Field evaluation of the protective efficacy of Mycobacterium bovis BCG vaccine against bovine tuberculosis.

Abstract

The protective efficacy of Mycobacterium bovis BCG (1 x 10(6) single dose) was evaluated under field conditions. A total of 140 male Holstein Friesian calves, one to two week-old were selected. Two groups of 70 each were formed, one group was vaccinated and the other was injected with a placebo during their second week of age and followed until 12 months of age. The study considered a positive case of tuberculosis to be an animal that had a positive reaction to the three following tests in a row: tuberculin, IFNgamma PPD-B and IFNgamma ESAT6-CFP10 during the 12 months of exposure. The results showed a 59.4% efficacy (IC95%: 47.64-71.16). The non-vaccinated calves were 2.4 times more at risk of becoming infected (IC95%: 1.07-5.68) compared to vaccinated animals. As a complementary test a PCR test was performed using nasal exudates in some animals from both groups using a Mycobacterium complex detection kit. All the positive PCR reactions (5/44) were found in the non-vaccinated animals. These findings suggest that the use of the BCG vaccine, even though it is not capable of protecting 100%, does prevent TB vaccinated animals from excreting bacilli in their nasal secretions at their first year of age.

• Authors: G Lopez-Valencia, T Renteria-Evangelista, J de Jesús Williams, A Licea-Navarro, A De la Mora-Valle, G Medina-Basulto
• Journal: Research in veterinary science (Res Vet Sci) Vol. 88 Issue 1 Pg. 44-9 (Feb 2010) ISSN: 1532-2661 [Electronic] England
• PMID: 19564029 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2009 Elsevier Ltd. All rights reserved.

Chemical References

• BCG Vaccine
• Interferon-gamma

Topics

• Age Factors
• Animals
• BCG Vaccine (therapeutic use)
• Cattle (immunology, microbiology)
• Interferon-gamma (blood)
• Male
• Mycobacterium bovis (immunology)
• Nasal Mucosa (microbiology)
• Polymerase Chain Reaction (veterinary)
• Tuberculin Test (veterinary)
• Tuberculosis, Bovine (immunology, prevention & control)