Microbiological quality assessment of laboratory mice in Korea and recommendations for quality improvement.

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.

Experimental evaluation of rodent exclusion methods to reduce hantavirus transmission to residents in a Native American community in New Mexico.

We conducted a pilot study to evaluate the efficacy of rodent proofing continuously occupied homes as a method for lowering the risk for hantavirus pulmonary syndrome (HPS) among residents of a Native American community in northwestern New Mexico. Rodent proofing of dwellings was paired with culturally appropriate health education. Seventy homes were randomly assigned to treatment or control categories. Treatment homes were rodent-proofed by sealing openings around foundations, doors, roofs, and pipes and repairing screens and windows. Repairs to each dwelling were limited to $500 US. After repairs were completed, 15-20 snap traps were placed in each treatment and control home and checked approximately every 2 days for an average of 3-4 weeks. During 23,373 trap nights, one house mouse (Mus musculus) was captured in one treatment home, and 20 mice (16 deer mice, Peromyscus maniculatus, two Pinyon mice, Peromyscus truei, and two unidentified mice) were captured in five control homes (one house had 14 captures, two had two captures, and two had one capture). Trap success was 0.01% in treatment homes and 0.15% in controls. Intensity of infestation (mean number of mice captured per infested home) was 1 in treatment homes and 4 in controls. Observations of evidence of infestation (feces, nesting material, gnaw marks, or reports of infestation by occupant) per 100 days of observation were 1.2 in treatment homes and 3.1 in controls. Statistical power of the experiment was limited because it coincided with a period of low rodent abundance (August-November 2000). Nevertheless, these results suggest that inexpensive rodent proofing of occupied rural homes can decrease the frequency and intensity of rodent intrusion, thereby reducing the risk of HPS among rural residents in the southwestern United States.