A polymerase chain reaction and enzyme linked immunosorbent assay based approach for diagnosis and differentiation between vaccinated and infected cattle with Mycobacterium bovis

Abstract

Background:In most African and Arabic countries tuberculosis (TB) causes great economic losses in bovine species and constitutes serious zoonotic problem. As the traditional diagnostic method delay the research because of low sensitivity and specificity, a rapid method of diagnosis is of outmost importance.Aim:The study was designed to evaluate the two rapid diagnostic methods of TB in cattle, further to differentiate between infected and bacillus Calmette-Guerin (BCG) vaccinated animals.Materials and Methods:Intradermal tuberculin test was applied to 300 cattle. Of these cattle, 15 cattle were vaccinated from cattle negative to tuberculin test with BCG. Blood samples were taken for lymphocyte separation to apply polymerase chain reaction (PCR) upon and for serum preparation for the enzyme-linked immunosorbent assay (ELISA) application, this blood collected from 65 cattle classified into three groups, viz. positive tuberculin test (35 animals), negative tuberculin test (15 animals), and vaccinated cow with BCG (15 animals). From blood samples lymphocytes were separated and the isolated lymphocytes were subjected to PCR and serum for ELISA application. Blood samples, specimens from lymph nodes and specific tissues were taken for PCR and for cultivation and isolation of Mycobacterium bovis.Results and Conclusions:The results of this study revealed that PCR can be used as rapid efficient and accurate diagnostic test in detection of ruminant TB. Moreover, cattle's ELISA reading showed higher sensitivity in positive tuberculin animals. However, the differentiations between vaccinated and infected animals not clear by using a single antigen only.

Prevalence and risk factors of bovine tuberculosis in dairy cattle farms in Egypt

“…On the other hand, the finding that body condition and reproductive status weren't risk factors associated with BTB agrees with previous studies (48). Postmortem findings in (Table-4) were comparable with (49)(50)(51) and disagree with (53,48).The number of non -visible lesion (NVL) reactors 11 (14.29%), may be attributed to the non-specific reaction to the tuberculin test which may be due to sensitization by other mycobacterium rather than M. bovis or closely related microorganisms especially Nocardia or a combination of liver fluke infestation with saprophytic mycobacteria (51). Moreover non-specific reactors may be slaughtered at a stage of invisible lesions of the disease or the lesions may be found in parts of carcass such as bone or skin (51,52).…”

“…The isolation rate of M. bovis for non-visible reactors was 1 (9.09%). The total recovery rate of M. bovis for both visible and nonvisible reactors was 50 (64.93%), these results agreed with (22,24,53,54). and the number of atypical mycobacteria isolates was 3 (3.9%) which agree with (26,54).…”

Zoonotic Tuberculosis: A Neglected Disease in the Middle East and North Africa (MENA) Region

“…The trends in the prevalence of BTB also changed over time. In Egypt, Iran, Iraq, Morocco and Sudan, the prevalence of infection among cattle varied between 0.2% [ 42 ] and 4.3% [ 43 ], 8.5% [ 44 ] and 26.3% [ 45 ], 1.3% [ 46 ] and 10.2% [ 47 ], 1.7% [ 48 ] and 51.3% [ 49 ] and 0.2% [ 50 ] and 20.8% [ 51 ] over the last two decades, respectively.…”