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Questionnaires and fever scanners

An epidemiologist from the Robert Koch Institute examines the exit screenings at the international airport in Sierra Leone

Passengers during a health check at the Lungi International Airport in Freetown, Sierra Leone. Source: Andreas Gilsdorf/RKI

The passenger is sick. He is already lying on the floor in the check-in area of the terminal at the airport in Monrovia. He vomits on the flight to Lagos, Nigeria. Shortly after his arrival, he vomits again, and once again in the car that is sup­posed to take him to a private clinic. He tells the hospital staff that he suffers from malaria. It is July 20, 2014. Five days later, he is dead.

On behalf of the European Commission, the epidemiologist, Andreas Gilsdorf (right), and two colleagues watch the exit screening at the airport. Source: Andreas Gilsdorf/RKI On behalf of the European Commission, the epidemiologist, Andreas Gilsdorf (right), and two colleagues watch the exit screening at the airport.

The man had been infected with Ebola in Liberia. His sister had died of the di­se­ase. He had visited her in the hospital and went to her burial. The au­tho­ri­ties in Nigeria learned all this much too late. Before he died, the passenger infected nine doctors and nurses who came in contact with hun­dreds of people. Lagos is a metropolis with more than 20 million inhabitants. It could have been the beginning of a disaster. The fact that the outbreak was comparatively small − in Nigeria, there were a total of 20 cases, including eight deaths − can only be attributed to the quick reaction of the local health authorities.

Since spring 2014, Ebola virus di­se­ase (EVD) has been raging in West Africa. In Guinea, Sierra Leone and Liberia, more than 27,000 people have been infected. Today, there is a tight ship at the inter­na­tio­nal airports: anyone who is sick is not even allowed on the premises. And anyone who boards a plane has had their temperature taken at least three times. “Nobody presenting symptoms gets on board,” says Andreas Gilsdorf. The epi­de­mio­lo­gist from the Robert Koch Institute (RKI) investigates how infectious diseases spread through inter­na­tio­nal air traffic. On behalf of the European Commission, he helped examine the exit screenings at the inter­na­tional airports in West Africa.

In July 2014, the Ebola case in Nigeria was a wake-up call for the World Health Organization (WHO). It was the first time that EVD in West Africa was spread to another country by air and triggered an outbreak. On August 8 2014, the WHO declared the Ebola virus epidemic in West Africa a public health emergency of international concern (PHEIC). To keep the virus from spreading, the WHO recommended exit controls in the affected countries. At international airports, seaports and major border crossings, travelers are screened for symptoms of EVD and, in case of doubt, they are prevented from journeying on. In November 2014, the EU Com­mis­sion wanted to ensure that the recommended standards are still being maintained on-site. The Com­mis­sion sent three expert teams to the inter­na­tio­nal airports in the out­break area: to Monrovia in Liberia, to Conakry in Guinea. Andreas Gilsdorf visited the Lungi International Airport in Freetown, Sierra Leone, with a colleague from the United Kingdom and a representative of the European Centre for Disease Prevention and Control (ECDC).

A concern of many

Sierra Leone is a relatively small country of six million people on the West African coast. Its capital Freetown lies in the far West, surrounded by a state forest re­serve. “The country is beautiful,” the epidemiologist says. However, it is among the most impoverished in the world. The public health system in Sierra Leone was wretched even before the EVD outbreak. There are just two hundred doctors for the whole country. Maternal mortality is one of the highest in the world. The life expectancy is only 45 years.

Since spring 2014, EVD has claimed around 4000 lives in Sierra Leone. On the streets of Free­town, he says, peop­le are made a­ware of the di­se­ase. There are warning signs, tem­pe­ra­ture checks and canisters of chlorine bleach for wa­shing hands eve­ry­where. But the virus doesn’t dictate everyday life. The markets are open. “The beach is full of people playing sports in the morning.” In Sierra Leone, Ebola is only a concern of many.

The Lungi In­ter­na­tio­nal Airport is located at the coast north of Freetown, on the other side of the Sierra Leone River. It takes half an hour to get there by boat. In November 2014, Andreas and his colleagues spent five days here. They looked at the handling of three international flights: one to Brussels, one to Casa­blanca in Morocco and one to Abidjan in Ivory Coast. More flights no longer existed at that time, most foreign airlines had dropped the route for fear of Ebola, Andreas says.

With a body temperature of 37.5° C, the journey is over

A thermal scanner in the terminal. The health check is carried out by trained medical personnel. Source: Andreas Gilsdorf/RKI A thermal scanner in the terminal. The health check is carried out by trained medical personnel.

The health checks at the Lungi In­ter­na­tio­nal Airport are tight. The au­tho­ri­ties follow the re­com­men­da­tions of the U.S. Centers for Di­se­ase Control and Pre­ven­tion (CDC). At the wrought-iron gates to the airport, workers are already waiting with fever scanners − these are in­fra-red ther­mo­me­ters which are held at a safe distance from the forehead of the traveler. Passengers must indicate on a questionnaire whether they have vo­mi­ted in the last two days, experienced pain in their limbs or bleeding, whether they have had contact with Ebola patients in the last three weeks, or perhaps even helped care for an Ebola patient or came into contact with a corpse.

Before check-in, passengers pass through the actual health check. Nurses, doc­tors and medical students scan the questionnaires and take their tem­pe­ra­tu­res again. “It is important that the personnel here are medically-trained,” says Andreas Gilsdorf. Only they are able to recognize if the passenger appears ill.

If everything is fine, the questionnaire is stapled to the boarding pass with stamp and signature. At Lungi International Airport, about four hours elapse from the time of entering the airport premises to departure. “In this period, every pas­sen­ger has had their temperature taken four times. The last time is just before departure,” says Andreas.

For passengers whose body temperature is more than 37.5°C at one of the checks, the journey is over. The same applies to passengers who report to have had direct contact with Ebola patients or their body fluids. They are questioned further in a separate room, examined, and if necessary, moved to an EVD treatment centre.

The measures are the same at all three inter­na­tio­nal airports in the West African outbreak area: in Freetown in Sierra Leone, in Conakry in Guinea and in Monrovia in Liberia. At all three airports, they work well. “The probability that a feverish passenger will board a plane is prac­ti­cal­ly nil,” the team concludes in their report to the European Commission. The experts, however, have found a few vul­ne­ra­bi­li­ties. It still re­mains to be ensured that passengers suspected of having Ebola virus di­se­ase are transported quickly to a treatment center for further exa­mi­na­tion. In ad­di­tion, re­sour­ces must be secured so that the departure con­trols can still be car­ried out long-term.

Andreas Gilsdorf says: The exit scree­ning has its limits. You can only filter out those passengers who are obviously ill. People who are indeed infected with the virus but not yet exhibiting symptoms slip through. The incubation period of EVD can take up to three weeks. In case of doubt, a questionnaire doesn’t help. “Anyone who absolutely wants to leave the country won’t answer the questionnaire honestly,” he says. “But that's not a prob­lem with Sierra Leone or the other countries. That’s rather an inherent problem of the screening methods.” Additional entry controls, as performed in the United States or the United Kingdom, don’t alter the fact. There will never be absolute certainty.

So far, it happened four times that an infected person departed from the affected countries during the incubation period. Three of them were foreign aid workers, a physician from the United States, a nurse from the United Kingdom and a nurse from Italy. They treated EVD patients in the outbreak, always wearing personal protective equipment. It is still not clear how they became infected.

When Andreas Gilsdorf examined the departure controls at the Lungi International Airport in Freetown in the five days in November 2014, not a single passenger was pulled out. “In the past few months, there has only been a handful in Sierra Leone,” he says. Each of them was tested. None had EVD.

Probably, the exit screenings discourage sick people from coming to the airport. However, it is more likely that those who are most at risk of EVD never even enter the airport. Ebola is a disease of the poor. They will never afford a flight abroad.

Date: 13.08.2015