{"id":24,"date":"2026-06-29T12:06:01","date_gmt":"2026-06-29T04:06:01","guid":{"rendered":"https:\/\/sdic-tcca.hbkaixuan.cn\/?p=24"},"modified":"2026-06-29T12:06:01","modified_gmt":"2026-06-29T04:06:01","slug":"white-spot-virus-and-vibriosis-prevention-in-shrimp-farms-using-sdic-a-2026-practitioner-guide","status":"publish","type":"post","link":"https:\/\/sdic-tcca.hbkaixuan.cn\/?p=24","title":{"rendered":"White Spot Virus and Vibriosis Prevention in Shrimp Farms Using SDIC: A 2026 Practitioner Guide"},"content":{"rendered":"<p><strong>Quick answer:<\/strong> To prevent White Spot Syndrome Virus (WSSV) and Vibrio bacterial infections, implement a four-stage SDIC biosecurity protocol: <strong>(1) 50 ppm SDIC pre-stocking pond sterilization with 72-hour retention<\/strong>, <strong>(2) 100 ppm SDIC footbath at all farm entry points refreshed daily<\/strong>, <strong>(3) 200\u2013400 ppm SDIC equipment immersion disinfection between batches<\/strong>, and <strong>(4) 0.5 ppm SDIC weekly grow-out treatment with continuous aeration<\/strong>. Combined with PCR screening of post-larvae and biofloc management, this protocol reduces WSSV outbreak rates by up to 80% based on field data from Southeast Asian shrimp farms.<\/p>\n<p>White Spot Syndrome Virus (WSSV) and Vibrio parahaemolyticus (causing Early Mortality Syndrome \/ EMS) together cause over <strong>USD 6 billion in annual losses<\/strong> to global shrimp aquaculture. Chemical disinfection with Sodium Dichloroisocyanurate (SDIC) is the cornerstone of any effective biosecurity program. This guide consolidates field-tested protocols from <strong>Shilan Chemical<\/strong>&#8216;s customers operating shrimp farms in Vietnam, India, Ecuador, Indonesia, and Thailand.<\/p>\n<h2>Understanding the Two Major Shrimp Pathogens<\/h2>\n<h3>White Spot Syndrome Virus (WSSV)<\/h3>\n<ul>\n<li><strong>Pathogen type:<\/strong> DNA virus (family Nimaviridae)<\/li>\n<li><strong>Mortality rate:<\/strong> 90\u2013100% within 3\u20137 days of clinical onset<\/li>\n<li><strong>Affected species:<\/strong> Pacific white shrimp, black tiger shrimp, crayfish<\/li>\n<li><strong>Transmission:<\/strong> Water-borne, carrier crustaceans, contaminated equipment<\/li>\n<li><strong>SDIC inactivation threshold:<\/strong> 5 ppm free chlorine, 30-minute contact<\/li>\n<\/ul>\n<h3>Vibrio parahaemolyticus (EMS\/AHPND)<\/h3>\n<ul>\n<li><strong>Pathogen type:<\/strong> Gram-negative bacterium<\/li>\n<li><strong>Mortality rate:<\/strong> 70\u2013100% within 20\u201330 days of stocking<\/li>\n<li><strong>Affected species:<\/strong> Primarily Pacific white shrimp<\/li>\n<li><strong>Transmission:<\/strong> Sediment, biofilm, carrier shrimp post-larvae<\/li>\n<li><strong>SDIC inactivation threshold:<\/strong> 1 ppm free chlorine, 15-minute contact<\/li>\n<\/ul>\n<h2>The 4-Stage SDIC Biosecurity Protocol<\/h2>\n<h3>Stage 1: Pre-Stocking Pond Sterilization<\/h3>\n<p>The single most important step. Performed once at start of each grow-out cycle on completely drained ponds.<\/p>\n<ul>\n<li><strong>Dose:<\/strong> 50 ppm SDIC 60% (50 kg per 1,000 m\u00b3)<\/li>\n<li><strong>Procedure:<\/strong> Re-flood empty pond to 30 cm depth, broadcast pre-dissolved SDIC, hold 72 hours<\/li>\n<li><strong>Target organisms killed:<\/strong> WSSV, EHP (microsporidia), Vibrio, hydra, crab carriers, snail intermediate hosts<\/li>\n<li><strong>Critical:<\/strong> Test free chlorine = 0 before stocking PL; if residual remains, add sodium thiosulfate at 1:0.5 ratio<\/li>\n<\/ul>\n<h3>Stage 2: Personnel and Vehicle Footbaths<\/h3>\n<p>Front-line defense against farm-to-farm transmission. WSSV is highly stable on contaminated boots and tires.<\/p>\n<ul>\n<li><strong>Dose:<\/strong> 100 ppm SDIC solution (1 kg SDIC 60% in 6,000 L water = ~1.7g per 10L)<\/li>\n<li><strong>Locations:<\/strong> Every farm entry point, between pond clusters, lab and feed room thresholds<\/li>\n<li><strong>Refresh:<\/strong> Daily, or immediately after visible contamination<\/li>\n<li><strong>Contact time:<\/strong> Boots and wheels submerged minimum 60 seconds<\/li>\n<\/ul>\n<h3>Stage 3: Equipment Immersion Disinfection<\/h3>\n<p>Nets, sample buckets, aerator parts, harvest tools \u2014 all major outbreak vectors if reused without proper cleaning.<\/p>\n<ul>\n<li><strong>Dose:<\/strong> 200 ppm SDIC for routine equipment, 400 ppm for known-contaminated tools<\/li>\n<li><strong>Procedure:<\/strong> Soak 30 minutes, rinse with clean water, dry in sunlight<\/li>\n<li><strong>Frequency:<\/strong> Daily for shared equipment, between batches for dedicated equipment<\/li>\n<\/ul>\n<h3>Stage 4: In-Pond Routine Prophylaxis<\/h3>\n<p>Maintains low-level antimicrobial pressure without disrupting beneficial pond ecology.<\/p>\n<ul>\n<li><strong>Dose:<\/strong> 0.5 ppm SDIC 60% weekly (or 1 ppm bi-weekly for higher-risk seasons)<\/li>\n<li><strong>Timing:<\/strong> Early morning, immediately after partial water exchange<\/li>\n<li><strong>Aeration:<\/strong> Run all aerators at maximum for 6 hours post-dosing<\/li>\n<li><strong>Pause if mortality observed:<\/strong> &gt;0.5% daily mortality requires immediate diagnostic workup before next SDIC application<\/li>\n<\/ul>\n<h2>Field-Validated Outbreak Recovery Protocol<\/h2>\n<p>When clinical signs appear (WSSV: white spots on carapace + lethargy; Vibrio: empty gut + red gill + mass mortality), follow this 5-step recovery procedure:<\/p>\n<ol>\n<li><strong>Stop feeding immediately<\/strong> \u2014 reduces metabolic load on stressed shrimp<\/li>\n<li><strong>Increase aeration to 100% capacity<\/strong> \u2014 affected shrimp have compromised oxygen uptake<\/li>\n<li><strong>Apply 5 ppm SDIC shock dose<\/strong> \u2014 kills free-swimming pathogen in water column (note: this is a salvage operation, not a guaranteed cure)<\/li>\n<li><strong>Partial water exchange (30\u201340%) after 24 hours<\/strong> \u2014 removes dead biomass and pathogen load<\/li>\n<li><strong>If mortality continues &gt;20%, emergency harvest<\/strong> \u2014 salvage value of survivors and prevent catastrophic loss<\/li>\n<\/ol>\n<h2>Comparison: SDIC vs Other Aquaculture Disinfectants<\/h2>\n<table>\n<thead>\n<tr>\n<th>Disinfectant<\/th>\n<th>Effective Against<\/th>\n<th>Pond Safety<\/th>\n<th>Cost \/ 1,000 m\u00b3 (USD)<\/th>\n<th>Best Use Case<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>SDIC 60%<\/strong><\/td>\n<td>WSSV, Vibrio, EHP, fungi<\/td>\n<td>High (pH neutral)<\/td>\n<td>4\u20136<\/td>\n<td>All-purpose, recommended<\/td>\n<\/tr>\n<tr>\n<td>Calcium hypochlorite<\/td>\n<td>Most pathogens<\/td>\n<td>Medium (raises pH)<\/td>\n<td>3\u20135<\/td>\n<td>Pre-stocking only<\/td>\n<\/tr>\n<tr>\n<td>Formalin<\/td>\n<td>External parasites<\/td>\n<td>Low (carcinogenic)<\/td>\n<td>8\u201315<\/td>\n<td>Rarely; being phased out<\/td>\n<\/tr>\n<tr>\n<td>Iodine compounds<\/td>\n<td>Bacteria and viruses<\/td>\n<td>High<\/td>\n<td>20\u201340<\/td>\n<td>Egg disinfection only<\/td>\n<\/tr>\n<tr>\n<td>Potassium permanganate<\/td>\n<td>External bacteria<\/td>\n<td>Low (toxic if overdosed)<\/td>\n<td>10\u201315<\/td>\n<td>Emergency only<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Real Field Outcomes from SDIC-Based Programs<\/h2>\n<p>Anonymized data from Shilan Chemical customer farms running the 4-stage protocol for 18 months:<\/p>\n<ul>\n<li><strong>WSSV outbreak rate:<\/strong> dropped from 18% of cycles to 4%<\/li>\n<li><strong>EMS\/AHPND incidence:<\/strong> dropped from 12% to 3%<\/li>\n<li><strong>Average survival rate:<\/strong> increased from 62% to 81%<\/li>\n<li><strong>Average harvest weight:<\/strong> improved by 12% due to better water quality<\/li>\n<li><strong>Disinfection cost per cycle:<\/strong> USD 380\u2013520 per hectare (small fraction of saved revenue)<\/li>\n<\/ul>\n<h2>Common Misconceptions That Defeat Biosecurity<\/h2>\n<h3>&#8220;Disinfection kills all my probiotics, so I won&#8217;t use it&#8221;<\/h3>\n<p>Re-inoculate probiotics 48 hours after SDIC treatment. The pathogen reduction far outweighs probiotic loss.<\/p>\n<h3>&#8220;SDIC is too expensive for routine use&#8221;<\/h3>\n<p>At ~USD 5 per 1,000 m\u00b3 for 1 ppm dosing, weekly treatment costs less than 1% of feed cost \u2014 and prevents disasters worth 100\u00d7 more.<\/p>\n<h3>&#8220;My pond is small, I don&#8217;t need biosecurity&#8221;<\/h3>\n<p>Smaller ponds face higher relative biosecurity risk because of denser stocking and shared water sources.<\/p>\n<h3>&#8220;SDIC will affect my organic certification&#8221;<\/h3>\n<p>SDIC residues are undetectable within 24 hours and are permitted under most organic aquaculture standards (e.g., EU 2018\/848 for pre-stocking use).<\/p>\n<h2>FAQ<\/h2>\n<h3>How fast does SDIC kill WSSV in pond water?<\/h3>\n<p>At 5 ppm free chlorine, WSSV is inactivated within 30 minutes at typical pond temperatures (28\u201330\u00b0C). Lower temperatures require longer contact time.<\/p>\n<h3>Can I use SDIC during shrimp molting?<\/h3>\n<p>Use the lowest effective dose (0.5 ppm) and skip if &gt;30% of population is observed molting. Newly molted shrimp are extra sensitive.<\/p>\n<h3>Does SDIC work in salt water as well as fresh?<\/h3>\n<p>Yes, equally effective in salinities up to 35 ppt. Slightly higher doses (1.2\u00d7) recommended above 30 ppt salinity.<\/p>\n<h3>How do I store SDIC at a humid coastal farm?<\/h3>\n<p>Use original sealed HDPE drums in a ventilated room below 30\u00b0C. Avoid direct contact with steel surfaces. Even with humidity, properly stored SDIC retains potency for 24 months.<\/p>\n<h2>Ready to Implement a Biosecurity Program?<\/h2>\n<p><strong>Shilan Chemical<\/strong> supplies aquaculture-grade SDIC 60% (Veterinary GMP certified) with technical support tailored to your pond layout, target species, and regional regulations. Free 500g sample plus customized biosecurity protocol available for serious enquiries. <a href=\"https:\/\/sdic-tcca.hbkaixuan.cn\/contact.html\">Connect with our aquaculture team<\/a> for an initial consultation.<\/p>\n<h2>Related Articles<\/h2>\n<ul>\n<li><a href=\"https:\/\/sdic-tcca.hbkaixuan.cn\/?p=15\">SDIC Dosage for Shrimp and Fish Ponds: Complete Guide<\/a><\/li>\n<li><a href=\"https:\/\/sdic-tcca.hbkaixuan.cn\/?p=11\">Top 7 Industries Using Chlorine Donors<\/a><\/li>\n<li><a href=\"https:\/\/sdic-tcca.hbkaixuan.cn\/?p=14\">TCCA Buyer Checklist: 12 Questions to Ask Your Supplier<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>A comprehensive playbook for using Sodium Dichloroisocyanurate (SDIC) to prevent White Spot Syndrome Virus (WSSV) outbreaks and Vibrio parahaemolyticus infections in shrimp aquaculture. Includes biosecurity protocols, dosing windows, and recovery procedures.<\/p>\n","protected":false},"author":1,"featured_media":27,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-24","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/sdic-tcca.hbkaixuan.cn\/index.php?rest_route=\/wp\/v2\/posts\/24","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sdic-tcca.hbkaixuan.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sdic-tcca.hbkaixuan.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sdic-tcca.hbkaixuan.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/sdic-tcca.hbkaixuan.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=24"}],"version-history":[{"count":0,"href":"https:\/\/sdic-tcca.hbkaixuan.cn\/index.php?rest_route=\/wp\/v2\/posts\/24\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/sdic-tcca.hbkaixuan.cn\/index.php?rest_route=\/wp\/v2\/media\/27"}],"wp:attachment":[{"href":"https:\/\/sdic-tcca.hbkaixuan.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=24"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sdic-tcca.hbkaixuan.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=24"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sdic-tcca.hbkaixuan.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=24"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}