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Regular monitoring of commercial laboratory rodents and institutional research animal residents is essential for microbiological quality control programs. The objective of our study was to investigate the recent prevalence of infectious pathogens in laboratory mice from eight experimental animal vendors and 56 institutional animal facilities in Korea. Our investigation was conducted in 2006-2007. Specific Pathogen Free (SPF) mice from four commercial breeders were clean according to serological, bacteriological, parasitological, and histopathological examination results. However, mice from one intermediate vendor that distributed SPF animals from main commercial vendors to local districts had Syphacia obvelata and Mycoptes musculinus infections. Additionally, mice from conventional animal breeders were highly contaminated. Among the 56 institutional animal facilities, mouse hepatitis virus (MHV), Sendai virus and Mycoplasma pulmonis positive results were obtained in 23.2, 8.9, and 1.8% of animals tested, respectively. These results indicate that quarantine and eradication efforts of infectious pathogens in these facilities are sub-optimal and need to be improved. The use of commercial conventional mice for research should be eliminated and appropriate vendor selection as well as thorough quarantine before releasing animals into a facility are needed. Finally we suggest qualified veterinary experts are needed at each animal facility to ensure an adequate health surveillance program.

The present study contains information about proper microbiological monitoring of laboratory animals' health and the standardization of microbiological monitoring methods in Korea. Microbiological quality control for laboratory animals, composed of biosecurity and health surveillance, is essential to guard against research complications and public health dangers that have been associated with adventitious infections. In this study, one hundred and twenty-two mice and ninety rats from laboratory animal breeding companies and one animal facility of the national universities in Korea were monitored in 2000-2003. Histopathologically, thickening of the alveolar walls and lymphocytic infiltration around the bronchioles were observed in mice and rats from microbiologically contaminated facilities. Cryptosporidial oocysts were observed in the gastric pits of only conventionally-housed mice and rats. Helicobacter spp. infection was also detected in 1 of 24 feces DNA samples in mice and 9 of 40 feces DNA samples in rats by PCR in 2003, but they were not Helicobacter hepaticus. This paper describes bacteriological, parasitological, and virological examinations of the animals.

Mycoplasma pulmonis and Mycoplasma arthritidis were differentially identified using PCR-restriction fragment length polymorphism (RFLP). A genus-specific sequence of mycoplasma was amplified by PCR and the PCR products were digested with the restriction enzyme SmaI. Each PCR product from the four isolates of M. pulmonis was digested with SmaI into two fragments; however, there was no digestion in the PCR product from M. arthritidis. This method might be useful to differentiate infection of M. pulmonis from that of M. arthritidis.

A transgenic zebrafish strain was generated expressing the aryl hydrocarbon receptor (AhR)-regulated green fluorescent protein (GFP) reporter gene. Following exposure to β-naphthoflavone (βNF), the transgenic fish exhibited up-regulation of GFP in the face and vertebrae compared to vehicle controls. βNF-exposed fish exhibited gross dysmorphogenesis in vertebral development by 5 days after fertilization.