A Regional Proficiency Testing Program for Aquatic Animal Disease Diagnostic Laboratories in Asia-Pacific (the ‘regional PT program’) was developed in 2011 to strengthen diagnostic capability across Asia—a region that produces most of the world’s aquatic animal products. This capability was identified as a requirement to facilitate the sanitary safety of trade in aquatic animal products and to assist countries to improve accurate detection of potentially damaging trans-boundary diseases. The need for improved diagnostic capabilities across Asia was widely agreed and documented prior to developing the regional PT program, however few previous activities had made significant or lasting impacts at the regional level.
The regional PT program provided 41 laboratories across the Asia-Pacific with the opportunity to assess their diagnostic performance for 10 regionally significant aquatic animal pathogens, and to adapt or modify practices where necessary to improve. Through collective participation and improvement, regional capability to diagnose important aquatic animal pathogens has been strengthened.
Shrimp aquaculture in tropical regions is facing a disease-induced catastrophe of lost production. It is estimated that more than 40% of tropical shrimp production is lost to disease annually. The devastating impacts of disease on lost incomes, livelihoods, increased operational costs, trade restrictions and loss of consumer confidence has been a subject of many consultations and policy dialogues. Discussions of disease crisis have to date been largely focused on identification of pathogens, guidelines and standards for disease detection and surveillance, regulations to limit trans-boundary movement of animals, and adoption of better management practices.
There is reason to believe that current broodstock management practices may induce genetic erosion that increases susceptibility to disease and vulnerability to epizootics:
The basic tenet for this Expert Consultation is that an important aggravating factor in the disease crisis is an agro-economic system that locks shrimp breeders, hatcheries and farmers into behaviour that induces high levels of inbreeding. If inbreeding does increase the severity and frequency of epidemics, this disease crisis will only get worse over vast areas of Asia, Central and South America, Africa and the Middle East until it is addressed.
This Expert Consultation was organized in conjunction with the annual meeting of the NACA Aquatic Animal Health Advisory Group (NACA-AG) to take advantage of the physical presence and expertise of a small group of world renowned Aquatic Animal Health experts from several national and international institutions. The list of participants and workshop agenda are presented in Annexes 1 and 2. This consultation is perhaps the first of its kind to bring together a balanced group of experts from diverse fields – epidemiology, microbiology, disease diagnostics & surveillance, aquaculture genetics, fish breeding, and evolutionary biology – to take a fresh, in-depth, and wider perspective on the possible interaction between genetic side-effects of broodstock management and the looming threat of aquatic animal diseases, in particular the contemporary shrimp disease crisis.
This study focused on events in a representative, 50-pond Indonesian shrimp farming system in Pangkep district, South Sulawesi. Ponds were stocked with Penaeus monodon and the study extended across a single cropping period between May and October 2010. It was designed to improve our understanding of the main causal pathways for white spot disease (WSD), the most serious cause of production loss in these systems. The longitudinal observational study focused on recording the occurrence of different genotypes of the causal infectious agent, white spot syndrome virus (WSSV), in selected components of the system across time, and looking for relationships with pond outcomes, particularly WSD occurrence. We expected that findings would (a) enable relevant Indonesian agencies, and ultimately farmers themselves, to better identify localities suitable for smallholder shrimp farming using better management practice (BMP) programs and (b) inform modification and simplification of these programs, thereby improving both profitability and adoption rates.
Our transmission trials showed that genotypy variations did not occur during three sequential passages (four including the preparation of the stock inoculums) in L. vannamei or alternatively in other crustacean hosts. This indicates the genotypes are likely to be sufficiently stable for use in local epidemiological studies during disease outbreaks in shrimp ponds.
WSD outbreaks were recorded in 11 of the study ponds. Outbreaks were attributed to WSSV genotype TRS5 in seven ponds and to genotypes TRS4 and TRS6 in two ponds each. Data analysis showed that:
These findings suggest that stocking PCR test-negative PLs, coupled with careful management of water intake during nearby WSD outbreaks are the two most useful practice changes farmers can adopt to reduce the risk of outbreaks in their ponds. Establishment of an active, well-resourced and trained extension service, committed to fostering cohesive, informed farmer groups, is the key to enabling these inexpensive practice changes.
Under the auspices of the FAO TCP/VIE/3304 (E) Emergency assistance to control the spread of an unknown disease affecting shrimps, being implemented by Vietnam’s Ministry of Agriculture and Rural Development (MARD), the FAO/MARD Technical Workshop on “Early Mortality Syndrome (EMS) or Acute Hepatopancreatic Necrosis Syndrome (AHPNS) of Cultured Shrimp” held in Hanoi, Viet Nam from 25 to 27 June 2013 was attended by 63 experts and shrimp aquaculture stakeholders from public and private sectors.
The Workshop participants were informed of: (i) relevant findings and outcomes of the work carried out under TCP/VIE/3304 project and (ii) updates on EMS/AHPNS situation and experiences in affected Asian countries. To assist in further understanding this disease in terms of its aetiology additional technical presentations from other experts were given. Nineteen technical presentations provided the basis for discussions on actions and measures to reduce the risk of EMS/AHPNS.
The Workshop recognized that complacency in the shrimp aquaculture sector resulting in that laxity, during a period of relatively trouble-free shrimp production, led to vulnerability of the sector to any newly emerging pathogen that might arise unexpectedly, as is the case of EMS/AHPNS. Poor management practices, weak compliance with standard, good biosecurity and good aquaculture practices both at farm and hatchery facilities were evident. It is now clear that shrimp aquaculture needs to improve and continue to develop into a sector that implements responsible and science-based farming practices.
With the current understanding that EMS/AHPNS has a bacterial aetiology, a strain of Vibrio parahaemolyticus, the Workshop recommended that a proper name be now given to EMS/AHPNS, i.e. acute hepatopancreatic necrosis disease (AHPND).
The Workshop drew a number of recommendations on specific and generic actions and measures for reducing the risk of AHPND, directed to wider shrimp aquaculture stakeholders (public and private sectors) pertinent to important areas such as: AHPND diagnosis; AHPND notification/reporting; international trade of live shrimp, shrimp products (frozen, cooked), and live feed for shrimp; advice to countries affected and not affected by AHPND; measures at farm and hatchery facilities; advice to pharmaceutical and feed companies and shrimp producers; actions on knowledge and capacity development; AHPND outbreak investigation/emergency response; and specific AHPND-targetted research on various themes (i.e. epidemiology, diagnostics, pathogenicity and virulence, public health, mixed infections, non-antimicrobial control measures, environment, polyculture technologies).
The current trend towards increasing intensification and diversification of global aquaculture has led to its dramatic growth, thus making aquaculture an important food-producing sector that provides an essential source of aquatic protein for a growing human population. For both developed and developing countries, the sector is recognized as creator of jobs and an important source of foreign export earnings. The expansion of commercial aquaculture, as is the case in commercial livestock and poultry production, has necessitated the routine use of veterinary medicines to prevent and treat disease outbreaks owing to pathogens, assure healthy stocks and maximize production. The expanded and occasionally irresponsible global movements of live aquatic animals have been accompanied by the transboundary spread of a wide variety of pathogens that have sometimes caused serious damage to aquatic food productivity and resulted in serious pathogens becoming endemic in culture systems and the natural aquatic environment. The use of appropriate antimicrobial treatments is one of the most effective management responses to emergencies associated with infectious disease epizootics. However, their inappropriate use can lead to problems related to increased frequency of bacterial resistance and the potential transfer of resistance genes in bacteria from the aquatic environment to other bacteria. Injudicious use of antimicrobials has also resulted in the occurrence of their residues in aquaculture products and, as a consequence, bans by importing countries and associated economic impacts, including market loss, have occurred. As disease emergencies can happen even in well-managed aquaculture operations, careful planning on the use of antimicrobials is essential in order to maximize their efficacy and minimize the selection pressure for increased frequencies of resistant variants. The prudent and responsible use of veterinary medicines is an essential component of successful commercial aquaculture production systems.
The FAO/AAHRI Expert Workshop on Improving Biosecurity through Prudent and Responsible Use of Veterinary Medicines in Aquatic Food Production was convened in Bangkok, Thailand, from 15 to 18 December 2009, in order to understand the current status of the use of antimicrobials in aquaculture and to discuss the concerns and impacts of their irresponsible use on human health, the aquatic environment and trade. Such discussions became the basis for drafting recommendations targeted for both government and private sectors and for developing guiding principles on the responsible use of antimicrobials in aquaculture to be considered as part of future FAO Code of Conduct for Responsible Fisheries (CCRF) Technical Guidelines on Prudent and Responsible Use of Veterinary Medicines in Aquaculture.
Because aquaculture is expected to continue to increase its contribution to the world’s production of aquatic food, offer opportunities to alleviate poverty, increase employment and community development and reduce overexploitation of natural aquatic resources, appropriate guidance to aquaculture stakeholders on the responsible use of veterinary medicines has become essential. Safe and effective veterinary medicines need to be available for efficient aquaculture production, and their use should be in line with established principles on prudent use to safeguard public and animal health. The use of such medicines should be part of national and on-farm biosecurity plans and in accordance with an overall national policy for sustainable aquaculture.
This publication is presented in two parts: Part 1 contains 15 technical background papers presented during the expert workshop, contributed by 29 specialists, and which served as a basis for the expert workshop deliberations; Part 2 contains the highlights of the expert workshop.