Margarida Buss Raffi

Equine monocytic Ehrlichiosis (Potomac horse fever) in horses in Uruguay and southern Brazil

A disease named locally as churrío or churrido equino (i.e., equine scours) has occurred for at least 100 years in Uruguay and southern Brazil in farms along both shores of the Merín lake. This report describes cases of churrido equino and provides serologic, pathologic, and DNA-based evidence indicating that the disease is in fact equine monocytic ehrlichiosis (Potomac horse fever). Results of an epidemiological investigation conducted on an endemic farm are also presented. Clinical signs in 12 horses were fever, depression, diarrhea, dehydration, and sometimes colic and distal hind limb edema. Postmortem findings of 3 horses were of acute enterocolitis. Inclusion bodies containing ehrlichial organisms were found in the cytoplasm of macrophages of the large colon of 1 horse. Eleven of the 12 horses were serologically positive to Ehrlichia risticii (indirect fluorescent antibody assay) and, of 3 paired samples, 2 showed seroconversion. Ehrlichia risticii DNA was identified by a nested polymerase chain reaction in peripheral blood of an affected horse. A healthy horse inoculated with peripheral blood from an affected horse developed the disease and antibodies to E. risticii. The disease had a peak incidence in March (summer) and was statistically associated with a marshy ecosystem near the Merín lake, where large numbers of Pomacea spp. (Ampullariidae) snails were found. Incidence density was almost 8 times higher in nonnative horses than in native horses. It was concluded that the previous diarrheic disease of horses known in Uruguay and southern Brazil as churrido equino is equine monocytic ehrlichiosis.

Epidemiologia da pitiose equina na Região Sul do Rio Grande do Sul

A survey of cases of equine pythiosis received by the Laboratorio Regional de Diagnostico, Faculdade de Veterinaria, Universidade Federal de Pelotas, from January 1979 to July 2011, was made to determine the epidemiological conditions in which the disease occurs in southern Rio Grande do Sul. Samples from 1888 horses were received; 435 samples were from the integumentary system, of which 63 (14.5%) corresponded to pythiosis. The affected animals were of both sexes and their age ranged from 8 months to 22 years. Crioulo was the most prevalent breed. Most cases of pythiosis were sent to the laboratory between March and June. The evolution of the lesions due to pythiosis ranged from 2 weeks to 1 year. The municipalities with the greatest number of cases were Pelotas (22/63), Santa Vitoria do Palmar (15/63) and Rio Grande (8/63). With respect to the climatic data, in most cases the maximum temperature in the probable month of infection was above or close to 30°C during at least one day. The observation of cases in the colder seasons of the year could be due to the stagnant water temperature higher than the temperature of the air, which allows the development of infective structures of Pythium insidiosum.

Avian pox virus infection in a common barn owl (Tyto alba) in southern Brazil

A young common barn owl (Tyto alba) was referred to the Nucleo de Reabilitacao da Fauna Silvestre (Nurfs), Federal University of Pelotas (UFPel), after been found in a barn of a brick factory in the urban area of Pelotas, Rio Grande do Sul, Brazil. The bird was apathic, weak and with crusty lesions in the featherless areas (eyes, beak, legs), and died soon after arrival at Nurfs. Necropsy and histopathological examination of the lesions were carried out. The hyperplasia and hypertrophy of the cutaneous lesions, several eosinophilic intracyto-plasmic inclusion bodies in epithelial cells (Bollinger bodies), as well as particles characteristic of poxvirus, observed by electronic microscopy, confirmed the infection by avian poxvirus, what highlights the importance of Tyto alba as carrier of the virus in the wild.

Raiva em bovinos na Região Sul do Rio Grande do Sul: epidemiologia e diagnóstico imuno-histoquímico

A retrospective study of paralytic rabies in cattle in southern Rio Grande do Sul, Brazil, diagnosed from 1978 to 2007 by the Regional Diagnostic Laboratory (LRD) of the Veterinary School, Federal University of Pelotas (UFPel), with 77 outbreaks or isolated cases of paralytic rabies in cattle, is reported. A study of 11 outbreaks of rabies, observed from 2008 to 2010 in the same region, where 42 cattle aged 1-6 years died from a total of 686 at risk, with a clinical course of 4 to 14 days, was also made. The morbidity of all outbreaks diagnosed from 1978-2010 ranged from 0.37% to 20%; 24 cases occurred in autumn, 7 in spring, 14 in summer, and 16 in winter. The diagnosis was achieved by epidemiology, clinical signs and histological lesions. Immunohistochemistry using rabies virus polyclonal antibody was positive in all cases. In two cases non-suppurative meningoencephalitis was not observed, and the diagnosis was confirmed by immunohistochemistry. This technique is an important tool for the diagnosis of rabies and should be used in all suspected cases in which no evidence of encephalitis is observed.

Estudos histomorfométrico e histológico das lesões ósseas causadas por flúor em aves

Sodium fluoride was administered in the water to 2 groups of 25 Shaver female poultry. Group A received fluoride from 1 to 120 days of age and group B from 61 to 120 days. Each group was divided into 5 treatments, with 5 chickens each, which received 0, 25, 50, 200, and 400 ppm of fluoride in the water, respectively. All animals were killed at 120 days of age. For histomorphometric studies the left femur and tibia were used, and for histologic studies the right femur and tibia. In the cortical bone, cortical porosity was slightly increased by fluoride, but the differences with the control group were not significant. Cortical thickness increased in the animals treated with fluoride (p<0,05, r2 = 0,59 ). In the trabecular bone, of group A, trabecular thickness (TT) (p<0,05, r2 = 0,63) and trabecular bone volume (TBV) (p<0,05, r2 = 0,72) increased in treatments receiving 25-200 ppm, and decreased in the 400 ppm treatment, as it was demonstrated by quadratic regression analysis. In group B there was a positive linear correlation on TT (p<0,05, r2 = 0,98) and TBV (p<0,05, r2 = 0,77) with fluoride ingestion.The osteoid surface was also positively correlated with the amount of fluoride ingested by the animals (p<0,001, r2 = 0,80). These results suggest that fluoride improves osteoblastic function resulting in increased osteoid production and bone apposition. In the other hand, in the animals treated with 400 ppm of fluoride for 120 days bone apposition was reduced suggesting a functional alteration of the osteoblasts or improved bone resorption. In the histological study of bone tissue all animals that received fluoride showed an increased trabecular thickness which was more marked in the 200-400 ppm treatments. In chickens treated with 200-400 ppm of fluoride osteoblasts and osteoclasts were more numerous suggesting an increased bone turnover. In cortical bone Haversian canals were narrowed on the periosteal surfaces and resorption spaces were enlarged on the endosteal surfaces.

Intoxicação por organofosforados em búfalos (Bubalus bubalis) no Rio Grande do Sul

This paper describes organophosphate (ORF) poisoning in a herd of water buffaloes (Bubalus bubalis) in southern Brazil, which were treated with a single dose of 12mg/kg body weight of Expertan® pour-on (chlorpyriphos) to control ectoparasites. Clinical signs, observed 7-45 days after exposure, were diarrhea, hypersalivation, ataxia, muscular tremors, weakness of pelvic limbs, paresis and flaccid paralysis and lateral recumbence. Out of 267 buffaloes 61 died. Necropsy of three animals that died 24-72 hours after onset of clinical signs, revealed congestion and serosal hemorrhages scattered along the bowel, emphysema and edema of the lungs. No significant histopathological changes were found. Residues of chlorpyriphos were detected in liver, kidneys and nervous system of the one necropsied buffalo. Despite the absence of histological lesions in the central and peripheral nervous system, the epidemiological, clinical, gross and toxicological findings suggest delayed neurotoxicity induced by organophosphates.

Evolução e reversibilidade das lesões neurológicas e cardíacas em ovinos intoxicados experimentalmente por Ateleia glazioviana e Tetrapterys multiglandulosa

To determine the reversibility of neurological and cardiac lesions in Ateleia glazioviana and Tetrapterys multiglandulosa poisoning, 3 groups of four sheep each were fed orally with the plants. In Group 1, 2 and 3, when sheep with nervous signs showed considerable increase of symptoms and risk of death, the plant administration was suspended. Group 4 with two sheep was used as control. Sheep from Group 1, fed 10g/kg during 6 days of fresh A. glazioviana collected in autumn were euthanized 8, 11, 16, and 21 days after the start of the experiment; they had shown regression of nervous signs, but had progressive cardiac lesions. Sheep from Group 2, fed during 8 days the same dose of fresh A. glazioviana collected in spring, were euthanized on days 9, 23, 38 and 68; they had shown regression of nervous signs and had no cardiac lesions. This suggests that the plant is less toxic in spring. Sheep from Group 3, fed 10g/kg during 11 days dry and ground T. multiglandulosa mixed with concentrated food, were euthanized on days 33, 33, 92 and 92; they had shown regression of nervous signs, and cardiac lesions were less severe on day 33 than on day 92. These results indicate that nervous lesions are reversible after the end of feeding, but cardiac lesions are progressive after discontinuation of the plant administration; these can be afterwards reversible if the animals do not anymore show clinical signs or die as a consequence of the poisoning. Results of those and previous experiments show that lesions of the nervous system are induced by lower doses than cardiac lesions and occur within a shorter period, what suggests that in spontaneous cases cardiac signs are always preceded by nervous signs, and that nervous signs can occur in the absence of cardiac lesions.

Estudo histológico, imuno-histoquímico e ultra-estrutural das lesões induzidas experimentalmente por Ramaria flavo-brunnescens (Clavariaceae) em bovinos

The objective of this study was to investigate the pathogenesis of the lesions observed in cattle experimentally poisoned by Ramaria flavo-brunnescens. The mushroom was given to three 9 to10-month-old Jersey calves immediately after harvesting. Daily doses were around 20g/kg of body weight during 7 (Calf 1) or 13 days (Calves 2-3), and the total doses of mushroom given were 140, 268, and 261g/kg of body weight, respectively. One calf (Calf 4) with same age and breed was used as control. Clinical signs were characterized by prostration, anorexia, hyperemia of oral mucosa, and loosening of long hairs of the tail tip under mild traction. The calves were submitted to euthanasia and necropsied on days 8 (Calf 1) and 15 (Calves 2-4) after the beginning of the experiment. Microscopically, there was smoothness of dorsal epithelium of tongue with absence of filiform papillae, vacuolation of keratinocytes, and loosening of the keratin layer. In the hooves, there was vacuolation and irregular keratinization of the laminar epidermis and hyperplasia of keratinocytes. Hyperkeratosis, vacuolation of the external root sheath, thickening of tricholemal keratin, and inflammatory infiltration around hair follicles were observed on the skin of the tail tip. Immunohistochemical results with anti-pancytoceratin and anti-Ki67 (cell proliferation marker) antibodies showed no differences between the tongue dorsal epithelium of the control and experimental calves. Ultrastructural study demonstrated decrease in tonofilaments and increased intercellular spaces of the spinous layer of the tongue dorsal epithelium. The results of this study favor the hypothesis of an interference with the epithelial keratinization mechanisms by the toxic principles of Ramaria flavo-brunnescens.

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.