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Crossing While Contagious

The 1,200-mile border it shares with Mexico makes Texas one the most vulnerable states when it comes to imported infectious diseases. In a majority of cases, Customs and Border Protection officers are unable to detect these public health threats at ports of entry, according to a new Centers for Disease Control study.

Scene from the Laredo port of entry

Illicit drugs, human trafficking, illegal immigration, terrorism and, yes, strep throat and H1N1: At Texas' ports of entry, U.S. Customs and Border Protection officers are on the lookout for far more than criminals and contraband. They're responsible for stopping infectious disease at the border.

The task is enormous, if not impossible. CBP agents are supposed to report any incoming traveler exhibiting symptoms of a communicable disease to Centers for Disease Control quarantine stations. But with more than 1 million travelers to screen and process every day, identifying those who might be ill is incredibly difficult.

A CDC study released in June shed light on the problem. Researchers reviewed emergency medical services logs at the four ports of entry in El Paso, which receive nearly 100,000 travelers a day, or 10 percent of all incoming travelers to the United States every year. They found that of the 898 trips El Paso emergency medical services made to ports of entry in 2009 for potentially ill travelers, infectious diseases were identified in just nine people.

Unless "the illness is plainly visible and unambiguous, or travelers indicate that they are ill, in most cases CBP cannot detect illnesses of public health significance at the border,” the study notes.  

With 14 international airports and a 1,200-mile border with Mexico, Texas is among the most vulnerable states when it comes to imported infectious diseases. The state was on the frontline of the H1N1 scare last year: After the outbreak in Mexico, the disease quickly spread into Texas, claiming the first casualty in the United States, a toddler from Mexico visiting relatives in Brownsville. Texas reported more than 6,000 cases of H1N1, with 231 resulting in death — the second-highest number in the nation.

Although CBP works closely with the CDC to prevent contagious travelers from entering the United States, its broad mandate to anticipate and confront every threat imaginable hinders its ability to effectively screen for communicable diseases. When CBP officers suspect a traveler is ill, they notify CDC quarantine stations managed by the organization’s Division of Global Migration and Quarantine. In 2005, Congress approved the funding for the creation of 17 additional quarantine stations at ports of entry across the country, tripling the total number of stations.

Despite the name, the quarantine stations are not physical "stations." Instead, they consist of a small staff — often fewer than a half dozen officers — who inspect people, animals and cargo suspected of carrying communicable diseases. Under federal law, the quarantine stations may detain and isolate any incoming traveler suspected to be ill. Beyond performing routine inspections, quarantine stations are expected to identify any large-scale threat of public health significance.

Between the CBP’s broad mandate and the CDC quarantine stations’ limited resources and personnel, that’s a lofty goal. To complicate the Division for Global Migration and Quarantine’s objective, most communicable diseases go through an incubation phase that can last days — or even weeks — when an individual may not exhibit visible symptoms but is still highly contagious.

CBP officers only have limited public health training, but they like to be “better safe than sorry” when reporting travelers they believe have infectious diseases, says Roger Maier, spokesman for CBP. “We receive training in illness recognition,” he says. “But we’re not expected to diagnose illness in arriving travelers.”

The H1N1 scare last year demonstrated the need for effective public health surveillance at ports of entry — but it also highlighted the limitations within the current system. On a normal day, says Dr. Miguel Escobedo, chief medical officer of the CDC quarantine station in El Paso, he and his team of three other officers receive a handful of calls from CBP to inspect travelers or cargo suspected of carrying a communicable disease. During the H1N1 scare, his office was overwhelmed. “The biggest challenge was the sheer volume,” he says. “We were getting 30 or 40 calls a day.”

When Escobedo isn’t inspecting suspected contagious travelers, he and his staff have their hands full reviewing immigrant medical records, working with other public health agencies and conducting training exercises for CBP. While they're eager to implement new measures to enhance detection at border crossings, Escobedo says they're limited by the reality of the problem: the number of travelers entering every day and the small window of time to inspect each one.

“One of the things we try and do is make sure whatever new measure we implement works efficiently and works in such a manner that it does not interfere with other port of entry operations,” he says. “We wouldn’t want to implement a measure that would disrupt the flow of traffic.”

The CDC has seen some success in detecting potential outbreaks by monitoring EMS logs — its study claims that doing so more than doubled reports of probable infectious disease. But EMS does not routinely measure body temperatures when transporting ill travelers to hospitals, a key step in early outbreak detection, as fever is associated with most communicable diseases. Since CBP cannot prevent every infected traveler from entering the U.S., the CDC has to rely on whatever data it receives from CBP and local hospitals to predict and detect surges in disease activity.

In 2005, the Institute of Medicine published a report detailing the shortcomings of the current quarantine system. To illustrate the potential danger of a foreign-born outbreak, the study pointed to the case of a man exhibiting early symptoms of Lassa fever, a deadly virus that claims 5,000 lives every year, who flew from Sierra Leone to Newark in 2004. A week after his arrival, he was dead — and he had exposed 188 people to the disease. Although a simple, noninvasive screening of the visibly sick man could have prevented his death and the exposure of the virus to others, he was still one out of the hundreds of thousands of travelers who enter the country every day, managing to slip through the gaping cracks in a struggling system.

“The traditional, primary activity of the CDC quarantine stations no longer protect the U.S. sufficiently against microbial threats of public health significance that originate abroad,” that report concluded.

The problem, according to the report, is a lack of central leadership in the quarantine system. Overwhelmed by millions of incoming travelers every year and the need to work closely with a vast bureaucratic network spanning dozens of international, federal, state and local agencies and organizations, the Division of Global Migration and Quarantine also lacks any central authority to manage the quarantine system. The Institute of Medicine report recommended that CDC quarantine stations shift from the “legacy activity of inspection” to a leadership role of managing a nationwide public health policy to prevent the spread of communicable diseases. Despite the recommendations laid out by the Institute of Medicine more than five years ago, little has changed.

Despite the problems and limitations with the current system, CBP insists this is a matter it can handle. “We enforce hundreds of laws for dozens of agencies,” Maier says. “This is a duty we are capable of performing.”

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