Determination of the nature of a cause of a disease
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advancesindiagnostictechnology-160814055424
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- Classical methods
- Advanced diagnostic technique PCR based method
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Diagnosis Determination of the nature of a cause of a disease Improved, quality assured diagnostics are important for disease control in animals They provide a basis for appropriate treatments of animal patients for monitoring diseases and for the enhancement of disease-surveillance capacity For this Diagnostic methods should be sensitive, specific, rapid and cost effective Advanced Diagnostic approach ?? Classical methods • Microscopic method : Organisms must be present in sufficiently high concentration and use of appropriate set stains and conditions make them visible • Cultivation method : Certain microbes may require special culture media and conditions and failure to consider these microbes may yield negative culture results • Cell culture can be used to detect some viruses and intracellular microbes but the cost, labor, and time required for this approach beg for better diagnostic method • Serologic assays : May not be helpful for rapidly evolving diseases, the host may succumb to infection before antibodies can be produce Advanced diagnostic technique PCR based method PCR is an enzyme-driven process for replicating DNA in vitro • Using this technology, one is capable of turning a few molecules of DNA into large quantities Why used: • The levels of microbial DNA present in clinical samples are frequently too low for meaningful manipulation and measurement PCR can produce sufficient amounts of DNA so that microbes can be detected and identified. • Because each unique microbe has a unique complement of DNA (or RNA), DNA can function as a molecular fingerprint to help identify microbes Lumpy skin disease is an infectious, eruptive, occasionally fatal disease of cattle • The clinical onset is characterized by fever, watery eyes, increased nasal secretions and loss of appetite, severe in cows at the peak of lactation causes a sharp reduction in milk production • In July 2012 a massive LSD outbreak began in the northern part of Israel • In order to strengthen the efforts to control the disease the Israeli Veterinary Services initiated the use of a Neethling vaccine strain (LSDV)-based vaccine • But typical LSD symptoms appeared in a few vaccinated animals and proved to be L SDV positive • It was of extreme importance to develop a differentiation approach that could specifically identify the strain responsible for affecting the livestock (field or vaccine strain) • The approach was initiated following a BLAST analysis between the vaccine strain and other complete virus sequences to try to find mark differences between them • The alignment analysis identified a unique 27- base deletion in the vaccine strain • PCR enabled virus identification in case that vaccinated animals demonstrate clinical symptoms confirmed the presence of the deletion only in the vaccine strain and not in the virulent strains • The finding raised the possibility that this sequence could be important for virulence in the field viruses, and that when this 28-base fragment is missing the virus exists in an attenuated state Real time PCR technology Better over general PCR • Quantitative • More rapid • Sensitive • Accurate • Easy to perform Download 0.97 Mb. Do'stlaringiz bilan baham: 
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