Present phytosanitary situation of Portuguese forests

Surveys carried out in conifer stands in the Azores and on the Portuguese mainland identified fungi causing serious new damage to pines and other conifer species. The most important are Dothistroma septospora found on needles of Pinus spp., Seiridium cardinale causing stem and twig canker of cypress and a new pathogen of the genus Elytroderma infecting needles of Pinus pinea with a subsidiary effect on stem and branches. After fires, new pathogens appeared in P. pinaster stands in North Portugal. Surveys in burnt plots showed the presence of the two very important root parasites, Rhizina undulata and Heterobasidion annosum , as well as species of the Ceratocystis complex producing not only blue stain, but also a wilt disease. Forest fires are often also associated with scolytid attacks on P. pinaster , specially by Tomicus piniperda, T. minor and Ips sexdentatus.     

Plasma levels of chloramphenicol after oral administration in calves during the first weeks of life

Three experiments were carried out to investigate the mechanisms whereby adequate plasma levels of chloramphenicol may be obtained following oral administration in young calves but not in older animals. In the first experiment, plasma levels of chloramphenicol following an oral dose of 50 mg/kg were followed in six calves, given weekly doses for the first 11 weeks of life. A plasma chloramphenicol level of 5 μg/ml, taken as the minimum therapeutic level, was attained only for a few hours in the 1 week old calves. Thereafter plasma levels decreased very rapidly until the fourth week, and rather more slowly between the fourth and eleventh weeks. At 11 weeks the plasma chloramphenicol level fell to around 0.3 μg/ml, which was the lower limit of sensitivity for the assay technique used. In the second experiment, the same single dose was administered to calves in the twelfth or eighteenth weeks of life which had not previously been exposed to the antibiotic. Plasma levels of 1 μg/ml were barely reached. This suggests that the non-absorbtion of chloramphenicol is unlikely to be related to repeated administration of the antibiotic. In the third experiment, the same single dose was administered orally to two cows. Chloramphenicol could not be detected in the plasma following such administration, and some side-effects were observed in the 48 h following dosing. It is suggested that rumen function may interfere with the absorbtion of chloramphenicol following oral administration to ruminants, even in relatively young animals.