An overview of calf diarrhea - infectious etiology, diagnosis, and intervention

Cho, Yong-il; Yoon, Kyoung-Jin

Laboratory methods for identifying enteric pathogens have typically included pathogen isolation and characterization along with histopathology as the gold standard for etiologic agent and disease confirmation [114] . However, many enteric pathogens are difficult to isolate from the gastrointestinal environment [31] . Direct visualization (e.g., light microscopy or electron microscopy [EM]) of pathogens in feces or intestinal contents as well as the detection of antigens (e.g., Ag-ELISA) or nucleic acids (e.g., PCR) in specimens have been widely accepted as alternative methods. Most veterinary diagnostic laboratories concurrently use numerous techniques when testing samples for enteric pathogens. The characteristics along with advantages and disadvantages of common laboratory methods for identifying enteric pathogens are briefly described below and summarized in Table 1 .