Enterocytozoon hepatopenaei (EHP)
EHP is a hepatopancreas-targeting microsporidian that does not cause mass mortality but stunts growth — turning a 100-day cycle into a 140-day cycle with sub-economic ABW.
Clinical signs
- Growth divergence — same pond shows 8 g and 20 g shrimp at 80 DOC
- Low ADG (Average Daily Growth) — typically <0.15 g/day vs expected 0.25–0.30 g/day
- Soft shells and pale hepatopancreas
- White feces strings floating on the pond surface (often co-infection with vibrio)
- No acute mortality — losses are economic, not biological
Transmission
- Oral: cannibalism of infected shrimp, contaminated polychaete worms or live feed
- Waterborne via spores released in feces
- Vertical from infected broodstock (suspected but unconfirmed)
- Spores survive 2+ years in dried pond sediment
Diagnosis
- PCR on hepatopancreas tissue (SWP gene primers — most sensitive)
- Quantitative PCR for spore load grading
- Histopathology: spores visible in hepatopancreatic tubule epithelium
- Field clue: stunted growth + white feces + normal mortality = PCR for EHP
Treatment & emergency response
- No registered drug treatment for EHP
- Curcumin (turmeric extract) at 0.5–1% of feed shows reduced spore load in trials
- If detected before 30 DOC: emergency harvest rarely justified; carry to harvest with reduced expectations
- If detected after 60 DOC with low ABW: harvest early and reset the pond aggressively
Prevention
- PCR-screen PLs and broodstock for EHP (most Indian hatcheries now offer this)
- Pond sediment treatment: CaO (quicklime) at 1,000 kg/ha + sun-drying for 14+ days between cycles
- Avoid feeding raw polychaete worms or live tubifex — autoclave or skip
- Disinfect intake water with chlorine 30 ppm, dechlorinate before stocking
- Do not re-use water from a previously EHP-positive pond
- Probiotic feed additives (Bacillus subtilis, Lactobacillus) reduce co-infection severity
Biosecurity checklist
- 14-day minimum pond drying between cycles, longer in wet season
- Quicklime application at 1,000 kg/ha, mixed into top 10 cm of sediment
- No shared equipment with EHP-positive ponds within the same farm
- Source PLs only from PCR-tested batches (request the lab report)
- Weekly ABW sampling — track growth divergence as an early signal
Regional prevalence
See where EHP is being reported right now across India and Southeast Asia, with weekly trend lines and per-district drilldowns.
Open the heatmap →Frequently asked questions
What is EHP in shrimp?
EHP (Enterocytozoon hepatopenaei) is a microsporidian parasite that infects the hepatopancreas of penaeid shrimp. It doesn't kill the animal, but stunts growth severely — Indian farms report 30–50% reduction in harvest weight in heavily-infected ponds, which destroys cycle economics.
How do you treat EHP in shrimp?
There's no approved drug for EHP. Management is the only lever: PCR-screen PLs before stocking, treat sediment between cycles with CaO and sun-drying, and use curcumin feed additives (0.5–1%) which trial data shows reduce spore load.
How is EHP diagnosed in shrimp farms?
PCR on hepatopancreas tissue using SWP-gene primers is the standard. The field clue that should trigger a PCR test is growth divergence — a clear bimodal size distribution in the same pond at 60–80 DOC, especially when combined with white feces.
Why is EHP a problem in Indian shrimp farms?
India's shrimp belt (Andhra Pradesh, Tamil Nadu, Gujarat) has reported steadily rising EHP prevalence since 2014. Lack of mandatory PL screening, water reuse, and short between-cycle gaps all favor spore accumulation. The pathogen's invisibility — no mortality — means many farms only diagnose it after the harvest comes in 30% under target.
Does EHP affect humans?
No. EHP is not zoonotic and infected shrimp are safe to eat. The economic damage is entirely on the farm side: smaller shrimp, longer cycles, higher FCR.
Catch EHP before it costs a cycle
CAMARON's Disease Vision module flags EHP from a single farm photo, ties findings to the regional heatmap, and walks you through the protocol.