By the time you read this, all those who arrive in Bangkok with a Kinshasa or Entebbe stamp in their passports are on a bus going to a hospital ward in Nonthaburi and on the way there for 21 days.

Thailand has led the way. As of 6 PM May 27, the kingdom was the first in the world to physically arrest all travellers from the Democratic Republic of the Congo and Uganda, regardless whether they were coughing, feverish or perfectly healthy, for the entire length of the incubation period of the Bundibugyo strain of Ebola. The job has been given to the Bamrasnaradura Infectious Diseases Institute, the red-roofed campus on the outskirts of the capital that held SARS suspects in 2003 and the first MERS patient in the Kingdom in 2015. Symptomatic persons who are arriving are taken to isolation wards. Asymptomatic ones are provided with a clean room, three meals, a thermometer and the best part of a month all to themselves.

The scaffolding is the legal framework that is the 2015 Communicable Diseases Act, and the fines are no picnic. If you slip out of the facility, you're facing a year in a Thai prison, 100,000 baht in fine, or both. If you refuse to enter the first time, the fine is 20,000 baht, about $600. The move by authorities comes as hotels in Bangkok already had stealthily declined to book rooms for African passport holders for the last fortnight. The old "report yourself and monitor" system – which was something akin to the honour system was coming undone on its own. To avoid the check in each day, people were jumping from one guest house to another. On connecting flights, between five and seven Congolese/Ugandan nationals were arriving daily. One day recently it was raised to nineteen. Approximately one hundred have passed through since the outbreak was declared and 10 asymptomatic arrivals were already in quarantine prior to the order coming into effect on Wednesday.

It is what is happening four thousand miles to the west that is the trigger. On 17 May, the World Health Organization (WHO) declared a Public Health Emergency of International Concern (PHEIC), which is the eighth time such a designation has been used since the framework was established. The numbers behind it are inescapable. On the 25th, the Congolese health ministry reported 105 laboratory confirmed and 906 suspected cases of Bundibugyo virus disease in Ituri, North Kivu and South Kivu provinces. Ten confirmed deaths. Another 223 suspected. The Wikipedia merge, which was updated within the past day, has 1,018 suspected and confirmed cases and at least 234 fatalities. Seven cases and one death have been reported in Uganda, mostly linked to travellers from the other side of the border. On the 25th, 2 travellers from Uganda were admitted to hospital in Milan with viral haemorrhagic fever symptoms. Testing of samples continues. Italy is holding its breath.

The strain itself is what makes this outbreak particularly nasty. Bundibugyo is not the Zaire strain of Ebola that the world now has a Merck vaccine for, Ervebo. No approved drug and no approved jab for Bundibugyo. The previous two outbreaks of this species, in the Ugandan district that lends its name to the virus, in 2007 and Isiro in northern Congo, in 2012, claimed between a quarter and half of those who it infected. There are some animal data indicating Ervebo might provide some cross-protection, but no public health authority is willing to bet on a maybe as it comes to responding to an outbreak. One reason that caused the WHO's director-general Tedros Adhanom Ghebreyesus to declare the emergency, even before convening the formal committee, is the lack of medical countermeasures. He expressed gratitude to Uganda's president Yoweri Museveni for calling off the annual pilgrimage for martyrs' Day at Namugongo, which attracts two million people from eastern Africa. After convening the committee, it approved him. The risk level was considered to be low in global scale. The risk was high in the region.

For Thailand, the calculation is not really about the numbers and it is almost entirely about the value of tourism to the Thai exchequer. The sector has an indirect and direct contribution to GDP of approximately twelve per cent, employs 4.19 million and is responsible for generating approximately forty-five billion dollars in 2025. The Tourism Authority of Thailand has projected that it will earn 95.35 billion dollars in tourist revenue in 2026, when 36.7 million tourists from around the globe are expected, marking an increase of 35.3 per cent from last year. That was already a target that was in danger prior to this outbreak. The drop in arrivals between 1 January and 15 February was already 7.59 per cent year-on-year. Foreign tourists numbers dropped 2.43 per cent in the first quarter, to 9.31 million. The Bank of Thailand and the National Economic and Social Development Council have cautioned that the GDP growth rate in 2026 could range from 0.8 to 1.4 per cent based on the Middle East conflict's resolution. The government has approved a $12.2 billion economic bailout package. The Chinese market's collapse in 2025, thirty-four per cent, is bad enough, and Bangkok can't risk a whiff of Ebola.

Memory matters here. What happened in 2014 was seen by Thailand's south-east Asian neighbours. According to the World Travel and Tourism Council, the West African outbreak, which was also a single-strain Ebola event, resulted in a reduction of Africa-wide tourism arrivals by approximately 50 percent in the period 2013-2014. Kenyan safari operators, thousands of miles away in Kenya, saw their bookings being cancelled. One Thai insurance firm alone canceled a trip to Cape Town for 1,500 people as an incentive. Ebola's economic impact is not confined to geography, and that was a costly lesson learned by Asian capitals.

Hence a senior strand of regional thinking on this, heard all over Asian public-health circles in the last fortnight, views Bangkok's action, not so much as epidemiology but as market signalling. It is exactly what Hong Kong and Singapore did in the time of SARS, and again in 2014; they went overboard with the visible measures to preserve the rest of their inbound traffic. None of the countries have been as tough as Thailand, although Indonesia, Singapore, Malaysia and Vietnam have all stepped up their surveillance in the last week, with Vietnam requiring the returnees from the affected areas to self-monitor for the entire 21 days. It's the gamble from this side of the Bay of Bengal that the kingdom is buying insurance, and the price, a few dozen detained travellers, some diplomatic mumbling, a manageable bill for the Bamrasnaradura facility, is cheap relative to what the alternative would be, a wholesale collapse in Chinese, Indian and European bookings for the high season, which starts in November.

There is another argument, less noisy, which is the one the Africans need to be afraid of. It is more deadly to kill by stigma than by virus. The West African experience resulted in Liberia, Sierra Leone and Guinea being cut off commercially long after the last patient was discharged, and airlines would not accept even relief supplies for the countries. Aid workers were not kept out, Ebola was, by the border closures. Then regional director of the WHO for Africa called it out at the time. The lesson then was that it is not possible to quarantine an entire continent and slow a pathogen only bankrupt those who are trying to. Thailand has wisely avoided the "Africa" response that it gave in 2014, but the optics in Kinshasa and Kampala will be poor and the diplomatic cost will be borne in the coming months.

Now it's a matter of what Italy does. The outbreak will become a crisis for everyone with an East African travel corridor if the two possible cases in Milan are confirmed as positive. If they come back with negative results, the WHO will maintain a low risk for the rest of the world, and the Bamrasnaradura's wards will slowly be emptied as the outbreak runs its course in the Congolese forest. In any case, there is now a precedent. The first country to lock down for a 100 case confirmed outbreak halfway the globe, is also the country whose economy is most vulnerable to any contagion fear. That's not just a coincidence. It's the new math of tourism in the pandemic era, and Bangkok has made the calculations.