Types of Flu

Influenza, a respiratory disease has lead to many dreaded epidemics and pandemics. It normally spreads through airborne droplets of infected respiratory fluid (from the coughing and sneezing of an infected person). Influenza seldom causes gastrointestinal symptoms and should not be mistaken with "stomach flu" (characterized by vomiting, nausea, and diarrhea).

Physicians usually diagnose influenza by the presence of flu symptoms in the community and if the patient's complaints fit the current pattern. Rarely is laboratory testing used to identify the virus. Flu viruses can be classified into three groups or types - Influenza A, Influenza B, and Influenza C. Type A is the most prevalent form of flu and associated with the most serious epidemics. Type B is milder and has rarely been associated with epidemics. Type C has never been associated with epidemic outbreaks.

Influenza A is the most common form of flu and unfortunately the root cause behind most of the serious epidemics. Influenza A virus is essentially a bird flu virus that has recently shifted into mammals. Birds have the greatest number and range of influenza strains. Apart from birds, it sometimes appears in pig, human and horse influenza strains as well.

Influenza B is restricted to humans only and it changes less often as compared to influenza A viruses. Occurrence of influenza B is unpredictable but there's a possible chances of its occurring at the same time as influenza A does. An influenza B virus is always included in the annual vaccine, so anyone who receives a flu shot during a particular will stay away from this virus.

Influenza C is the mildest form of flu. It's normally transmitted from person to person via contagious droplets that are spread when an infected person sneezes or coughs. It's very common but rarely causes disease symptoms. The common indication of this flu is high temperature, flushed face, body aches, and lack of energy.