Sensitivity of a LAMP Assay for Detection of the Dinoflagellate Amyloodinium ocellatum in Simulated Field Conditions and Freeze Tolerance of the Parasite

<p>The obligate parasitic dinoflagellate <em>Amyloodinium ocellatum </em>causes amyloodiniosis in warm water marine fishes. The prolific parasite, which has a direct, three-stage life cycle, is highly infectious and can cause heavy losses in aquaculture. Prevention, biosecurity, and early detection are vital for control. In this work, microscopy and a loop-mediated isothermal amplification (LAMP) assay were compared for early diagnosis of <em>A. ocellatum</em> in cultured stocks, and the freeze tolerance of tomonts was assessed to determine if frozen wild fish used as fish food can serve as a potential vector for the parasite.</p> <p>The lowest dinospore concentration that could be detected by the LAMP assay in water samples was 0.5 dinospores/L, while positive detections occurred only at 5 dinospores/L or higher when using LAMP or microscopy on gill samples. Thus, LAMP of water samples is a superior diagnostic tool. Simulations of replicated assays indicated that a 95% probability of detection was achieved with 10 replicated assays of water samples when the dinospore concentration is as low as 1 dinospore/L.</p> <p>All tomonts frozen for either 0, 24, 36, 48, or 72 hrs sporulated in <em>in vitro </em>experiments. Dinospore production decreased as freeze duration increased. Heavy infections were produced in <em>in vivo</em> experiments<em> </em>from tomonts frozen for all freeze durations, but tomonts frozen for 72 hrs took longer to establish a heavy infection. Tomont viability was negatively correlated with freeze duration suggesting longer freezing durations may successfully inactivate tomonts, a hypothesis that will require further experimental evaluation.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Year dc:date.available

2022

Author dc:creator

• Gonzales, Robert

Contributors dc:contributor

• Eric A. Saillant
• Reginald B. Blaylock
• Stephen A. Bullard

• Amyloodinium ocellatum
• Loop-mediated isothermal amplification
• freeze tolerance
• parasite
• aquaculture
• sensitivity
• Aquaculture and Fisheries
• Parasitology

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/907

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1971