Paratuberculosis in cattle – the outspread, diagnostics and control

Abstract: Paratuberculosis is chronic incurable granulomatose enteritis, caused by Mycobacterium avium subsp. paratuberculosis (MAP). The disease can be found in cattle, sheep and goats and it can appear among all age groups. The disease spreads slowly, the condition can vary, but it always ends with severe dehydration, weight loss and complete exhaustion of the animal. Diagnosis of paratuberculosis is established by direct detection of causative agent using selective media or by detection of agents’ genome using the PCR method. Indirect methods are based on the detection of specific antibodies in blood sera or milk, or on the measuring of cellular immunity. The detection of antibodies using ELISA method is considered the method of choice for the diagnosis of paratuberculosis, because of the rapidity of the test and relatively low expenses. The first serological analysis on the presence of paratuberculosis in cattle was carried out 20 years ago in the region of AP Vojvodina (Republic of Serbia). Blood sera taken from cattle originating from 12 farms were examined. The AGID (agar gel immunodiffusion) test revealed positive results in 13 cows coming from four farms, which makes 1.5% from the total number of cows. Furthermore, CF (complement fixation test) method revealed 35 positive cows, which makes 4.1% out of the total number of cows. In 1991, similar analysis applying ELISA test revealed 29 positive cows, i.e. 2.9% of positive cattle, which reflects a favourable epizootiological situation in the region. Lack of well-established laboratory tests, long periods of incubation and small number of clinical cases impede appropriate control of paratuberculosis. Control programs are based on reduction of transmission of the agent to host animals, elimination of infected animals, hygiene-sanitary measures and vaccination. The efficacy of the recommended programs would directly depend on elimination of infected animals. Despite the continuous research and numerous studies, the problem of detecting the infection caused by MAP is still present. This fact, together with the complex procedure of laboratory diagnostic, has caused a permanent spreading of the infection in cattle herds, while measures taken so far for the control of paratuberculosis have not been efficient enough.