A/H1N1 indistinguishable from pandemic flu

Jenny Decker RN's picture
H1N1 Swine Flu

Where did swine flu come from? This question probably makes one think that of course swine flu comes from pigs. But H1N1 is called a triple reassortment influenza virus. This means it contains genes from human, porcine (pigs) and avian influenza viruses. Interestingly, there have been some occasional swine origin infections in humans in the United States since 1999. This is from mostly younger people who have been in contact with pigs.

As of June 17, 2009, there are a total of 88 countries reporting H1N1, with a total of 39,620 confirmed cases of the pandemic flu. However, a recent report indicates a new strain of H1N1. It is being referred to as A/H1N1. Three individuals with A/H1N1 in China were followed to observe how A/H1N1 affected them and others who were exposed to the new strain.


All 3 patients were tested for the pandemic flu and these results came back largely negative. Flu symptoms were relatively mild as well. Each one developed fever and all contacts with each of these patients were quarantined, tested, and observed. None of the contacts (from planes, trains, and households) developed A/H1N1. Only one person developed pandemic H1N1. This was a household member with direct patient contact, a caregiver.

It is unclear how the A/H1N1 is passed or how it works. Scientists are a little confused at this point. The three cases developed the perfect profile of pandemic H1N1. Mild symptoms with fever and relatively young age were the main characteristics. There was no severe respiratory illness or unusual symptoms such as diarrhea either. In fact, researchers were concerned because the symptoms were indistinguishable from the pandemic flu. Even all blood counts came back normal.

It is estimated by studies that the greatest risk for transmitting A/H1N1 is in the household. Further study is crucial at this point in order to better understand this new strain of flu. It is important to wash hands frequently and use hand sanitizer in order to slow the spread of any type of flu. Good handwashing goes a long way in limiting the spread of any disease.

Source: USDHHS, Doi: 10.3201/eid1509.090794