Juliano de Souza Leal

Intoxicação espontânea por Baccharis coridifolia (Compositae) em ovinos

An outbreak of Baccharis coridifolia (Compositae) poisoning in sheep is reported, which occurred in November 2004 in the county of Caxias do Sul, Rio Grande do Sul (RS), southern Brazil. From a herd of 212 sheep, coming from a Baccharis coridifolia free area, in the county of Jaguarao, RS, 35 sheep died until 5 days after the arrival in the new area where the plant was found with abundance. The clinical signs began 8 hours after introduction of the animals into the new pasture and included apathy, anorexia, abdominal retraction or mild distension, weakness of hind limbs, dry feces, sternal ou lateral decumbency, struggling movements, coma and death. Clinical evolution was from 5 to 48 hours. Other sheep that were already before on the pasture were not affected. Main necropsy findings were in the gastrointestinal tube, with wall and serosal oedema, mainly in the reticulo-ruminal fold and of the abomasum, reddening and detachment of the mucosa of forestomachs, and intense hemorrhage in the submucosa. Histopathological findings were degeneration and necrosis of the epithelium of the forestomachs with polymorphonuclear infiltration associated with bacterial colonies, congestion, hemorrhage and oedema, and lymphoid tissue necrosis.

Intoxicação natural e experimental por Nerium oleander (Apocynaceae) em bovinos no Rio Grande do Sul

This paper describes natural and experimental poisoning of cattle by Nerium oleander in Rio Grande do Sul. Two out of eight cattle died acutely after consumption of leaves of Nerium oleander, branches of which had been cut and placed into a paddock where the animals were kept. An affected cow did not show clinical signs, but a 4-month-old calf presented lateral recumbence, paddling, vocalization and death. Main gross findings in the cow naturally poisoned and in two experimentally intoxicated heifers were observed in the heart and included hemorrhages in the left atrium, clots and hemorrhages in the left ventricular endocardium, and pale areas in the interventricular septum and ventricular myocardium. Histologically, there was coagulation necrosis of individual cardiac fibers or small groups of fibers, characterized by enhanced cytoplasmic eosinophily and picnotic nuclei. These lesions were most severe in the papillary muscle. The diagnosis was based on presence of the trimmed N. oleander in the paddock where the animals stayed, evidence of consumption of the plant, consistent clinical and pathological findings, and experimental reproduction of the disease through oral administration of 0.5 and 1.0g/kg of its green leaves to two cattle.

Aborto ovino associado com infecção por Sarcocystis sp

Protozoal infection has worldwide distribution and may cause abortion, premature parturition or fetal death in almost all domestic animals. In July 2004, eight Corriedale sheep showed abortion and stillbirth in the third trimester of gestation. Of these reproductive losses, one stillborn male was submitted to the Laboratory of Veterinary Pathology for necropsy investigation. The direct immunofluorescence test for Leptospira sp. was negative. No significant bacteria was isolated from lung and liver by aerobic and microaerobic cultures. Macroscopic lesions were not found in any fetal tissue. The histological lesions were observed mainly in the brain and heart and consisted primarily of severe multifocal nonsupurative encephalitis and nonsuppurative myocarditis. Schizonts of a protozoan parasite consistent with Sarcocystis sp. were found in the endothelial cells and vascular endothelium in several organs. Many schizonts with merozoites arranged in a rosette-like pattern were observed in brain and kidney tissues. In sections stained with periodic acid-Schiff (PAS), the limiting membrane of some schizonts appeared to be weakly PAS-positive. Merozoites and nuclei were PAS-negative. Protozoa did not react immunohistochemically to the antibody anti-Toxoplasma gondii; however, cross-reactivity was observed with Neospora caninum antibody. These findings were consistent with the diagnosis of Sarcocystis sp.

Polimorfismos de nucleotídeos únicos em 15 códons do gene da proteína priônica em um rebanho Suffolk afetado com scrapie no Brasil

Scrapie is a transmissible spongiform encephalopathy of sheeps and goats, associated with the deposition of a isoform of the prion protein (PrPsc). This isoform presents an altered conformation that leads to aggregation in the hosts central nervous and lymphoreticular systems. Predisposition to the prion agent infection can be influenced by specific genotypes related to mutations in amino acids of the PrPsc gene. The most characterized mutations occur at codons 136, 154 and 171, with genotypes VRQ being the most susceptible and ARR the most resistant. In this study we have analyzed polymorphisms in 15 different codons of the PrPsc gene in sheeps from a Suffolk herd from Brazil affected by an outbreak of classical scrapie. Amplicons from the PrPsc gene, encompassing the most relevant altered codons in the protein, were sequenced in order to determine each animals genotype. We have found polymorphisms at 3 of the 15 analyzed codons (136, 143 and 171). The most variable codon was 171, where all described alleles were identified. A rare polymorphism was found at the 143 codon in 4% of the samples analyzed, which has been described as increasing scrapie resistance in otherwise susceptible animals. No other polymorphisms were detected in the remaining 12 analyzed codons, all of them corresponding to the wild-type prion protein. Regarding the risk degree of developing scrapie, most of the animals (96%) had genotypes corresponding to risk groups 1 to 3 (very low to moderate), with only 4% in the higher risks group. Our data is discussed in relation to preventive measures involving genotyping and positive selection to control the disease.

Postweaning multisystemic wasting syndrome in farmed wild boars (Sus scrofa) in Rio Grande do Sul

This report concerns an outbreak of postweaning multisystemic wasting syndrome in wild boars from commercial herds in Rio Grande do Sul, Brazil. The main clinical signs were progressive wasting, respiratory distress, diarrhea, and ocular discharges. Enhanced lymph nodes and spleens, ascites, hydrothorax, and non collapsed lungs were the principal gross lesions. Varying degrees of lymphohistiocytic infiltrates in lymph nodes, spleen, and intestines were the most significant microscopic changes. Although a total of 26 animals had showed clinical and pathological findings consistent with the disease, only in 11 of them it was possible to confirm a PMWS diagnosis through the association of specific lesions in lymphoid tissues with the presence of the viral antigen detected by immunohistochemistry. These findings were similar to those reported in the swine disease.

Utilização de biópsias da terceira pálpebra e mucosa retal em ovinos para diagnóstico de scrapie em uma propriedade da região sul do Brasil

Scrapie, a form of transmissible spongiform encephalopathy (TSEs) is a fatal neurodegenerative disorder that affects sheep and goats. The disease is characterized by an accumulation of the abnormal prionic protein (PrPSc) in the encephalic and lymphoreticular tissues. This paper describes the use of anti-prionic protein immunohistochemical (IHC) procedure as a method of pre-clinical diagnosis of scrapie.The test was carried out in biopsied lymphoreticular tissues from third eyelid and rectal mucosa. Anti-prion protein monoclonal antibodies F89/160.1.5 and F99/97.6.1 were used. Scrapie diagnosis in lymphoreticular tissues through IHC was achieved when the samples had a minimum of three lymphoid follicles in well delimited germinal centre. Positive immunostaining was identified in 19 out of 318 samples of the third eyelid. Material sampled at post-mortem examination in 18 of these scrapie-positive sheep, which were previously verified by biopsy, and in 21 of its relatives, was confirmed with IHC tests. Positive immunostaining from rectal mucosa tissue was not observed. Third eyelid and tonsil were the organs with the larger amount of positive immunostaining (18/18 and 8/18 respectively) at post-mortem examination. None positive result was obtained along the 21 animals related to the positive ones, and none of the positive cases showed IHC labeling in the brain. The use of lymphoid tissues for scrapie diagnosis by IHC through biopsies showed to be a viable and efficient method for pre-clinical diagnostic.

Immunohistochemical and ultra-structural detection of Pneumocystis in wild boars (Sus scrofa) co-infected with porcine circovirus type 2 (PCV2) in Southern Brazil

Pneumocystis spp. are fungi that are able to infect a variety of host species and, occasionally, lead to severe pneumonia. Porcine circovirus type 2 (PCV2) is an important viral pathogen which affects both swine and wild boar herds worldwide. Co-infection between PCV2 and other pathogens has been reported, and the secondary immunodeficiency caused by the virus may predispose to these co-infections. In the present study, postmortem tissue samples obtained from wild boar herds in Southern Brazil were analyzed by histopathology, ultra-structural observation, and immunohistochemistry. Forty-seven out of seventy-eight (60%) wild boars showed clinical signs, gross, and histopathological lesions characteristic of infection by PCV2. Pneumocystis was detected by immunohistochemistry in 39 (50%) lungs and viral antigens of PCV2 were found in 29 (37.2%) samples. Concomitant presence of Pneumocystis and PCV2 were observed in 16 (20.5%) of the wild boars. Cystic and trophic forms of Pneumocystis were similar to previously described ultra-structural observations in other mammals.

Timpanismo espumoso em bovinos leiteiros em pastagens de Trifolium spp. (Leg.Caesalpinoideae)

Leguminous bloat may occur in cattle which graze pastures consisting of lush forages. In a dairy farm located on the municipality of Sao Francisco de Paula, Rio Grande do Sul, eight out of 66 cows died suddenly after being transferred to a paddock whose pastures were composed of Trifolium repens and Trifolium pratense. Animals were found dead in the morning of the next day after being transferred; no clinical signs were noticed. Main gross findings included enhanced abdominal volume, protrusion and congestion of the tongue and vagina, ruminal distension, pale liver, and enhanced spleen. Histologically, there were lung congestion and edema, and splenic lymphoid hyperplasia. The evidence of leguminous forages consumption associated with the pathological findings and the absence of growth on bacteriology confirmed the diagnosis.

Intoxicação experimental por monensina em búfalos e bovinos

Monensin is widely used as a feed additive to improve performance of livestock; however accidental poisoning by this ionophore compound has been reported in a number of animal species. Typical clinical signs and lesions of monensin poisoning were induced in water buffaloes dosed with single dosages of 15, 10, 7.5, and 5mg/kg of the compound. Only buffaloes dosed with 2.5 mg/kg (1 day) and 1mg/kg (7 days) survived. Clinical signs initiated about 6 h post-dosing and included apathy, anorexia, diarrhea, drooling, muscular weakness, locomotion disorders, dyspnea, tachycardia, jugular distension and pulse, recumbency and death. The creatine kinase (CK) levels were highly augmented in blood samples of buffaloes dosed with monensin. Most prominent gross changes were ascites, hydrothorax, hydropericardium, cardiomegaly, hepatomegaly, and focal pale areas in the myocardium and in skeletal muscles. Degeneration and necrosis of myofibers were the principal histopathological findings. Conversely, no evidence of disease, neither change in CK levels were observed in the beef cattle steers dosed with same doses, confirming preliminary findings that buffaloes are more susceptible to monensin than cattle. In addition, this communication presents the minimal toxic dosage of monensin to buffaloes and suggests that CK tests may serve as health monitoring tools in the management of buffalo herds supplemented with monensin.Monensin is widely used as a feed additive to improve performance of livestock; however accidental poisoning by this ionophore compound has been reported in a number of animal species. Typical clinical signs and lesions of monensin poisoning were induced in water buffaloes dosed with single dosages of 15, 10, 7.5, and 5mg/kg of the compound. Only buffaloes dosed with 2.5 mg/kg (1 day) and 1mg/kg (7 days) survived. Clinical signs initiated about 6 h post-dosing and included apathy, anorexia, diarrhea, drooling, muscular weakness, locomotion disorders, dyspnea, tachycardia, jugular distension and pulse, recumbency and death. The creatine kinase (CK) levels were highly augmented in blood samples of buffaloes dosed with monensin. Most prominent gross changes were ascites, hydrothorax, hydropericardium, cardiomegaly, hepatomegaly, and focal pale areas in the myocardium and in skeletal muscles. Degeneration and necrosis of myofibers were the principal histopathological findings. Conversely, no evidence of disease, neither change in CK levels were observed in the beef cattle steers dosed with same doses, confirming preliminary findings that buffaloes are more susceptible to monensin than cattle. In addition, this communication presents the minimal toxic dosage of monensin to buffaloes and suggests that CK tests may serve as health monitoring tools in the management of buffalo herds supplemented with monensin.

Report of outbreaks of classical scrapie in Dorper sheep and associated prion protein gene polymorphisms in affected flocks

Scrapie is an infectious neurodegenerative disease affecting sheep and goats, related with conformational alteration of an isoform of the prion protein that leads to deposition and aggregation in the host’s central nervous system. Occurrence of the natural disease can be influenced by host genetic factors, such as a single nucleotide polymorphism of the prion protein gene. This study reports three scrapie-affected Dorper flocks located on three different farms in Brazil. The objective of this study was to analyze these three flocks using scrapie diagnostics, combining histology, immunohistochemistry, genotyping, and western blot assays. For immunohistochemistry, 192 sheep were selected and 308 sheep blood samples were taken for genotyping. A total of 22 sheep were scrapie positive by immunohistochemistry. Of these, four presented clinical signs and had scrapie immunoreactivity at the obex in western blot assays. The sheep without clinical signs were positive in lymphoid organs, such as the third eyelid and rectal mucosa. The major genotypes found on the flocks were ARQ/ARQ, ARQ/ARR, and ARQ/VRQ for codons 136, 154, and 171. Most of the sheep were considered to be at moderate to high risk, based on risk groups for developing scrapie. Some blood samples were sequenced, and polymorphisms were identified in other codons, such as 127, 142, and 143. Our data demonstrate the importance of preclinical scrapie diagnosis in Brazilian sheep, as most of the affected sheep showed no clinical signs, and emphasize the relevance of genotyping other Dorper sheep to determine the genotypic profile of the breed.