Claudio Estevao Farias da Cruz

Study of experimentally induced lesions in sheep by grazing Brachiaria decumbens.

A histologic and ultrastructural study of the alterations found in the lymph nodes and livers of nine sheep with experimental cholangiohepatopathy by grazing on Brachiaria decumbens has been performed. Sheep were euthanized in three groups, on the 77th, 89th, and 150th days of the experimental feeding. The main gross lesions were whitish spots of multifocal distribution scattered throughout the hepatic parenchyma from all B. decumbens-grazed animals and whitish foci surrounded by reddened halos in the mesenteric and hepatic lymph nodes of sheep necropsied on the 150th. The principal histologic findings included hepatocellular cloudy swelling, marked multifocal cholangitis in the portal triads with bile duct proliferation and infiltration of macrophages and lymphocytes. Crystals were observed within bile ducts and surrounded by macrophages. Ultrastructurally, there were criytaloid structures within the macrophages and hepatocytes, which also presented hyperplasia of smooth endoplasmic reticulum. These findings suggest that hepatocytes were the initial target of the toxic effects, which depending on the degree of severity developed would cause both, subsequent cholangiopathy or occasional photosensitization. Additionally, the developmental stages of the hepatic lesions observed in this study have been presented.

Immunopathological investigations on bovine digital epidermitis.

Paraffin-embedded fragments of bovine digital skin lesions were sectioned and stained with Warthin-Starry, haematoxylin and eosin, Grocott’s methenamine silver and immunohistochemical techniques. Microorganisms observed in the silver-stained sections were classified into four major morphological groups. Spirochaetes were the most prevalent organisms, but bacillary and coccoid elements were also present in most sections. Immunohistochemical probing demonstrated that approximately 80 per cent, 46 per cent and 41 per cent of the digital and interdigital dermatitis sections stained positively with polyclonal antisera to Treponema pallidum, Campylobacter jejuni and Fusobacterium necrophorum, respectively. An unidentified branching filamentous organism (presumed to be an actinomycete) was consistently present in the sections of samples from mild interdigital lesions.

Bovine Mastitis due to Prototheca zopfii: Clinical, Epidemiological and Pathological Aspects in a Brazilian Dairy Herd

The clinical, epidemiological and pathological aspects of protothecal mastitis in a Brazilian dairy herd are described. Prototheca zopfii infection was diagnosed in 11 of 121 milking cows. Clinical mastitis refractory to usual therapy was observed in 7 cows. Several environmental conditions conducive to the growth of Prototheca spp., such as wetness, muddiness and the presence of organic material, were present in the dairy. Improper milking practices and insanitary infusion of the intramammary antibiotics were also observed. Six cows with protothecal mastitis were slaughtered and the affected quarters of each cow were examined by histology and immunohistochemical staining for bovine keratin and P. zopfii. The histological lesions were characterized by interstitial infiltrates of macrophages, plasma cells and lymphocytes; algae were seen in the alveolar lumen and interstitium. The lack of a positive reaction with an antiserum against bovine keratin in the mammary alveolar epithelial layer in some affected areas suggests destruction of milk-producing tissues, which may be related to the low milk production observed. The algal organisms stained positively with a polyclonal antibody against P. zopfii.

Intoxicação experimental por Trema micrantha (Ulmaceae) em caprinos

Green leaves of Trema micrantha were ground and mixed with water in a domestic blender and then administered by stomach tube to seven goats. One additional goat was fed ad libidum with the green leaves of T. micrantha. Clinical signs were observed in six goats that became ill 2 days after having been dosed with or fed the plant. There were five deaths, which occurred until 4 days after ingestion. Affected goats remained static during long periods and kept their heads low. Incoordination, rhythmical movements of the head, apathy, anorexia, and tenesmus were also noticed. Paddling movements and coma were seen in one goat. T. micrantha was toxic at dosages of 30 g/kg or higher. The most significant gross lesions were observed in the livers, which were yellowish, friable, and with pronounced lobular pattern. Their cut surfaces were reddened and depressed areas alternated with whitish ones. The liver of one goat was slightly but homogeneously reddened but did not show accentuated lobulation. Petechial haemorrhages in the region between the chest and scapula, in the epicardium, mediastinum and serosal membranes of the abdominal organs were also observed. The most important histologic finding was hepatic centrilobular coagulative necrosis, which was associated with congestion, haemorrhages and degenerative changes in the circumjacent hepatocytes. Additional microscopic lesions were found in the nervous system and included perineuronal and perivascular edema and swollen neurones, especially those of the frontal cortex.

An outbreak of aflatoxin poisoning in dogs associated with aflatoxin B1–contaminated maize products

An aflatoxicosis outbreak affected 65 dogs from 9 different farms after they were fed diets with cooked corn meal as a common ingredient. Of the dogs, 60 died. Numerous dogs died on additional farms, but those dogs were not included in the study. The farmers acquired the contaminated maize products, in the form of whole corn grain or as corn meal, from the same supplier. The corn product was mixed with meat that was left over from home or commercial rations to form corn polenta, which was fed to the dogs. Necropsy was performed on 3 dogs. Two of the dogs died after a few days of refusing food, showing anorexia, polydipsia, icteric mucous membranes, hematemesis, hematochezia, or melena, and bleeding of the skin, eye, ear, and mouth. The primary necropsy findings included jaundice, hemorrhages in several organs, and yellowish enlarged liver with enhanced lobular pattern. The dog that experienced chronic ascites had a yellowish liver with reduced volume, irregular surface, and increased consistency. The main histological findings included hepatocyte fatty degeneration, biliary duct hyperplasia, cholestasis and, in the chronic case, hepatic fibrosis. High-performance liquid chromatography analysis of the corn meal from 2 affected farms revealed 1,640 ppb and 1,770 ppb of aflatoxin B1, respectively. The current study demonstrates an additional way that dogs can be exposed to, poisoned, and killed by aflatoxin.

Experimentally induced cholangiohepatopathy by dosing sheep with fractionated extracts from Brachiaria decumbens

Cholangiohepatopathy was induced in 5 lambs by oral administration of extracts from signal grass (Brachiaria decumbens) in Brazil. Grossly there were pale foci multifocally distributed throughout the hepatic parenchyma in 4 lambs. The microscopic changes, which were similar to those produced by other steroidal sapogenins–containing plants such as Tribulus terrestris and Panicum spp., included multifocal chol-angitis, bile duct proliferation, and the presence of crystals in the biliary system.

Mortes súbitas em bovinos causadas por Amorimia exotropica (Malpighiaceae) no Rio Grande do Sul

Cases of sudden death in cattle were associated with the consumption of Amorimia (Mascagnia) exotropica and occurred in six ranches located in the mountainous region of Rio Grande do Sul and the metropolitan region of Porto Alegre, Brazil. Affected cattle were found dead with no history of previous clinical signs, or showed muscular tremors, falls, paddling, opistotonus, panting, and lateral recumbence after being induced to move, few minutes before death. Most cases were recorded between May and August. Nine cattle were necropsied and main gross findings were oral mucosae slightly cyanotic (3/9), mild to intermediate hydropericardium (3/9), epicardial petechiae and ecchymoses (5/9), clot within the left ventricle (4/9), lung edema (5/9), apart of abomasal and small intestinal reddened mucosa (6/9). Histologically, there was myocardial coagulation necrosis (9/9), which was characterized by cellular retraction, enhanced cytoplasmic eosinophilia, lack of cytoplasmic striations, intracytoplasmic vacuoles, nuclear piknosis, intranuclear vacuoles, chromatin marginalization and occasional nuclear karyorrhexis and karyolysis. There also were interstitial edema (3/9) and interstitial inflammatory infiltrate (mainly mononuclear) (7/9) in the heart, apart of multifocal vacuolar-hydropic degeneration in the epithelial cells of the distal convoluted tubules associated with pyknotic and eccentric nuclei in the kidneys of three cattle.

Clinical and pathological study of an outbreak of obstructive urolithiasis in feedlot cattle in southern Brazil

The epidemiology, clinical picture and pathology of an outbreak of urolithiasis in cattle in southern Brazil are described. The disease occurred in August 1999 in a feedlot beef cattle herd. Five out of 1,100 castrated steers were affected. Clinical signs included colic and ventral abdominal distension. White, sand-grain-like mineral deposits precipitated on the preputial hairs. Affected cattle died spontaneously 24-48 hrs after the onset of the clinical signs. Only one animal recovered after perineal urethrostomy. Necropsy findings included calculi blocking the urethral lumen of the distal portion of the penile sigmoid flexure, urinary bladder rupture with leakage of urine into the abdominal cavity and secondary fibrinous peritonitis. Daily water intake was low since water sources were scarce and not readily available. The animals were fed rations high in grains and received limited amounts of roughage. Biochemical analysis revealed that the calculi were composed of ammonium phosphate. A calcium-phosphorus imbalance (0.4:0.6) was detected in the feedlot ration. For the outbreak, it is suggested that contributing factors to urolith formation include insufficient fiber ingestion, low water intake and high dietary levels of phosphorus. No additional cases were observed in that feedlot after preventive measures were established. Similar dietary mismanagement in fattening steers has been associated with obstructive urolithiasis in feedlot beef cattle in other countries.

Bovine digital dermatitis in southern Brazil

near the heel bulbs (WVeaver and others 1981, Blowey and Sharp 1988, Read 1994). The disease was first described in Italy by Cheli and Mortellaro (1974). Since then, digital dermatitis and a similar condition named papillomatous digital dermatitis have beeni reported worldwide (Peterse 1986, Blowey and Sharp 1988, Van Amstel and others 1991, Read and others 1992, Rodriguez-Lainz and others 1999). Lately, both designations appear to represent the same disease complex, which in the USA is also known as footwarts, hairy footwarts, heel warts and strawberry foot disease (Read 1994, Read and Walker 1998). The rapid therapeutic response following topical treatment with antibiotics in most affected animals supports the involvement of bacterial species in the development of the disease (Read and others 1992, Read and Walker 1998). In addition, several bacterial agents, including spirochaetes related to human treponemes (Blowey and others 1992, Read and others 1992, Walker and others 1995, Dopfer and others 1997), Bacteroides species (Peterse 1986, Blowey and Sharp 1988) and Catinpylobacter species (Dopfer and others 1997, Ohya and others 1999), have been implicated in the aetiology of digital dermatitis. Outbreaks of the disease have mainly been reported in housed cattle (Peterse 1986, Blowey and Sharp 1988, Bassett and others 1990, Bergsten and others 1998, Read and Walker 1998, Rodriguez-Lain7z and others 1999) suggesting that environmental or biological factors associated with those systems of managenment may be important risk factors (RodriguezLainz and others 1996, 1999). Typical lesions have been described as red in colour, circular to oval in shape, alopecic, prone to bleeding, moist and painful to the touch. Larger ulcerative lesions or characteristic raised proliferative processes are associated with later stages of the disease (Blowey and Sharp 1988, Bassett and oth-

Co-infection by porcine circovirus type 2 and porcine parvovirus in aborted fetuses and stillborn piglets in southern Brazil

Porcine circovirus types 1 and 2 (PCV1, PCV2) and porcine parvovirus (PPV) are widespread in pig populations around the world. Nevertheless, only PCV2 has been associated with different clinical syndromes, thus representing a major problem to the pig industry. The association of cases of swine abortions and stillborns with PCV1 and PCV2 and PPV was studied retrospectively (2005-2007). Additional pathogens were also investigated in lesioned fetuses. The studied litters included stillborn piglets and several mummified fetuses of varied sizes. Ventricular dilatation, myocardial pale areas, and mesocolic edema were the gross lesions. Escherichia coli was detected as co-infecting with PCV2 the cases in which mesocolic edema was seen. Microscopic lesions included non-suppurative myocarditis, myocardial necrosis and fibrosis, mineralization foci and intranuclear inclusion bodies in cardiomyocytes, and interstitial mononuclear pneumonia. Samples from 7 (5.78 per cent) of 121 aborted fetuses and stillborn piglets had lesions consistent with a viral cause and showed both positive anti-PCV2 immunostaining as well as PCV2-PCR. In samples from 3 (2.47 per cent) of these 7 fetuses, co-infection with PPV was confirmed by Nested-PCR. Both viruses were detected in fetuses at different stages of gestation. Viral antigens of PCV2 were detected by immunohistochemistry mainly in macrophages and myocytes. PCV1 individually was not detected in any of these affected fetuses, but it was associated with PCV2 and/or PPV in some of them. These findings indicate that PCV2 alone or in association with PPV should be kept in mind when investigating causes of infectious abortion in pigs in Brazil.