Shrimp disease (bacterial) - Acute Hepatic Pancreatic Necrosis

Primary reference(s)

WOAH, 2023. Manual of Diagnostic Tests for Aquatic Animals: Acute Hepatopancreatic Necrosis Disease. Chapter 2.2.1. World Organisation for Animal Health (WOAH). Accessed 12 March 2025

Annotations

Key relevant UN convention / multilateral treaty

Sendai Framework for Disaster Risk Reduction 2015-2030.

Drivers

Acute hepatopancreatic necrosis disease is caused by unique strains of V. parahaemolyticus and four other Vibrio species. Vibrio bacteria are ubiquitous in marine and brackish-water environments, and their populations are affected in these ecosystems by temperature, salinity, and turbidity. These AHPND-related bacteria can be present in both the cultured shrimp as well as in the water, sediments, and associated organisms in the farm ponds and in the surrounding aquatic environment (OIE, 2019a). 

Impacts

Clinical signs and mortality of AHPND can start as early as 10 days post-stocking. Major clinical signs involve shrimp hepato-pancreas: significant atrophy, loss of colour, and the presence of black spots or streaks due to melanised tubules. Additional clinical signs include soft shells and an empty stomach or near-empty midgut (OIE, 2019a).

Multi-hazard context

Shrimp disease outbreaks, which are considered as the primary cause of production loss in shrimp farming, have brought socio-economic and environmental unsustainability to the shrimp aquaculture industry (Kumar et al., 2021)

Risk Management

Several therapeutic methods have been tried, with mixed results, to combat AHPND in populations of infected shrimp on farms, but there is a lack of scientific data to corroborate claims of their effectiveness. These include antibiotics, bacteriophage therapy, probiotics, etc. (FAO, 2020). 

Since the emergence of AHPND, shrimp producers in Southeast Asia and Latin America have changed farm designs and operations to facilitate the management of this disease; such changes include the use of smaller, lined ponds; central drains; prefiltered clean water; tilapia for removal of sediments; increased aeration; frequent feeding regimes to reduce uneaten feed; and probiotics applied to the ponds. Biosecurity measures have been implemented such as the use of pathogen-free postlarvae and access control to the rearing site to prevent the introduction of pathogens. These management strategies seem to have been effective, as global shrimp production has shown a gradual recovery since 2016 (FAO, 2020). 

Good aquaculture and biosecurity practices include farm management (screening prior to stocking; pond water and bottom preparation); proper destruction and disposal of diseased shrimp; disinfection of affected premises; vector control; containment through movement control and zoning; and avoiding sources of stress (high stocking density, poor water quality or other less optimal environmental conditions such as suboptimal temperature or salinity) (FAO, 2020). 

The World Organisation for Animal Health (WOAH) provides recommendations on AHPND that include advice on importation, transit and maintenance of free status from AHPND (WOAH, 2024). 

A report jointly published by the Food and Agriculture Organization of the United Nations (FAO) and the Asian Fisheries Society in 2018, aimed at updating knowledge and experience in dealing with AHPND and related topics from the perspective of government, academe and producer sectors (FAO, 2018).

Monitoring

The section and the table below offer an overview of monitoring for shrimp disease - acute hepatic pancreatic disease. This information can be used for forecasting within a national early warning system (EWS). Since EWS capacities and processes differ across countries, the most current and specific information regarding EWS should be obtained from the appropriate national or regional agency/authority responsible for disaster management.