Eliza S.V. Sallis

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.

Aspectos epidemiológicos e padrões de lesões hepáticas em 35 surtos de intoxicação por Senecio spp. em bovinos no sul do Rio Grande do Sul

The study aimed to characterize morphological patterns of 59 liver samples of Senecio spp. poisoned cattle from 35 outbreaks, observed in southern Rio Grande do Sul, Brazil, from 2000 to 2009. The lesions were associated with epidemiological changes during these years. The climate changes concerning accumulated rain and mean temperature during the different seasons were analyzed. The macroscopic and histological lesions were classified into 6 different patterns. The macroscopic classification was made according to capsular pattern, hepatic cut surface discoloration, and the presence of nodules. The histological classification was based on the distribution of fibrosis, the amount of megalocytes in 10 high magnification fields, and on bile duct proliferation. Pattern 1 was characterized by a whitish liver, diffuse fibrosis, severe bile duct proliferation, and discrete megalocytosis; pattern 2 was characterized by nodules consisting of groups of hepatocytes surrounded by fibrosis, severe bile duct proliferation, and discrete to mild megalocytosis; pattern 3 was characterized by a macro-nodular aspect to the cut surface with hepatic lobules surrounded by a thin septa of fibrous tissue, severe bile duct proliferation, and mild megalocytosis; pattern 4 was characterized by a non-nodular surface with marble aspect, mild to severe bile duct proliferation, and megalocytosis; pattern 5 was characterized by a non-nodular surface and bridging or diffuse fibrosis, mild megalocytosis, and severe bile duct proliferation; and pattern 6 was characterized by a non-nodular surface, severe megalocytosis, discrete bile duct proliferation, and incipient fibrosis of the portal system, central vein or among hepatocyte cords. The results of macroscopic and histological liver analysis showed that patterns 1, 2 and 4 were the most frequently observed. The results of this study demonstrated that the macroscopic lesion observed in Senecio poisoned cattle is variable. Histologically this variation is related to the amount and distribution of fibrosis, megalocytosis and bile duct proliferation observed in each liver. Age of the cattle, evolution period of poisoning and clinical signs did not interfere on the pattern of lesions observed. On the other hand, climatic conditions probably had influence on increased disease prevalence due to major availability of Senecio spp. plants.

Intoxicação espontânea por Baccharis coridifolia (Compositae) em equinos no Rio Grande do Sul

An outbreak of spontaneous Baccharis coridifolia poisoning in horses in July 2008 is reported from southern Brazil. The poisoning affected three mares out of four that were transported from the state of Parana to a farm in the municipality of Acegua, Rio Grande do Sul, and occurred 3 days after arrival of the animals in a paddock with sprouting B. coridifolia. The fourth mare introduced to another paddock without B. coridifolia was not affected. The mares had received only one third of the concentrate ration previously ingested and stayed during the night in a stall. Clinical signs were abdominal discomfort, increased cardiac and respiratory rate, anorexia, hypermotility of the gut, cecal tympany, and diarrhea. The clinical course was of 18-36 hours. One affected mare survived after symptomatic treatment. Gross lesions were severe congestion, hemorrhages, edema and ulcers of the glandular stomach. Congestion, edema and hemorrhages were also observed in ileum, cecum and large colon. Histologic examination revealed degeneration and necrosis of the aglandular epithelium of the stomach, gastritis and enteritis with infiltration by mononuclear cells and neutrophils, edema of the mucosa, and dilatation of lymphatic vessels. One horse was poisoned experimentally with 1g/kg body weight of B. coridifolia. Clinical signs and lesions were similar to those observed in the spontaneous cases.

A case of yellow fever in a brown howler (Alouatta fusca) in Southern Brazil

Many brown howlers (Alouatta fusca) have died in a 3-month period in a subtropical forest in Southern Brazil. One was examined after a systemic illness. According to clinical signs, and necropsy and histopathology findings, yellow fever virus (YFV) infection was suspected. Tissue sections from liver, kidney, and lymphoid organs were screened by immunohistochemistry for YFV antigens. Cells within those tissues stained positively with a polyclonal antibody against YFV antigens (1:1,600 dilution), and yellow fever was diagnosed for the first time in the brown howler in the area.

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.

Intoxicação experimental aguda por Senecio brasiliensis em ovinos e indução de resistência à intoxicação

Sheep are more resistant to poisoning by Senecio spp. than cattle and horses. To determine whether this resistance could be induced by ingestion of small and repeated doses of the plant and to know how long the resistance could last, three experiments with fresh green leaves and stalks of Senecio brasiliensis were conducted. In Experiment 1, to determine the minimum dose for acute poisoning, single doses of 60, 80, 90, 100 and 100g/kg body weight (bw) were administered to five 1 and a half-year-old male Corriedale sheep. The sheep fed 60g/kg bw and 80g/kg bw of S. brasiliensis did not get sick; however, the sheep that received 80g/kg bw, developed mild fibrosis and megalocytosis in liver biopsies performed 90, 120 and 150 days after the end of plant administration. The sheep that received 90 and 100g/kg bw showed clinical signs of anorexia, prostration, paddling movements and abdominal pain, and died 12-48 hours after the onset of clinical signs. At their necropsy, ascites, disseminated petechiae and accentuated lobular pattern of the liver were found, and histologicaly hemorrhagic centrilobular necrosis was observed. In Experiment 2, the dose of 100g/kg bw fractionated into 2, 5 and 10 daily doses was administered to three sheep respectively. The fractioned dosage did not cause clinical signs of poisoning in any of the sheep, but periportal fibrosis and moderate megalocytosis were observed in liver biopsy performed at day 60 after the end of the plant administration. No histological lesions were observed in hepatic biopsies of sheep that received 10 daily doses of 10g/kg bw. In Experiment 3, to determine whether the sheep become resistant to the acute form of poisoning, four sheep ingested daily doses of 15g/kg bw of S. brasiliensis during 30 days and daily doses of 30g/kg bw for 10 days. On the day following the last dose of 30g/kg bw, two sheep were challenged with 100g/kg bw of the plant in a single dose. No clinical signs were observed in both sheep and no histological lesions could be found in the liver biopsies obtained 15 and 30 days after administration of the challenge dose. The third and fourth sheep received the challenge dose (100g/kg bw) 15 and 45 days after the end of plant administration. These animals showed anorexia, abdominal pain, and died about 12 hours after the onset of clinical signs. Gross and microscopic lesions were similar to those observed in sheep from Experiment 1. The results of this study demonstrate that sheep are susceptible to acute S. brasiliensis poisoning at doses of 90 and 100g/kg bw, but they become resistant after the continuous ingestion of small daily doses. This resistance has been lost 15 days after the end of the plant ingestion. Natural acute poisoning by S. brasiliensis probably does not occur in sheep, because they would have to eat large amounts of the plant in a short period of time.

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.

Intoxicação experimental em ovinos com Ramaria flavo-brunnescens congelada ou dessecada

Ramaria flavo-brunnescens is a toxic mushroom affecting cattle and sheep. Its active principle is unknown. The experiment was done to obtain information about the toxicity of the mushroom after been frozen or dried. R. flavo-brunnescens was collected in autumn 1991. One part was frozen at -15°C for 2-4 months, and another was dried in the shade. Other samples collected at the same time were given immediately after harvest to two sheep, at a total dose of 200 g/kg for 3 and 4 days, causing severe poisoning. The dried mushroom did not cause clinical signs at doses of 60 and 75 g/kg bw (equivalent to 400 and 500 g/kg of the fresh mushroom). The frozen mushroom at 200 g/kg bw caused hyperthermia, depression, hyperemia of the sclera and hemorrhages of the anterior chamber of the eye. Sheep that ingested 350 and 400 g/kg bw showed also nervous signs, and with the highest dose hyperemic lesions of the coronary band. All sheep recovered within 3 to 12 days. Clinical signs when given the frozen mushroom were less severe than clinical signs induced by the fresh mushroom. These results showed loss of toxicity of the dried material and decrease of toxicity of the frozen mushroom. It is suggested that chemical analyses for the toxic principle can be performed with the frozen or lyophilized mushroom.

Doenças de equinos na região Sul do Rio Grande do Sul

A retrospective study of the diagnoses of injuries and deaths in equine in Southern Brazil was conducted between 1978 and 2012. All necropsy protocols and other materials of the Regional Diagnostic Laboratory of the Veterinary School of the Federal University of Pelotas were reviewed. The collected data consisted of 2,026 equine materials, including 514 necropsy protocols of and 1,512 other biologic materials, including the protocols of biopsies, organs, swabs, feces, blood, and skin scrapings. From the resulting 2,026 diagnoses, 467 (23.05%) corresponded to neoplasms and tumor like lesions; 168 (8.29%) to parasitic diseases; 135 (6.66%) to bacterial diseases; 31 (1.53%) to viral diseases; 86 (4.24%) to diseases caused by fungi and oomycetes; 50 (2.47%) to intoxication and poisoning by mycotoxins; 9 (0.44%) to metabolic diseases; 60 (2.96%) to other diseases; and 75 (3.70%) to non-transmittable diseases of the digestive tract. Three hundred twenty cases (15.79%) were classified as diseases of unknown etiology. Other diagnoses accounted for 489 of the total 2,026 cases (24.14%). In 44 (8.56%) of the 514 necropsies and 91 (9.47%) of the 961 biopsies of organs mailed into the laboratory, the diagnoses were inconclusive, totaling 135 (9.15%) of the 1,475 in the category. This study demonstrates the importance of skin lesions in horses, as 31.88% (642) of the biopsies received were lesions on the skin of the animals. The most significant tumors observed were equine sarcoid, at 33.18%, and squamous cell carcinoma, at 7.94%. The most common observed causes of death were leucoenceflomalacia (7.59%), rabies (3.70%) thromboembolism by Strongylus vulgaris (2.33%) and monocytic ehrlichiosis (1.75%).

Aflatoxicose em cães na região Sul do Rio Grande do Sul

Clinical pathological aflatoxicosis in dogs is described in southern Rio Grande do Sul. It was conducted a retrospective study of cases diagnosed as aflatoxicosis in dogs necropsied at the Regional Diagnostic Laboratory (LRD) of the Veterinary School of the Federal University of Pelotas (UFPel) in the period 1978-2012. In four cases the diagnosis was confirmed by detection of levels of aflatoxins B1 and G1, with the finding of 89-191ppb in the feed. The macroscopic and histologic lesions and the diet observed in six of 27 dogs with liver cirrhosis led to suspicion of aflatoxicosis. Clinical signs evidenced in confirmed or suspected cases were lethargy, diarrhea, jaundice and ascites, progressing to death within 8 to 30 days in confirmed cases, and within 15 to 60 days in suspected cases. The diet was corn and rice byproducts and peanut meal, and one of the dogs received commercial ration. Gross changes were characterized by ascites, jaundice, enlarged liver, with or without regenerative nodules, hemorrhages in serous membranes and bloody intestinal content. The cases were classified according to the main histological pattern, characterized by diffuse vacuolation of the cytoplasm of hepatocytes in acute cases, by proliferation of bile ducts, and mild fibrosis in subacute cases, and by severe fibrosis in chronic cases. Apparently the disease is not important as a cause of death in dogs in the region, nevertheless the possibility of cases of cirrhosis of unknown etiology would be caused by aflatoxicosis.