Taura Syndrome Virus (TSV)
TSV is a picornavirus that strikes vannamei post-larvae and juveniles, causing reddish-tail discolouration, soft shells and 40–90% mortality in the acute phase.
Clinical signs
- Acute phase: reddish-orange tail and pleopods (the diagnostic 'red-tail' sign) in PL15–juvenile shrimp
- Soft, expanded shells with the animal frequently moulting and dying mid-moult
- Lethargy, surface swimming and edge-of-pond mortality at dusk
- Anorexia 24–48 hours before mortality peaks
- Cumulative mortality 40–90% within 7–10 days of onset; strikes between 14 and 40 DOC
- Chronic phase: irregular melanised black spots on the cuticle in survivors
- Most affected size class: 0.05–5 g; older shrimp (>12 g) usually clear the infection
Transmission
- Vertical — infected broodstock seed nauplii and PLs (the main intercontinental route)
- Horizontal — cannibalism of dying shrimp; waterborne spread within and between ponds
- Carrier — birds (especially seagulls and herons) shed live virus in faeces after eating dead shrimp
- Mechanical — shared nets, buckets and worker hands moving between affected and clean ponds
- Stress triggers — DO crashes, ammonia spikes and salinity swings precede most outbreaks
Diagnosis
- RT-PCR on hepatopancreas, gill or pleopod tissue (gold standard) — single-step or nested
- Field: red-tail + soft shells + mortality between 14 and 40 DOC = high-probability TSV
- Histopathology: characteristic pyknotic and karyorrhectic nuclei ('peppered' appearance) in cuticular epithelium
- In-situ hybridization or immunohistochemistry for definitive confirmation
- Differentiate from AHPND (empty gut + pale HP, 10–35 DOC) and WSSV (white spots on inner carapace)
Treatment & emergency response
- No antiviral treatment exists
- Reduce feed by 50% to lower organic load and bacterial co-infection pressure
- Maintain DO above 5 mg/L through 24/7 aeration — survivors clear virus faster in stable water
- If mortality crosses 30% before 25 DOC and ABW <2 g: drain, disinfect (chlorine 30 ppm, 24 h), reset
- If mortality stabilises after 40 DOC with ABW >5 g: carry to harvest — surviving stock is TSV-resistant
- Net out dead shrimp at least twice daily to break the cannibalism transmission loop
- Bird netting and crab fencing to interrupt the carrier route during active outbreaks
Prevention
- Source PLs only from SPR (Specific Pathogen Resistant) vannamei lines with current TSV-negative PCR certificates
- PCR-screen every PL batch on arrival; reject any positive batch
- Disinfect intake water (chlorine 30 ppm, hold 24 h, dechlorinate) where TSV is regionally prevalent
- Bird netting and crab fencing on every pond — birds are documented vectors
- Stable salinity (15–25 ppt for vannamei) and DO above 5 mg/L reduce stress-driven outbreaks
- Avoid mixing PL batches from different hatcheries in the same pond
- Full pond dry-out + CaO 1,000 kg/ha + 14-day sun-drying between cycles
Biosecurity checklist
- Demand and file the TSV-negative PCR certificate for every PL batch
- Bird netting + crab fencing on every pond — non-negotiable in TSV-endemic regions
- Foot baths (200 ppm chlorine) at every pond entry, refreshed daily
- Dedicated nets, buckets and aerators per pond; colour-code to prevent cross-use
- Daily morning + evening mortality count — red-tail clusters trigger same-day RT-PCR
- Quarantine pond for any new PL batch (5 days minimum) with PCR clearance
- Remove and incinerate moribund shrimp twice daily — never leave dead shrimp in the pond overnight
Regional prevalence
See where TSV 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 Taura Syndrome Virus?
TSV is a picornavirus that infects Pacific white shrimp (Penaeus vannamei) and is one of the four OIE-listed shrimp viruses. It strikes post-larvae and juveniles between 14 and 40 days of culture, producing reddish-tail discolouration, soft shells and 40–90% mortality. Older shrimp above 12 g typically clear the infection.
How do you treat TSV in shrimp ponds?
There is no antiviral treatment for TSV. Management is the only lever: reduce feed by 50%, maintain DO above 5 mg/L, net out dead shrimp twice daily to break cannibalism, and install bird netting to interrupt the carrier route. If mortality stabilises after 40 DOC, carry surviving stock to harvest — survivors are TSV-resistant and marketable.
How is TSV different from WSSV?
Timing, signs and host range. TSV is a picornavirus that strikes vannamei post-larvae and juveniles (14–40 DOC) with reddish tails and soft shells. WSSV is a much larger DNA virus that strikes all shrimp species at any age with white spots on the inner carapace. TSV mortality stabilises around 40 DOC; WSSV typically runs to 80–100% within 3–10 days regardless of age.
Can you prevent TSV?
Yes — far better than you can treat it. The three highest-impact preventive measures are: source PCR-negative SPR vannamei PLs from certified hatcheries, install bird netting on every pond (birds are documented carriers), and disinfect intake water with chlorine in TSV-endemic regions. SPR genetic lines have made TSV a manageable disease in Latin America and Asia.
Is TSV dangerous to humans?
No. TSV is shrimp-specific and does not infect humans. Properly cooked shrimp is safe to eat. The economic risk is on the farm side — 40–90% mortality during the most expensive growth phase — and on export documentation, since TSV is OIE-listed and disease-free certification may be required by some import markets.
Catch TSV before it costs a cycle
CAMARON's Disease Vision module flags TSV from a single farm photo, ties findings to the regional heatmap, and walks you through the protocol.