In an embattled enclave in Syria, doctors have seen patients die from what looks like the coronavirus but are unable to treat them because they lack beds, protective gear and medical professionals.

A refugee camp in Bangladesh is so cramped that its population density is nearly four times that of New York City, making social distancing impossible. Clinics in a refugee camp in Kenya struggle in normal times with only eight doctors for nearly 200,000 people.

As wealthy countries like the US and Italy struggle with mass outbreaks of the coronavirus, international health experts and aid workers are increasingly worried that the virus could ravage the world’s most vulnerable people: the tens of millions forced from their homes by violent conflict.

Refugee camps across Africa, West Asia and Asia are packed with traumatised and undernourished people with limited access to health care and basic sanitation, perfect breeding grounds for contagion. Extended families jam into tarpaulin shelters with mud floors. Food, water and soap are often lacking. Illnesses, from hacking coughs to deadly diseases, go untreated, facilitating their spread.

The coronavirus, which has already infected hundreds of thousands of people around the globe, could rip through these camps with devastating speed and mortality.

“If we think this is a big issue in the US and Europe, we haven’t seen anything yet if Covid gets into the refugee population,” said Adam Coutts, a public health researcher at Cambridge University. “People can’t even wash their kids, let alone wash their hands.”

So far, the number of confirmed coronavirus cases among refugees is low, but that may be the result of a lack of testing.

Testing is severely limited, and refugees are rarely a priority.

Doctors treating refugees in Syria and Bangladesh say that in recent weeks they have treated and lost patients with symptoms consistent with the virus.

“To think that it is not in refugee and displaced populations is a bit naïve,” Coutts said.

If the virus is present, the camps are profoundly ill-equipped to handle it. Many camp clinics are already struggling to fight outbreaks like dengue and cholera, leaving them without the resources to treat chronic conditions, such as diabetes or heart disease.

The coronavirus, which has no vaccine or agreed upon treatment regimen for Covid-19, the respiratory disease it causes, could be even more devastating, medical experts warn.

“We are preparing for the worst,” said Avril Benoit, the executive director of Doctors Without Borders in the US, which has deployed teams to work with refugees around the world.

“We know that in the places where we work we are underequipped and understaffed.”

Daily life in a refugee camp is an ideal incubator for infectious disease. Many lack running water and indoor sanitation.

People often stand in line for hours to get water, which is insufficient for frequent showers, much less vigilant hand washing.

“If it came into the camp, it would be a disaster,” said Ahmadu Yusuf, a community leader in the Bakassi camp in northeastern Nigeria, most of whose residents fled Boko Haram, the militant group. “It would be more devastating than the insurgency that brought them here.”