THE USE OF THE MOSQUITO BIOASSAY FOR DETERMINING THE TOXICITY TO MAN OF CIGUATERIC FISH

Moderately well-correlatedwith the mouse bioassay, requiringa much smaller amount of raw fish flesh, and employing a fasterchemical extraction procedure,the mosquito bioassay represents significant progress in detecting ciguatoxin in fish mus cle. We use the mosquito bioassayto evaluate the approximateamount of ciguatoxin present in the remains of 25 fish of 17 different species involved in 99 documented cases ofciguatera poisoning. From the data provided by mosquito bioassay and hu man symptomatology, we determine a dose-effect relationshipfor ciguatoxin (CTX) to man. Three average pathogenic doses (PD) are established. The minimum PD is estimated to be 0.6 ng CTX/kg, the PD5O to be 2 ng CTX/kg, and the PD 100 to be 8 ng CTX/kg. These data suggest a MLD (minimal lethal dose) value of 20 ng CTX/kg.