The alarming report of new Covid-19 variants found in a construction worker camp in Bangkok and in the deep South again shed light on the problem of illegal migration.
Migrants crossing Thailand's borders illegally is a chronic problem that puts the country at risk of endless Covid-19 outbreaks unless the government takes decisive action.
On Friday, at least 36 cases of a new variant first found in India were confirmed testing at a workers' camp in Laksi district.
Comprising 21 Thais, 10 Myanmar nationals and five Cambodians, they are among dozens of workers at the site who contracted the coronavirus, though mostly the ordinary strain.
Then, on Saturday, Covid variant B.1.351, first found in South Africa, was detected in samples collected from a cluster of undocumented migrants in Tak Bai district of Narathiwat province.
This is the first time the South African strain has been found outside quarantine centres in Thailand. The two variants may have carried into the country by illegal migrants.
Although Prime Minister Prayut Chan-o-cha has instructed authorities to ramp up border surveillance to prevent the entry of illegal migrants, the problem of migrants being smuggled across border remains.
New cases are found almost every day. Between Jan 1-May 20, a total of 13,956 foreign migrants were arrested for illegal entry.
Among them, 7,365 were from Myanmar, 5,464 were Cambodian, 1,089 were Lao nationals, and 33 were Malaysians.
Unfortunately, those illegal migrants may be just the tip of the iceberg. Many more are thoght to have made it across the border successfully.
Samut Sakhon governor Verasak Vichitsangsri, a recuperated Covid-19 patient, recently expressed concern that the trafficking of migrant workers would hamper disease control efforts in the province. The prime destination for migrants smuggled into Thailand are Bangkok and Samut Sakhon, he said.
"One thing that makes me feel uncomfortable is that some Thais even 'open the door' for illegal smuggling in exchange for cash without being aware that it will result in big trouble of the country," the governor said.
Of course, with a 5,526 km borderline, it is not easy to prevent migrant smuggling. Yet it is impossible that these migrants can just slip onto Thai soil and travel to workplaces as far away as Bangkok without help.
It is not preposterous to think that traffickers are able to operate, despite the strict Covid checkpoints, because they get help from unscrupulous officials.
In a recent operation that netted 77 illegal Myanmar migrants in Kanchanaburi, the migrants told police they had come from Dawei in Myanmar and walked for four days in forests, waiting for their trafficker to take them to their promised employers in Samut Prakan, about 200km away. They said they had each paid the trafficker 13,000-20,000 baht.
Many illegal migrants were arrested. Again, officials nabbed just the underlings, not the people behind these lucrative trafficking networks.
After the May 2014 coup, several laws have been issued to deal with migrant trafficking but the outcome is disappointing.
This is a challenging time for the government as contagious variants of Covid-19 continue to spread.
If it is to win the war against Covid-19, the government must first win the battle against illegal entry and trafficking.