The United States has confirmed its fourth death from swine influenza A-H1N1.
The Centers for Disease Control and Prevention said Friday there are more than 4,700 confirmed and probable cases of the virus in the United States, spread out in nearly every state.
The latest death was a woman in the state of Arizona who had a lung condition.
The World Health Organization said Friday the illness has been confirmed in 34 countries. That count does not include Malaysia and Peru, which both confirmed their first cases this week.
The WHO said Mexico has confirmed nearly 2,500 cases of the illness, including 60 deaths. Canada and Costa Rica each have confirmed one death.
The WHO said the outbreak has not become a pandemic, and it is not recommending travel restrictions related to the virus.
Meanwhile, New York City has shut down three schools for a week in response to a new outbreak in the city. A school employee has been hospitalized in critical condition, and several students have been infected.
The strain appeared last month in New York City, sickening dozens of students who had visited Mexico. Students at two other schools also became ill.
Argentina has authorized the resumption of flights from Mexico following a two-week suspension. Peru also has lifted a ban on flights to and from Mexico.