| yersinia pseudotuberculosis | 99 | species | bacteria | bacteria | 633 |
| yersinia pestis | 105 | species | bacteria | bacteria | 632 |
| yersinia enterocolitica | 126 | species | bacteria | bacteria | 630 |
| west nile virus | 97 | species | viruses | viruses | 11082 |
| visna/maedi virus | 61 | species | viruses | viruses | 11741 |
| variola virus | 80 | species | viruses | viruses | 10255 |
| trichinella spiralis | 78 | species | invertebrates | helminths | 6334 |
| transmissible gastroenteritis virus | 60 | no rank | viruses | viruses | 11149 |
| toxoplasma gondii | 148 | species | invertebrates | protozoa | 5811 |
| suid herpesvirus 1 | 106 | species | viruses | viruses | 10345 |
| streptococcus agalactiae | 62 | species | bacteria | bacteria | 1311 |
| staphylococcus epidermidis | 114 | species | bacteria | bacteria | 1282 |
| staphylococcus aureus | 271 | species | bacteria | bacteria | 1280 |
| scrapie agent | 79 | species | | | |
| salmonella enterica subsp. enterica serovar typhimurium | 77 | no rank | bacteria | bacteria | 90371 |
| salmonella enterica subsp. enterica serovar enteritidis | 87 | no rank | bacteria | bacteria | 149539 |
| salmonella enterica | 107 | species | bacteria | bacteria | 28901 |
| reticuloendotheliosis virus | 68 | species | viruses | viruses | 11636 |
| rabies virus | 96 | species | viruses | viruses | 11292 |
| pseudomonas aeruginosa | 243 | species | bacteria | bacteria | 287 |
| proteus mirabilis | 80 | species | bacteria | bacteria | 584 |
| propionibacterium acnes | 77 | species | bacteria | bacteria | 1747 |
| porphyromonas gingivalis | 113 | species | bacteria | bacteria | 837 |
| porcine reproductive and respiratory syndrome virus | 65 | species | viruses | viruses | 28344 |
| porcine circovirus | 65 | species | viruses | viruses | 46221 |
| penicillium chrysogenum | 74 | species | plants | fungi | 5076 |
| pasteurella multocida | 65 | species | bacteria | bacteria | 747 |
| parainfluenza virus 5 | 65 | no rank | viruses | viruses | 2905673 |
| newcastle disease virus | 93 | species | viruses | viruses | 11176 |
| neospora caninum | 72 | species | invertebrates | protozoa | 29176 |
| mycobacterium bovis | 132 | species | bacteria | bacteria | 1765 |
| mycobacterium avium subsp. paratuberculosis | 79 | subspecies | bacteria | bacteria | 1770 |
| mycobacterium avium complex | 95 | species | bacteria | bacteria | 37162 |
| mycobacterium avium | 125 | species | bacteria | bacteria | 1764 |
| murine leukemia virus | 184 | species | viruses | viruses | 11786 |
| mouse mammary tumor virus | 125 | species | viruses | viruses | 11757 |
| mannheimia haemolytica | 67 | species | bacteria | bacteria | 75985 |
| lymphocytic choriomeningitis mammarenavirus | 148 | species | viruses | viruses | 11623 |
| listeria monocytogenes | 207 | species | bacteria | bacteria | 1639 |
| leishmania donovani | 98 | species | invertebrates | protozoa | 5661 |
| klebsiella pneumoniae | 146 | species | bacteria | bacteria | 573 |
| klebsiella oxytoca | 66 | species | bacteria | bacteria | 571 |
| influenza a virus | 135 | species | viruses | viruses | 11320 |
| infectious bronchitis virus | 66 | no rank | viruses | viruses | 11120 |
| helicobacter pylori | 246 | species | bacteria | bacteria | 210 |
| haemonchus contortus | 74 | species | invertebrates | helminths | 6289 |
| gallid herpesvirus 2 | 63 | species | viruses | viruses | 10390 |
| fusarium solani | 73 | species | plants | fungi | 169388 |
| francisella tularensis | 74 | species | bacteria | bacteria | 263 |
| foot-and-mouth disease virus | 89 | species | viruses | viruses | 12110 |
| feline leukemia virus | 69 | species | viruses | viruses | 11768 |
| feline immunodeficiency virus | 80 | species | viruses | viruses | 11673 |
| fasciola hepatica | 68 | species | invertebrates | helminths | 6192 |
| escherichia coli | 524 | species | bacteria | bacteria | 562 |
| equine infectious anemia virus | 62 | species | viruses | viruses | 11665 |
| equine arteritis virus | 61 | species | viruses | viruses | 11047 |
| enterococcus hirae | 63 | species | bacteria | bacteria | 1354 |
| enterobacter cloacae | 90 | species | bacteria | bacteria | 550 |
| entamoeba histolytica | 98 | species | invertebrates | protozoa | 5759 |
| encephalomyocarditis virus | 105 | no rank | viruses | viruses | 12104 |
| echinococcus granulosus | 61 | species | invertebrates | helminths | 6210 |
| cryptosporidium parvum | 92 | species | invertebrates | protozoa | 5807 |
| cryptococcus neoformans | 126 | species | plants | fungi | 5207 |
| coxiella burnetii | 67 | species | bacteria | bacteria | 777 |
| cowpox virus | 71 | species | viruses | viruses | 10243 |
| clostridium perfringens | 101 | species | bacteria | bacteria | 1502 |
| clostridium botulinum | 106 | species | bacteria | bacteria | 1491 |
| clostridioides difficile | 127 | species | bacteria | bacteria | 1496 |
| classical swine fever virus | 84 | species | viruses | viruses | 11096 |
| citrobacter freundii | 70 | species | bacteria | bacteria | 546 |
| chlamydia psittaci | 63 | species | bacteria | bacteria | 83554 |
| chlamydia pneumoniae | 143 | species | bacteria | bacteria | 83558 |
| chlamydia abortus | 63 | species | bacteria | bacteria | 83555 |
| canine parvovirus | 65 | no rank | viruses | viruses | 10788 |
| canine distemper virus | 60 | species | viruses | viruses | 11232 |
| candida albicans | 181 | species | plants | fungi | 5476 |
| campylobacter jejuni | 130 | species | bacteria | bacteria | 197 |
| campylobacter coli | 65 | species | bacteria | bacteria | 195 |
| brucella abortus | 76 | species | bacteria | bacteria | 235 |
| bovine viral diarrhea virus 1 | 80 | species | viruses | viruses | 11099 |
| bovine spongiform encephalopathy agent | 101 | species | | | |
| bovine papillomavirus | 95 | species | viruses | viruses | 10571 |
| bovine leukemia virus | 65 | species | viruses | viruses | 11901 |
| bovine herpesvirus 1 | 70 | species | viruses | viruses | 10320 |
| borreliella burgdorferi | 144 | species | bacteria | bacteria | 139 |
| borna disease virus | 65 | species | viruses | viruses | 12455 |
| bluetongue virus | 64 | species | viruses | viruses | 40051 |
| bartonella henselae | 77 | species | bacteria | bacteria | 38323 |
| bacteroides fragilis | 97 | species | bacteria | bacteria | 817 |
| bacillus licheniformis | 78 | species | bacteria | bacteria | 1402 |
| bacillus cereus | 111 | species | bacteria | bacteria | 1396 |
| bacillus anthracis | 122 | species | bacteria | bacteria | 1392 |
| aspergillus niger | 110 | species | plants | fungi | 5061 |
| ascaris suum | 65 | species | invertebrates | helminths | 6253 |
| anaplasma phagocytophilum | 62 | species | bacteria | bacteria | 948 |
| aeromonas hydrophila | 89 | species | bacteria | bacteria | 644 |
| acinetobacter calcoaceticus | 77 | species | bacteria | bacteria | 471 |
| acinetobacter baumannii | 88 | species | bacteria | bacteria | 470 |
| acanthamoeba castellanii | 78 | species | invertebrates | protozoa | 5755 |
| [enterobacter] aerogenes | 75 | species | bacteria | bacteria | 548 |