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Update: Swine-Origin Influenza A (H1N1) Virus --- United States and Other Countries

MMWR in spanish

Since April 21, 2009, CDC has been reporting cases of respiratory infection with a swine-origin influenza A (H1N1) virus (S-OIV) transmitted through human-to-human contact (1--3). In the United States, as of April 29, a total of 91 confirmed cases had been reported, including one death (in Texas). By state, the following numbers of cases had been reported: New York (51); Texas (16); California (14); Kansas, Massachusetts, and Michigan (two each); Arizona, Indiana, Nevada, and Ohio (one each).

Outside of the United States, as of April 29, a total of 57 confirmed cases had been reported, including seven deaths (in Mexico). By country, the following numbers of laboratory-confirmed cases had been reported: Mexico (26); Canada (13); United Kingdom (five); Spain (four); Germany and New Zealand (three each); Israel (2); and Austria (one). Additional information is available at and


  1. CDC. Swine influenza A (H1N1) infections---California and Texas, April 2009. MMWR 2009;58:435--7.
  2. CDC. Update: infections with a swine-origin influenza A (H1N1) virus---United States and other countries, April 28, 2009. MMWR 2009;58:431--3.
  3. CDC. Update: drug susceptibility of swine-origin influenza A (H1N1) viruses, April 2009. MMWR 2009;58:433--5.

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Date last reviewed: 4/30/2009


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