Background and Rationale
Both human and rodent tissues, tumors and biologicals may be infected with viruses or mycoplasmas that can be infectious to humans or rodents and may be hazardous to human health. At least 16 rodent viruses, mycoplasmas, and protozoa are known to infect tumors: Lactate dehydrogenase-elevating virus (mice), Minute Virus of Mice (mice), Kilham’s Rat Virus (rats), Toolan’s H-1 parvovirus (rats, mice, human), Rat Parvovirus (rats), Mouse Parvovirus (mice), Mouse Hepatitis Virus (mice), Lymphocytic Choriomeningitis Virus (mouse, rat, hamster, human), Reovirus-3 (rodent, human), K virus (mouse), polyoma virus (mouse), Sendai virus (mouse, rat), Adenovirus (mouse), ectromelia virus (mouse), hantavirus (mouse, rat, human), various mycoplasmas including Mycoplasma pulmonis (mouse, rat) and M arthriditis (rat), and protozoa such as Encephalitozoon cuniculi. Human viruses managed at Biosafety Level 2, such as HIV-1 or Hepatitis B virus, could also infect permissive hosts such as immunosuppressed rodents.
In the United States in 1972, 69% of screened tumors were shown to have one or more contaminating pathogens (Collins, 1972). In Europe in 1993, 55% of mouse tumors, 7% of human tumors and 3.5% of rat tumors harbored pathogens (Nicklas, 1993). The prevalence of pathogen-contamination of tumors today in the United States is not known and can only be surmised, but is probably substantially lower than incidences reported over 25 years ago. However, it is of concern that over 10% of research institutions report that there are parvoviruses, MHV and Sendai virus in their rodents and that such devastating pathogens as Ectromelia virus and LCMV are lurking at low levels in mouse colonies (Jacoby, 1998). This taken in concert with the fact that biological materials are not uncommonly shared between researchers and institutions and that 33% of research institutions, including the ATCC, do not screen biological materials for rodent viral pathogens is cause for continued concern and surveillance. Historically, parvoviruses and lactate dehydrogenase-elevating virus have been the most common contaminants of biological materials.
Many rodent pathogens cause either subclinical disease that alter rodent immune function and confound cancer, infectious disease and immunologic research or, as in the case of Lymphocytic Choriomeningitis Virus, may be transmitted as a zoonotic disease to humans. A tumor inoculated into nude mice was the source of an LCMV outbreak with human illness reported in 1992 (Bigger, 1992). In rare cases, severe, uncontrollable clinical disease may require depopulation of entire colonies. In the spring of 1995, for example, all mice housed at the Naval Medical Research Institute had to be depopulated due to an outbreak of ectromelia virus that was introduced into the colony via mouse serum (Dick, 1996). A second outbreak occurred in the U.S. in 1999 was specifically related to virus-contaminated mouse serum imported from China (Lipman, 1999).
Targets
What Should be Screened? Tumors, tissues, immortal cell lines, embryonic stem cells, serum and mammalian components of cell culture media used to culture cells that will be inoculated into rodents should be screened for pathogens. The screening of these materials for pathogens prior to use is a requirement for their use by the IACUC.
Test Methodology
Screening of biological materials is done by direct or reverse transcriptase polymerase chain reaction at the Research Animal Diagnostic and Investigative Laboratory (RADIL) of the University of Missouri. This technology replaces the antibody production test which involved the use of live animals and had a lengthy turnaround time (25-30 days).
Test Panel
Screening is done for the following pathogens: Mycoplasma spp, Sendai virus, Mouse Hepatitis Virus (MHV), Pneumonia Virus of Mice (PVM), Minute Virus of Mice (MVM), Mouse Parvovirus, Theiler’s Meningoencephalomyelitis Virus (TMEV, GD-7), Reovirus-3, Rotavirus, Ectromelia Virus (Mouse Pox), Lymphocytic Choriomeningitis Virus (LCMV), Polyoma Virus, K Virus, Murine Adenovirus, and Lactate Dehydrogenase-elevating Virus (LDEV).
Disclaimer
Screening is not done for Hantavirus or Encephalitozoon cuniculi due to their absence from domestic research mice. Biological materials also are not assessed for the presence of HIV-1, Hepatitis B virus or other human pathogens that could grow permissively in immunosuppressed rodents. Universal precautions should be used when handling biologicals, injecting them into recipient animals or handling inoculated animals.
Arrangements for Testing
The program is managed mutually by faculty from both the Laboratory Animal Medicine and Pathology Units. Arrangements for biological screening should be made by contacting the DAR Diagnostic Laboratory at 404-727-1269. The turnaround time is normally 7-10 business days. Consult the DAR fee schedule for current charges.
Samples
The minimum quantity to submit is 10 million cells frozen in culture media and delivered on dry ice or 10 ml of ascites fluid.
Use of Pathogen-free Biological Materials. Providing screened materials are not passaged through rodents that are not housed in Emory University animal facilities or that cell lines are not supplemented with cells or biological fluids from an untested source, biological materials may be used in rodents in research colonies managed by the DAR without special restriction or containment beyond the usual husbandry program. Certification of testing is forwarded by the veterinary staff to the IACUC as verification that the material is free of specific infectious zoonotic agents and rodent pathogens.
Clinical Pathology Lab
All CELL LINES are tested for the following Agents
Cell Line Testing Instruction Form
PI Information Form for Cell Lines
References
Bhatt, P.N., et al. Viral and Mycoplasmal Infections of Laboratory Rodents: Effects on Biomedical Research. Academic Press, Orlando 1986.
Bhatt, P. N., Jacoby R.O. and S. W. Barthold. Contamination of transplantable murine tumors with lymphocytic choriomeningitis virus. Lab Anim Sci 36: 136-9, 1986.
Biggar, R.J., et al. LCM in laboratory personnel exposed to hamsters inadvertently infected with LCMV. JAVMA 1977; 171(9): 827-32.
Collins MJ, Parker JC. Murine virus contaminants of leukemia viruses and transplantable tumors. J Natl Cancer Inst 49: 1139-43, 1972.
Henderson KS, Banu LA, Havens RB, Jennings SM. Development of a 5 inch nuclease fluorogenic reverse transcriptase (RT) polymerase chain reaction (PCR) for the detection of Mouse Hepatitis Virus (MHV) in rodents and biological materials [Abstract] Cont Top Lab Anim Sci 38(4): 41, 1999.
Jacoby RO, Lindsey JR. Risks of infection among laboratory rats and mice at major biomedical research institutions. ILAR J 39(4): 266-71, 1998.
Lindsey JR, et al. Infectious Diseases of Rats and Mice, NRC, 1991.
Lipman NS. Mousepox: A threat to US mouse colonies. Lab Animal 28(6): 15, 1999.
Loew FM, Fox JG. Animal health surveillance and delivery systems. In: The Mouse in Biomedical Research. Vol III. Normative Biology, Immunology and Husbandry (Foster HL, Small JD, Fox JG, eds.), Academic Press, pp. 69-82, 1983.
Nicklas W, Kraft V, and Meyer B. Contamination of transplantable tumors, cell lines, and monoclonal antibodies and rodent viruses. Lab Anim Sci 43: 296-300, 1993.
Riley LK, Carty AJ, Besch-Williford CL. PCR-based testing as an alternative to MAP testing [Abstract] Cont Top Lab Anim Sci 38(4): 41, 1999.
Russell SP, Riley LK. PCR-based environmental monitoring for the detection of pathogenic organisms in rodents [Abstract] Cont Top Lab Anim Sci 38(4): 41, 1999.
