Acute dermatitis in farmed trout: an emerging disease

Abstract

A new skin condition, known as puffy skin disease (PSD), emerged in farmed rainbow trout Oncorhynchus mykiss (Walbaum) in 2002. The number of new cases increased considerably from 2006. Clinical signs include white or grey skin patches, which become raised and red with excessive mucous production and scale loss. Fish are inappetant and lose condition. Histologically, the key feature is epithelial hyperplasia. We undertook a questionnaire study of trout farmers in England and Wales to investigate prevalence and risk factors. PSD was reported on 37% (n = 49) of rainbow trout sites, located in 28 river catchments. The increase in cases from 2006 onwards was mirrored by the increase in red mark syndrome (RMS). Prevalence and severity of PSD were highest in the summer months. The presence of PSD was associated with RMS (OR = 9.7, P < 0.001). Sites receiving live rainbow trout in the previous 12 months were considerably more likely to have PSD (OR = 5.3. P < 0.01), which suggests an infectious aetiology. The size of affected fish and prevalence varied between farms, indicating that farm-level factors are important. Future research should further investigate the aetiology of PSD and practices to manage the disease.

Epitheliocystis in fish: An emerging aquaculture disease with a global impact

“…Given that it is also a disease that is often overlooked compared to other emerging diseases of aquaculture systems (Murray et al., ), it is perhaps unsurprising that thorough systematic studies of epitheliocystis in specific fish species are currently lacking and that there are extensive gaps in our basic knowledge of the pathogenesis of this disease and the factors that may influence it. Epitheliocystis is not alone in this respect, with a number of similar emerging bacterial diseases of complex or unknown aetiology such as “strawberry” disease (Lloyd et al., ), acute dermatitis (Peeler et al., ) and puffy skin disease (Cano et al., ) causing serious economic losses in established aquaculture species with little basic information available on the epidemiology and pathogenesis of these agents either.…”

A novel use of social media to evaluate the occurrence of skin lesions affecting wild dusky grouper, Epinephelus marginatus (Lowe, 1834), in Libyan coastal waters

“…The digital domain can offer a rich repository of visual material (Vilnai‐Yavetz & Tifferet ), which can be important as visual material is considered to be a key resource in describing and characterising skin lesions affecting fish (Peeler et al . ), with the use of images avoiding errors inherent in purely verbal descriptions. When the morphology of the skin lesions in the pictures posted on Facebook is compared with the DGD skin lesions described in Rizgalla et al .…”

“…More accurate estimation therefore requires further investigation including direct contact with Facebook users to enquire whether dusky grouper with skin lesions are seen in their area and whether individuals might be prepared to provide images for assessment. The digital domain can offer a rich repository of visual material (Vilnai-Yavetz & Tifferet 2015), which can be important as visual material is considered to be a key resource in describing and characterising skin lesions affecting fish (Peeler et al 2014), with the use of images avoiding errors inherent in purely verbal descriptions. When the morphology of the skin lesions in the pictures posted on Facebook is compared with the DGD skin lesions described in Rizgalla et al (2016), there are close similarities in their gross morphologies, potentially indicative of common pathology/aetiology.…”

Ulcerative dermatitis in wild dusky grouper Epinephelus marginatus (Lowe) from Libyan waters

“…Reports on skin lesions seem to be on the rise in recent years for both farmed and wild fish stocks (Peeler et al . ; Maddocks et al . ).…”

“…While skin lesions are easily spotted, the limited range of pathological responses to injury makes the diagnosis of the causative agent difficult (Ferguson 2006). Reports on skin lesions seem to be on the rise in recent years for both farmed and wild fish stocks (Peeler et al 2014;Maddocks et al 2015).…”