Davis, Calif. ? When a monkey slipped from its cage at a University of California medical research lab, handlers peered into sewers, poked behind cages and baited traps to try to catch it.

A week and a half later, though, all they’ve found in their search is an angry town armed with new ammunition against a proposed biodefense research center that the university says would study the world’s deadliest diseases for the effort to protect the country from bioterrorism.

The monkey, a rhesus macaque, disappeared from the California National Primate Research Center, which would supply animals to the proposed Biosafety Level 4 lab to study diseases with no known cure, such as the Ebola and West Nile viruses.

School officials promised that the runaway was disease-free — the center currently raises animals for research on Level 2 and 3 diseases, which have vaccines or treatments — and would never have escaped from the proposed biodefense lab, which would have armed guards.

But that was little comfort to residents working to prevent the biodefense lab from being built. They learned about the disappearance Thursday, a week after the monkey got away.

“If they can’t manage these monkeys when they’ve got Level 2 and 3 diseases, how will they manage monkeys with Level 4 diseases?” asked Joshua English.

The University of California, Davis, is one of about a half-dozen institutions across the country that applied this month to the National Institutes of Health for a grant to build the $200 million disease research lab.

The United States already has five high-containment disease laboratories and two others are being built or designed. UC Davis is competing against institutions in Texas, Maryland, Illinois, Massachusetts and New York to build another.

The proposed facility would have strict security. Still, opponents fear a lab just 65 miles northeast of San Francisco could be a terrorism target or a rogue scientist could smuggle out a deadly pathogen.

Dr. Dallas Hyde, director of the primate center, said he can understand why the incident has fed fears, but he said the security level of the primate center and the lab would be quite different.

“Animals that go in there don’t come out alive,” he said.