Cryptocaryon: the other itch

Abstract

This case report describes an outbreak of Cryptocaryon irritans that occurred in a 120 gallon recirculating tropical saltwater mixed-species system. Mortalities were found on morning observation with more occurring slowly throughout the day. A full diagnostic work up was performed on a freshly dead specimen, which included external and internal microscopic examination and bacteriology culture. The external examination included gross observations, skin scrape, fin clip and gill clip. The internal examination included wet mount preparations of the liver, spleen, stomach, intestines, anterior and posterior kidneys. The diagnosis was made on skin scrape by finding the adult feeding stage of Cryptocaryon irritans called the trophont. Upon questioning the owner, it was discovered that one species present in the tank was introduced about 10 to 14 days previously without quarantine. Another issue was that the tank was placed in direct contact with another tank. Therefore, there was a high probability of transmission to the neighboring tank. Live specimens in the neighboring tank were skin scrapped to look for feeding stages of Cryptocaryon and those skin scrapes were negative. Both tanks were treated with Chloroquine at 10 mg/L for three weeks duration. All of the fish in the original tank died by the following day. Fortunately, there were no mortalities in the neighboring tank. This case report demonstrates the importance of quarantine and biosecurity to prevent outbreak of disease. It also demonstrates the feasibility of the private practioners to diagnose fish diseases.