Ivon M. Tabosa

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.

Intoxicação por Crotalaria retusa (Fabaceae) em Eqüídeos no semi-árido da Paraíba

From 2000 to 2003 eight cases of poisoning by Crotalaria retusa L. were observed in horses on 8 farms in the semiarid region of Paraiba and Ceara. C. retusa was found in all farms. The main clinical signs were characteristic of hepatic encephalopathy, with dullness or hyperexcitability, head pressing, compulsive walking or circling and, occasionally, violent uncontrollable galloping. Decreased cranial nerve reflexes, ataxia and weakness were also observed. Other clinical signs were anorexia, weight loss, photosensitization and jaundice. The clinical manifestation period varied from 4 to 40 days, but most horses had a previous history of weight loss. At necropsy the livers were hard, with irregular surface and white areas mixed with dark red areas and increased lobular pattern. Mild jaundice, ascitis, hydropericardium and hydrothorax were also observed. Edema and moderate congestion were seen in the lungs. Histologic changes of the liver were characterized by fibrosis, mainly periportal, megalocitosis and bile duct cell proliferation. Multifocal areas of centrilobular or midzonal hemorrhages were also observed. Centrilobular hemorrhagic necrosis was present in two horses. Alzheimer type II astrocytes were observed, isolated or in groups, mainly in the caudate nucleus and cortex in 4 horses. The poisoning was experimentally produced in 1 adult horse and 3 adult donkeys. The horse received daily 100 g of C. retusa seeds and died 52 days after the beginning of the experiment. The dried whole C. retusa was mixed with grass and given to the 3 experimental donkeys at daily doses of 10g/kg, 5g/kg and 2.5g/kg, respectively. The donkey treated with 5g per kg died 48 days after beginning of the experiment and the other two were sacrificed at 120 days. Clinical signs and pathology were similar to those observed in spontaneous cases, but Alhzeimer type II astrocytes were observed only in the donkey that died 48 days after the beginning of ingestion of the plant material. The concentration of monocrotaline in the whole plant given to the donkeys was 0.5%.

Mortalidade perinatal de cordeiros no semi-árido da Paraíba

The causes of perinatal lamb mortality were studied, from March 2002 to October 2004, on 27 farms in the semiarid region of Paraiba, northeastern Brazil. In 90 lambs necropsied the following frequency of different causes of death was found: neonatal infections (41.1%), malformations (23.3%), dystocia (10%), starvation/hypothermia (10%), abortion (4.4%), and predation (2.2%). Regarding the time of death, 4.4% of the lambs died before parturition, 10% during parturition, 30% on the first day after parturition, 20% between the second and the third day, and 35.6% between the 4th and the 28th day after parturition. The assistance during parturition, umbilical disinfection of the neonates, colostrum ingestion between 2 and 6 hours after parturition, and keeping the ewes in healthy environmental conditions during and after parturition could improve lamb surviving. The high frequency of malformations in different breeds suggests that malformations are due to a toxic plant. The main defects were permanent flexure of the front legs, brachygnathia, cleft palate, and other head malformations. In a recent report the authors demonstrated the teratogenic effects of Mimosa tenuiflora, a very common plant in the semiarid region, which is probably the cause of those malformations. Lambs which died due to starvation/hypothermia and had low birth weight (1.37 ± 0.70kg), suggesting that a better nutrition of the ewe during the last trimester of gestation is a way to control this cause of lamb mortality. Considering that in the northeastern region, in most farms, the rams stay with the ewes during the whole year, the adoption of a breeding season would help to control the different causes of perinatal lamb mortality.

Contagious agalactia by Mycoplasma agalactiae in small ruminants in Brazil: first report

Two outbreaks of contagious agalactia by Mycoplasma agalactiae occurred in Paraiba State, Northeastern Region of Brazil are reported. The disease was characterized by mastitis, agalactia and polyarthritis in does and polyarthritis and conjunctivitis in kids and lambs. Fever and anorexia were also observed. Morbidy was from 26.1% to 100% in does, 36.5 to 100% in kids and 49% in lambs. In one farm 14.3% of the lactating goats and 6.4% of the kids died or were euthanized. In the other, 3.3% of the does, 36.5% of the kids and 22.9% of the lambs died and 84 affected goats were euthanized to control the disease. M. agalactiae was isolated from milk, joint exudates, nasal swabs and ear washings. The colonies were characteristic of Mycoplasma and the agent did not ferment both glucose and arginin. It was typed as Mycoplasma agalactiae by immunoperoxidase and PCR. This is the first report of M. agalactiae infection in Brazil, but the source of the infection remains unknown.

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.

Polioencefalomalacia em caprinos e ovinos na região semi-árida do Nordeste do Brasil

Seven outbreaks of polioencephalomalacia in goats and 3 in sheep are reported from the semiarid region of northeastern Brazil. Animals of different ages were affected in various seasons of the year. In 5 outbreaks the animals were supplemented with concentrate ration and in 5 others they were only grazing on pastures. In one outbreak sheep were supplemented with an energy-protein-mineral mixture containing 1.3% of sulfur flower. Clinical signs were characterized by blindness, depression, head pressing, circling, grinding of the teeth, incoordination, spastic paralysis, ataxia, depression of the palpebral and pupillary reflexes, lateral strabismus, nystagmus, and dilated pupils. Nine affected animals were treated with thiamine and dexamethasone; 7 of them recovered but 2 died. The diagnosis of the disease was based on the recovered animals after treatment and/or on the histologic lesions. The clinical course varied from 2 to 15 days. On three animals post-mortem examination was made. One had herniation of the cerebellum through the Foramen magnum and softening of the cerebral cortex. The cut surface of the cerebral cortex showed cavitation and yellowish discoloration. Another animal had only cerebellar herniation. In a third animal no gross lesions were observed. Histological changes in the 3 animals were laminar necrosis of the cerebral cortex, and in 2 malacia of the thalamus and the rostral colliculi was also observed. In 9 outbreaks the cause of the disease was not determined, but one was probably due to sulfur toxicosis caused by the high sulfur content of the energy-protein-mineral mixture containing 1.3% of sulfur flower (96% sulfur) and 30% chicken litter (0.39% sulfur).

Intoxicação por nitratos e nitritos em bovinos por ingestão de Echinochloa polystachya (capim-mandante) e Pennisetum purpureum (capim-elefante) no sertão da Paraíba

Three outbreaks of nitrate poisoning are reported from the semiarid region of the state of Paraiba, northeastern Brazil. One outbreak caused by Echinochloa polystachya (capim-mandante) and two others caused by Pennisetum purpureum (capim-elefante) occurred at the end of the dry season, after the first rains. In one of the outbreaks caused by Pennisetum purpureum part of the pasture had been fertilized with cattle manure. Five out of 11 cattle died on one farm, 27 out of 81 on another, and 3 out of 9 on a third one. Clinical signs were anorexia, respiratory distress, teeth grinding, depression or hyperexitability, tremors, abdominal contractions, salivation, nasal discharge, uncoordinated gait, cyanosis, and finally recumbency. Nitrates and nitrites in the blood of affected cattle and pastures were determined by the diphenylamine test. It is suggested that the main reason for nitrate accumulation in the grasses was the prolonged draught followed by rain. In one of the outbreaks caused by Pennisetum purpureum, another reason was probably the fertilization of the soil with cattle manure.

Síndrome do Cabrito Mole ("Floppy Kid")

The Floppy Kid Syndrome is an acute disease of unknown cause, which affects 3 to 10 day-old kids. It is characterized by severe depression, flacid paralysis, dilatation of the abdomen and metabolic acidosis, without dehydration (paradoxical acidosis). The disease was decribed for the first time in the United States in 1987 and later in Canada and several countries in Europe (Tremblay et al. 1991, Meier 2002). This paper has the objective to show the characteristics of the disease, which already has been diagnosed in Paraiba and occurs probably in other states of Brazil, so that veterinarians and research workers could recognize it and give informations, which may clarify its etiology and pathogenic aspects. Additionally, the epidemiology, clinical signs and pathology of four outbreaks of floppy kid syndrome in Paraiba are reported.

Pythiosis of the digestive tract in sheep

Cutaneous and rhinofacial infections by Pythium insidiosum have previously been reported in sheep in Brazil. In the current study, a new form of pythiosis involving the alimentary tract of 2 nursing lambs from 2 different farms in the semiarid region of Brazil is described. The first lamb showed food regurgitation, lethargy, and anorexia, and died 5 days after the presentation of clinical signs. The second lamb had no history of gastrointestinal disease before death. Necropsy findings were similar in both lambs. The mucosa of the esophagus, reticulum, rumen, omasum, and abomasum showed ulcerated areas covered by yellowish caseous granular exudate. The lesions were transmural and extended to the serosal surfaces, and adhesions were observed between the serosa of the forestomachs and abomasum to the liver and diaphragm. Histologic lesions consisted of pyogranulomatous necrotizing transmural esophagitis, rumenitis, reticulitis, omasitis, and abomasitis with vascular thrombosis and intralesional hyphae. Pythium insidiosum was confirmed as the etiology by immunohistochemistry and culture. The presence of sheep in the vicinity of water ponds during the hot, dry season when forage is not available in the pastures seems to be the main predisposing factor for the occurrence of pythiosis in sheep in the Brazilian semiarid region.

Utilização de vagens de Prosopis juliflora na alimentação de ovinos e caprinos

The ingestion of pods of Prosopis juliflora causes nervous signs in cattle due to lesions in the trigeminal nuclei, and colics in horses due to the formation of phytobezoars in the gut. The objective of this research was to study the toxicity for of P. juliflora pods in horses, and to establish if 30% of pods in the feed are not toxic for cattle. Three experiments were performed. In Experiment 1, two steers were fed, during one year, with food containing 30% of P. juliflora pods. None of the experimental animals showed nervous signs. In Experiment 2, two horses received pods of P. juliflora in amount equivalent to 1% of their bw during four months. For other 3 months this amount was increased to 1.5% bw. In Experiment 3, two horses received P. juliflora pods ad libitum during 30 days. None of the horses showed nervous signs or colic due to the presence of phytobezoars in the gut. These results suggest that P. juliflora pods, despite their toxicity, can be used to feed cattle at concentrations of 30% of the food during one year. There are no restrictions for the use of P. juliflora pods in horses in confined or semi-confined systems, but it is not recommended to maintain equidae grazing in areas where P. juliflora is fructificating. It is suggested that there is a loss in the capacity of the pods to form phytobezoars after harvesting. Cattle may be kept in areas invaded by P. juliflora, during fructification, for no more than 30 days.