Strategies for managing diseases in non‐native shrimp populations

Abstract

The shrimp industry is now largely based on Litopenaeus vannamei. Current strategies for disease management in Asia emphasizing exclusion and eradication with strict quarantine and importation protocols have not been effective in controlling disease epidemics. New diseases have been introduced on illegal importations; commercial shrimp populations are derived from imported SPF stocks susceptible to endemic diseases; and local breeding programmes are based on populations not resistant to a range of diseases. Broodstock are largely poorly adapted to local conditions and repeated disease epidemics occur. Strategies for disease management should concentrate on: (i) minimizing the risk of introducing new diseases to the region; (ii) development of populations more resistant to endemic diseases; and (iii) better management practices that minimize the likelihood of serious epidemics and delay infection, but do not depend on attempts to eradicate diseases already present. This can be implemented by building on the better management practices already established in the region and in addition: (i) applying strict quarantine procedures for diseases not reported in the region whilst making the processes sufficiently agile to reduce illegal introductions; (ii) eliminating standard rigid importation protocols and tailoring protocols in accordance with the disease situation of both the country of origin and destination; (iii) increasing genetic variation available within Asia by public sector support for programmes to enlarge the pool of genetic variation and encouraging collaboration with breeding programmes that encompass a broad genetic base; (iv) establishing selection programmes that permit reincorporation of animals exposed to disease into the breeding nucleus; and (v) establishing propagation systems that provide growers with high health status stocks without requiring overly strict SPF certification of facilities.

Heritability and genetic correlations for infectious hypodermal and hematopoietic necrosis virus load, body weight at harvest, and survival rate in Pacific white shrimp (Litopenaeus vannamei)

“…Assuming that the higher VL ln was related to a higher susceptibility to IHHNV, this negative correlation implies lower susceptibility among shrimp genetically superior with regard to growth. This outcome is interesting and perhaps unexpected because IHHNV is often considered nearly innocuous and a virus for which many shrimp populations have developed a high degree of tolerance (Cock et al, ; Flegel, ; Walker & Winton, ).…”

“…In L. vannamei farming, diseases are limiting factors and are important causes of economic losses (Cock, Gitterle, Salazar, & Rye, ). One such disease is infectious hypodermal and hematopoietic necrosis virus (IHHNV), which affects a large number of populations worldwide (Chai et al, ; Cock, Salazar, & Rye, ; Escobedo‐Bonilla & Ibarra, ; Srivinas, Venkatrayalu, & Laxmappa, ). IHHNV is a 20–22 nm, icosahedral, nonenveloped parvovirus containing a single‐stranded DNA genome, approximately 4.1 kb in length, with three open reading frames (Pantoja & Lightner, ).…”

Facts, truths and myths about SPF shrimp in Aquaculture

“…; Cock et al . ). When these stocks are challenged with lethal isolates of TSV they become infected but show no gross signs of disease.…”

“…The phenomenon of tolerating infectious viral pathogens for long periods of time without signs of disease has been called viral accommodation (Flegel 2007(Flegel , 2009Utari et al 2017), but the mechanisms underlying it are still unclear. Shrimp stocks tolerant to TSV but uninfected with TSV have been developed using genetic selection (Moss et al 2005;Cock et al 2017). When these stocks are challenged with lethal isolates of TSV they become infected but show no gross signs of disease.…”

Transfronterización de enfermedades infecciosas en la camaronicultura.

“…En el 2010, la región fue de nuevo afectada por otra patología, la necrosis aguda del hepatopáncreas. Estos brotes sugieren que las estrategias actuales de manejo de enfermedades no han sido completamente efectivas y se requieren cambios y mejoras, con el fin de reducir las probabilidades de futuras crisis (Cock et al, 2015).…”