Life Technologies

2 Life Technologies | Animal Health Detection of pathogens by microscopy—Some protozoa and several helminth parasites or their eggs, e.g., Ascaris suis, Balantidum coli, Strongyloides ransomi, Isospora suis, Oesophagostomum dentatum, Trichuris suis, as well as some viruses, e.g., rotaviruses and coronaviruses, can be suspected or identified by different microscopy techniques. Detection of pathogens by cultural testing—Fecal samples can be tested by culture for the presence of a range of enteric pathogens, including Brachyspira hyodysenteriae, Brachyspira pilosicoli, Clostridium perfringens, hemolytic Escherichia coli, and Salmonella species. Cultural testing is not suitable for Lawsonia intracellularis or viruses shed with feces. For E. coli, further characterization by PCR is recommended in order to identify AEEC (attaching and effacing E. coli), ETEC (enterotoxic E. coli) and STEC (Shiga toxin-producing E. coli). Similarly, PCR on bacterial cultures can be used to differentiate the subspecies of Brachyspira and test for the presence of the ϐ2-toxin gene in Clostridium perfringens isolates. Detection of pathogen RNA/DNA by PCR-based tests—The presence of pathogens causing diarrhoea, such as Brachyspira hyodysenteriae, Brachyspira pilosicoli, Lawsonia intracellularis, PCV2, and Salmonella species, can be confirmed in feces. However, the detection of PCV2 alone does not confirm its relevance in clinical disease, and the detection of Lawsonia intracellularis should only be considered when a significant concentration has been shown by quantitative PCR. Animal selection Deciding which animals to take samples from depends on the desired outcome: Detection of infection—Select animals with clinical signs. Absence of disease—Select animals with clinical signs considered typical; if there are no symptoms present, take samples from animals selected at random during a walk through the pens. Tracking infection status over time (i.e., longitudinal examination)*—Take the first samples on day 1 and repeat sampling from the same animals 2 to 4 weeks later. To determine the infection status in different groups (i.e., cross-sectional examination)*—Take samples from animals of different ages, e.g., 4, 8, 12, 16, 20, and 24 weeks of age. * If serological testing is to be used, send all samples to the laboratory in one batch to avoid potential variation between different batches of test kits. Diagnostic use

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