Including human cases of avian and swine influenza viruses.
Major pandemic The appearance of a new influenza strain in the human population
Pandemic“Spanish flu” H1N1The most devastating flu pandemic in recent history, killing more than 500,000 people in the United States, and 20 million to 50 million people worldwide.
Pandemic"Asian flu" H2N2First identified in China, this virus caused roughly 70,000 deaths in the United States during the 1957-58 season. Because this strain has not circulated in humans since 1968, no one under 30 years old has immunity to this strain.
Pandemic"Hong Kong flu" H3N2First detected in Hong Kong, this virus caused roughly 34,000 deaths in the United States during the 1968-69 season. H3N2 viruses still circulate today.
Four soldiers in a US army base in New Jersey are infected with swine influenza, resulting in one death.
Appearance of a new influenza strain in humans“Russian flu” H1N1Isolated in northern China, this virus was similar to the virus that spread before 1957. For this reason, individuals born before 1957 were generally protected; however children and young adults born after that year were not because they had no prior immunity.
Appearance of a new influenza strain in humansH5N1The first time an influenza virus was found to be transmitted directly from birds to people, with infections linked to exposure to poultry markets. Eighteen people in Hong Kong were hospitalized, six of whom died.
Appearance of a new influenza strain in humansH9N2Appeared for the first time in humans. It caused illness in two children in Hong Kong, with poultry being the probable source.
Appearance of a new influenza strain in humansH7N2Evidence of infection is found in one person in Virginia following a poultry outbreak.
Appearance of a new influenza strain in humansH5N1Caused two Hong Kong family members to be hospitalized after a visit to China, killing one of them, a 33-year-old man. (A third family member died while in China of an undiagnosed respiratory illness.)
H7N7In the first reported cases of this strain in humans, 89 people in the Netherlands, most of whom were poultry workers, became ill with eye infections or flu-like symptoms. A veterinarian who visited one of the affected poultry farms died.
H7N2Caused a person to be hospitalized in New York.
H9N2Caused illness in one child in Hong Kong.
Appearance of a new influenza strain in humansH5N1Caused illness in 47 people in Thailand and Vietnam, 34 of whom died. Researchers are especially concerned because this flu strain, which is quite deadly, is becoming endemic in Asia.
H7N3Is reported for the first time in humans. The strain caused illness in two poultry workers in Canada.
H10N7Is reported for the first time in humans. It caused illness in two infants in Egypt. One child’s father is a poultry merchant.
H5N1The first case of human infection with H5N1 arises in Cambodia in February. By May, WHO reports 4 Cambodian cases, all fatal. Indonesia reports its first case, which is fatal, in July. Over the next three months, 7 cases of laboratory-confirmed H5N1 infection in Indonesia, and 4 deaths, occur.
On December 30, WHO reports a cumulative total of 142 laboratory-confirmed cases of H5N1 infection worldwide, all in Asia, with 74 deaths. Asian countries in which human infection with H5N1 has been detected: Thailand, Vietnam, Cambodia, Indonesia and China.
H5N1In early January, two human cases of H5N1 infection, both fatal, are reported in rural areas of Eastern Turkey, while cases in China continues to spread. As of January 25, China reports a total of 10 cases, with 7 deaths. On January 30, Iraq reports its first case of human H5N1 infection, which was fatal, to the WHO.
In March, the WHO confirmed seven cases of human H5N1 infection, and five deaths, in Azerbaijan. In April, WHO confirmed four cases of human H5N1 infection, and two fatalities, in Egypt.In May, the WHO confirmed a case of human H5N1 infection in the African nation of Djibouti. This was the first confirmed case in sub-Saharan Africa. Throughout 2006, 115 human cases of H5N1 infection occur, with 79 deaths.
In early January, two human cases of H5N1 are confirmed in Indonesia. By the end of 2007, 88 confirmed cases occur in Indonesia, Cambodia, China, Lao People’s Democratic Republic, Myanmar, Nigeria, Pakistan and Vietnam, with 59 deaths.
H7N7In May, four cases of H7N7 avian influenza were confirmed in the United Kingdom among individuals exposed to infected poultry.
H5N1On May 28, Bangladesh reports its first case of human H5N1 infection to the WHO. By the end of the year, 40 cases are confirmed in Bangladesh, Cambodia, China, Egypt, Indonesia and Vietnam.
H5N1On January 7, Indonesia confirmed a new case of human infection with H5N1 influenza. Since that time, new cases have been identified in Egypt, China, Indonesia and Vietnam.
H1N1In April, human infection with a new strain of H1N1 influenza is confirmed in Mexico. Within weeks, human infections spread to the United States and cases begin occurring in other regions around the world.
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Last Updated January 14, 2011