly lymphocytes was observed on the submucosa and lamina propria of the gut. In the four cases acid-alcohol positive rods, positive for Mycobacterium spp. on immunohistochemical examination were observed in macrophages and lymphocytes. New studies are necessary to know the prevalence and economical impact of paratuberculosis in goats and sheep in Brazil, to determine control measures, and to evaluate the risk of human transmission.

Intoxicações por plantas diagnosticadas em ruminantes e equinos e estimativa das perdas econômicas na Paraíba

ABSTRACT This paper reports plant poisonings in ruminants and horses, diagnosed between 2000 and 2007, in the Veterinary Pathology Laboratory at the Federal University of Campina Grande, in the city of Patos, state of Paraiba. In cattle, 7.4% of the diseases diagnosed were caused by poisonous plants. Outbreaks were caused by Centhraterum brachylepis (1), Brachiaria spp. (1), Crotalaria retusa (2), Ipomoea batatas (1), Marsdenia sp. (1), grass containing nitrites (3 outbreaks, 1 by Echinochloa polystachya and 2 by Pennisetum purpureum), Palicourea aeneofusca (1), Prosopis juliflora (3), Nerium oleander (1), and Mimosa tenuiflora (7). In sheep, 13% of the diseases diagnosed were caused by toxic plants. Four outbreaks were caused by Ipomoea asarifolia, 3 by Brachiaria spp., 2 by Crotalaria retusa, 2 by Tephrosia cinerea, 1 by Panicum dichotomiflorum, 1 by Mascagnia rigida, and 20 by Mimosa tenuiflora. In goats, 6.4% of the diseases were caused by toxic plants. Seven outbreaks were caused by Mimosa tenuiflora, 1 by Ipomoea asarifolia, 1 by Ipomoea carnea, 1 by Ipomoea riedelli, 3 by Prosopis juliflora, 1 by Arrabidaea corallina, 2 by Aspidosperma pyrifolium, and 2 by Turbina cordata. In horses, 14% of the diagnosed diseases were due to plants poisonings including 12 outbreaks caused by Crotalaria retusa and one by Turbina cordata. Annual losses in the state of Paraiba by deaths of livestock are estimated in 3,895 cattle, 8,374 sheep, 6,390 goats, and 366 horses, which represent about US

Intoxicação por Cnidoscolus phyllacanthus (Euphorbiaceae) em caprinos

1,380,000. Epidemiologic, clinical and pathologic aspects of poisonings by Crotalaria retusa in cattle, Brachiaria spp. in sheep, Prosopis juliflora in cattle and goats, Nerium oleander in cattle, Opuntia ficus-indica in goats, and Turbina cordata in horses and goats are reported.

Bovine cryptococcal meningoencephalitis

Cnidoscolus phyllacanthus (Euphorbiaceae), with the common name favela, is a generally spiny plant of the Brazilian semiarid. Mainly during the dry season livestock browse its leaves from the shrubs or ingest the dry leaves fallen to the ground. Farmers report the spontaneous poisoning by this plant when livestock has access to shrubs or branches that had been cut. Different parts of the ground fresh plant, diluted in water, are used by people in the semiarid to hunt birds. To determine the toxicity of C. phyllacanthus, leaves of the non-spiny plant were fed by hand to a goat by putting small amount into its mouth. After the consumption of 4.7g/kg body weight, the goat had tachycardia, tachypnoea, dyspnoea, nystagmus, opisthotonos and sternal recumbence. The death occurred 30 minutes after the onset of clinical signs. Fresh leaves from the same plants were given to 8 goats at doses of 0.5-2.5g/kg without causing clinical signs. Three goats showed clinical signs after the ingestion of 3g/kg. Clinical signs were similar to those observed in cyanide poisoning. Two goats given 0.5mg/kg of a 20% solution of sodium thiosulphate recovered immediately after treatment. Another goat recovered spontaneously. Leaves from the same plants were sun-dried during variable periods for 8-30 days, and then given to 8 goats. The goat that ingested the plant dried at the sun during 8 days died after the ingestion of 3 g/kg. The goat that ingested the plant, exposed to the sun for 9 days, showed clinical signs after the ingestion of 1.13g/kg, but recovered spontaneously. The goats that ingested the leaves exposed to the sun during 10-29 days showed clinical signs after the ingestion of 3g/kg, but recovered spontaneously or after treatment with sodium thiosulphate. No clinical signs were observed in the goat that ingested the plant that had been exposed to the sun during 30 days. In another experiment ground leaves of the plant were dried at the sun for 1, 2, 3, and 4 days and given to goats at the dose of 3g/kg. Goats that received the plant dried for 1, 2 or 3 days showed clinical signs, but recovered spontaneously. The goat that ingested the plant dried 4 days showed no clinical signs. Leaves of the spineless C. phyllacanthus used in the experiments, 20 samples of leaves from spiny plants, 3 samples of the ground plant stem, and 2 samples of fruits were positive with the picrosodic paper test for HCN. These results demonstrated that C. phyllacanthus is a cyanogenic plant. After being cut the entire leaves maintain their toxicity for up to 30 days, and the ground leaves for up to 3 days. After the end of the raining season dry leaves fallen to the ground and tested within a short period were negative for HCN. These results have to be taken into account for the use of C. phyllacanthus as forage.

Focal symmetrical encephalomalacia in a goat.

Cryptococcal meningitis and encephalitis is reported in a 5-year-old bull. The clinical signs included multifocal neurological deficits manifested by hypermetria, ataxia, depression, circling, impaired vision, head pressing, low head carriage, wide-based stance, and falling to the side or backwards. At necropsy, 6 cavities with a gelatinous content were observed in the brain and brain stem, and the meninges were thickened and off white. Numerous yeasts, with a nonstaining capsule, and associated mild inflammatory reaction were observed histologically. Specimens for culture were not collected at necropsy, but the identity of the yeast in tissue sections as Cryptococcus neoformans var. grubii was supported by immunohistochemistry.