Linfadenite granulomatosa suína

Abstract

The results of meat inspection in slaughterhouses indicate that there might be risks due to unsafe meat from swine carcasses, but these hazards can be eliminated through a thorough veterinary inspection of the animals prior to the slaughter, as well as the examination of the meat and organs after. The information obtained during the meat inspection in slaughter houses is important to the development of a pork quality improvement system. My observations during the final internship of my graduation as a veterinary, in which I was able to accompany the meat inspector tasks, allowed me to conclude that there are a lot of gaps when it comes to community regulations and food safety policies. It was also noticed that there are no well established parameters when it comes to this pathology (swine granulomatosis lymphadenopathy) in the recent legislation and this further contributes to the rising difficulty in making a decision whether to approve or disapprove the meat, not for lack of knowledge about the physiopathology of the disease, but for the absence of a legal document describing the sanitary decision, guaranteeing the meat safety. Tuberculosis (TB) continues to cause significant economic losses for swine explorations around the world; pigs are susceptible to the infection with Mycobacterium avium complex (MAC), M. tuberculosis complex, M. bovis and conditionally pathogenic mycobacteriae. MAC includes an heterogeneous group of slow growing ubiquitous bacilli divided into two species (M. avium and M. intracellulare) that may origin disease in animals and human. The great incidence of granulomatous lesions associated with Rhodococcus equi could be considered a reason for misdiagnosis of M. avium subsp. avium in places where the meat inspection is based solely in the observation of granulomatous alterations of the lymph nodes, as this bacterium is also linked to swine granulomatosis lymphadenopathy in the head and neck. In slaughterhouses these type of lesions are easily confused with TB which makes R. equi an important microorganism for this particular motive, as it does not course with major clinical disease. According to the meat inspection legislation, the carcasses of animals with generalized TB should be rejected, but in case of localized granulomatosis lesions, only the affected body parts or organs as well as the adjacent lymph nodes should be considered improper. When it comes to granulomatosis lymphadenopathy caused by R. equi, the sanitary decision consists only in the removal of the affected lymph nodes. The national veterinary authority erroneously considers that the swine granulomatosis lymphadenopathy lesions are exclusively due to bacteria of the Mycobacterium gender, and the sanitary inspector is obligated to act on these terms. The main objective of this study was the attempt of demonstration of the possible presence of R. equi in submandibular lymph nodes affected by granulomatous lesions; these were collected during meat inspection in slaughterhouses (Central and Linda Rosa). Considering the study results, it was assumed that there is the probability that this type of lesions found in swine submandibular lymph nodes may be due to R. equi instead of Mycobacterium spp.

Date of Award	2012
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Paula Teixeira (Supervisor) & Joana Silva (Co-Supervisor)