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Arizona—The University of Arizona’s Aquaculture Pathology Lab


The Aquaculture Pathology Laboratory (APL), housed within the College of Agriculture and Life Sciences’ School of Animal and Comparative Biomedical Sciences at the University of Arizona (UA), works with commercial shrimp farming enterprises, research institutions and nongovernmental organizations around the world to diagnose infectious diseases of penaeid shrimp.  It also certifies pathogen-free stock, tests feed ingredients, conducts research and trains shrimp disease specialists.


Shrimp seedstock and broodstock can't be sold to large shrimp farms around the world unless they are certified.  APL conducts the tests so that they can be certified.  Clients pay for these services, which helps them maintain the biosecurity of their products and ultimately the health and profitability of their businesses.


APL is the only lab in North America that’s certified for crustacean diseases by the World Organisation for Animal Health (OIE) in Paris.  It’s also an approved laboratory of the USA Department of Agriculture Animal and Plant Health Inspection Service.  “This lab has done a wonderful job of addressing the needs of the shrimp industry in terms of disease diagnosis and disease prevention worldwide,” said Arun K. Dhar, associate professor of shrimp and director of the lab since January 2017.  He succeeded longtime professor and founding director Donald V. Lightner, who developed and guided the lab for more than 30 years, as it became a facility recognized around the world.


“We identify the pathogen.  We get the specifics,” Dhar said.  “When a disease emerges, we jump on it to determine the etiology (cause), the methods to detect it and the tools to prevent the spread of the disease.  Then we tell that story to various audiences.”


APL has a wet lab (live animals) facility at the University of Arizona’s West Campus Agricultural Center and a diagnostics lab for histology (tissue diagnostics) and molecular detection on the main campus.


A staff of three at the wet lab maintains tanks of specific pathogen-free (SPF) or specific pathogen-resistant quarantined stocks for companies and agencies, where they evaluate live shrimp samples from across the world to detect (or rule out) diseases.  “We deal with the worst of the worst of the emerging pathogens,” said senior research specialist Brenda Noble, who dips her boots in disinfectant when entering and exiting the quarantined areas.  “Acute hepatopancreatic necrosis disease, also called EMS—early mortality syndrome—is big now, killing a lot of animals on farms in Asia and Latin America.  EMS is a bacterial disease that kills up to 100 percent in a day at the lab, although not on farms, where it’s spread out.”


The staff conducts challenge studies on shrimp brought in from all over the world to find family lines that are resistant to disease.  They and also test commercial products—probiotics, for example—on SPF shrimp to see if they enhance survival.


At the dry lab, a team of seven tests tissue samples sent from the wet lab and national and international companies and agencies.  Most are from Hawaii, Florida and Latin America.  Clients specify the tests they want: viral, bacterial, fungus, prokaryote or protozoa.


In the histology lab, a team of two uses histopathology to diagnosis tissue samples.  Each sample is dissected into pieces, put into a cassette, processed overnight and embedded in wax blocks that cool and harden.  The blocks are cut into thin sections, put on racks, cooked in a tissue oven to affix them and then stained.  Each section is put into a slide folder to be read and diagnosed.  These tests are conducted for regular surveillance of a company's stock, or as a general health check on shrimp to make sure the shrimp population is safe.  “Our department consists of different labs, but we are a team of lab technicians, scientists and specialists that help diagnose diseases and send results to clients in an ongoing relationship,” research specialist Jasmine Millabas said.


In the PCR lab, extracts of shrimp feed are run in PCR (polymerase chain reaction) machines to note any presence of disease.  “We have run samples from 461 clinical cases so far in 2017,” said postdoctoral research associate Siddhartha Kanrar.



The University of Arizona Shrimp Pathology Short Course


At the University of Arizona campus, faculty and staff at APL teach an annual, intensive, one-week, shrimp-pathology short course, and around the world, they conduct several workshops annually.  The course and workshops are for professionals who conduct testing for companies and institutions dealing mainly with farm-raised shrimp.


Dhar recently taught classes at the Bangladesh Fisheries Research Institute in Bangladesh and Yangon University in Myanmar.  He said shrimp is dubbed “white gold” in Bangladesh because it’s the country’s third-largest export, based on revenue.


In addition to methods for detecting and diagnosing diseases in farmed shrimp, the hands-on course takes participants through the steps of preparing tissue samples to ensure accurate results when the samples are sent to the APL.  The participants learn what to look for in the cells of diseased animals and how to follow the proper procedures to get the detection correct.  The West Campus experimental lab has inoculum for all the World Organisation for Animal Health pathogens, which are kept in a freezer at minus 80 degrees Celsius (minus 112 Fahrenheit).


Nearly every shrimp pathologist in the world has taken the course.  In July 2017, the class included 19 participants from nine countries on four continents, mainly from commercial aquaculture businesses.


Jessica Fox, director of veterinary services and biosecurity for Trū-Shrimp, a shrimp farm under development in Minnesota, sent three employees to the UA who will prepare the histology samples that will be sent to Arizona.  “We wanted to learn more about shrimp diseases to help us understand what to watch for, what screening measures we need to do and to help us develop other biosecurity protocols,” Fox said.  “There’s quite a bit of hands-on here.  We know what to look for and have done this before in-house, but it’s good to have experts checking your work.”


Information: Arun K. Dhar, The University of Arizona, School of Animal and Comparative Biomedical Sciences, Aquaculture Pathology Laboratory, 1117 E. Lowell Street, Room 102 Tucson, Arizona 85721, USA (Phone 520-621-4438, Fax 520-626-5602, Email, Webpage


Source: UA News.  Global Shrimp Industry Depends on UA.  Susan McGinley.  September 11, 2017.


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