| mouse mammary tumor virus | 125 | species | viruses | viruses | 11757 |
| murine leukemia virus | 184 | species | viruses | viruses | 11786 |
| mycobacterium avium | 125 | species | bacteria | bacteria | 1764 |
| mycobacterium avium complex | 95 | species | bacteria | bacteria | 37162 |
| mycobacterium avium subsp. paratuberculosis | 79 | subspecies | bacteria | bacteria | 1770 |
| mycobacterium bovis | 132 | species | bacteria | bacteria | 1765 |
| mycobacterium tuberculosis | 238 | species | bacteria | bacteria | 1773 |
| mycoplasma genitalium | 78 | species | bacteria | bacteria | 2097 |
| mycoplasma pneumoniae | 93 | species | bacteria | bacteria | 2104 |
| myxoma virus | 59 | species | viruses | viruses | 10273 |
| neisseria gonorrhoeae | 136 | species | bacteria | bacteria | 485 |
| neisseria meningitidis | 130 | species | bacteria | bacteria | 487 |
| neospora caninum | 72 | species | invertebrates | protozoa | 29176 |
| newcastle disease virus | 93 | species | viruses | viruses | 11176 |
| parainfluenza virus 5 | 65 | no rank | viruses | viruses | 2905673 |
| pasteurella multocida | 65 | species | bacteria | bacteria | 747 |
| porcine circovirus | 65 | species | viruses | viruses | 46221 |
| porcine reproductive and respiratory syndrome virus | 65 | species | viruses | viruses | 28344 |
| porphyromonas gingivalis | 113 | species | bacteria | bacteria | 837 |
| proteus mirabilis | 80 | species | bacteria | bacteria | 584 |
| pseudomonas aeruginosa | 243 | species | bacteria | bacteria | 287 |
| pseudomonas stutzeri | 76 | species | bacteria | bacteria | 316 |
| rabies virus | 96 | species | viruses | viruses | 11292 |
| respiratory syncytial virus | 164 | species | viruses | viruses | 12814 |
| reticuloendotheliosis virus | 68 | species | viruses | viruses | 11636 |
| rhizopus oryzae | 86 | species | plants | fungi | 64495 |
| rotavirus a | 58 | species | viruses | viruses | 28875 |
| salmonella enterica | 107 | species | bacteria | bacteria | 28901 |
| salmonella enterica subsp. enterica serovar enteritidis | 87 | no rank | bacteria | bacteria | 149539 |
| salmonella enterica subsp. enterica serovar typhimurium | 77 | no rank | bacteria | bacteria | 90371 |
| sars coronavirus | 76 | no rank | viruses | viruses | 227859 |
| scrapie agent | 79 | species | | | |
| serratia marcescens | 100 | species | bacteria | bacteria | 615 |
| shigella dysenteriae | 80 | species | bacteria | bacteria | 622 |
| shigella flexneri | 142 | species | bacteria | bacteria | 623 |
| staphylococcus aureus | 271 | species | bacteria | bacteria | 1280 |
| staphylococcus epidermidis | 114 | species | bacteria | bacteria | 1282 |
| stenotrophomonas maltophilia | 80 | species | bacteria | bacteria | 40324 |
| streptococcus agalactiae | 62 | species | bacteria | bacteria | 1311 |
| streptococcus mutans | 104 | species | bacteria | bacteria | 1309 |
| streptococcus pneumoniae | 199 | species | bacteria | bacteria | 1313 |
| streptococcus pyogenes | 113 | species | bacteria | bacteria | 1314 |
| suid herpesvirus 1 | 106 | species | viruses | viruses | 10345 |
| toxoplasma gondii | 148 | species | invertebrates | protozoa | 5811 |
| transmissible gastroenteritis virus | 60 | no rank | viruses | viruses | 11149 |
| treponema pallidum | 87 | species | bacteria | bacteria | 160 |
| trichinella spiralis | 78 | species | invertebrates | helminths | 6334 |
| trichomonas vaginalis | 87 | species | invertebrates | protozoa | 5722 |
| vibrio cholerae | 145 | species | bacteria | bacteria | 666 |
| visna/maedi virus | 61 | species | viruses | viruses | 11741 |
| west nile virus | 97 | species | viruses | viruses | 11082 |
| yersinia enterocolitica | 126 | species | bacteria | bacteria | 630 |
| yersinia pestis | 105 | species | bacteria | bacteria | 632 |
| yersinia pseudotuberculosis | 99 | species | bacteria | bacteria | 633 |