The U.S. Centers for Disease Control and Prevention (CDC) announced two cases of flu caused by two new viruses associated with swine.  The illnesses affected children in West Virginia and Minnesota, who both eventually recovered.

The virus found in West Virginia, known as H3N2, has a mixture of genes from swine, human and bird flu viruses.  There have been 10 other cases of infection with this virus across the country in previous years.

The child in Minnesota became ill with a form of the virus called H1N2, also found in swine.  It's only the second known case of infection with this virus in the U.S.

In both current cases, there was no contact with any swine, meaning the virus was transmitted from person to person.  The virus has not spread to other humans, CDC reported.

The number of humans infected by viruses previously found only in swine has increased over the past couple of years, and the agency says that could be due to better identification of virus strains, more monitoring of flu cases, or an actual increase in the number of cases either from direct or close contact with swine or as a result of person-to-person transmission.

While CDC does recommend that people get a flu shot, the shot will not protect against viruses found in swine.  There are two antivirals - oseltamivir and zanamivir - that are effective against illnesses caused by these viruses.  In addition, people should not eat pork products that are not properly cooked or handled.