Tag Stephen G. Newman

Polymerase chain reaction testing is a powerful tool that can detect very low levels of pathogens, but its ability to screen and produce results that represent the population is often oversimplified. Screening of the wrong tissues or too few animals can lead to incorrect conclusions. 

The development of polymerase chain reaction testing to detect the bacteria that cause EMS is important, but confirmation by bioassay of presumptive positives to ensure pathogenicity is a prudent intermediate step. 

Ideally, farmers need to create conditions that make it harder for the pathogenic Vibrio that causes AHPN to colonize animals’ stomachs and for the toxin to produce its pathology. Exclusion where possible and appropriate management of ecosystems offer hope in addressing AHPN. 

Vibrio parahaemolyticus, a strain of which is the cause of acute hepatopancreatic necrosis (AHPN), has both virulent and benign strains. This strain colonizes the stomachs of shrimp by the formation of a biofilm, which protects it from antibiotics and other potential treatments. 

Research continues in the global efforts to identify the cause of acute hepatopancreatic necrosis syndrome in farmed shrimp and find solutions to stop the major losses caused by its spread. 

Most aquaculture farms rely on general strategies for biosecurity that implement protocols learned from others. Establishing effective biosecurity, however, can be complicated due to multiple interacting variables. 

The quality of postlarvae supplied by a shrimp hatchery can vary considerably. Common myths, such as acceptance of low survival and insufficient concern for water quality, can contribute to lower animal quality. 

Those charged with determining the underlying cause of a disease outbreak have a wide variety of detective tools at their disposal. 

The toxins from blue-green algae pose a threat to animal health and potentially to consumers if they are present in farmed product. Culture animals that ingest these toxins may not die, but can be weakened, increasing their susceptibility to pathogens. 

As research on WSSV continues, commonsense steps can lessen the potential impacts of white spot syndrome virus on shrimp-farming operations. 

The slipping shrimp production in Southeast Asia due to disease has a number of causes. Emerging viral diseases take a toll, as do bacterial diseases caused by vibrios and other pathogens. 

In the evolution of shrimp farming, white shrimp emerged as the primary species. While some farms in the Americas successfully converted to intensive practices, wide adoption has been limited. 

Although many companies avoid the costs associated with setting up proactive disease management infrastructure, failure to do so can result in losses that far outweigh the costs. 

Vertical integration to control the product from the first stages of production through packaging is an excellent way to minimize preventable risks. 

Shrimp do not produce antibodies and therefore do not remember prior exposure to pathogens, a critical component of long-term protective immunity.