Halden frowned. They were proving themselves less and less expert biologists. And this plague—there had to be a reason to leave, and sickness was as good as any—but unless he was mistaken, plague wasn't used in the strict semantic sense. It might be the fault of the translation.
"The colonists refused to settle; they came back at once and reported. We sent out our fastest ships, heavily armed. We didn't have the time to retrace our path completely, for we'd stopped at innumerable places. What we did was to check a few planets, the outward and return parts of all four voyages. In every place, the plague was there, too, and we knew that we were responsible.
"We did what we could. Exhausting our nuclear armament, we obliterated the nearest planets on each of the four spans of our journeys."
"I wondered why the route came to an end," crinkled Taphetta, but there was no comment, no answer.
"We reconstructed what had happened. For a long time, the plague had lived in our sewers, subsisting on wastes. At night, because they are tiny and move exceedingly fast, they were able to make their way into our ships and were aboard on every journey. We knew they were there, but because they were so small, it was difficult to dislodge them from their nesting places. And so we tolerated their existence."
"They weren't so smart," said Taphetta. "We figured out that angle long ago. True, our ship is an exception, but we haven't landed anywhere, and won't until we deverminize it."
"We didn't guess that next to the hull in outer space and consequently exposed to hard radiation," the message went on, "those tiny creatures would mutate dangerously and escape to populate the planets we landed on. They had always been loathsome little beasts that walked instead of rolling or creeping, but now they became even more vicious, spawning explosively and fighting with the same incessant violence. They had always harbored diseases which spread to us, but now they've become hot-houses for still smaller parasites that also are able to infect us. Finally, we are now allergic to them, and when they are within miles of us, it is agony to roll or creep."
Taphetta looked around. "Who would have thought it? You were completely mistaken as to your origin." Kelburn was staring vacantly ahead, but didn't see a thing. Meredith was leaning against Halden; her eyes were closed. "The woman has finally chosen, now that she knows she was once vermin," clicked the Ribboneer. "But there are tears in her eyes."
"The intelligence of the beast has advanced slightly, though there isn't much difference between the highest and the lowest—and we've checked both ends of all four journeys. But before, it was relatively calm and orderly. Now it is malignantly insane."