LOLS10在线直播下注

无极二彩票开户_{实时热点} 真实赌博游戏_{实时热点} pk彩票投注_{实时热点} 烈火电竞app_{实时热点} 28元体验金_{实时热点} 星球娱乐下载_{实时热点} 欧洲杯app网投_{实时热点} 万博体彩app_{实时热点} 全民福利彩票_{实时热点} 258竞彩官网_{实时热点} 网上兼职彩票登录_{实时热点} 尊亿APP_{实时热点} 皇冠足彩盘_{实时热点} 英亚体育app_{实时热点} mg老虎机赌博_{实时热点} bt365体育老牌_{实时热点} 湖南福彩官网_{实时热点} 金鲨银鲨网站_{实时热点} 山西体彩app_{实时热点}

Gill-Associated Virus Disease

What is it?

The causative agent is gill-associated virus (GAV), genotype 2 of six distinguished genotypes in the yellowhead complex of viruses.

GAV occurs commonly as a chronic infection in healthy broodstock and farmed black tiger prawns in eastern Australia.

GAV has been associated with mortalities of up to 80 per cent in black tiger prawn ponds in Australia, mainly affecting early to late juveniles.

The disease also affects Brown, Gulf Banana and Kuruma prawn species.

When and Where Might it Occur?

Transmission can be horizontal, directly from the water column and through ingestion of infected material.

Vertical transmission can also occur via surface contamination or infection of tissue surrounding the fertilised egg.

Viral multiplication and disease appear to be induced by environmental stress.

LOLS10在线直播下注 Experimental infections with GAV indicate that larger (~20 g) kuruma prawns are less susceptible to disease than smaller (~613 g) prawns of the same species.

Diagnosis

The disease often results in high mortality (of up to 80 per cent)

Affected prawns may cluster near the surface at the edge of the pond and may initially show a sudden increase in feeding, followed by a sudden decline.

Gross pathological signs are:

  • reddening of body and appendages
  • biofouling with exoparasites
  • emaciation
  • pink to yellow colouration of the gills.

LOLS10在线直播下注Microscopic pathological signs are:

  • lymphoid organ necrosis (hypertrophied nuclei, marginated chromatin and vacuolation).

LOLS10在线直播下注SOURCE: Australian Government, Department of Agriculture, Fisheries and Forestry