Cristina Gevehr Fernandes

Epidemiological Findings and Laboratory Evaluation of Sporotrichosis: A Description of 103 Cases in Cats and Dogs in Southern Brazil

Sporotrichosis is a subcutaneous mycosis, which affects mainly small animals, and is considered an important public health disease. This paper describes the epidemiological and laboratory characteristics of 103 clinical cases of sporotrichosis diagnosed over a 10-year period in southern Brazil. The 92 cats and 11 dogs from eight municipalities in Rio Grande do Sul State developed especially the disseminated cutaneous and fixed cutaneous forms of the disease. Respiratory signs such as sneezing, serous nasal discharge and dyspnea were found in about 57% of the animals. The detection of Sporothrix schenckii in different clinical samples showed highest isolation in testicles (46.6%), oral cavity (45.2%) and conjunctival mucosa (38.1%). A differentiated histological pattern was found between the fixed cutaneous and disseminated cutaneous (DC) manifestations of the disease; well-organized granulomas of nodular distribution and various fungal structures prevailed in the DC form in cats. Melanin detection in S. schenckii cells by the Fontana–Masson technique was positive in 45.4% of the samples. The study revealed that the State of Rio Grande do Sul is an endemic sporotrichosis area and demonstrated the possibility of involvement of other pathways in the infection and spread of the disease. In addition, it emphasized the importance of laboratory tests for mycosis confirmation, especially in dogs that develop clinical manifestations without the presence of cutaneous lesions.

Role of melanin in the pathogenesis of cutaneous sporotrichosis.

In this study, we evaluate the clinical, histopathological and ultra structural aspects of the infection by field strain (MEL(+)) and mutated strain (MEL(-)) of Sporothrix schenckii. The development of sporotrichosis at the inoculation sites was similar for both groups of animals after the second week of the experimental period. Statistical differences appeared only at weeks 3 and 5. The pigmented isolate had greater tissue invasive capacity, promoting the formation of multifocal granulomas, whereas the albino isolate induced an enhanced inflammatory response, restraining the agent to the core of the granulomas.

Tumores em animais de produção: aspectos comparativos

Aiming at a complete study on all neoplastic lesions in farm animals (cattle, sheep, horses and swine), a retrospective review was performed covering a 24 years period (1978-2002) at the Regional Diagnostic Laboratory of the Veterinary School in Pelotas, Southern Brazil. The analysis included the review of epidemiological data and the standardization of classification parameters considering current rules of international classification of tumors. Six thousand two hundred and sixty seven samples were analyzed. The distribution among the species was: 98 in cattle, 9 in sheep, 65 in horses and 3 in pigs, over 175 cases detected. Prevalence studies as for the breed, sex, age and anatomical distribution of the tumors were analyzed. Lymphoma in cattle, squamous cell carcinoma in cattle and sheep, and sarcoids in horses were the tumors with higher incidence.

Behaviour of oligodendrocytes and Schwann cells in an experimental model of toxic demyelination of the central nervous system

Oligodendrocytes and Schwann cells are engaged in myelin production, maintenance and repairing respectively in the central nervous system (CNS) and the peripheral nervous system (PNS). Whereas oligodendrocytes act only within the CNS, Schwann cells are able to invade the CNS in order to make new myelin sheaths around demyelinated axons. Both cells have some limitations in their activities, i.e. oligodendrocytes are post-mitotic cells and Schwann cells only get into the CNS in the absence of astrocytes. Ethidium bromide (EB) is a gliotoxic chemical that when injected locally within the CNS, induce demyelination. In the EB model of demyelination, glial cells are destroyed early after intoxication and Schwann cells are free to approach the naked central axons. In normal Wistar rats, regeneration of lost myelin sheaths can be achieved as early as thirteen days after intoxication; in Wistar rats immunosuppressed with cyclophosphamide the process is delayed and in rats administered cyclosporine it may be accelerated. Aiming the enlightening of those complex processes, all events concerning the myelinating cells in an experimental model are herein presented and discussed.Oligodendrocitos e celulas de Schwann realizam a producao e manutencao das bainhas de mielina, respectivamente no sistema nervoso central (SNC) e periferico (SNP). As celulas de Schwann, a diferenca dos oligodendrocitos, sao capazes de invadir o SNC para remielinizar axonios desmielinizados, sempre que os astrocitos tenham sido destruidos. O brometo de etidio e uma droga gliotoxica usada para induzir desmielinizacao com o desaparecimento precoce de astrocitos, de modo que as celulas de Schwann tem liberdade para invadir o SNC. Em ratos Wistar normais, a remielinizacao e detectada treze dias apos desmielinizacao; em ratos Wistar imunossuprimidos com ciclofosfamida a reparacao do tecido e tardia, enquanto que em animais tratados com ciclosporina ela e acelerada. O objetivo do artigo e discutir todas as etapas do processo de destruicao e reparacao da mielina em um modelo experimental de desmielinizacao em ratos.

Enfermidades do sistema nervoso dos ruminantes no sul do Rio Grande do Sul

The main epidemiological, clinical and pathologic aspects of the diseases of the nervous system in cattle in Southern Rio Grande do Sul are described, including, the following conditions: cerebellar abiotrophy; cerebellar hypoplasia; congenital hypermetria; arthrogryposis; congenital hypomyelinogenesis; brain abscess; listeriose; tetanus; botulism; focal symmetrical encephalomalacia; rabies; leucosis; encephalitis by Herpesvirus Bovine-5; bovino malignant catarrh; intoxications by Solanum fastigiatum, Claviceps paspali, Halimium brasiliense, Diplodia maydis, and Ramaria flavo-brunnescens; hepatoencephalopaty caused by Senecio spp. and Echium plantagineum; ketosis; coenurosis; and spinal syndrome.

Ethidium bromide-induced demyelination of the sciatic nerve of adult Wistar rats

Peripheral nerve ultrastructure was assessed after single or multiple local injections of the intercalating dye ethidium bromide. Thirty-four adult Wistar rats of both sexes were divided into five groups and maintained in a controlled environment with rat chow and water ad libitum throughout the experiment. The experimental animals were injected with 1 microl of 0.1% ethidium bromide in 0.9% saline into the central third of the left sciatic nerve 1 (group 1), 2 (group 2), 4 (group 3), 6 (group 4) or 8 (group 5) times. In groups 2 to 5 the injections were made at 28-day intervals. Control animals received the same amount of 0.9% saline. The animals were killed at different times after injection: group 1 at 7 days (2 rats) and 15 days (2 rats); for groups 2, 3, 4 and 5, all rats were killed 10 days after the last injection and the lesions were investigated by light and transmission electron microscopy. In the acute lesions, intoxicated Schwann cells showed a vacuolated cytoplasm and separation of the sheaths from the axon. Myelin sheaths underwent progressive vesiculation and subsequent segmental demyelination. Myelin debris were withdrawn by macrophages and remyelination by Schwann cells was prominent. With the increase in the number of injections collagen fibers also increased in number and progressively enveloped smaller numbers of remyelinated axons composing new fascicles. Wallerian degeneration of fibers apparently not affected by ethidium bromide was more intense in the nerves from groups 4 and 5. The peripheral nerve repairs itself after demyelinating challenges with a profusion of collagen fibers and new fasciculations. This experimental model is valid to mimic recurrent demyelinating neuropathies.

Pituitary abscess in young calves associated with the use of a controlled suckling device.

Figure 2. Affected calf with exophthalmos, palpebral paralysis, and ulcerative keratitis. Pituitary abscesses were observed in cattle in Rio Grande do Sul, southern Brazil. On 1 farm, 3 (1.2%) of 250 3month-old crossbred Devon calves were affected. On a second farm, 7 (1.5%) of 470 crossbred Aberdeen Angus 3 Nelore calves were affected. Sucking by all animals was controlled by use of a plastic nose device (Fig. 1) for 7 days. When the nose device was removed, some animals had extensive ulcerative lesions in the nostrils. Six to 7 days after removal of the device, the affected calves had nervous system signs characterized by dysphagia, ataxia, depression, dropped jaw, inability to close the mouth, drooling, and partial mandibular paralysis with difficulty in chewing and swallowing. There was unilateral prolapse of the ocular globe with palpebral paralysis and corneal opacity or hemorrhagic and ulcerative traumatic keratitis and conjunctivitis (Fig. 2). Ptosis of the tongue was also noted. Two animals from the first farm were euthanized 19 and 26 days, respectively, after the onset of clinical signs. The third animal recovered after treatment with a penicillin–streptomycin combination. On the second farm, 5 calves died and 2 survived after similar treatment with the same antibiotics. The surviving animals had moderate neck extension and paralysis. Two calves from the first farm and 1 calf from the second farm were necropsied. The brains were removed and fixed in buffered formalin. In all calves, the dura mater covering the pituitary area was thickened and yellowish and protruded into the cranial cavity, causing compression of cranial nerves. A solitary, well-encapsulated focal abscess above the basisphenoid bone occupied the sella turcica area in all calves. The abscesses were approximately 3 cm in diameter and were filled with a viscous yellow to green liquid or a caseous material and surrounded by a 1–3-mm-wide whitegray capsule. No lesions were observed in the cribriform plate or in the basilar pore of the frontal lobes. In 1 calf, abscesses 1–3 cm in diameter were found in the ventral and medial nasal sinuses. No lesions or signs of sepsis were seen in any other organs. Histologic examination of the grossly affected areas revealed pyogranulomatous inflammation and abscessation. Arcanobacterium pyogenes was isolated by aerobic culture on blood-agar medium. In these calves, mandibular paralysis suggested involvement of the trigeminal nerve, which is responsible for facial sensibility and chewing. Signs of ocular prolapse suggested involvement of the abducent nerve.9 Arcanobacterium pyogenes is the most common isolate in chronic suppurative lesions of the brain, but other bacteria,

Evaluation in broilers of the probiotic properties of Pichia pastoris and a recombinant P. pastoris containing the Clostridium perfringens alpha toxin gene.

The probiotic properties of Pichia pastoris and of a recombinant P. pastoris containing the Clostridium perfringens alpha toxin gene were evaluated in broilers. One-day-old chicks randomly divided in four groups were fed with commercial feed devoid of antibacterials. The control group (1) received plain food, while the other groups were supplemented with either P. pastoris (2), the recombinant P. pastoris (3) or Bacillus cereus var. Toyoi (4). At day 49, live weights, feed efficiency and seroconversions were higher (P<0.05) in the supplemented groups than in the control groups. Group 3 showed the best results, while group 2 had lower weight gain than groups 3 and 4 although food conversion was better than in group 4. Seroconversions were not different (P>0.05) among the supplemented groups. Adverse reactions were not observed in histopathologic evaluation. We concluded that P. pastoris and the recombinant P. pastoris could be used as probiotics in broilers.

Intoxicação aguda e abortos em cobaias pelas favas de Enterolobium contortisiliquum (Leg. Mimosoideae)

The objective was to study the acute toxicity and the abortive properties of Enterolobium contortisiliquum pods in guinea pigs. Pods of E. contortisiliquum were administered orally to 4 groups of 3 guinea pigs each. Another group of 3 guinea-pigs was used as control. Group 1 and 2 were fed with one dose of 5 and 10g of pods for kg body weight, respectively. The guinea pigs of Group 3 and 4 received 10 and 15g/kg, respectively, divided into daily doses of 5g/kg. One guinea pig from Group 2 and one from Group 4 died 12 and 18 hours after the end of the administration. Gross lesions were hemorrhages of the stomach and of the large and small gut, enlarged liver, and dilated gall bladder. Histologically, the liver had severe vacuolation and necrosis of periportal hepatocytes. In another experiment a ration containing 4% of pods of E. contortisiliquum was fed to 2 groups of 4 guinea-pigs, 35 days after mating. Four of the 8 guinea pigs aborted 6-15 days after the beginning of ingestion. The other 4 guinea pigs were not pregnant. All guinea pigs were euthanized after abortion or at the end of the experiment. Histologically all animals had mild to severe periportal hemorrhagic necrosis. All fetuses had variable degree of autolysis. In 4 fetuses studied no significant histologic lesions were observed. The acute lesions observed in guinea-pigs are similar than those observed in the spontaneous poisoning by Enterolobium spp. in cattle. Similar lesions are observed in guinea-pigs poisoned experimentally with saponins from E. gummiferum. The results of the experiments in pregnant guinea pigs suggest that E. contortisiliquum can be used to study the abortive effect of its pods or its toxic compounds.

Ehrlichiose monocítica eqüina no Rio Grande do Sul: aspectos clínicos, anátomo-patológicos e epidemiológicos

A spontaneous outbreak of equine monocytic Ehrlichiosis (EME) is described. The disease occurred from November 2001 to February 2002 on a farm in the municipality of Arroio Grande, located at the western edge of the Mirim Lake, state of Rio Grande do Sul. Out of 50 horses 13 were affected and 6 died. The morbidity was 26% and the mortality 46.1%. The affected horses were 1-5 years old. The most important clinical sign was a profuse acute diarrhea. At necropsy of a horse that died with clinical signs of the disease, the main alterations were characterized by hemorrhagic areas of the mucosa of the large intestine with liquid contents, and congested and hemorrhagic areas alternating with normal areas as well as nodules with purulent secretion in the mucosa of the small intestine. The histological changes were characterized by moderate mononuclear infiltration of the mucosa, characterizing a lympho-histiocytic enteritis with predominance of macrophages. In the jejunum and ileum, related to the invagination of crypts and villi, a granulomatous enteritis was observed. To confirm the diagnosis of infection by Neorickettsia (Ehrlichia) risticii, blood samples of seven affected horses were taken and a polimerase chain reaction (PCR) was performed. Three tested blood samples were positive (42.8%) with observation of a band of 529pb characteristic of N. risticii.