Peru tried to do everything right. Officials declared an early national lockdown — and backed it up with 16,000 arrests. Yet confirmed cases of the novel coronavirus are surging, up nearly 60 percent since last weekend.

In Egypt, observers say a repressive government is vastly undercounting the infected. In Brazil, where the president has dubbed Latin America’s largest outbreak a “fantasy,” numbers are skyrocketing.

New York hospitals and Italian villages are the current front lines of the global pandemic. But ­epidemiologists and other public health experts say the coronavirus is poised to spread dangerously south, engulfing developing nations already plagued by fraying health-care systems, fragile governments, and impoverished populations in which social distancing can be practically impossible.

They warned of an amplified global crisis in the coming weeks, one striking nations that can least handle it at a time when wealthy countries are likely to be too preoccupied with outbreaks of their own to offer the kind of assistance they’ve extended during episodes of disease that were confined to the developing world. Add the extreme population density and poor sanitary conditions in vast urban slums, and experts warn that the pain of the pandemic is about to tilt quickly from richer nations to poorer ones.

“In three to six weeks, Europe and America will continue in the throes of this — but there is no doubt the center will move to places like Mumbai, Rio de Janeiro and Monrovia,” said Ashish Jha, director of the Harvard Global Health Institute. “We need to be very worried.”

It’s unknown whether the outbreak will decline as spring and summer come to the Northern Hemisphere. But if so, there’s rising concern that it will nonetheless continue to build and spread in the Southern Hemisphere winter, raising the potential for retransmission to North America, Europe and Asia later this year.

“There is certainly a significant risk,” said Stephen Morisson, director of the Global Health Policy Center at the Center for Strategic and International Studies. “It is a highly fast-moving, highly transmissible virus that is expected to continue its circulation around the planet. Downstream, as we approach the next wave — winter 2020-2021 — we have to be worried about importation of the virus from the Southern Hemisphere.”

The pandemic is already confronting some of the world’s poorest nations with their greatest economic challenge in decades. Income losses in the developing world are expected to exceed $220 billion, the United Nations warned on Monday. Nearly half of all jobs in Africa could be lost.

Wealthy European governments are paying furloughed workers the majority of their salaries, and millions of Americans who lose their jobs will have access to unemployment benefits. But billions of people in Africa, South Asia and parts of Latin America and the Caribbean work in the informal economy, living life on the margins with little to no social safety net.

They are street vendors, house cleaners, motorcycle-taxi drivers. They live off what they earn for the day. They frequently lack property or savings. Many are without ­running water or refrigerators. They’re being told to distance themselves socially while they sleep in rooms crammed in some cases with a dozen or more people.

Umm Muhammad, a single mother in Alexandria, Egypt, has lived without a salary since the outbreak forced the clothing factory where she worked to close three weeks ago.

“We are the people who are below rock bottom,” she said. “Now we are perishing.”

In Egypt, experts fear the number of infected could be at least 10 times the 609 confirmed by the authoritarian government. Officials dispute such estimates and forced a Western journalist to leave the country in March for publishing them.

Without her $75 monthly salary, Umm Muhammad has cut back on meat and vegetables for her family. Now she’s grappling with a critical decision: whether to spend her limited reserves on food or the face mask doctors recommend for her daughter with cancer. A high-quality mask costs 100 Egyptian pounds, nearly $7.

“If I am going to slave for a hundred pounds, should I use it to buy a single face mask for my daughter or to buy her food?” she asked. “And where can I get money now?”

India, one of the first nations in the world to impose social distancing rules, has reported 1,397 cases of covid-19. Analysts say the health system would not be equipped to deal with larger numbers. The country has 0.5 hospital beds for every 1,000 people, according to the Organization for Economic Cooperation and Development. The United States has 2.8. South Korea has 12.3.

Experts say there’s no official count of intensive-care beds or ventilators. Mumbai anesthesiologist Atul Kulkarni, editor of the Indian Journal of Critical Care Medicine, has estimated there are about 67,000 intensive-care beds in the country of 1.3 billion. State-level resources offer a grimmer picture: One study found that Madhya Pradesh, home to more than 70 million people, had just 1,816 intensive-care beds.

A spike in infections would quickly overwhelm those resources. In a worst-case scenario, a group of epidemiologists and biostatisticians predicted, India could have 915,000 infections by May 15. To prepare, India has banned the export of goods that could be crucial in the fight against the coronavirus, including ventilators, surgical masks and the anti-malaria drug hydroxychloroquine, now being studied as a possible treatment for covid-19 — a decision that could complicate the ability of other developing nations to obtain such items.

Ibrahima Soce Fall, the World Health Organization’s assistant director general for emergency response, said the extent to which the virus spreads in a country depends on how authorities manage their first clusters — “and a lot of countries are not responding well.” One silver lining, he said, is that outbreaks of diseases such as Ebola have trained some developing countries to hew closely to WHO advice — something many are now rigorously doing.

“In Congo, we were dealing with more than 6,000 alerts per day during the recent Ebola outbreak,” he said. “Of course, Congo or others would not be able to contend with a huge covid-19 outbreak. That’s why the beginning is so crucial.”

The International Monetary Fund and World Bank are moving to offer billions of dollars in emergency loans to poor and middle-income nations. But the agencies have warned that the loans are unlikely to be enough, and some developing nations will require substantial debt relief.

Citizens of poor nations living under weak or repressive governments are at particular risk of finding themselves at the bottom of the global scramble for scarce medicines and ventilators.

In many countries, assessing the scope of the outbreak remains the most basic challenge. In Peru, a stable, proactive government won praise for rapidly accelerating testing — one reason for a recent surge in confirmed cases. In Bolivia, meanwhile, a precarious transitional government has struggled with limited capacity for testing, averaging only about 12 results per day.

“We have some countries that we are more concerned about,” said Jarbas Barbosa, assistant director of the Pan American Health Organization. “The top priority are places like Haiti, where they have a very weak health system, and Venezuela, where they have very limited access to medicines.”

In socialist Venezuela — where broken hospitals struggle with a lack of power or water, acute shortages of medicine and supplies, and nonfunctioning equipment — experts estimate there are fewer than 200 functioning ICU beds for a nation of roughly 30 million. Critics say the government is undercounting the infected; at least four journalists have been arrested for reporting on suspected cases.

“If we start getting large numbers of patients, we will collapse,” said Maria Eugenia Landaeta, head of the infectious-diseases department at Caracas University Hospital. “Long lines of patients waiting, all beds full and patients we won’t be able to hospitalize. To sum up: total chaos.”

In the developing world, the pandemic is setting the vast gap between small enclaves of rich elites and the poor masses in stark relief. In Nairobi’s wealthy neighborhoods, for instance, restaurants are closed, streets are deserted, and the pantries and freezers of big houses in gated compounds are stocked with food for weeks. But the city’s vast slums, where the majority of its 4 million residents live, remain bustling by necessity.

Meanwhile, Kenya’s dusk-to-dawn curfew — intended to encourage social distancing — has seen security forces unleashing beatings and tear gas, and counterproductively corralling detainees into groups.

Joy Okumu, 48, sells tomatoes in the sprawling Nairobi shantytown of Kibera to feed her five children.

“Our lives cannot stop,” she said. “We are poor people. We work with our hands and not the computer. If everything stops, we die.”

Some in warm, tropical nations are trying to find comfort in the hope that warmer climates will slow or kill the virus. But the science behind that belief remains unproven, experts say, and complacency is a threat.

In Brazil, Latin America’s most populous nation and also the one with the most reported cases, the government response has been a stew of presidential inattention, infighting and contradictory signals that health experts fear could yield devastating consequences. The most-populous states, on the country’s southeastern coast, have effectively shut down. But President Jair Bolsonaro has called the crisis a “fantasy” driven by “a little cold.” In a national address last week, he called on Brazilians to return to the streets, commerce and schools. Then he boasted that if he were infected, he would overcome the disease with his athletic physical strength.

The federal inaction has overlaid a political crisis on a public health crisis as the number of cases skyrockets.

Paulo Roberto Nunes, 52, sells peanuts in Rocinha, Rio’s largest favela. He says he can’t stop working. Nunes has five children, four of whom live with him, so he’s still walking nearly empty streets, pushing his peanut cart.

“I would like to stay home to try to stop the disease from spreading,” he said. “But who will put food on the table? What does a person like me do?”

Faiola reported from Miami, Raghavan from Cairo, Bearak from Nairobi and McCoy from Rio de Janeiro. Joanna Slater in New Delhi, Simeon Tegel in Lima, Peru, Heba Farouk Mahfouz in Cairo, and Ana Vanessa Herrero and Mariana Zuñiga in Caracas, Venezuela, contributed to this report.