Contemporary Prevalence of Infectious Agents
of Mice and Rats in Europe and North America
Robert S. Livingston, Cynthia L. Besch-Williford,
Matthew H. Myles, Marcus J. Crim and Lela K. Riley
IDEXX BioResearch
Columbia, Missouri USA
BACKGROUND
METHODS
Laboratory rodents can serve as sources of infectious agents for
disease outbreaks in laboratory animal facilities. Agents with a
higher prevalence pose an increased risk of introduction into
naive rodent populations. Knowledge of infectious agent
prevalence can help with risk assessments to develop agent
exclusion lists and determine testing frequencies for excluded
agents. In this study, the prevalence of infectious agents in
samples submitted from Europe and North America for
diagnostic testing in the year 2015 is presented as the
percentage of positive samples of the total samples tested.
Tests to detect viral, bacterial and fungal pathogens as well as
endoparasites and ectoparasites were performed on up to
112,000 rodent samples.
• Detection of viruses: Viral agents were tested from dried
blood spot or serum samples by MFI2 technology.
• Detection of bacteria: Bacteria were tested from feces, oral
swabs or pelt swabs by real-time PCR with the exception of
CAR bacillus, Clostridium piliforme, and Mycoplasma
pulmonis which were tested from dried blood spot or serum
samples by MFI2 technology.
• Detection of parasites: Parasites were tested from feces or
pelt swabs by real-time PCR or from intestinal contents or
fur/pelt samples by microscopic examination.
RESULTS
Bacteria & Fungi Prevalence in Mice
Viral Prevalence in Mice
Parasite Prevalence in Mice
17.84%
29.97%
0.60%
0.51%
18.00%
12.96%
14.00%
16.00%
14.68%
30.00%
0.50%
12.00%
0.45%
14.00%
25.00%
10.00%
12.00%
0.40%
20.00%
10.00%
7.87%
15.00%
0.06%
0.00%
0.01%
0.00% 0.00%
0.02%
0.04%
0.01% 0.01%
1.66%
1.51%
2.00%
2.00%
0.00%
0.00%
0.00%
3.31%
4.00%
4.00%
0.06%
0.03%
6.00%
4.66%
5.00%
0.03%
7.85%
6.00%
0.13%
0.10%
7.86%
8.00%
10.00%
0.20%
8.00%
8.80%
0.28%
0.30%
MNV
1.12%
0.00%
0.20%
0.07%
0.42%
0.03%
0.60%
0.02%
0.45%
0.00%
0.00%
Pinworms
Spironucleus muris
Entamoeba muris
Giardia muris
Fur mites
Parasite Prevalence in Mice
PCR vs. Microscopic Examination
3.31%
3.50%
3.00%
2.50%
2.00%
1.47%
1.50%
1.05%
1.00%
0.64%
0.50%
0.04%
0.05%
0.07%
0.19%
0.10%
0.05%
0.00%
Viral Prevalence in Rats
11.00%
2.50%
Parasite Prevalence in Rats
Bacteria & Fungi Prevalence in Rats
2.29%
10.42%
30.00%
26.84%
10.00%
25.00%
9.00%
8.00%
2.00%
8.00%
20.00%
7.00%
1.50%
6.00%
15.00%
5.00%
0.92%
1.00%
10.00%
3.55%
4.00%
0.72%
0.70%
0.39%
0.50%
0.00%
0.08%
1.02%
0.05%
0.00%
1.00%
0.80%
0.48%
0.05%
3.96%
5.00%
1.79%
2.00%
0.16%
4.00%
3.81%
3.00%
0.55%
0.14%
0.10%
0.00%
1.13%
0.49%
0.36%
0.00%
0.95%
0.04%
0.55%
0.40%
0.00%
0.00%
H1
KRV
RMV
RPV
LCMV
PVM
RCV/SDAV
REO3
RTV
Sendai
CONCLUSIONS
• Most prevalent agents in MICE
• Most prevalent agents in RATS
• Viruses: MNV, MPV, MHV, MAD and EDIM
• Viruses: RTV, parvoviruses, REO3 and SDAV
• Bacteria: Helicobacter spp., C. bovis and P. pneumotropica
• Bacteria: Helicobacter spp. (but much less prevalent than in mice)
• Parasites: Entamoeba muris, Spironucleus muris and pinworms • Parasites: Entamoeba muris, Tritrichomonas muris and Syphacia muris
• Increased detection of parasites by PCR vs. microscopy
• Fungi: Pneumocystis carinii (more prevalent than P. murina in mice)