A few weeks ago, precautions had been taken due to suspicions of ISAv in AquaChile. Last Thursday, the Servicio Nacional de Pesca y Acuicultura (Sernapesca) confirmed that it was declared "Center in Outbreak" and protocols were being followed to ensure the control of the virus.
The AquaChile farm called Punta Entrada is categorized as an "Outbreak Farm" after two positive results. These ISAv-infected fish would present a different sequence of the HPR0 variation and the presence of clinical symptoms. According to Sernapesca, the sequencing of one of the positive ISAv results identified the presence of the HPR7b variants.
For this reason, the measures taken by Sernapesca have been the requisition of the total harvest of the center, keeping 6 cages stocked within 15 days. Moreover around Punta Entradas, that is the "Infected Zone" has been 22 km around an area at risk of an outbreak. This 22km area will be controlled too.
Sernapesca is currently conducting a sanitary campaign in 9 fish farms in the infected area and up to now there aren't signs of ISA or high mortalities in the farms visited.
In addition, the harvesting operations of the positive cages has supervised in situ. The objective is to ensure that the work is carried out with high biosafety standards.
ISAv is an infection of the Infectious Salmon Anemia virus. This virus has a significant impact on salmon production, because it causes high mortalities in infected groups. As its name indicates, it infects salmonid species, especially Salmon sar.
The term "clinical symptoms" refers to the symptoms presented by species in relation to a disease. In other words, the objective and reliable manifestations subtracted from the observations and explorations in a medical examination.
For instance, the "clinical symptoms" of ISav are the presence of mucous fluid in the stomach, splenomegaly, and hepatic congestion.
The acronym HPR stands for High Polymorphic Region, which is a region inside the ISAv virus that has a high array capacity producing heterogeneous dellections. In genetics, dellections are a type of chromosomal structural anomaly that consists of the loss of a fragment of the chromosomes' DNA, which is the reason for the existence of variants.
These variants, depending on what they lose or gain, are more or less aggressive for salmon. In fact, there are 40 variants, from HPR0 that is an asymptomatic to HPR7b is the most aggressive one in Chile.