She has donated all manner of biological samples and agreed to keep journals of everything she’s eaten, inhaled or rubbed on her skin. Researchers attended the birth of her second son, Emilio, looking on as she pushed, leaving with Tupperware containers full of tissue samples, the placenta and the baby’s first stool.

Now the family is in yet another study, part of an effort by a network of scientists across North America to look for signs of autism as early as 6 months. (Now, the condition cannot be diagnosed reliably before age 2.) And here at the MIND Institute at the University of California Davis Medical Center, researchers are watching babies like Emilio in a pioneering effort to determine whether they can benefit from specific treatments.

So when Emilio did show signs of autism risk at his 6-month evaluation — not making eye contact, not smiling at people, not babbling, showing unusual interest in objects — his parents eagerly accepted an offer to enroll him in a treatment program called Infant Start.

The treatment is based on a daily therapy, the Early Start Denver Model, that is based on games and pretend play. It has been shown in randomized trials to significantly improve I.Q., language and social skills in toddlers with autism, and researchers say it has even greater potential if it can be started earlier.

“What you ultimately might be doing is preventing a certain proportion of autism from ever emerging,” said David Mandell, the associate director of the Center for Autism Research at the Children’s Hospital of Philadelphia. “I’m not saying you’re curing these kids, but you may be changing their developmental trajectory enough by intervening early enough that they never go on to meet criteria for the disorder. And you can’t do that if you keep waiting for the full disorder to emerge.”

Sally Rogers, a MIND Institute researcher who has been working with the Aguilars, said she faced several challenges in adapting the toddler therapy for infants.

Even normally developing babies cannot speak or gesture, let alone pretend. Instead, Ms. Rogers has parents focus on babbling and simple social interactions that occur in the normal routine of feeding, dressing, bathing and changing the baby.

“Patty-cake and peekaboo or tickle games, those are people games,” she explained to Carmen and Saul Aguilar during their first session with their son Emilio at 7 months old. Ms. Rogers talked about the next 12 weeks and how they would focus on getting Emilio to exchange smiles, to respond to his name, to babble with them, starting with single syllables (“ma”) and moving on to doubles (“gaga”) and more complex combinations (“maga”).

“Most babies come into the world with a built-in magnet for people,” Ms. Rogers said. “One thing we know about autism is that it weakens that magnet. It’s not that they’re not interested, they have a little less draw to people. So how do we increase our magnetic appeal for his attention?”

Lesson 1 was eye contact. Ms. Rogers had the parents take turns playing with Emilio, encouraging them to get face to face with the baby and stay in his line of vision. Mrs. Aguilar leaned down on the blue blanket and rattled a toy. “Emilio? Where’s Emilio?”

On the other side of a two-way mirror, another researcher watched the session and an assistant monitored three video cameras in the room. Sally Ozonoff, a researcher who first identified Emilio as a candidate for the study, stopped by to observe.

“He’s just staring at that object even though her face is three inches away,” she said. “He has that flat, very sober-looking face.”

Mr. Aguilar tried next. He put Emilio in a red beanbag chair and folded the sides together over the baby. “Squish, squish, squish!” he said. No response.

He picked Emilio up over his head and flew him like an airplane. Emilio stared at the ceiling.

Mr. Aguilar put the baby back in the beanbag and picked up a stuffed wolf toy. He put it on his head and let it drop into his hands. “Pschooo! Uh-oh!” Finally, Emilio was watching.

“That was great,” Ms. Rogers told the father. “You put that toy on your head and he was drawn to your face. You were using the toy to enhance the social interaction. When you bring it up to your face, he’s with you.”

While the causes of autism are still a mystery, scientists agree that it has some genetic or biological trigger. Experimental treatments like Infant Start are intended to address the social environment the baby grows up in, and to see whether changes at home might alter the biological development of the condition once triggered.

“Experiences shape babies’ brains in a very physical way,” Ms. Rogers said. “Experience carves synapses; some are built, some are dissolved.”

If a baby starts focusing on objects instead of faces, the theory goes, a “developmental cascade” can begin: brain circuits meant for reading faces are used for something else, like processing light or objects, and babies lose their ability to learn the emotional cues normally taught by watching facial expressions. The longer a baby’s brain runs this developmental course, the harder it becomes to intervene.

But the effort to stop autism in its tracks with earlier interventions presents a scientific problem.

Because there is no formal diagnosis for autism before age 2, it is impossible to distinguish between infants who are helped by the intervention and infants who never would have developed autism in the first place. Researchers must see enough improvement with babies like Emilio before they can do a randomized trial, comparing babies who get the treatment and babies who don’t.

Emilio’s parents are happy to have their son in the first wave of the pilot program. They saw their older son, Diego, make so much progress in behavioral therapy between ages 3 and 5 that they’re very hopeful about what might happen with Emilio.

Mr. Aguilar quit his job at a telecommunications company so he could care for Emilio and work on their objectives all day. Mrs. Aguilar had quit her job in social work when their first son received his diagnosis. But the commitment to the future is much revised since Emilio’s 6-month evaluation.

“I’m the first in my family to go to college, and grad school,” Mrs. Aguilar said. “My thought was, ‘Now I’ve set the bar for my son.’ ”

But after learning that Emilio too may have autism, “you stop looking that far into the future,” she said. “We’re forced to think day by day.”

That is where the anthrax is kept.

Senator Richard G. Lugar, Republican of Indiana, and a delegation of Pentagon officials visited the laboratories on Wednesday for the first stop on a three-country tour of East Africa to assess the next generation of American security concerns.

The team also visited the Uganda Virus Research Institute, where the Ebola and Marburg viruses are taken to study and kept in a spare room in a regular refrigerator near the bottom of the compound. Warning signs say “restricted access,” but the doctors there say that hardly means the area is secure.

The laboratories here in Entebbe, a warm and sleepy city on the shores of Lake Victoria, are part of what the delegation called the front lines of the struggle to counter terrorist threats around the world.

“We need to tighten the security of vulnerable public health laboratories in East Africa,” said Andrew C. Weber, assistant to the secretary of defense for nuclear and chemical and biological defense programs. “Preventing terrorist acquisition of dangerous pathogens, the seed material for biological weapons, is a security imperative.”

The rise of the Shabab, the powerful Islamist insurgent group that claimed responsibility for deadly suicide bombings in Uganda as crowds gathered to watch the final match of the World Cup, has refocused attention on East Africa as a frontier in American security interests.

In 2004, Congress expanded the mandate of the Nunn-Lugar program, which originally focused on dismantling warheads in former Soviet states, to include geographic regions like this one. Now, Mr. Lugar’s trip will take the delegation to Uganda, Burundi and then Kenya.

Uganda, a longtime military ally of the United States, may be the most vivid illustration of the concerns. Warm, wet and on the equator, Uganda is a biological petri dish. Anthrax has killed hundreds of hippopotamuses in recent years. In 2008, a Dutch tourist died from Marburg disease after visiting a cave in a national park. In 2007, an Ebola outbreak killed more than 20 people.

This is the stuff of “The Hot Zone” and “Outbreak” books that have dramatized the dangers of viral outbreaks. But the underlying threat, American officials contend, is that lax security at the poorly financed labs that collect and study these diseases pose a bioterrorism risk.

Ugandan officials also say the country’s push to create new federal districts, part of what the government calls an effort to decentralize the country, has spread the bureaucracy so thin that disease samples can take weeks to make it to a laboratory, or never arrive at all.

“It makes it difficult to report new cases,” said Dr. Nicholas Kauta, a commissioner at the Ministry of Agriculture. “We don’t know what is around us.”

The laboratories at the Ministry of Agriculture, built in the 1920s, have broken windows, and a chain-link fence surrounding the compound is ripped. According to the commissioner, there used to be over 200 technical staff members, but now there are only six. In the anthrax laboratory, one doctor showed how to use a cellphone camera placed on top of a microscope to study the bacteria, a demonstration of the lack of proper equipment.

“These are cries for assistance that the U. S. is eager to provide,” Mr. Lugar said.

At the Uganda Virus Research Institute, there are state-of-the-art facilities run by the Centers for Disease Control and Prevention, an American agency, but not at all of it. The deadliest agents, including Ebola, are still kept downstairs in a room intended to handle lesser infectious diseases like influenza.

“This is the end-state,” said Lt. Col. Jay Hall, from the Defense Threat Reduction Agency, pointing out the disease control agency laboratories upstairs. “This is where we want to get all other labs.”