Maria de Lourdes Adrien

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.

Amorimia exotropica poisoning as a presumptive cause of myocardial fibrosis in cattle

The current study reports the investigation on the cause of sudden deaths associated with cardiac fibrosis in cattle in northern Rio Grande do Sul, Brazil. The exclusion of known causes of bovine cardiac fibrosis as well as the absence of the plants in that region whose consumption has already been linked to the disorder motivated this investigation. The condition, which was attributed to the consumption of Amorimia exotropica, affected draft oxen, most of which died suddenly without showing any clinical signs during usual management or work. Globular hearts with white foci at their cut surfaces were the main gross findings, which corresponded microscopically from multifocal to coalescent areas of myocardial fibrosis. To confirm the condition, A. exotropica from the ranches where cattle died from the disease was dosed to rabbits, which showed similar lesions to those seen in dead cattle after receiving 10 doses of 3.6 g/kg at 4-day intervals. Electron microscopy on rabbit tissues revealed severe tumefaction of the cardiomyocytes associated with mitochondrial swelling, displacement, and rupture of the mitochondrial crests, and of the bundles of myofibrils, apart from large glycogen deposits within the sarcoplasm. It is suggested that mitochondrial changes triggered alterations that lead to cardiac fibrosis and that all of these changes were induced by A. exotropica cardiotoxicity.

Abortos em equinos na região sul do Rio Grande do Sul: estudo de 72 casos

A retrospective study of the causes of equine abortion occurred in southern Rio Grande do Sul, Brazil, diagnosed from January 2000 to June 2011 by the Regional Diagnostic Laboratory (LRD) of the Veterinary School, Federal University of Pelotas (UFPel), is reported. Necropsy protocols were reviewed, and from 1.154 horses or equine materials received 72 (6.2%) were abortions. The main cause of abortion in this study was bacterial infection on 36.1% of the cases. Non-infectious causes accounted for 8.3% of the cases, viral abortions for 4.2%, parasitic for 1.4% and inflammatory for 2.8%. In 47.2%, it was not possible to determine the cause/etiology of abortions. Characteristic macroscopic and histological lesions were observed in abortion by Leptospira sp. and equine herpesvirus-1. No lesions were observed in the other cases. It was demonstrated that the analyses of whole fetus with the placenta under refrigeration increases the efficiency of diagnosis. The high number of abortions of undetermined cause was attributed in part to inadequate delivery of fetus material for diagnoses.

Fasciolose aguda em bovinos no Sul do Brasil

Descrevem-se os aspectos epidemiologicos e patologicos de um surto de fasciolose aguda diagnosticado em bovinos na regiao sul do Rio Grande do Sul. De um lote de 70 vacas de tres anos de idade 15 apresentaram perda de peso 30-40 dias antes da paricao. Dessas, 10 vacas abortaram e 5 morreram. Os sinais clinicos caracterizaram-se por diarreia, fraqueza, anemia discreta e ictericia. Na necropsia havia liquido escuro na cavidade abdominal. Na cavidade toracica havia fibrina e coagulos de sangue aderidos ao pericardio e pulmoes, principalmente nos lobos diafragmaticos. O figado estava aumentado de tamanho e a superficie capsular estava irregular com areas claras e petequias. A superficie de corte estava irregular, firme e edematosa e podiam ser observadas estrias hemorragicas atraves do parenquima. Areas de fibrose e trombos esbranquicados ocluindo vasos sanguineos foram, tambem, observados. Os figados das 10 vacas que nao morreram foram condenados no abate por lesoes de fasciolose similares as observadas na necropsia. Microscopicamente, o figado apresentava areas de necrose de coagulacao, focos de hemorragia acentuada e desorganizacao do parenquima com acentuada infiltracao de neutrofilos e eosinofilos. Havia, ainda, fibrose e hiperplasia de celulas de ductos biliares. Formas imaturas de Fasciola hepatica foram observadas no parenquima rodeadas por hepatocitos em degeneracao, neutrofilos e eosinofilos, e hemorragia. O surto ocorreu em uma propriedade localizada em uma area endemica para a fasciolose, embora a forma aguda da enfermidade nao seja frequente em bovinos nesta regiao. E provavel que as vacas tenham se infectado pelas metacercarias liberadas do hospedeiro intermediario no final do outono ou no inicio da primavera na resteva de arroz onde foram colocadas antes da paricao. Embora mortalidade em bovinos devido a fasciolose seja infrequente, surtos podem ocorrer e a utilizacao de fasciolicidas eficientes para controlar as formas imaturas ou adultas deste parasita devem ser administradas aos bovinos para evitar eventuais perdas economicas.

Conditioned food aversion to Ipomoea carnea var. fistulosa induced by Baccharis coridifolia in goats

Baccharis coridifolia is a plant that induces strong conditioned food aversion in ruminants. This research aimed to induce a conditioned food aversion to Ipomoea carnea var. fistulosa in goats, using B. coridifolia as an aversive agent, and to compare the aversion induced by this plant with the aversion induced by lithium chloride (LiCl). Thirteen goats were allotted into two groups: Group 1 with six goats was averted with 175mg/kg of body weight of LiCl and Group 2 with seven goats was averted with 0,25g/kg of bw of dried B. coridifolia. All goats were averted on day 1 after the ingestion of I. carnea. The aversion procedure with LiCl or B. coridifolia in goats from Groups 1 and 2, respectively, was repeated in those goats that again consumed the plant during tests on days 2, 3, and 7. The goats of both groups were challenged in pens on 23 and 38 days after the last day of aversion and challenged in the pasture on days 11, 15, 18, 20, 22, 25, 27 and 29 after the last day of aversion. After this period goats were challenged every 15 days on pasture until the 330o day after the last day of aversion (7th day). Two goats from Group 1 ingested I. carnea on the first day of the pasture challenge, 4 days after the last day of aversive conditioning in the pen. In addition, another goat in Group 1 started to consume the plant on day 18, and other two goats ate it on day 20. One goat in Group 1 that had never eaten I. carnea died on day 155. One goat from Group 2 started to ingest I. carnea on the first day of the pasture challenge, and a second goat started to consume this plant on day 182. At the end of the experiment, on day 330, the other five goats averted with B. coridifolia remained averted. These results suggest that B. coridifolia or an active compound from the plant could be used to induce aversion to toxic plants. Using B. coridifolia would be cheaper and, particularly in flocks with large number of animals, possibly easier than using LiCl, which requires the use of oral gavage and qualified personnel for its implementation.

Surto de criptosporidiose em bezerros no Sul do Rio Grande do Sul

This paper describes the epidemiology, clinical signs and pathology of an outbreak of cryptosporidiosis in calves in Southern Brazil. Thirty-five out of 400 calves with 30-45 days of age were affected and 16 died. The calves were born weak and just after birth they had yellow diarrhea, weight loss, dehydration, depression, and death between 10 and 15 days after onset of clinical signs. Congestion of the bowel and mesenteric blood vessels were observed at necropsy. Intestinal distension by gas and dilation of lymphatic vessels were also observed. Microscopically, the intestine showed flattening of the villi with necrosis and atrophy. Adhered to the surface of the villus epithelial cells there were round basophilic structures of 2- to 5-μm-diameter compatible with Cryptosporidium spp. Electron microscopy revealed the presence of different stages of the agent adhered to the microvilli of enterocytes. We alert the importance of cryptosporidiosis as a primary agent of diarrhea in calves. Preventive measures to reduce economic losses, environmental contamination, and also decrease of risk for public health are necessary.

Paratuberculose em bovinos de corte na região Sul do Rio Grande do Sul

The epidemiological, clinical and pathological aspects of paratuberculosis diagnosed in southern Rio Grande do Sul in a beef cattle property are described. Two cattle raised extensively and that presented progressive weight loss and chronic diarrhea were necropsied. The mesenteric lymph nodes were enlarged and edematous. The intestinal mucosa was thickened and wrinkled with cerebroid aspect, especially in the final portion of the ileum, ileocecal valve and cecum. Fragments of the organs were fixed in 10% formalin, embedded in paraffin, sectioned and stained with hematoxylin and eosin (HE) and Ziehl-Neelsen (ZN). Feces samples were referred to Departamento de Medicina Veterinaria, Area de Medicina Veterinaria Preventiva da Universidade Federal Rural de Pernambuco, for the cultivation of Mycobacterium avium subsp. paratuberculosis with Lowenstein Jensen for mycobacterial and PCR analysis. Histologically, granulomatous enteritis was observed in the jejunum, ileum, cecum and rectum, and in multifocal areas the duodenum and colon. Lymphangitis and granulomatous adenitis was also observed. In ZN staining numerous resistant acid-fast bacilli (AFB) within macrophages, giant cells of Langhans and mesenteric lymph nodes in the jejunum, ileum cecum and rectum were observed. There was no bacterial growth in stool samples. Five samples amplified the gene sequence IS900 specific for Mycobacterium aviumsubsp. paratuberculosis. It can be concluded that paratuberculosis, despite the few reports, occurs in beef cattle raised extensively in southern Rio Grande do Sul, Paratuberculosis may have a higher prevalence in the region than it is assumed. There is need for diagnosis of this disease and to assume effective measures for its control, as for many it is still considered an exotic malady in Brazil.

Aversão alimentar condicionada a Ipomoea carnea var. fistulosa em ovinos

Fifteen sheep were adapted to consume I. carnea for 36 days. Subsequently sheep were randomly divided into three groups of five sheep each. Group 1 was averted with LiCl, group 2 was averted with B. coridifolia, and Group 3 was the control group. The sheep were periodically tested by exposing to I. carnea in the pasture and in individual pens up to the 74th day after the first day of aversion. On the 14th and 19th days the number of sheep in Group 3 that consumed I. carnea was significantly higher than the number of sheep that consumed I. carnea in Groups 1 and 2 (P=0.004 and P=0.0004, respectively). On day 24 the number of sheep that consumed I. carnea was significantly higher in Group 3 than Group 1 (P=0.004). After the challenge on the 29th day no significant difference (P>0.05) was observed in the consumption of the plant among the three groups. On day 7 of the aversion period control sheep (group 3) consumed more I. carnea than did the sheep from Groups 1 and 2 (P=0.0002 and P=0.01, respectively). After this period there was no difference in the amount of I. carnea ingested by the sheep in other individual challenges. The maximum time spent by the sheep grazing I. carnea was 2.4%±1.6% of the total grazing time and no difference was observed among the groups. I. carnea was never consumed avidly by the experimental sheep, and some LiCl animals did not learn to avoid the plant on a consistent basis. Conditioning an incomplete aversion indicates that neither LiCl or B. coridifolia will work with sheep in field settings to reduce or eliminate consumption of I. carnea.

Intoxicação por organoclorados (endosulfan) em bovinos no Uruguai

An outbreak of organochlorine (endosulfan) poisoning in cattle registered in April 2009 on a farm for calf rearing is reported. Cattle showed neurological symptoms one day after an accidental discharge of a crop duster releasing 700 liter of pesticide with a water-based solution of endosulfan and cypermethrin had occurred. The morbidity was 7.7% and the mortality 6.0%. The symptoms in the cattle were sialorrhea, ataxia, hypersensitivity, muscle twitching, pedaling, teeth grinding, excitability, convulsions, recumbency and death. At necropsy of the animals and histopathological examination non significant lesions were found. There was also a significant mortality of fish in the gorge of the affected paddock. Through gas chromatography the presence of endosulfan and/or its metabolite above references levels was identified in samples of fat, liver and rumen contents of affected animals, as well as in fish and water collected, what confirmed the organochlorine poisoning.

Ultrastructural lesions in the myocardium and kidneys of rabbits in experimental acute Amorimia exotropica poisoning

Amorimia exotropica is an important plant associated with sudden death in cattle in Southern Brazil. In order to understand the mechanisms by which A. exotropica causes acute lesions in the heart and kidney of intoxicated animals, an experiment was conducted to determine the histopathology and ultrastructure of myocardial and renal lesions of intoxicated rabbits. After receiving 18g/kg of dried plant, six rabbits died suddenly. At necropsy, the liver was swollen and no other macroscopic lesions were observed. Histologically, centrolobular and midzonal hepatocytes were vacuolated. These vacuoles were strong PAS stained positive, suggesting that they corresponded to glycogen accumulations. In some regions of the ventricular septum and ventricles were found vacuoles of different sizes and the kidneys of two rabbits showed vacuolar degeneration on distal convoluted tubules. Ultrastructurally, the myocardium had cardiomyocytes swelling with separation of myofibrils bundles and rupture and disorganization of the sarcomeres. The mitochondria displayed swelling, disorganization, disruption of the mitochondrial cristae, and electron-dense matrix. Some mitochondria exhibited eccentric projections of their membranes with disruption of both outer and inner membranes. The sarcoplasmic reticulum had no alterations, whereas the T-tubule system was occasionally dilated and ruptured. The kidneys had mitochondrial swelling with disorganization and disruption of the mitochondrial cristae. The vacuoles result from the swelling of the endoplasmatic reticulum and usually were located between two basolateral infoldings and mitochondria, occurring preferentially around the nucleus. The myocytes and T system damages induced by A. exotropica result in acute heart failure and death. Furthermore, this mechanism of cardiotoxicity may be common to all plant containing monofluoroacetate.