This bacteria causes lesions in the vascular endothelium, leading to hemorrhages and petechias at the surface of internal organs.

In later years, L. garvieae was isolated from several septicemic processes in fish and phenotypical and molecular taxonomic studies confirmed the same agent as E. seriolicida.

[5] Lactococcus garvieae is a facultatively anaerobic, non-motile, non-spore forming, Gram-positive ovoid coccus, occurring in pairs and short chains.

[5] Several virulence experiments have been performed in order to determine the possible correlation between pathogenicity of L. garvieae in rainbow trout and the two antigenic profiles (KG- and KG+).

The results revealed that capsulated strains (KG-) were more virulent than non-capsulated (KG+), showing LD50 values as low as 102 bacteria per fish.

[5] Warm water lactococcosis has been detected in a variety of host organisms, including cage cultured cobia, grey mullet, freshwater prawn and Tilapia.

The gross pathology of lactococcosis arises with the presence of a rapid and general anorexia, melanosis, lethargy, loss of orientation, and irregular swimming.

Due to infection, fish have produced lesions in the vascular endothelium that cause blood extravasation, leading to hemorrhages and petechiae at the surface of internal organs.

[5] Macroscopic lesions in affected fish are typical of acute systemic disease with strong congestion in the internal organs and different levels of hemorrhages in the swim bladder, intestine, liver, peritoneum, spleen and kidney.

Diseased fish typically show signs of acute meningitis, consisting of an exudate covering the brain surface.

[5] According to a series of studies in 2006, L. garvieae is an emerging pathogen that is causing significant economic losses both in marine and freshwater aquaculture when water temperature increases over 16 °C in summer months.

[5] Several vaccines have been developed to tackle L. garvieae infection in the face of rising antibiotic resistance, with whole-cell killed cells being the most common.

[3] The signs and symptoms of United States cases ranges from urinary tract, blood, skin and pneumonic processes.

[2] A patient with L. garvieae septicaemia in absence of infective endocarditis was successfully treated with a combination of ampicillin and gentamicin and showed a favourable clinical course.