Histological changes caused by experimental Riedeliella graciliflora (Leg. Papilionoideae) poisoning in cattle and laboratory animals

Tissues from cattle, mice, rats and guinea pigs experimentally intoxicated by Riedeliella graciliflora were studied histologically. Cattle lymph nodes, spleen, Peyer patches and peribronchial lymphoid tissues had diffuse necrosis of lymphocytes, mainly in the germinal centers of the follicles. This lesion was less severe in laboratory animals. All species had severe enteritis with infiltration of the lamina propria by mononuclear cells. Some cells in this infiltrate were necrotic. Degeneration and necrosis of the epithelial cells, mainly in the tip of the villi, and detachment of the epithelial lining from the lamina propria were also observed. In the liver the trabecular structure was disrupted and the hepatocytes had some degree of individual necrosis and degeneration. A tubular nephrosis was observed in the kidneys. Liver, lung, kidney, intestine and lymph nodes had different degrees of congestion. Those lesions are similar than those caused by Polygala klotzschii, a plant that contains 5-metoxi-podophyllotoxin.

Crystal-associated cholangiopathy in sheep grazing Brachiaria decumbens containing the saponin protodioscin

An outbreak of hepatogenous photosensitization is reported in a flock of 28 sheep grazing Brachiaria decumbens in Mato Grosso do Sul State, Central-Western Brazil. Seven lambs and an adult sheep were affected and 6 of them died. Two surviving affected lambs and one lamb without clinical signs had increased serum values of gamma glutamyltransferase, bilirubin, and cholesterol. In two adult unaffected sheep those parameters were within normal values. An adult sheep submitted to necropsy presented moderate body condition, unilateral corneal opacity, drying of the muzzle, moderate jaundice, increased lobular pattern of the liver, and a distended gallbladder. Histological lesions were epithelial degeneration, necrosis, and hyperplasia of small bile ducts. Mild amounts of foamy macrophages were observed, mainly in the centroacinar zone. Diffuse swelling and vacuolation were observed in hepatocytes. Crystal negative images were found within bile ducts, foamy macrophages, and the lumen of some renal tubules. The heart showed multifocal areas of degeneration and necrosis of the muscle fibers. Pasture samples (Brachiaria decumbens) contained 2.36% of protodioscin. No Pithomyces chartarum spores were found in the pasture. Samples from a similar neighboring B. decumbens pasture grazed by cattle without photosensitization contained 1.63% of protodioscin isomers. Outbreaks of photosensitization caused by Brachiaria spp. are common in cattle in the Brazilian Cerrado (savanna) with about 51 million hectares of Brachiaria spp pastures. Sheep farming has been recently developed in this region, and the number of sheep is increasing significantly. Because sheep are more susceptible than cattle to lithogenic saponins, poisoning by Brachiaria should be an important limiting factor for the sheep industry.

The materno-fetal interface in llama (Lama guanicoe glama)

Samples from 9 llamas (28 through 36 weeks of gestation) were collected and fixed in 4% buffered paraformaldehyde (light microscopy) and in 2.5% buffered glutaraldehyde (transmission and scanning electron microscopy). The material was processed in paraplast and slides (5mm) were stained with HE, PAS, Masson-Trichrome, acid phosphatase and Perl's. The uteroferrin was immunolocalized. The results show that llama placenta is chorioallantoic, diffuse, folded and epitheliochorial, and the fetus is covered with an epidermal membrane. The trophoblast cells have variable morphology: cubic, rounded and triangular cells, with cytoplasm containing PAS-positive granules. Binucleated cells with large cytoplasm and rounded nuclei, as well as giant trophoblastic cells with multiple nuclei were also observed. Numerous blood vessels were observed beneath the cells of the uterine epithelium and around the chorionic subdivided branches. Glandular activity was shown by PAS, Perl's, and acid phosphatase positive reactions in the cytoplasm and glandular lumen, and by immunolocalization of the uteroferrin in the glandular epithelium. The uterine glands open in spaces formed by the areoles, which are filled by PAS-positive material. The llama fetus was covered by the epidermal membrane, composed of stratified epithelium, with up to seven layers of mono-, bi- or trinucleated cells. The high level of maternal and fetal vascularization surfaces indicates an intense exchange of substances across both surfaces. The metabolic activity shown in the uterine glands suggests an adaptation of the gestation to the high altitudes of the natural habitat of this species.

Reactivation of latent bovine herpesvirus type 5 in cattle with polioencephalomalacia induced by ammonium sulphate

In the state Mato Grosso do Sul, Brazil, outbreaks of meningoencephalitis by BoHV-5 and polioencephalomalacia (PEM) display similar epidemiological features, suggesting that meningoencephalitis may be associated with reactivation of a latent BoHV-5 infection, during the development of PEM. To test this hypothesis, four 7-8 months old steers negative for BoHV-5 antibodies were inoculated intranasally with BoHV-5 and received amprolium from day 35 to day 105 after inoculation. Because PEM was not produced during this period, ammonium sulphate was given from day 114 to day 180 after inoculation. Two uninfected control steers received amprolium and ammonium sulphate for the same periods. All inoculated cattle developed antibodies against BoHV-5 after inoculation and the virus was isolated from nasal swabs, indicating that they were infected. Two inoculated steers had clinical signs of PEM after 118 and 146 days after virus inoculation. One was euthanized after a clinical manifestation period of seven days and had severe lesions of PEM and meningoencephalitis. BoHV-5 was isolated from the central nervous system of this animal. The other animal recovered but continued to manifest chronic signs of PEM and was euthanatized. On histological examination, the cerebral cortex, caudate nucleus and thalamus had multifocal areas of malacia and mild meningoencephalitis of the cortex. BoHV-5 was not isolated from the brain. One uninfected control steer had signs of neurological disease on day 158 and had lesions of PEM without meningoencephalitis at necropsy. The simultaneous production of PEM and diffuse meningoencephalitis, with isolation of BoHV-5, in one steer treated with ammonium sulphate, 118 days after BoHV-5 inoculation, suggests that latent BoHV-5 was reactivated in this animal submitted to experimental induction of PEM.

Spontaneous poisoning by larvae of Perreyia flavipes (Pergidae) in sheep

From a flock of 175 Texel sheep 25 animals died after consumption of a sawfly larvae subsequently identified as Perreyia flavipes. The disease occurred in June-July 2006 on a farm located in the county of Encruzilhada do Sul, Rio Grande do Sul, Brazil. Although there were 11 cattle in the same paddock, none of them was affected. High numbers of compact masses containing up to 150 larvae were scattered in the paddock where the animals were grazing. Most affected sheep showed severe apathy during 24-36 h before death, but weakness, muscular tremors and depression were also observed. Necropsy was performed on six sheep and the main macroscopic lesions were hemorrhages in the subcutaneous tissues, endocardium, gallbladder wall, and abomasal mucosa. In all animals was found hydrothorax, hydropericardium, ascites, and mild jaundice. Edema in the abomasal folds, mesentery, perirenal tissues, and gallbladder wall were also seen. The livers were yellowish with disseminated pinpoint hemorrhages in the parenchyma and had an enhanced lobular pattern. Perreyia flavipes larval body fragments and heads were found in the forestomach contents of the six sheep. Feces were scant, dry and formed balls coated by mucus and streaks of blood. Similar contents were also present at the end of the cecum. Prominent microscopic lesions included severe and diffuse periacinar or massive necrosis of hepatocytes associated with multifocal random hemorrhages. Diffuse necrosis of lymphoid follicles in lymph nodes and Peyer's patches, lymphoid depletion and necrosis in germinative centers of the spleen, and diffuse vacuolization in the renal tubular epithelia were also seen.

Intestinal lesions in pigs affected with postweaning multisystemic wasting syndrome

Samples of mesenteric lymph nodes and intestines from 79 unthrifty 3- to 5-month-old postweaning pigs, confirmed as naturally affected with postweaning multisystemic wasting syndrome (PMWS), were studied. Pigs originated from 12 farms in southern Brazil and were selected on the basis of clinical signs and/or gross lesions suggestive of enteric disorder. Lymphohistiocytic infiltrates of varying intensity were associated with anti-porcine circovirus type 2 (anti-PCV2) immunostaining (IS) in samples of intestines and mesenteric lymph nodes from all pigs. Although most findings were similar to those described in PCV2-associated enteritis, anti-PCV2 IS in association with depletion of the goblet cell mucin stores (24 pigs), diffuse ileal villous atrophy and fusion (18 pigs), and dilatation of the lymphatic vessels (11 pigs) combined or not with lymphangitis were also observed. PCV2 antigen was immunohistochemically demonstrated in the cytoplasm and nuclei from intralesional epithelial cells, histiocytes, and endothelial-like cells in intestinal tissues. Together these findings imply an association with PCV2. The presence of co-infections by Lawsonia intracellularis, Brachyspira spp., Mycobacterium spp., Salmonella spp., rotavirus, parvovirus, coronavirus and enteric calicivirus with PCV2 in the intestinal lesions was investigated.

Spontaneous coffee senna poisoning in cattle: report on 16 outbreaks

Sixteen outbreaks of Senna occidentalis (coffee senna) that occurred in cattle in the state of Rio Grande do Sul, Brazil, were reviewed. The great majority (75%) of the outbreaks occurred in adult cattle at pasture during the autumn and winter months with 50% in May, evidencing a striking seasonality. Mortality rates varied from 4.2% to 55.2% and cattle died 2 days up to 2 weeks after showing clinical signs that included dry feces (occasionally diarrhea), muscle weakness, reluctance to move, tachypnea, instability of the hind limbs with dragging of the toes, tremors in muscles of the thighs, neck, and head, ear dropping, sternal recumbency, lateral recumbency and death. Myoglobinuria characterized by a dark red or black discolored urine was a consistent finding in cattle affected at pasture but not in those poisoned by ration contaminated with coffee senna beans. Creatine phosphokinase serum activity was marked ly elevated. Main gross changes observed in 23 necropsies involved skeletal muscles of the hind limbs. These changes consisted of varying degrees of paleness of muscle groups. Subepicardial and subendocardial hemorrhages were present in the hearts of all affected cattle. Histologically a segmental degenerative myopathy of striated muscles was present in every case and had a multifocal polyphasic or monophasic character. Myocardial (3/23), hepatic (3/13), renal (3/10), and splenic (1/6) microscopic lesions were observed occasionally. Myocardial lesions were mild and consisted of vacuolation of cardiomyocytes or focal fibrosis. Hepatic changes consisted of diffuse hepatocelular vacuolation, cytosegrosomes within hepatocytes, and individual hepatocellular necrosis. Kidneys had vacuolar degeneration of tubular epithelium associated with acidophilic casts (proteinosis) within tubular lumina. In the spleen there was marked necrosis of lymphocytes of the white pulp. No histological changes were found in the brains of 13 affected cattle. The data of this study suggest that coffee senna poisoning is an important cause of death in cattle in southern Brazil.

Nutritional fibrous osteodystrophy in goats

Seven out of 25 goats from a southern Brazilian flock developed nutritional fibrous osteodystrophy. Affected animals were younger than 1 year of age and were confined in stalls and fed a concentrate ration containing 1:6 calcium:phosphorus ratio. The remaining flock (35 goats) was managed at pasture and showed no disease. Clinical signs were characterized by mandibular and maxillary enlargements, varying degrees of mouth opening and protruding tongue, dyspnea, apart of abnormalities of prehension and mastication. Affected animals had increased seric levels of phosphorus and parathormone, as well as higher alkaline phosphatase activity. Postmortem examination on three succumbed goats revealed bilateral enlargement of the maxilla and mandibula, and loose teeth, apart of multiple incomplete rib fractures in one of them. Severe diffuse proliferation of loose connective tissue surrounded the osteoid trabeculae, many of which were partially or completely non-mineralized. Mineralized osteoid trabeculae showed osteoclasts in the Howship's lacunae.

Spinal cord compression in cattle after the use of an oily vaccine

An outbreak of compressive myelopathy in cattle associated with the improper use of an oil vaccine is described. Neurological signs were observed in 25 out of 3,000 cattle after 60 days of being vaccinated against foot and mouth disease. The clinical picture was characterized by progressive paralysis of the hind limbs, difficulty in standing up, and sternal recumbency during the course of 2-5 months. A filling defect between the L1 and L3 vertebrae was seen through myelography performed in one of the affected animals. A yellow-gray, granular and irregular mass was observed in four necropsied animals involving the spinal nerve roots and epidural space of the lumbar (L1-L4) spinal cord; the mass was associated with a whitish oily fluid. This fluid was also found in association with necrosis of the longissimus dorsi muscle. Microscopic changes in the epidural space, nerve roots, and spinal musculature were similar and consisted of granulomas or pyogranulomas around circular unstained spaces (vacuoles). These spaces were located between areas of severe diffuse hyaline necrosis of muscle fibers and resembled the drops of oil present in the vaccine.

Anatomical and radiographic appearance of the capuchin monkey thoracic cavity (Cebus apella)

The capuchin monkey is widespread both north and south of the Legal Amazon and in the Brazilian cerrado. Ten clinically healthy capuchin monkeys were submitted to an anatomical and radiographic study of their thoracic cavities. The radiographic evaluation allowed the description of biometric values associated with the cardiac silhouette and thoracic structures. Application of the VHS (vertebral heart size) method showed positive correlation (P<0.05) with depth of the thoracic cavity, as well as between the body length of vertebrae T3, T4, T5 and T6 and the cardiac length and width. The lung fields showed a diffuse interstitial pattern, more visible in the caudal lung lobes and a bronchial pattern in the middle and cranial lung lobes. The radiographic examination allowed preliminary inferences to be made concerning the syntopy of the thoracic structures and modification of the pulmonary patterns and cardiac anatomy for the capuchin monkey.

Spontaneous poisoning by Ricinus communis (Euphorbiaceae) in cattle

The aim of this study is to report cases of spontaneous poisoning of cattle by Ricinus communis (castor beans) in Paraíba, a semiarid region of northeastern Brazil. The cases were observed in 2 herds on neighboring properties in 2013. Clinical signs developed within 6-24 h and consisted of weakness, tachycardia, dyspnea, profuse watery diarrhea, dehydration, depression, instability, cramps, permanent lateral recumbency and death within 48-72 h. Of the 60 cattle at risk, 19 were affected and 14 died. Five fully recovered after the course of 12 days. Three animals were necropsied. The main gross lesions were hemopericardium, hemothorax, pulmonary edema, petechial hemorrhages in the epicardium and endocardium, ecchymoses at the papillary muscles and suffusions on the intercostal muscles. Hemorrhages were also observed in the abdominal cavity, spleen and mucosa of the abomasum and small intestine. The rumen content was liquid with a large amount of castor bean seeds. There were circular, whitish and focally diffuse areas in the liver parenchyma. The main microscopic lesions consisted of multifocal coagulative myocardial necrosis with the presence of mononuclear cell infiltration and varying degrees of bleeding between cardiac muscle fibers. The abomasum and small intestine mucosae and submucosa had mild edema and mononuclear and polymorphonuclear inflammatory cell infiltration. The diagnosis of R. communis was based on the history of plant consumption, clinical signs, pathology of the disease and the presence of large amounts of castor bean seeds in the forestomachs.

Fatal Human herpesvirus 1 (HHV-1) infection in captive marmosets (Callithrix jacchus and Callithrix penicillata) in Brazil: clinical and pathological characterization

Fatal Human herpesvirus 1 (HHV-1) was diagnosed in 12 captive marmosets (Callithrix jacchus and Callithrix penicillata) from metropolitan region of São Paulo, São Paulo State. Clinical signs were variable among the cases, but most affected marmosets presented signs associated with viral epithelial replication: oral, lingual and facial skin ulcers and hypersalivation, and viral replication in the central nervous system: prostration, seizure and aggressive behavior. Consistent microscopic findings were diffuse mild to severe nonsuppurative necrotizing meningoencephalitis with gliosis, vasculitis and neuronal necrosis. Additionally, in the brain, oral cavity, skin, adrenal gland and myoenteric plexus intranuclear inclusion bodies were present. Immunohistochemistry confirmed the presence of the HHV-1 antigen in association with lesions in the brain, oral and lingual mucosa, facial skin, adrenal gland and myoenteric plexus. HHV-1-specific polymerase chain reaction (PCR) analysis of the brain was carried out and the virus was detected in 7/8 infected marmosets. It is concluded that HHV-1 causes widespread fatal infection in marmosets.

Red eyes in the necropsy floor: twenty cases of hyphema in dogs and cats

Hyphema (hemorrhage within the anterior chamber of the eye) can be caused by several mechanisms and can easily be detected in routine ophthalmic or necroscopic examination as discolored red eye(s). The purpose of this study is to report the cause of hyphema diagnosed as a postmortem finding in dogs and cats. Twenty cases, 14 dogs and six cats of several ages and breeds and of both sexes were included in the study. Hyphema presented as a unilateral (14 cases out of 20) or bilateral (6/20) disorder in dogs and cats and extension of hemorrhage varied from minimal to diffuse. Hyphema was secondary to systemic disease (15/20) or occurred as a primary ocular lesion (5/20) in four dogs and one cat. Primary hyphema was always unilateral. In four of these cases, the cause of hyphema was trauma and remaining case was caused by phacoclastic uveitis in a dog with bilateral hypermature cataract. Various causes of bleeding disorders were found related to secondary hyphema: in decreasing order of frequency, they included vasculitis (8/15), systemic hypertension (5/15), and acquired coagulopathies (2/15). Vasculitis due to feline infectious peritonitis accounted for half of the cases (n=3) of systemic hyphema in cats. The various pathological aspects and pathogenesis of hyphema in dogs and cats are described and discussed.

Equine proliferative enteropathy on a Brazilian farm

Abstract:Lawsonia intracellularis infection on a horse farm in the Midwest region of Brazil is described. Thirty-nine foals a few days to months old from a herd with 300 horses, experienced diarrhea with variable characteristics and intensities, weight loss, hyperemic mucous membranes and dehydration. In foals 3 to 6 months of age, hypoproteinemia associated with submandibular edema were also common. Intestinal fragments of a 7-month-old foal were sent to an animal disease laboratory for diagnosis. The observed macroscopic lesions were hyperemic serosa, thickening of the intestinal wall with a corrugation, thickening of the mucosa folds and reduction of intestinal lumen. Histological analysis of the small and large intestine revealed enterocyte hyperplasia of the crypts associated with diffuse marked decrease in the number of goblet cells and positive L. intracellularis antigen labeling by immunohistochemistry. Three out of 11 animals of the same property were seropositive for L. intracellularis, demonstrating the circulation of the agent throughout the farm, but none were PCR positive in fecal samples. Based on clinical signs and pathological findings, the diagnosis of equine proliferative enteropathy was confirmed.

Origin of successive cambia on stem in three species of Menispermaceae

The lianas observed in this study, Abuta convexa (Vell.) Diels, Abuta imene (Mart.) Eichler, and Chondrodendron platiphyllum (A. St.-Hil.) Miers, all have successive cambia in their stems. The terminology applied to stem histology in species with successive cambia is as diverse as the interpretations of the origins of this cambial variant. Therefore, this study specifically investigates the origin of successive cambia through a developmental analysis of the above-mentioned species, including an analysis of the terminology used to describe this cambial variation. For the first time, we have identified several developmental stages giving rise to the origins of successive cambia in this family. First, the pericycle originates in 1-3 layers of conjunctive tissue. After the differentiation of the first ring, the conjunctive tissue undergoes new divisions, developing approximately 10 rows of parenchyma cells. In the middle portion, a layer of sclereids is formed, again subdividing the conjunctive tissue into two parts: internal and external. New cambia originate in the internal part, from which new secondary vascular strands will originate, giving rise to the second successive vascular ring of the stem. The external part remains parenchymatous during the installation of the second ring and will undergo new periclinal division, repeating the entire process. New cambia will originate from the neoformed strands, which will form only rays. In the literature, successive cambia are formed by a meristem called "diffuse lateral meristem."However, based on the species of Menispermaceae studied in this report, it is demonstrated that the diffuse lateral meristem is the pericycle itself.