SINGAPORE -- Surging coronavirus infections in Singapore's migrant worker communities have underscored the difficulty of stomping out the disease -- and may offer lessons for other countries.

The city-state earned praise for its strong containment measures in the early days of the pandemic. But on Saturday, it recorded 942 new cases, the biggest daily jump so far. Another 596 cases on Sunday brought the total to 6,588, surpassing Indonesia's 6,575 cases and the Philippines' 6,259 despite a population of just 5.7 million.

About 95% of the weekend's cases were foreign workers who live in densely packed dormitories -- typically 10 to a room. The migrants come from lower-income countries like Bangladesh and India to work on the construction sites and shipyards that keep Singapore's wealthy economy going. Some of their work sites, such as local conglomerate Keppel's shipyard, have had virus clusters as well.

The spread of COVID-19 among these workers has exposed the limits of the multifaceted tactics, including contact tracing and social distancing campaigns, that made Singapore something of a model for the world. The new takeaway from the city-state is that this virus, which has already killed 160,000 globally, can prey on the weak links in even a well-organized and disciplined society.

Other countries should learn "that the social environments of different sectors of the economy vary considerably," said Garry Rodan, emeritus professor at Australia's Murdoch University and a long-time Singapore watcher.

Like Singapore, many countries depend heavily on foreign labor. There were some 164 million migrant workers worldwide as of 2017, according to research by the International Labor Organization.

"Countries with high levels of low-cost foreign workers should be very mindful of the facilities and conditions available to these people," Rodan told the Nikkei Asian Review.

Human rights groups have warned wealthy Gulf nations, such as Qatar and the United Arab Emirates, about the risk of coronavirus infections spreading among their large populations of migrant workers from South Asia, Southeast Asia and Africa.

"Low-paid migrant workers remain acutely vulnerable to human rights abuses that increase their risk of infection from COVID-19," rights groups said in a joint letter to the UAE government dated April 10. "These include crowded labor accommodations and inequitable access to medical care and health insurance, and immigration detention centers and prisons that have often been found to hold detainees in cramped, dismal and unhygienic conditions."

Japan, too, has tens of thousands of what it calls "technical intern trainees" -- de facto low-cost labor -- from countries like Vietnam and China. Thailand hosts over 1 million workers from Myanmar, Laos and Cambodia. Though living conditions vary by country, these workers tend to occupy a weak position in society.

Migrant workers are not the only ones at increased risk. In the U.S., research suggests low-income individuals in general are over-represented among COVID-19 cases. A recent Time magazine analysis of New York City found ZIP codes with the bottom 25% of average incomes accounted for 36% of all infections, while the wealthiest 25% made up less than 10%.

Blue-collar jobs are rarely suited to teleworking, exposing employees to a higher risk of infection unless their workplaces shut down. In some cases, workers who fall ill may lack access to health care as well.

Now, Singapore's struggle to stop the dormitory outbreaks is a test for its government and a reminder for others to watch over their most vulnerable residents.

Singaporean government ministers have repeatedly said they feel a "responsibility" to protect the workers. Over the past two weeks, the city-state has locked down several dorms, worked with dorm operators to improve hygiene, and offered income support for the residents.

On Saturday, the Ministry of Manpower issued a stay-home order for all work permit and S Pass visa holders in the construction sector, effective from Monday through May 4. The order obliges employers to monitor the workers' health, ensure they have food and "take care of their well-being."

Opposition politicians, however, say the government was too slow to react. The first migrant worker infection was detected back in February, and a local rights group highlighted the danger in March.

"Warning signs were flashing," said Chee Soon Juan, secretary-general of the opposition Singapore Democratic Party, in a video message posted on the party's Facebook page.

It remains uncertain how the worsening crisis could affect the upcoming general election, which must be called by next April. What is clear is that Singapore still needs migrant workers, and the workers still need jobs in the city-state to send money home.

Murdoch University's Rodan stressed that "regional and international awareness of the conditions under which these workers are housed and other problems they experience will have been raised" by the coronavirus pandemic.

"The Singapore government," he said, "can limit the potential diplomatic and reputational damage depending on how it responds, not just during the crisis but after."