Table 2.
Detection methods and specimen type for the diagnosis of calf diarrhea agents
| Pathogen | Specimen | Test Methods |
|---|---|---|
|
Clostridium perfringens Type C Clostridium difficile |
Small intestine contents (frozen) Feces (if alive) Intestine lesion (fixed) Colon contents or feces (fresh or frozen) Colon and ileum (fixed) |
Culture and genotyping, toxin: agELISA, PCR HP (tissue) Culture and toxin testing HP (tissue) |
| E coli, K99 (F5) | Feces and/or ileum content Ileum (fixed) |
agELISA Culture IC, LA, SA, PCR HP |
| E coli, attaching and effacing | Ileum and colon (fresh and fixed) | HP and culture (typing, PCR eae gene and/or toxin detection) |
| Salmonella spp | Feces Intestine Tissues |
Culture, IC, PCR |
| Coronavirus | Colon and ileum (fresh-FA) Feces |
FA, HP agELISA, EM, IC, PCR |
| Rotavirus | Feces, small intestine (fresh- FA) | agELISA, EM, FA, IC, LA, PCR |
| Cryptosporidium spp | Feces | AF, agELISA, FA, Flotation, IC, PCR |
| Coccidia | Feces Colon |
Flotation, McMaster’s HP, scraping- direct (unfixed) |
| Nematodes | Feces Abomasum, intestine |
Flotation, McMaster’s Gross examination |
| Septicemia | Lung and/or liver (fresh) | Culture |
| Copper deficiency | Liver Serum |
ICP-AES or AA |
Abbreviations: AA, atomic absorption; AF, acid-fast stain on direct smear; agELISA, antigen ELIZA; EM, electron microscopy; FA, fluorescent antibody test; HP, histopathology; IC, immune-chromatography assay (lateral-flow agELISA); ICP, inductively coupled plasma atomic emission spectroscopy; LA, latex agglutination; PCR, polymerase chain reaction with nucleic acid probe; SA, slide agglutination.