The “Little Balls Syndrome” (LBS) affects Penaeus vannamei zoea larvae at stages 2–3 in hatcheries across Latin America, causing high mortality rates. It is characterized by spherical “little balls” in the hepatopancreas that migrate to the intestine, accompanied by an empty digestive tract, epithelial detachment, hepatopancreatic necrosis, and damage to the peritrophic membrane. It is associated with Vibrio spp. (primarily V. alginolyticus) at high concentrations, with no detection of pathogenic viruses or AHPND. Gram-negative bacteria are abundant in affected tissues. Further research is needed to clarify the etiology and control strategies.
