Introduction to Acute Hepatopancreatic Necrosis Disease in shrimp and its impact in farming - Part 1

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 Hello all !!!


I am Dhivagar. In today's session we are going to discuss one of the known and threatful infections in Penaeus vannamei.


Yes, it is about AHPND which stands for Acute Hepatopancreatic Necrosis Disease and it was called Early Mortality Syndrome in earlier days. It is one of the significant diseases which causes huge mortality and leads to economic losses to the shrimp farmers.


AHPND was first observed in China in 2009. It caused higher mortality in the earlier DOC of shrimp culture. Lots of news about this case spread and the causative agent for this disease is later identified as Vibrio parahaemolyticus which contains PirA and PirB toxins.


Who is the real causative agent for AHPND:

In my experience, not all Vibrio parahaemolyticus will cause mortality or AHPND to the shrimp. It completely depends on the environment and adaptation of the strain. Yes, now realise the importance of the water quality management in the shrimp farm. Many researches are still ongoing to identify the treatment method for AHPND. In other hand, studies also found the correlation between vibrio and non-vibrio bacteria in causing earlier mortalities.


Here the causative agent for AHPND is identified as Vibrio parahaemolyticus possessing PirA and PirB toxins. 


Signs and symptoms:

  • External signs and symptoms including pale coloured hepatopancreas, empty stomach and gut, erosion in the internal cells of hepatopancreas, dull and lethargic swimming.


  • In this case most of the abnormal signs were observed internally. Because the mortality gets severe in the chronic phase which only shows the external signs. 


  • Farmers who physically observe the shrimp also need to check internal organs in a randomised manner.


Mortality rate : Most of the farms observed with 70-100% of mortality in earlier days and it depends on the toxicity of the strain. 


Treatment methods:

Yet, there are no specific treatment methods available for treating AHPND. But some of the in-vitro trials found to be effective but most of the performance in the field is still questionable. 


So what do I have to do to prevent it?

  1. There are a lot of ways to prevent the occurrence of AHPND in your farm. Selection of seeds needs more effort. Apart from the lab test several other tests need 

to be done before selecting seed. To better understand the procedure pls visit here : Seed selection for P.vannamei

  1. Better environment: Environmental measures should be properly taken and maintaining a stable microbial population,optimum stocking density,and applications based on the need.

  2. Track data daily: Farmers must ensure to track the daily data which includes feeding,check tray observations,DO,pH,animal health status,pond colour,presence of mud. If you want to monitor your shrimp pond with more precision, and technical support, pls contact at E-mail: dhivagarfcri2000@gmail.com

  3. Appropriate use of chemicals : some times farmers are using unwanted chemical that makes more stress to the animal which leads to easier infection and disease.



 Image-1 Left-AHPND infected;Right-Healthy shrimp



How does genetics selection play a role in AHPND?


The answer is YES!!! But how? There are researches that found the importance of broodstock in preventing AHPND or bacterial disease in shrimp. Even the country called Ecuador has also had an AHPND outbreak but it has not shown higher mortality like in Asia or other countries. The main reason behind this is broodstock. Researchers from a private organisation in Ecuador had run a trial.


In that trial they have taken different mothers to produce PL and had done bacterial challenge through immersion and oral route infection method for AHPND. They took the Vibrio parahaemolyticus strain containing PirA and PirB toxins to challenge the PL from different traits. The result is most of them showed reduced mortality during the challenge period. 

Even some of the shrimp showed Histopathological lesions similar to AHPND but it did not die.


Likewise many interesting things are going around. Be a part of the revolution to ensure safety and success for our aquaculture. 

To conclude this, yet more research should be focused on this area for the better and well-being of farmers. In our next blog, we will see the recent innovation for AHPND in a detailed manner.


Kindly read and subscribe to my blog and pls share with your contact.

For more info and technical support, pls E-mail : dhivagarfcri2000@gmail.com


Thank you,

Dhivagar



References:

  1. https://doi.org/10.3390/toxins13080524

  2. https://www.woah.org/fileadmin/Home/fr/Health_standards/aahm/current/2.2.01_AHPND.pdf

  3. https://doi.org/10.1016/j.aquaculture.2025.742458

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