First U.S. swine flu death confirmed
NEW: 2-year-old child in Texas is first fatality from swine flu in United States
World Health Organization says at least 105 cases confirmed worldwide
More than 159 deaths in Mexico are thought to have been caused by swine flu
(CNN) -- A two-year-old child in Texas has become the first fatality from swine flu in the United States, officials said Wednesday.
"A child has died from the H1N1 virus," the acting director of the Centers for Disease Control Dr. Richard Besser told CNN's "American Morning" on Wednesday. "As a parent and a pediatrician, my heart goes out to the family."
The child is the first person to die of swine flu outside of Mexico where the virus has caused more than 159 deaths and roughly 2,500 illnesses.
So far, the World Health Organization (WHO) says at least 112 cases have been confirmed worldwide -- 64 in the United States; 26 in Mexico (including seven deaths); six in Canada; three in New Zealand; and two each in Spain, the United Kingdom and Israel.
The WHO list does not include 11 additional cases reported by New Zealand health officials, five by British officials, three in Germany or one confirmed by Costa Rica's health ministry.
In the United States, California, Indiana, New York and Texas were also reporting additional cases not confirmed by the Centers for Disease Control and Prevention (CDC).
Earlier Mexican doctors said they believed a young boy who lives near a remote pig farm was the earliest documented case of the swine flu outbreak that has killed scores of people and spread across four continents.
Five-year-old Edgar Hernandez, known as "patient zero" by his doctors, survived the virus and playfully credits ice cream for helping him feel better.
Edgar lives with his family in the 3,000-population village of La Gloria in the state of Veracruz, where a flu outbreak was reported on April 2. State officials arrived and took samples from dozens of people.
Lab tests confirmed that Edgar was the only patient in Veracruz to test positive for the swine flu virus; the others had contracted a common flu. Health officials returned to Edgar's sample only after cases of the new flu strain were spotted around the country.
"In this case, there's a patient who turned out to be positive for the swine-flu virus, with the exception that at that time in no region of the world it had been established as an etiological, epidemic cause," said Mexico Health Secretary Jose Angel Cordova.
His mother -- and many other people in La Gloria, about two hours' drive north of Mexico City -- blame the virus on a huge pig farm in the neighborhood. Officials have conducted tests at the farm owned by U.S. company Smithfield Foods, but those tests came back negative.
The World Health Organization on Monday raised its alert level from three to four on its six-level scale.
The move means the U.N. agency has determined that the virus is capable of significant human-to-human transmission -- a major step toward a pandemic, but not necessarily inevitable, Dr. Keiji Fukuda said.
"In this age of global travel, where people move around in airplanes so quickly, there is no region to which this virus could not spread," said Fukuda, assistant director-general of the WHO.
Governments around the world scrambled to prevent further outbreak.
Some, like China and Russia, banned pork imports from the U.S. and Mexico. Several others, such as Japan and Indonesia, used thermographic devices to test the temperature of passengers arriving from Mexico.
The Philippines' health department urged people to avoid kissing and hugging in public.
U.S. President Barack Obama said the outbreak was a cause for concern, not for alarm. The government urged travelers to avoid non-essential travel to Mexico. Tell us what you think about the swine flu outbreak
About 35,000 public venues in Mexico City have been shut down and restaurants are serving only take-out meals as officials try to contain the outbreak.
Authorities have also closed bars, pubs, movie theaters, pool halls, theaters, gyms, sport centers and convention halls until May 6.
Armed police officers are also guarding hospitals in Mexico City while roads and schools in the city of 20 million people are deserted. Officials also have talked about shutting down the bus and subway systems.
Some health experts fear the disease could become a pandemic, partly because it has killed young, healthy adults in Mexico.
The U.S. Food and Drug Administration issued emergency authorization for the use of two of the most common anti-viral drugs, Tamiflu and Relenza. The authorization allows the distribution of the drugs by a broader range of health care workers and loosens age limits for their use. The median age of all the U.S. cases is 16 years.
In Mexico City, however, there is a shortage of such medication. And the government ran out of surgical masks after handing them out to one out of every five residents.
Panicked citizens continue to flood in night and day at hospitals, only to be turned away by armed guards.
Swine flu is a contagious respiratory disease that usually affects pigs. It is caused by a type-A influenza virus. The current strain is a new variation of an H1N1 virus, which is a mix of human and animal versions. iReport.com: Do you think we should be worried about swine flu?
When the flu spreads person-to-person, instead of from animals to humans, it can continue to mutate, making it harder to treat or fight off because people have no natural immunity.
Researchers also do not know how the new virus is jumping relatively easily from person to person, or why it is affecting society's healthiest demographic.
Its symptoms are similar to common flu. They include fever, lethargy, lack of appetite, coughing, runny nose, sore throat, nausea, vomiting and diarrhea.
The virus spreads when an infected person coughs or sneezes around another person. People can become infected by touching something with the flu virus on it and then touching their mouth, nose or eyes.
In 1968, a "Hong Kong" flu pandemic killed about 1 million people worldwide. And in 1918, a "Spanish" flu pandemic killed as many as 100 million people. Putting those figures into perspective about 36,000 people die from flu-related symptoms each year in the United States, according to the CDC.