SYBR, TaqMan, or both: Highly sensitive, non-invasive detection of Cardicola blood fluke species in Southern Bluefin Tuna (Thunnus maccoyii)

The parasitic blood flukes Cardicola forsteri and C. orientalis are an ongoing health concern for Southern Bluefin Tuna Thunnus maccoyii (SBT) ranched in Australia. In this study we compared the effect of treatment, company, and ranching year on blood fluke infections in ranched SBT. SBT were sampled during the 2018 and 2019 ranching seasons from praziquantel (PZQ) treated pontoons and untreated pontoons managed by two companies. Severity of infection was diagnosed by several criteria including adult fluke counts from hearts, egg counts from gill filaments and the use of specific quantitative polymerase chain reaction (qPCR) for detection of C. forsteri and C. orientalis ITS-2 DNA in SBT hearts and gills. PZQ treatment remains highly effective against C. forsteri infection. Prevalence and intensity of Cardicola spp. infection was lower in 2019 than 2018 for Company A in treated pontoons at week 12 and week 17 of ranching, and lower for Company A than Company B in untreated pontoons at month 5 of ranching. Results indicate re-infection may be less likely in the environment near Company A pontoons, and consistent years of treatment may have lowered the parasite load in the environment. qPCR demonstrated higher sensitivity when comparing diagnostic methods for C. forsteri in heart, and higher specificity when comparing diagnostic methods for Cardicola spp. in gills. Continuing to monitor blood fluke infections in ranched SBT can help to detect changes in drug efficacy over time and help industry to develop a best practice for treatment.

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Real-time pcr detection and differentiation of Cardicola blood fluke species from tissue and blood of southern bluefin tuna

Fish & Shellfish Immunology ◽

10.1016/j.fsi.2013.03.288 ◽

2013 ◽

Vol 34 (6) ◽

pp. 1730 ◽

Cited By ~ 3

Author(s):

M. Polinski ◽

A. Bridle ◽

B. Nowak

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Bluefin Tuna ◽

Pcr Detection ◽

Blood Fluke ◽

Southern Bluefin Tuna

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Pathological findings in southern bluefin tuna, Thunnus maccoyii (Castelnau), infected with Cardicola forsteri (Cribb, Daintith & Munday, 2000) (Digenea: Sanguinicolidae), a blood fluke

Journal of Fish Diseases ◽

10.1046/j.1365-2761.2001.00289.x ◽

2001 ◽

Vol 24 (4) ◽

pp. 225-229 ◽

Cited By ~ 47

Author(s):

S E Colquitt ◽

B L Munday ◽

M Daintith

Keyword(s):

Bluefin Tuna ◽

Pathological Findings ◽

Blood Fluke ◽

Southern Bluefin Tuna

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An epizootic and its decline of a blood fluke, Cardicola forsteri, in farmed southern bluefin tuna, Thunnus maccoyii

Aquaculture ◽

10.1016/j.aquaculture.2005.10.013 ◽

2006 ◽

Vol 254 (1-4) ◽

pp. 40-45 ◽

Cited By ~ 46

Author(s):

H.M. Aiken ◽

C.J. Hayward ◽

B.F. Nowak

Keyword(s):

Bluefin Tuna ◽

Blood Fluke ◽

Southern Bluefin Tuna

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Simulating blood fluke, Cardicola forsteri, infection in farmed southern bluefin tuna, Thunnus maccoyii, using stochastic models

Aquaculture ◽

10.1016/j.aquaculture.2009.04.034 ◽

2009 ◽

Vol 293 (3-4) ◽

pp. 204-210 ◽

Cited By ~ 14

Author(s):

Hamish Aiken ◽

Craig Hayward ◽

Angus Cameron ◽

Barbara Nowak

Keyword(s):

Stochastic Models ◽

Bluefin Tuna ◽

Blood Fluke ◽

Southern Bluefin Tuna

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Changes in the Splenic Melanomacrophage Centre Surface Area in Southern Bluefin Tuna (Thunnus maccoyii) Are Associated with Blood Fluke Infections

Pathogens ◽

10.3390/pathogens10010079 ◽

2021 ◽

Vol 10 (1) ◽

pp. 79

Author(s):

Barbara F. Nowak ◽

Mai Dang ◽

Claire Webber ◽

Lukas Neumann ◽

Andrew Bridle ◽

...

Keyword(s):

Surface Area ◽

Bluefin Tuna ◽

Its2 Rdna ◽

Farmed Fish ◽

Blood Fluke ◽

Blood Flukes ◽

Copy Numbers ◽

Southern Bluefin Tuna ◽

Gill Filaments ◽

Pre Treatment

Melanomacrophage centres (MMCs) are aggregates of macrophages accumulating various pigments. They have been proposed as an indicator of fish immune response. Blood flukes are common parasites in farmed fish. Two cohorts of wild Southern Bluefin Tuna (Thunnus maccoyi) were examined at transfer, before treatment against blood flukes (pre-treatment) and at harvest. MMCs were assessed in histological sections using image analysis, while Cardicola forsteri and Cardicola orientalis infection severity was determined using qPCR, count of adult flukes in heart flushes and count of eggs in gill filaments. Fish from both cohorts showed the same pattern in the changes in the surface area of MMCs. The surface area of splenic MMCs increased over the ranching duration and was positively correlated to the PCR determined copy numbers of Cardicola forsteri ITS2 rDNA in the gills of those fish. However, the infection with blood fluke was more variable, both between cohorts and individuals within the same cohort. Eggs of blood fluke were detected in renal MMCs using histology. Cardicola forsteri had a higher prevalence than Cardicola orientalis. This study contributes to our understanding of blood fluke infections in Southern Bluefin Tuna and their interactions with MMCs.

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Role of MRI evaluation in acute secondary inability to walk in children

Egyptian Journal of Radiology and Nuclear Medicine ◽

10.1186/s43055-021-00417-0 ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

K. H. Sedeek ◽

K. Aboualfotouh ◽

S. M. Hassanein ◽

N. M. Osman ◽

M. H. Shalaby

Keyword(s):

Transverse Myelitis ◽

High Sensitivity ◽

Acute Disseminated Encephalomyelitis ◽

Limb Weakness ◽

Non Invasive ◽

Highly Sensitive ◽

Common Causes ◽

Bilateral Lower Limb ◽

Severity Of The Disease

Abstract Background Acute bilateral lower limb weakness is a common problem in children which necessitates a rapid method for diagnosis. MRI is a non-invasive imaging technique that produces high-quality images of the internal structure of the brain and spinal cord. Results MRI was very helpful in reaching rapid and prompt diagnosis in children with acute inability to walk. Acute disseminated encephalomyelitis (ADEM), Guillain–Barré syndrome (GBS), and acute transverse myelitis (ATM) were the most common causes in our study. MRI proved to be of high sensitivity in detecting the lesions and reaching the diagnosis in ADEM and GBS; however, there was no significant relation between the lesions’ size, enhancement pattern, and severity of the disease or prognosis, yet in ATM the site of the lesion and number of cord segment affection were significantly related to the severity of the disease and prognosis. Conclusion MRI is a quick tool to reach the diagnosis of children with acute secondary inability to walk, and to eliminate other differential diagnosis which is essential for proper treatment and rapid full recovery. It is highly sensitive in detecting the lesions, their site and size.

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