Caracterização molecular do Mycobacterium avium subspécie paratuberculosis em leite de cabra produzidos na região semiárida da Paraíba do Nordeste Brasileiro.

Abstract

This thesis consists of three articles. In Chapter I it was carried out through a systematic review and meta-analysis to evaluate the detection of antibodies and molecular analysis for Mycobacterium avium subspecies paratuberculosis (MAP) in goat's milk. The following search parameters were used: “Mycobacterium avium subspecies paratuberculosis AND (goat OR small ruminant) AND (milk OR pasteurized milk) ”. Strictly obeying pre-established criteria, 437 articles were selected from the respective electronic bases of scientific content: ScienceDirect (285), PubMed (68), Web of Science (60) and Scopus (24), of which, nine papers were elected to the construction of the review systematic and meta-analysis. The prevalence of MAP in milk ranged from 1.1 to 67.7% in the Enzyme-linked Immunosorbent Assay (ELISA), and from 1.94 to 37.74% in the Polymerase Chain Reaction (PCR). The meta-analysis indicated a combined overall prevalence of 8.24%, but with high heterogeneity between studies (I2 = 98.7%). A significant presence of MAP was found in goat's milk, implying the need for surveillance of the agent, in order to preserve public and herd health. Chapter II aimed to confirm the presence and carry out the molecular characterization of MAP in the milk of goats destined for processing in processing plants in the semi-arid region of Northeast Brazil. Samples from 179 production units, five collective tanks and four samples of pasteurized goat milk were analyzed. The real time Polymerase Chain Reaction (qPCR) was used as a molecular test. MAP genetic material (DNA) was found in the goat's milk sample from a production unit (0.56%; 1/179). From this positive sample, eleven lactating goats were identified on the farm of origin and nine of them (81.82%; 9/11) presented MAP DNA in milk samples. In Chapter III, the clinical, histopathological and molecular findings of (MAP) were reported in dairy goats from the Northeastern semiarid, Brazil. From a positive sample composed of the goat milk pool of a production unit located in the municipality of Monteiro, state of Paraíba, Brazil. In the individual test of 11 lactating goats, 9 positive samples were found, as described in a previous study. Two goats (one positive and one negative in the first MAP qPCR) were acquired and euthanized. Animals 1 and 2 had milk and portions of the duodenum, ileum, colon and mesenteric lymph nodes positive for MAP qPCR. Animal 1 still had MAP DNA detected in a portion of the jejunum and cecum, while animal 2 was positive in the ileocecal valve portion. MAP was not detected in the blood and feces of both animals. The diagnosis of infection for MAP was confirmed by the association of clinical, histopathological and qPCR findings. The genes of the positive samples were sequenced and demonstrated 99% similarity with MAP. The presence of Mycobacterium avium subspecies paratuberculosis was found for the first time in milk and goat tissues in the semiarid region, which reveals a potential biological risk to man and implies the need for active surveillance of the agent.