BIOSECURITY AND THE RELEVANCE OF THE PROFICIENCY TEST (PT TEST)  

One of the critical steps in biosecurity in Aquaculture is to ensure the exclusion of pathogens. For instances, during the last twenty years, several shrimp farms around the world faced a WSSV outbreak that caused high mortalities in grow-out ponds affecting the shrimp production dramatically. The combination of the some factors such as the low water temperatures, the presence of the susceptible population of shrimp and the deficiency in the pathogens-detection system caused the WSSV outbreak.

One of the critical processes in the whole Biosecurity strategy is to determine the pathogens present in the shrimp industry environment. The main diagnostic technique, in which most if not all the shrimp farms rely, is the polymerase chain reaction (PCR) due to its high sensitive and specificity for shrimp-pathogen detection. Three different PCR approach have routinely used: commercial kits, OIE manual procedures and procedures published in a peer-reviewed journals. The shrimp industry trusts on these diagnostic laboratories and takes such an important decisions based on a given result. When a positive results for any of the OIE-listed diseases appears, (even if mortality is not reported) creates a panic in the shrimp industry especially when this pathogen can potentially cause high mortality at farm level and usually have economic consequences for the shrimp producers.

Based on the importance of having a reliable diagnostic lab results, it is important to inter-calibrate the performance with a reliable laboratory. One of the purposes of inter-laboratory performance testing, also known as a ring test, is to assure the clients or regulatory officials that the results provided are accurate, specific and reproducible.

As a World Organisation for Animal Health (OIE) reference laboratory, the University of Arizona's Aquaculture Pathology Laboratory has taken on the role of providing training and assistance to other shrimp diagnostic laboratories for the detection of shrimp pathogens through the use PCR testing. The lab has been routinely implementing ring tests since 2005. Based on the high demand for the diagnostic laboratories, since 2009 this process is being carried out twice per year (February and August). Laboratories from all over the world have actively participated in this inter-calibration ring test process. Participation in the ring testing is completely voluntary. There are no prescribed methods, and each participating laboratory employs the same PCR procedures it routinely uses in the analysis of clinical samples. On 2016, in addition of the OIE listed pathogens, the acute hepatopancreatic necrosis disease (AHPND) was added among the panel set. For the ring test on February 2017, the emerging disease enterocytozoon hepatopenaei (EHP) will be included in addition to the panel set of pathogens including WSSV, TSV, IMNV, IHHNV, YHV & NHP-B.