Identification and characterization of the pathogen associated with skin ulcer syndrome in lined seahorse, Hippocampus erectus

Abstract

The lined seahorse, Hippocampus erectus, is an Atlantic species, which mainly inhabits shallow sea beds or coral reefs. Seahorse has become very popular in China due to its wide use in traditional Chinese medicine (TCM). However, the aquaculture of the lined seahorse has been threatened by a variety of diseases, especially bacterial infections. Skin ulcer syndrome becomes more and more common in the culture of seahorses, leading to skin ulcer, liver erosion and minority tail rotting. These diseased seahorses die in only 72 hr, causing huge economic losses in aquaculture. Pathogen HMT-1 was isolated from the lined seahorses with skin ulcer syndrome, which was identified as Vibrio harveyi. The median lethal dose (LD50) of HMT-1 was 2.88 × 108 cfu/ml. The pathogenic mechanism of HMT-1 was preliminarily studied, and the pathological changes of the diseased lined seahorses were also investigated. Moreover, the activities of ACP, complement 3, SOD and LZM at different time post injection were measured by commercial kits. Our findings can provide reliable reference for diagnosis and treatment in the future.