Difficulties in Eradication of Tuberculosis Infected Cows from the Infected Dairy Herds in Taiwan

in Domestic Journal (NSC excellent journals), 國內期刊(國科會優良期刊)
標題Difficulties in Eradication of Tuberculosis Infected Cows from the Infected Dairy Herds in Taiwan
AuthorsYung(Yeong)-Huey Wu, 吳永惠
期刊Taiwan Vet J
出版日期2005 / 3

Using intradermal tuberculin test (ITT), gamma interferon test (IFN-γtest) and duplex polymerase chain reaction (duplex PCR) for tuberculosis, a total of 215 ITT negative cows from two infected diary herds, which have had ITT positive cows in the last ITT test, were continuously examined four times at interval of three months. The results showed that all 215 cows were negative reactions on ITT in four times of examinations, but 13.0﹪(28/215) and 7.9﹪(17/215) cows were positive on one to four times of IFN-γtest or duplex PCR, respectively. Using the duplex PCR, the nasal mucus and milk were examined on the 17 cows, which were negative for ITT but positive for duplex PCR of blood samples. The results revealed that 23.5﹪(4/17) cows were positive on the nasal mucus samples, but all the milk samples were negative. On the other hand, the blood, nasal mucus and milk samples of 72 ITT positive cows from five other infected farms were examined by above methods, and their mediastinal and retropharyngeal lymph nodes were sampled for Mycobacterium bovis isolation. The results showed that 95.8﹪(69/72) and 86.1﹪(62/72) cows were positive on blood samples for tuberculosis by IFN-γtest and duplex PCR, respectively. Sixty six point six percent (48/72) and 38.6﹪(17/44) cows were positive for tuberculosis by duplex PCR on nasal mucus and milk samples, respectively. M. bovis were isolation from 68.1﹪(49/72) ITT, 68.1﹪(47/69) IFN-γtest and 67.7﹪(42/62) duplex PCR positive cows, respectively. Besides, blood samples collected from 10 herdsmen, 10 dogs, 4 cats and 10 rats in these seven infected diary herds were examined by duplex PCR; only 30.0﹪(3/10) herdsmen were positive for M. bovis. From the above results, we concluded when only ITT were used, the infected cows would not be thoroughly eliminated from the infected herds. The ITT positive or PCR positive but ITT negative cows could easily spread M. bovis through their nasal discharge or raw milk to the ITT negative cows or nursing calves. This might be the most important causes of difficulty in eradicating tuberculosis from the infected diary herds.

校址:912 屏東縣內埔鄉學府路1號 總機:886-8-7703202 傳真:886-8-7740165 系統開發統維護單位:國立屏東科技大學 電算中心 版權所有