Carlos Magno Chaves Oliveira

Fotossensibilização hepatógena em eqüinos pela ingestão de Brachiaria humidicola (Gramineae) no Estado do Pará

Data on the clinical-pathological aspects and on the epidemioloy of a disease in horses, characterized by phototsensitization, which occurs in northeastern of Para, Brazil, are presented. Of a total of 40 horses examined clinically, post-mortem examination was performed on seven. Due to the characteristic lesions found on the non-pigmented skin, the macroscopic and histological alterations in the liver, and knowing that Brachiaria grasses contain saponins with toxic properties, which cause liver lesions and photosensitization in cattle and sheep, it is concluded that this disease in horses is caused by grassing exclusively Brachiaria humidicola.

Meningoencefalite e polioencefalomalacia causadas por Herpesvírus bovino-5 no estado do Pará

Four outbreaks of meningoencephalitis in 1 to 2 years old cattle caused by Bovine herpesvirus-5 are reported in four municipalities in the state of Para, northern Brazil. In three outbreaks only one animal was affected, in another 3 cattle were affected. Main clinical signs were incoordination, dullness, blindness, recumbence, and opisthotonus. Death occurred after a clinical manifestation period of 3-4 days. Softening and yellowish areas were observed grossly in the cerebral cortex. The histology revealed poliencephalomalacia in the cerebral cortex, thalamus and basal nuclei, and non suppurative encephalitis and meningitis, and eosinophilic intranuclear inclusion bodies in astrocytes. The diagnosis was based on the typical microscopic lesions.

Comparação da sensibilidade de bovinos e búfalos à intoxicação por Palicourea marcgravii (Rubiaceae)

In order to verify if buffaloes are more resistant than cattle to poisoning by Palicourea marcgravii, the plant was given per os simultaneously to buffaloes and cattle. Seven buffaloes and three head of cattle were used. Doses of 0.5, 1.0 and 2.0 g/kg did not cause signs of poisoning in buffaloes; but doses of 3.0, 4.0 and 6.0 g/kg caused death. In cattle 0.25 g/kg did not cause symptoms; but 0.5 and 2.0 g/kg were lethal. The influence of exercise on the onset of symptoms, the time which elapsed from the beginning of the administration of the plant to the appearance of symptoms, and the symptoms themselves, were similar in the two animal species. The clinical course was longer in buffaloes; whilst in cattle the period between the onset of severe symptoms and death lasted 9 to 17 minutes; in buffaloes it varied from 10 minutes to 1 hour 28 minutes. It can be concluded, that buffaloes are about six times more resistant than cattle to the toxic action of P. maracgravii. The lower incidence of deaths in buffaloes by poisonous plants in the Amazon region is, at least in part, due the lower sensibility of buffaloes to poisoning by this plant. Another factor responsible for the smaller number of buffaloes which die due to plant poisoning in the Amazon region, is possibly that buffaloes prefer the lowlands, e.g. temporarily flooded areas, which are the habitat of Arrabidaea bilabiata, the second most important poisonous plant of the Amazon region. This plant is less poisonous than P. marcgravii, and its habitat are the higher not flooded areas. So it would be safer, in order to diminish losses, to breed buffaloes instead of cattle in areas where P. marcgravii occurs. The reason for the greater resistance of buffaloes should be further investigated as a possible prophylactic measure to avoid poisoning by P. marcgravii in cattle. On the other hand, Australian investigators modified genetically the ruminal bacteria Butyrivibrio fibrisolvens by introducing a gene, isolated from a Moraxella sp, which codifies a dehalogenase, capable of hydrolyzing fluoroacetate, the poisonous principle of P. marcgravii. Transferring the genetically modified B. fibrisolvens into the rumen of animals, which consume plants that contain fluoroacetate, would be a viable method to control that poisoning through a ruminal detoxifying process for the toxin. Through preliminary contacts, the director of the consorcium in Australia, responsible for the modification of the bacteria, declared that he is interested to sell the technology to our country, but it would be necessary to know if it is permitted to introduce into Brazil the genetically modified bacteria. If allowed, it would be necessary to perform investigations on the viability and the methodology for using this bacteria to control P. marcgravii poisoning in our country.

Intoxicações experimental e natural por Ipomoea asarifolia (Convolvulaceae) em búfalos e outros ruminantes

Ipomoea asarifolia R. et Schult. is a plant responsible for occasional outbreaks of poisoning in cattle, sheep and goats. Its oral administration to cattle and buffalos showed that the buffalo is as susceptible as cattle. One to 4 daily doses of 10-20g/kg caused similar symptoms in both species, as incoordination, muscular twiching and swaying of the head and anterior part of the body (pendular movement). In buffaloes the signs of incoordination were observed to a smaller extent. There is no report yet on natural poisoning by I. asarifolia in buffaloes, possibly because cases are not being noticed.

Fotossensibilização em ovinos associada à ingestão de Brachiaria brizantha no estado do Pará

Two outbreaks of photosensitization by Brachiaria brizantha were studied and an experiment was performed in Santa Ines and Dorper crossbred sheep, two to three months old, on a farm in Santa Luzia do Para municipality. These animals were kept from birth until about two months of age in a suspended stall floor, fed purple elephant grass (Pennisetum purpureum cv. purple), and had minerals and water ad libitum. After this period they were placed into a paddock of B. brizantha. At the time of the outbreaks and the experimental studies, the farm was visited for epidemiological assessment and clinical examination of the sheep, collection of blood samples for measurement of gamma glutamyltransferase, aspartate aminotransferase, conjugated bilirubin, unconjugated bilirubin, urea, and creatinine. Pasture samples were collected for saponin determination and count of Pithomyces chartarum spores. Necropsies with collection of material for histopathological studies were performed. Outbreak 1 occurred at the time of low rainfall, when the grass was scarce and mature, and morbidity and lethality was 43.4% and 81.6%, respectively. Outbreak 2 occurred at the beginning of the rainy season, with morbidity and lethality rates of 16.3% and 76.9%, respectively. From the 50 animals in the experiment, 10 received three times 200ml of rumen fluid taken from mother sheep of the same batch. The first of these administrations was given one day before the sheep were introduced into the pasture and the other two at weekly intervals. After 15 days in the pasture, the animals were unquiet, looked for shade, had edema of the ears, yellowish mucosae, were apathic, had anorexia and showed sloughing of the skin followed by crusting in some areas of the body. Both, the sheep of the outbreaks as those from the experiment, showed increased levels of GGT, AST, BD, BI, BT, urea and creatinine. In sheep which received ruminal fluid the values of urea and GGT were similar to those which did not receive the ruminal fluid. The creatinine, AST and bilirrubine values were lower in sheep that received the ruminal fluid. Two types of saponins, methylprotodioscin and protodioscin, were detected in the samples of B. brizantha from the outbreaks and the experiment. The level of saponins in Outbreak 1 and 2 was 0.92% and 0.88% respectively. The levels of saponins in the experiment ranged from 1.13% to 1.62%. The numbers of spores of Pithomyces chartarum in both outbreaks and in the experiment were negligible. At necropsy there was widespread jaundice, the liver was brown-yellow with marked lobular pattern and increased consistency and the kidneys were enlarged yellowish-green. Histological changes occurred mainly in the liver and consisted of mild proliferation of bile ducts in portal tracts, presence of binucleate hepatocytes, foamy macrophages, necrosis of isolated hepatocytes, cholangitis, presence of crystals in hepatocytes and macrophages.

Molecular and serological prevalence of Anaplasma marginale in water buffaloes in northern Brazil.

Bovine anaplasmosis, caused by Anaplasma marginale, occurs in tropical and subtropical regions throughout the world and is a major constraint on cattle production in many countries. Approximately 60% of the buffalo herds in South America are located in northern Brazil. However, compared with the research on cattle, research on buffaloes has been neglected. Therefore, the present study was conducted to investigate the distribution of A. marginale in water buffaloes in northern Brazil. A total of 500 buffalo blood samples was randomly collected from 16 provinces and was analyzed using both nPCR assay and ELISA techniques. The percentage of animals that were seropositive for A. marginale according to ELISA was 49% (245/500). The main risk factors associated with seroprevalence were the region (p=0.021; OR=1.2) and the reproductive status (p=0.0001; OR=1.6). Anaplasma marginale DNA was detected in 5.4% (27/500) of the sampled buffaloes. Our data provide information about the incidence of A. marginale infection in water buffaloes and may guide future programs aimed at controlling the disease in the northern region of Brazil. Although these water buffaloes are exposed to A. marginale, a low rate of A. marginale PCR-positive animals was found, which could be explained by the habitat in which the sampled animals live because they exhibited a low rate of attached ticks on their skin.

Prevalência e etiologia da mastite bovina na bacia leiteira de Rondon do Pará, estado do Pará

The prevalence and the etiology of bovine mastitis in the dairy region of the county of Rondon of Para were investigated. The sensibility and the resistance of the isolated agents to the antimicrobiotics was evaluetad; 237 mixed-bred milk cows were used on nine properties, which were hand milked once a day and kept on Brachiaria brizantha pasture, with supply of mineral salt and water ad libitum. Clinical examination of the mammary gland, the test of the sieve and California Mastitis Test were performed. Of the 935 examined mammary quarters, 6.6% had subclinical mastitis, 1.3% clinical mastitis, and 92.1% were negative. The isolated bacteria in the clinical mastitis were coagulase negative Staphylococcus spp. (25%), Staphylococcus aureus (16.7%), Streptococcus spp. (8,3%), and Corynebacterium spp. (8.3%). In the subclinical mastitis coagulase negative Staphylococcus spp. (32.3%), Staphylococcus aureus (17.7%), Staphylococcus intermedius (1.6%), Streptococcus spp. (4.8%), Corynebacterium spp. (4.8%), and coagulase negative Staphylococcus spp./S.aureus (1.6%) were isolated. There was no microbial growth in 41.7% of the samples with clinical mastitis and in 37.1% with subclinical mastitis. In the antibiogram, 100% of the isolated negative coagulase Staphylococcus spp., S. aureus, S. intermedius, and Streptococcus spp. were sensitive to sulfazotrim. On the other hand, Corynebacterium spp. were 100% resistant to this same antimicrobiotic. Cefalotina, cefoxitina and gentamicina were efficient against the isolated Staphylococcus spp. which represent the greater part of the mastitis agents in this study. Mastitis was diagnosed in all flocks studied, however the number of affected animals was considered low; this probably is due to low milk production of the cows and to permanence of the calf with the mother after milking, what favors emptying the mammary gland. But hygienic sanitary measures and management practices have to be improved.

Estudo comparativo da toxidez de Palicourea juruana (Rubiaceae) para búfalos e bovinos

O estudo foi realizado com os objetivos de estabelecer a sensibilidade dos bufalos a Palicourea juruana e agregar novos dados sobre a toxidez dessa planta para bovinos. Embora os quadros clinico-patologicos tenham sido semelhantes, a comparacao das doses letais para bufalos (entre 1 e 2 g/kg) e para bovinos (0,25 g/kg) estabelece o bufalo como pelo menos quatro vezes mais resistente. Em experimentos realizados 10 anos antes - com amostras de P. juruana coletadas na mesma fazenda no Para, em julho de 1993, inicio da epoca de seca, portanto apenas 2 meses mais tarde do que os agora realizados em maio de 2003 - a dose letal para bovinos foi de 2 g/kg. Nao encontramos explicacao para a toxicidade extremamente elevada da planta verificada nesse estudo.

Multifocal Cutaneous Orf Virus Infection in Goats in the Amazon Region, Brazil

Orf virus is the etiological agent of contagious ecthyma, a severe exanthematic disease that affects small ruminants. Orf virus is zoonosis that is associated with occupational contact with infected animals in human disease. Clinically, contagious ecthyma is characterized by the appearance of vesicles, pustules, ulcers, and papillomatous proliferative lesions on the skin of the lips and nostrils. Here we describe a case of lethal cutaneous multifocal Orf virus infection in goats in the Amazon region of Brazil. Exanthematic lesions were collected and epidemiological and clinical data were obtained. Orf virus was detected using PCR amplification of the whole B2L, VIR, and VEGF open reading frame. Phylogenetic analysis revealed that this virus clustered together with the Orf virus samples isolated during classical contagious ecthyma. The present work is the first to report a severe proliferative Orf virus case in South America.

Carcinoma de células escamosas perineal em cabras no Pará

Squamous cell carcinoma in goats of two farms in the State of Para is described. Prevalence, correlation with the pigmentation of the perineal area and macro and microscopic characteristics of the lesions were studied. The tumors on the perineum were of varied development degrees, diameters and forms. On one farm, in the county of Viseu, from a total of 347 goats, 20 presented the neoplasia (5.8%). On the second farm, in the county of Garrafao do Norte, three cases of squamous cell carcinoma in a herd of 400 goats (0.75%) were observed. The tumor was only observed in animals in which the perineal area was despigmented. The high incidence of this tumor appears to be due to lack of pigmentation at the perineo and the high and short tail of the goats, that exposes the area to intense ultraviolet radiation in the tropics.