Infectious Disease Management in Animal Shelters. Группа авторов

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Infectious Disease Management in Animal Shelters - Группа авторов


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used to convert the viral RNA to DNA prior to the PCR process. Real‐time PCR allows for the quantification of DNA through the use of fluorescent labeling of the DNA (or a DNA probe), which can be tracked and quantified as the PCR progresses, allowing for the determination of initial DNA quantity, less susceptibility to contamination, and greater sensitivity of detection. Standard PCR techniques analyze DNA bands at the completion of a variable number of amplification cycles and rely on size discrimination for identification, which can result in comparatively lower precision and sensitivity of detection (Applied Biosystems n.d.; Tizard 2013). Real‐time PCR can also be completed on RNA viruses through reverse transcriptase real‐time PCR.

      For the detection of common causes of both respiratory and GI disease, diagnostic laboratories offer real‐time PCR analysis of a variety of pathogens common to either dogs or cats. Such services carry the benefit of screening for a variety of pathogens with a single sample (and single fee), fast turnaround time (one to three days), and ready identification of potential co‐infections. Pathogen detection may be inhibited in aged samples or those from patients receiving antimicrobial therapy and, in the case of respiratory PCR panels, recent modified live‐virus vaccination can interfere with the interpretation of results. Samples for respiratory PCR analysis should include a conjunctival and deep pharyngeal swab collected on a sterile, plastic‐stemmed swab and placed in a sterile tube. Samples obtained via trans‐tracheal wash or bronchoalveolar lavage may also be accepted and would be most appropriate to collect from animals with suspected lower airway disease. Samples for GI PCR analysis should include fresh feces (minimum 1 gram) placed in a sterile container. Both respiratory and GI samples can be refrigerated for up to 10 days (IDEXX Laboratories 2017).

      4.3.4.2 Microbiological Tests

      Virus isolation is a specialized type of microbiological culture that relies on the need for viruses to replicate in living tissue. Most commonly, laboratory cell cultures are inoculated with test samples, incubated, and evaluated for structural changes due to viral infection (i.e. cytopathic effect). Once an active virus is cultivated, identification can be confirmed through the use of the serological methods described above. Common samples for virus isolation include tissue (belonging to viral target organs), anticoagulated whole blood, respiratory secretions, and urine. Samples should be kept in sterile containers, refrigerated, and arrive at the diagnostic laboratory within 24 hours. In addition to its utility for the identification of novel organisms and to monitor the microevolution of certain viruses (e.g. influenza), virus isolation is commonly used for confirmation of infection with adenoviruses, FeLV, and parvoviruses. Virus isolation of these pathogens may take between one and 4 weeks, limiting the usefulness of this modality in urgent clinical cases.

      4.4.1 Individual Animal Testing

      Shelter Operations

      Does testing fall within the shelter's operational mission?

      Are there enough resources to devote to testing?

      Will test results alter current or future operations?

      Do the costs of testing impact other services?

      Testing Methodology

      What tests are available for the disease in question?

      How does disease prevalence impact test accuracy?

      Can samples be collected, handled, prepared, and stored appropriately?

      Do staff have the time, knowledge, skill, and training to conduct point‐of‐care tests accurately?

      Animal and Human Health

      Will test results alter the management of animals?

      Will test results impact human health?

      Disease Characteristics

      Is the disease common?

      Is infection or transmission within the shelter or community likely?

      Is


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