In shrimp, this infection causes a condition known as 'milk' or 'cotton' shrimp.

• A. Leech
• B. Dermocystidium marinum (dermo)
• C. Microsporidia
• D. Microbacteria

Answer: (B)

Recognizing shrimp diseases by appearance is key here. The milky or cottony look seen on shrimp is the hallmark of dermo, caused by the parasite Dermocystidium marinum. This infection produces cottony, milky-white masses in the animal’s tissues, often around the hepatopancreas and surface tissues, giving the shrimp a pale, cotton-like appearance and leading to illness or death in severe cases. The other organisms listed don’t produce this distinctive cottony/milk symptom in shrimp: leeches are external parasites that clamp onto hosts, while microsporidia and microbacteria cause different disease signs and tissue damage patterns that aren’t the classic cottony/milk appearance described here.