Testkits
| Polymerase chain reaction (PCR)
The polymerase chain reaction is a biochemical technology in molecular biology used to amplify a single copy or a few copies of a part of a DNA or RNA across severa orders of magnitude generating thousands to millions of copies of a particular DNA or RNA sequence of intrest.
PCR permits early diagnosis of diseases and infections like Herpes or Salmonella or PKD but also for discrimination between male and female animals for instance for parrots.
PCR allows rapid and highly specific diagnosis of infectious disease including non-cultivayable or slow growing micro-organisms like Mycobacteria, viruses. However standard PCR methods can't distinguish life from dead micro-organism from the majority of samples but it can detect pathogenic strains from less or non-pathogenic strains like for intance Influenza, Salmonella or E.coli.Summary PCR
- Based on multiplying DNA/RNA
- Uses specific probes
- Final detection:
- Agarose and EtBr+UV
- Real time using becams/probes marked with colored labels
- Micro-titer plate
- Gold or other labeled probes
- Based on temperature cycles
- Uses computerized equipment
- Need special PCR cabinet for pipetting steps
Clinical tips
Sensitivity, specificity, positive predictive value and negative predictive value vary with each PCR assay. Many of the infectious disease agents encountered in practive colonize normal animals as well as induce disease in some individuals. Thus, the PPV of many PCR assays can be low. Veterinarians generally need yo use a combination of findings to help diagnose infectious disease:
- Appropriate signalment and histoty for the infectious agent suspected
- Clinical signs referable to the agent
- Detection of the agent (cytology, culture, antigen assay, PCR assay) or antibodies against the agent
- Exclusion of other causes of the clinical syndrome
- Response to an appropriate treatment
When these criteria are met,m the suspected infectious agent might have been the cause of the clinical disease. However, iy is always possible that the disease process resolved in spite of the therapy prescibed.
All species
Bovine
Canine
Feline
Poultry
Rabbit
