Control measure for ruminant paratuberculosis have mainly focused on eradication. However, this goal seems now rather unreachable and new strategies give more weight to quality assurance. The oldest strategy which is vaccination has received little public attention in spite of having been successfully and continuously used in different countries and regions for over 70 years. In this paper we report some observations on the post-mortem findings of culling in vaccinated (32 cows) and non-vaccinated cattle herds (16 cows) in the short term. Variables studied included histopathological lesion type, ELISA, PCR and culture from different tissues. All the examined culling from non-vaccinated herds showed evidence of paratuberculosis while only 60% of the examined culling from vaccinated herds did it. Paratuberculosis reduction ranged between 20% and 100% depending on the indicator. The three cows examined more than one year after vaccination were confirmed as cases of paratuberculosis by Map detection and histopathological study. It is noticeable that all three were Jersey cows and were ELISA positive at vaccination. Taking into account the low cost of this strategy, this can be considered as a very successful outcome in such a short period. An interesting observation that came up from the post-mortem follow up was that Map was isolated from blood (5.6%) and muscle (2.5%) in three animals that were slaughtered for human consumption. In addition to the pathogenetic interest of cultural confirmation of blood PCR positive results, this indicates that meat might be another route of exposure for human population. More research is needed to precise the frequency of meat Map contamination and the long term effects of vaccination on it.

The relationship between paratuberculosis and Crohn's disease has been discussed along the time and there are several studies which link both diseases. Although the main way of introduction of the mycobacteria in the human food chain seems to be the milk and dairy products we can't reject the meet as a possible source of infection. Even though in Crohn's disease the bacteraemia has been described, this fact has not received enough attention in the study of the paratuberculosis. In this way, we will present our results proving the bacteraemia in Johne's disease and the presence of viable Map in muscle.

At the moment 31 dairy cattle from vaccinated and 17 from not vaccinated herds have been analyzed. All these animals were slaughtered or fallen stock and were sampled collecting faeces, different sections of gut tissues, mesenteric lymph nodes, muscle and blood. The diagnosis was based on histopathological and microbiological studies. On the one hand the lesions were classified following a previous described classification and on the other hand microbiological studies were based on isolation on Löwenstein Jensen and Herrold Egg Yolk media added with Mycobactine J.

Regarding the histopathological classification no difference has been detected between vaccinated and unvaccinated animals probably due to the short time from the vaccination. In the studied group we have observed that the presence of Map in faeces and tissues was 50% lower in vaccinated animals. Moreover we detected that the proportion of heavy faecal shedders was reduced 60% comparing the two groups. Two positive blood cultures and one positive muscle culture were obtained from three animals with clinical symptoms of paratuberculosis, which confirms the role of the bacteraemia in the spread of Map in infected animals, so this aspect of the pathogenesis should be considered in future studies.