This paper evaluated the epidemiological situation of the enzootic bovine leucosis from 1995 to 2005, in Portugal. With exception of the South region, Algarve, the disease was distributed throughout the country, being more prevalent in the north, between Douro and Minho and Trás-os-Montes, than in the centre. A decrease in prevalence and incidence of the infection throughout the studied period was also observed.

The identification of different bacterial strains and the occurrence of antibiotic resistance were investigated in several infection processes of pets as skin abscess with purulent discharge, bronco alveolar fluid, earwax, urine, mammary, and eye fluid. Streptococcus spp. and Staphylococcus spp. were the most detected in the different samples. A high frequency of antimicrobial resistance has been observed and this could reflect the wide use of antimicrobials in pets, making the effectiveness of antibiotic treatment to become more complicated.

The occurrence of vancomycin resistant enterococci (VRE) was investigated in feces of poultry, pigeons, deers and rats. Feces samples were collected from 25 broilers growing in poultry production farms that never used in the diets avaporcine as growth promoter, 6 broiler from different poultry production farms that used regularly avaporcine in the formulated diets until 1997, 8 deers from natural reservoirs, 15 pigeons, and 20 rats arrested from field conditions. The samples of Enterococcus gallinarum isolated from poultry feces were resistant to vancomycin independently of the use of avaporcine in the formulated diet.

The live B. melitensis Rev.1 strain is considered the best vaccine available for the prophylaxis of brucellosis in small ruminants, especially when used at the standard dose by the conjunctival route. In the present study a 1<FONT FACE=Symbol>´</FONT> 10(9) CFU dose for both sheep and goats conjunctivally vaccinated was tested to evaluate the duration of serological responses. Conjunctival vaccination with Rev. 1 performed in adult animals induced a rapid rise in serological titres as measured by Rose Bengal Plate Test (RBPT), Complement Fixation Test (CF) and Modified Rose Bengal Plate Test (MRBPT). Titres then decreased and became negative in most animals by four months after vaccination (except MRBPT). The goats responded better to the vaccination than the sheep as one month after vaccination 100% of the goats revealed positive results to RB and RBM and 93.4% to FC test. The RBM was the one that detected more positive animals along the study.