White Spot & IHHNV

A Battle Plan to Prevent the Worst Shrimp Diseases

Fellow producers, anyone involved in the day-to-day of shrimp farming knows that our work is a mix of science, art, and a healthy dose of resilience. We deal with the climate, the market, costs, and one of our biggest challenges: diseases. Among all the ghosts that haunt our ponds, two names send shivers down our spines: White Spot Syndrome (WSSV) and Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV).

These aren’t just any diseases. They are formidable adversaries, capable of wiping out entire productions in a matter of days, taking with them not only our profit but months of hard work. White Spot, for instance, is known for its rapid action and extremely high lethality, capable of causing mortality rates of up to 100% in a short period. Meanwhile, IHHNV, although often less lethal in Litopenaeus vannamei shrimp, is the cause of the “Runt Deformity Syndrome” (RDS), which severely compromises growth, batch uniformity, and, consequently, the economic viability of the cycle.

Living with these risks is part of our business, but that doesn’t mean we should accept them passively. On the contrary, experience has taught us that the best defense is a well-planned offense. A robust battle plan, focused on prevention and constant monitoring, is our main weapon to keep these enemies away from our farms. And today, I want to share with you the strategies I consider essential in this fight.

Knowing the Enemy: White Spot (WSSV)

White Spot Syndrome, caused by the White Spot Syndrome Virus (WSSV), manifests aggressively. Infected shrimp become lethargic, stop feeding, and display characteristic white spots on their exoskeleton, which are calcium deposits. Transmission is rapid, occurring through the water, by other carrier crustaceans (like crabs that invade the ponds), or through cannibalism of sick animals.

The impact is devastating. Once the virus takes hold and environmental conditions favor it, dissemination is nearly impossible to contain. The speed at which the disease spreads demands incessant vigilance and rigorous preventive actions from the producer, because once an outbreak is detected, management options are extremely limited.

The Silent Adversary: IHHNV

IHHNV, in turn, acts more subtly, but is no less harmful. In our main cultivated species, L. vannamei, it frequently causes RDS. The result is shrimp with deformities in the rostrum and carapace, extremely slow growth, and a non-uniform final batch. This lack of uniformity complicates sales and increases the feed conversion ratio, directly impacting the producer’s bottom line.

The major concern with IHHNV is its capacity for vertical transmission, meaning from broodstock to their larvae. This makes the origin of our post-larvae (PLs) one of the most critical points in the entire prevention chain. Buying PLs from reputable laboratories with health certification is not a cost, but an indispensable investment in the security of our crop.

Our Battle Plan: Prevention as the Main Strategy

Prevention is the keyword. A good producer doesn’t wait for the disease to arrive to think about what to do. They build a fortress of biosecurity around their farm. And this fortress is built on a few fundamental pillars.

Pillar 1: Biosecurity Taken Seriously

Biosecurity is the set of practices we adopt to prevent the entry and spread of pathogens on the farm. This includes everything from strict control of access for people and vehicles, with disinfection arches, to installing screens on all pond water inlets and outlets to block the entry of carrier animals.

Every detail matters. The use of exclusive utensils (like nets, buckets, and cast nets) for each pond, or their rigorous disinfection between uses, is a simple practice that breaks the contamination cycle. Similarly, an effective sanitary-dry out program after harvest, with proper drying and preparation of the pond bottom, is crucial to eliminate potential pathogens before starting a new stocking.

Pillar 2: The Choice of Post-Larvae (PLs)

As mentioned, the genetic and sanitary quality of the PLs is the starting point for a successful cycle. It is essential to acquire post-larvae from laboratories that perform PCR analysis to detect the presence of WSSV, IHHNV, and other diseases. Demand the reports, talk to the technicians, know the origin of the broodstock. This initial choice can define the fate of your entire production.

Pillar 3: Monitoring and Water Quality

The pond environment is the battlefield. If it is favorable to the shrimp, the animal’s immune system will be stronger. Water quality parameters, such as dissolved oxygen, pH, alkalinity, temperature, and ammonia, must be monitored daily. Abrupt variations in these parameters cause stress in the animals, making them more susceptible to infections.

This is where technology becomes our great ally. Using a management software like Despesca allows for the organized and historical recording of all this data. With the system, we can track the evolution of each parameter throughout the cycle, identify trends, correlate data from different ponds, and make faster, more assertive decisions. If oxygen is consistently dropping in the late hours of the night in a specific pond, the record in Despesca alerts us to adjust aeration before it becomes a critical problem.

Pillar 4: Nutrition and Feed Management

High-quality nutrition is essential for strengthening the shrimp’s immune system. Well-formulated feeds, with adequate levels of vitamins and minerals, prepare the animal to better resist health challenges. Furthermore, correct feed management, avoiding leftover feed at the bottom of the pond, is vital for maintaining water quality.

Precise control of the amount of feed offered, adjusted according to biomass and observed consumption, is a daily task. Tools like Despesca greatly assist in this control, allowing for the recording of daily feeding and the automatic calculation of the feed conversion ratio. With accurate data, we optimize feed use, reduce costs, and prevent the deterioration of water quality, a risk factor for the proliferation of diseases.

The Importance of Records: Our Logbook

A producer who doesn’t take notes, doesn’t manage. Keeping a detailed history of each cycle is fundamental. Noting stocking dates, PL origin, biometrics, water parameters, feeding, occurrences, mortalities, and management actions gives us immense analytical power.

When a problem arises, it is in this history that we will look for clues. Was it after a sharp drop in salinity? Was there an aeration failure? What was the survival rate of the last cycles with that PL supplier? A system like Despesca transforms these notes into intelligence, generating reports that help us learn from the past to protect the future.

The Battle is Continuous

In summary, fighting against White Spot and IHHNV is not a one-time action, but a state of constant vigilance and management. It is the sum of dozens of small, correct actions, carried out every day.

It’s about building a culture of biosecurity throughout the entire team, from the manager to the feeder. It’s about investing in quality PLs, tirelessly monitoring the water, feeding our animals well, and above all, recording and analyzing every step of the process.

Technology is here to support us, and management systems like Despesca are powerful tools in this arsenal. They help us turn raw data into strategic decisions, freeing up our time for what matters most: observing the ponds and ensuring the health of our stock.

Remember, prevention is the best investment. With a well-defined battle plan executed with discipline, we can keep our ponds productive and safe, ensuring the sustainability and profitability of our shrimp farming business.