“He’s the boss,” Blalok said. “Do as you’re told. This is his problem.” “Why the quarantine?” Jordan asked. “I want to get any carriers. We can check them with antigen, and then give Trematox.” “All that concentration in Bay Ten,” Jordan said. “Does it mean something?” “Blalok said that there was a Santosian in your division.” “Yeah--Joe Kryla--and come to think of it, he ran Bay Ten!” “That’s a help--now let’s see what makes that bay different from the others.” “Why?” “I’ll tell you--but you may not understand,” Kennon said. “I’ll take a chance.” Kennon grinned. “All right, you asked for it. The parasite that’s doing the damage is a flatworm, a trematode called Hepatodirus hominis. As I’ve told Blalok, it’s a tricky thing. Like all trematodes it has a three-stage life cycle, but unlike every other fluke, its life cycle is not fixed to definite intermediate hosts. Depending upon where it is, the fluke adapts. It still must pass through its life cycle, but its intermediate host need not be one species of snail, fish, or copepod. Any cold-blooded host will do. What you have here is a Kardonian variant which has adapted to some particular intermediate host on this world. Until now, its final host was either man or Varl. Now we have a third, the Lani. And apparently they are the most susceptible of the three. It never kills Varl. And humans, while they’re more susceptible, only occasionally succumb, but the Lani appear to be the most susceptible of all. I’ve never seen an infestation like those Lani had. Their livers were literally crawling with flukes.” Kennon paused and looked at Jordan. “You following me?” he asked. “Slowly and poorly,” Jordan said. “You’re assuming too much knowledge on my part.” Kennon chuckled. “You can’t say I didn’t warn you.” “Well--I’m really interested in only one thing--how do you break the parasite up in business?” “There’s only one sure way--and that’s to break the life cycle. The technique is thousands of years old, but it’s just as good today as it was then.” “Good--then let’s do it.” “To make a varrit stew,” Kennon said, “one must first catch the varrit.” “Huh?” “We have to learn the beastie’s life cycle before we can break it, and like I said, it adapts. Its intermediate host can be any one of a hundred cold-blooded animals.” “Is there no place else where it can be attacked?” “Sure, in the body of the final host, or on its final encysting place. But that won’t eliminate the bug.” “Why not?” “It’ll still survive in its infective form and enough Lani will get subacute dosage to propagate it until the time is right for another epizootic. We have to kill its intermediate host--or hosts if it has more than one. That will keep it from growing and will ultimately eradicate it.” Judson scratched his head. “It sounds complicated.” “It is. It’s so complicated that once the fluke becomes well established it’s virtually impossible to eradicate.” “And you think it can be done here?”