Flu

The flu is a respiratory illness caused by either influenza A or influenza B viruses. Flu can cause mild to severe illness and can be fatal.  The flu is usually a seasonal illness that is most commonly seen in the fall and winter months in Wisconsin.

Click on one of the links to the right for further information.

Additional Flu Resources

• Wisconsin Department of Health Services (DHS)
• U.S. Centers for Disease Control & Prevention (CDC)
• U.S. Department of Health & Human Services (DHHS)
• World Health Organization (WHO)

---

Other Types of Flu

Pandemic Flu

Pandemic Influenza is a worldwide outbreak of a new type of flu. This flu virus would be different than the normal, seasonal flu virus that affects people every year. Because the virus is new, it is expected that many people will become sick and that the virus will be easily passed from person-to-person. Pandemic flu may cause serious illness and affect many parts of the world in a short amount of time.

• The H1N1 ("Swine") Flu of 2009 was the most recent pandemic, which caused widespread illness in the U.S. during the Spring and Fall of 2009.  Current estimates on the total number of deaths associated with H1N1 are unavailable at this time. For more information on H1N1 Flu and MHD's response to the 2009 H1N1 pandemic, click here. 
• The Hong Kong Flu of 1968 was the mildest of the pandemics and made it to the U.S. by September of 1968, with widespread illness taking place around December. The highest number of deaths occurred between December of 1968 and January of 1969, estimated to be at 33,800 in the U.S. But the virus returned again in 1970 and 1972.
• The Asian Flu of 1957 was much less deadly than the Spanish Flu some 40 years before. Due to advances in science and technology the virus strain was quickly identified. In the U.S., approximately 69,800 people died from the Asian Flu
• The Spanish Flu of 1918 is widely considered to be the most severe pandemic of the 20^th century. Some reports suggest that as much as 20-40% of people in the world became sick and that 50 million died, globally. During the Spanish Flu, adults between 20-50 years old were the most vulnerable to the disease.

What is Avian (bird) Flu?

Avian influenza viruses are caused by influenza A viruses and occur naturally among birds. There are different subtypes of influenza A viruses. All known subtypes can be found in birds. The current influenza A subtype that has caused worldwide concern is the H5N1 subtype. Wild birds carry avian influenza viruses in their bodies, but do not get sick from them. However, avian influenza viruses can be passed very easily from bird to bird and can make domesticated birds, such as chickens, turkeys, and ducks very sick and kill them.