Migrants stand outside container houses in Moria refugee camp on the northeastern Aegean island of Lesbos, Greece, Monday,…
FILE - Migrants stand outside container houses in Moria refugee camp on the northeastern Aegean island of Lesbos, Greece, March 16, 2020.

ATHENS  -  Like the rest of Europe, Greece has ramped up measures to contain the spread of COVID-19, halting all commercial activity to keep Greeks at home. But Greek authorities are dealing with a more complex problem:  controlling the spread among tens of thousands of refugees that Greece is housing in camps across the country.  Greek officials say enforcing measures to keep refugees healthy is a huge challenge.   

Greek Prime Minister Kyriakos Mistotakis warns the country is gearing up for a major fight.

 "We are at war with an enemy who is not visible," he told Greeks in a nationally televised address.  

FILE - Greece's Prime Minister Kyriakos Mitsotakis waits for a meeting with Klaus Regling, Managing Director of EMS (European Stability Mechanism), in his office, in Athens, March 7, 2020.

He promised a stimulus package of nearly $2.2 billion to support struggling enterprises. At the same time, he ordered a complete shutdown of retail businesses with the exception of pharmacies, supermarkets and gas stations beginning Wednesday.   

"This new enemy is not invincible," Mitsotakis said.   

But human rights organizations and aid groups disagree.    

With Greece hosting more than 40,000 asylum seekers on five Aegean islands alone, aid groups like the Norwegian Refugee Council warn that the coronavirus may decimate refugee communities if they are left neglected. 

Other groups, including Doctors of the World, say that neglect is already showing in Greece.   

They are urging authorities to make sure refugees have access to soap and hot water to try to stop the spread of COVID-19 among migrants.   

They want prevention measures to be enforced fast.  Charities across Greece and throughout Europe are losing desperately needed volunteers as the coronavirus epidemic takes hold.   

Greece’s Migration Ministry has responded, announcing a list of measures to contain the contamination of refugee camps — mainly those of five Aegean islands on the forefront of Europe’s migration crisis.   

Medical personnel are now increasing screenings among new migrant arrivals and special isolation units have been set up within the camps to quarantine potential cases.   

No migrant had tested positive as of early Wednesday.   

FILE - Police block a road as migrants look on during clashes outside the Moria refugee camp on the northeastern Aegean island of Lesbos, Greece, March 2, 2020.

But on the island of Lesbos, many remain in isolation inside Moria camp after one of its residents, a Sudanese man, showed flu-like symptoms.  

Since the summer, Greece has seen migrant arrivals increase by as much as 300 percent.   

That means camps like Moria that were built to accommodate just over 2,000 people are now housing more than 20,000, leaving residents to eke out shelter and an existence in a surreal and overcrowded shanty town of tents.   

Add to that the four other Aegean islands, where more than 40,000 refugees remain squeezed into camps built to house 5,000. 

With most migrants housed in tiny tents, Greek migration officials say their greatest challenge is enforcing the most important measure to contain the coronavirus: social distancing.   

To limit the chances of an outbreak, officials say they will be transferring a batch of some 500 migrants to the country’s mainland in the coming week. 

Aid agencies fear that could be too little, too late.