Several diseases and water-quality problems can look alike. Sudden deaths, falling feed intake or breathing distress need prompt advice from a qualified aquatic animal health professional and an appropriate diagnostic laboratory.
What it is
Infectious hypodermal and haematopoietic necrosis virus infects susceptible shrimp. Its effects differ between species, viral variants and stocks; severe mortality described in blue shrimp should not be automatically applied to vannamei.
Runt-deformity syndrome describes poor and unequal growth with body abnormalities. Compare representative samples over time. A positive PCR screen needs laboratory interpretation and, where indicated, confirmation; it does not by itself establish the cause of poor growth.
Signs to watch for
- A widening spread of harvest sizes or falling average weight gain.
- Bent rostrum, abnormal body segments or tail deformity in some shrimp.
- Reduced feeding efficiency; infection may also occur without visible changes.
What else can look similar?
- EHP, poor seed quality, nutrition or unequal access to feed.
- Handling injury, environmental stress and other causes of deformity.
Spread & risk factors
- Infection may be introduced through infected breeding or seed stocks.
- Contaminated water and ingestion of infected material can spread infection within susceptible populations.
How to confirm the cause
- Use a validated IHHNV PCR assay selected by the laboratory, with tissue examination if indicated. Some assays can detect noninfectious virus-related sequences in shrimp DNA (endogenous viral elements, EVEs); ask how the assay distinguishes these and confirms unexpected results.
- Review sampling, seed-batch history, weight distribution and other growth-related tests. Do not interpret a screening result in isolation.
Prevention: your practical checklist
Buy traceable PL with relevant pathogen-screening records and a documented hatchery health programme.
Keep seed lots separate and check batch identity before stocking.
Avoid transferring slow-growing shrimp into healthy ponds to improve their growth.
Assign nets, trays and boots to each pond; clean and disinfect equipment under the farm’s biosecurity plan.
Keep seed-batch, feeding, water-quality and mortality records so a change is noticed early.
What to do if you suspect a problem
Arrange a professional assessment and appropriate laboratory tests.
Record average weight, size range, feed conversion assumptions and visible deformities.
Review feeding access and water quality while investigating infection; plan the crop using measured growth.
Keep affected stock, equipment and water separate. Agree on safe disposal and any harvest or discharge with your professional.
What not to do
- Do not call all size variation IHHNV or assume infection always causes mass mortality.
- Do not use antibiotics or growth-promoter claims as a viral treatment.
- Do not mix medicines or pond chemicals on guesswork; use only legally permitted inputs under qualified advice.
Farmer questions
Does a bent rostrum prove IHHNV?
No. It is a reason to investigate, not a definitive test. Compare the population and use appropriate laboratory methods.
Can apparently healthy shrimp carry infection?
Yes. Appearance cannot replace the hatchery’s screening and biosecurity programme, and a single negative test is not an absolute guarantee.
Sources & further reading
Sources support the discussion above. Their inclusion does not mean these organisations reviewed or approved this article. Some references cover other shrimp species; the guide states limitations where relevant.
- 01Infection with IHHNV — diagnostic and disease information ↗
World Organisation for Animal Health — Aquatic Manual (2023; assay limitations in section 4.4)
- 02IHHN — field observations and host differences ↗
NACA / Australian Government — historical Asia–Pacific identification field guide; not current surveillance
- 03Cultured Aquatic Species Information: Penaeus vannamei — diseases and management ↗
Food and Agriculture Organization of the United Nations (FAO); historical species profile
AI-assisted source check: 16 October 2026, not professional approval. Reference dates refer to the documents, not their URL filenames or live disease status.
AquaGrow completed an AI-assisted technical-source and translation-consistency check on 16 October 2026. This is educational content, not an individual pond diagnosis, a prescription or an endorsement by ICAR-CIBA, NACA or WOAH. An independent clinical review has not been completed. Translations also await independent review by native-speaking aquaculture specialists.
This is a selected learning library, not a complete disease list or a statement that every condition occurs in Andhra Pradesh or Odisha. No live outbreak surveillance is provided.