Comparison of tuberculin skin test with Interferon-gamma assay for the diagnosis of bovine tuberculosis in Korean cattle / 대한수의학회지

Bovine tuberculosis (bTB), caused primarily by Mycobacterium bovis, continues to exert an economic loss, even in countries with active control measures, and is one of zoonotic diseases enable to be transmitted to human. The control and eradication of bTB are mainly based on a test and slaughter policy and/or abattoir surveillance. Various factors including limitation of diagnostic tests have been considered as major constraints to eradication. Single intradermal test (SIT) is the official diagnostic test. New diagnostic methods are needed to be developed, because of limitations of the test. In the present study SIT was compared with single intradermal comparative cervical test (SICCT) and interferon (IFN)-gamma assay. There was very low correlation between SIT and SICCT. However, high correlation was shown between SIT and IFN-gamma assay while no correlation was observed between SICCT and IFN-gamma assay. Therefore, our results suggest the possibility of replacement of SIT with IFN-gamma assay for the diagnosis of bovine tuberculosis.

Seroprevalence of low pathogenic avian influenza (H9N2) and associated risk factors in the Gyeonggi-do of Korea during 2005-2006

Between November 2005 and March 2006, a total of 253 poultry flocks in the Gyeonggi-do of Korea were examined for seroprevalence against avian influenza (AI) using a hemagglutination inhibition (HI) test and an agar gel precipitation test. No low pathogenic avian influenza (LPAI) virus was isolated from 47 seropositive flocks that lacked clinical signs during sampling. The unadjusted percentage of seroprevalence rates of layer and broiler flocks were not significantly different, i.e., 26% (25/96) and 23% (22/97), respectively. The HI titer of the layers (mean = 89) was higher than the broilers (mean = 36; p < 0.001). A cross-sectional study was conducted for the seroprevalence of LPAI in the layers. Of 7 risk factors, farms employing one or more workers had a higher seropositive prevalence as compared to farms without hired employees (adjusted prevalence OR = 11.5, p = 0.031). Layer flocks older than 400 d had higher seropositivity than flocks younger than 300 d (OR = 4.9, p = 0.017). The farmers recognized at least one of the clinical signs in seropositive flocks, such as decreased egg production, respiratory syndromes, and increased mortality (OR = 2.3, p = 0.082). In a matched case-control study, 20 pairs of case and control flocks matched for type of flock, hired employees, age, and flock size were compared. Frequent cleansing with disinfectants was associated with a decreased risk of seropositivity (OR = 0.2, p = 0.022). Although there was a low statistical association, using a foot disinfectant when entering the building led to a decreased rate of seropositivity (OR = 0.3, p = 0.105).