MEXICO CITY - Mexicans will do almost anything to avoid a public hospital emergency room, where ailing patients may languish for hours slumped on cracked linoleum floors that smell of sweat, sickness and pine-scented disinfectant.

Many don't see doctors at all, heading instead to the clerk at the corner pharmacy for advice on coping with a cold or a flu.

So it's no surprise that when a dangerous new flu virus began to sweep across Mexico, many waited too long to seek medical help - more than a week on average, according to federal Health Secretary Jose Angel Cordova.

These initial delays complicated treatment, possibly explaining why 48 of the world's 50 confirmed swine flu deaths occurred in Mexico.

It also made it more difficult for Mexico to recognize the outbreak for what it was. By the time Cordova announced a swine flu epidemic on April 23, the virus had already spread across the country and beyond.

Mexico's big cities have fancy private hospitals stocked with modern equipment and staffed with U.S. board-certified specialists. Foreigners increasingly come to Mexico for good care at low prices. The best of the public system is world-class too, with top doctors at elite centres for specialized diseases.

But Mexico's everyday public hospital system is in crisis.

Some patients suspected of having the H1N1 swine flu virus told The Associated Press that public hospitals turned them away or forced them to wait for hours for treatment even after the government declared a national emergency.

Those who sought help before the alert - often arriving with headaches, high fevers and difficulty breathing - encountered baffled doctors who had not been warned to watch for a new virus.

Mexicans navigate a patchwork of public and private hospital systems. There are hospitals for government employees and hospitals for workers enrolled in government health plans through private employers. Most patients have to go to a hospital tied to a specific agency.

"If someone is sick, he can't simply say, 'I'm going to the doctor' or 'I'm going to the hospital,' because it depends on whether he has Social Security or if he has to go to another institution," said Dr. Malaquias Lopez Cervantes, a leading epidemiologist at Mexico's National Autonomous University.

"And if he comes (to the wrong hospital), somebody is going to tell him that he doesn't have the right to be treated."

While access to health care is a right enshrined in the Mexican constitution, millions of Mexicans have no health insurance at all.

Mexico spends only 6.6 per cent of its gross domestic product on health care - less than half the U.S. figure. No country in the 30-nation Organization for Economic Co-operation and Development puts a smaller share of public money into its health care system.

That means the hospitals serving most of Mexico's 44 million poor are often crowded, ill-equipped and staffed with harried, underpaid staff working for a dizzying array of bureaucracies.

It's so crowded, confusing and bureaucratic that the poor are more likely to head for a pharmacy, hoping to find a cheap remedy for "gripe" (pronounced GREE-pay) - a word that can cover anything from a mild cold to a deadly flu.

Most pharmacies dole out antibiotics and a host of other powerful drugs without a prescription. That encourages Mexicans to self-medicate, relying on a counter clerk's suggestion, dosing themselves with whatever worked the last time they had a fever and waiting a day or two to see what happens.

Some pharmacies even drum up business by tacking a doctor's office onto the side - offering basic checkups for as little as 25 pesos (US$2) - still roughly half a day's pay for a minimum-wage worker.

In Mexico City's working-class Padierna neighbourhood, Dr. Oscar Aguilera sees patients in a small office at the back of a discount pharmacy, with an open-air waiting room behind a row of graffiti-tagged taco stands.

Even in normal times, most of his patients come in with a cold or a flu. Most now show no signs of swine flu, he said, but "20 per cent show some symptoms and we send them to the hospital."

Following the public alert on April 23, fear has driven patients to his office even at the slightest symptom.

Mexicans with flu symptoms might have sought better care far earlier if the public health care system had done the same kind of flu surveillance common in the U.S. and other developed nations.

Mexico keeps close watch on dangerous tropical diseases such as dengue, but epidemiologists pay less attention to flu, just one class of viruses contributing to Mexico's 23 million annual cases of respiratory illness.

Mexican doctors "really were not trained thinking of the existence of influenza" as a specific threat, Lopez Cervantes said.

In all of 2008, Mexico's official epidemiological bulletin reported only 151 confirmed cases of flu. By comparison, U.S. officials ran tests that confirmed nearly 40,000 flu cases last season. Mexico has about a third the population of the United States.