H1N1 influenza from the CDC and NEJM, May 8, 2009

Although the onslaught of virus seems to have slowed, there is no reason to drop our guard too far just yet. Besides, this virus has some atypical manifestations that may make us not recognize the problem as quickly as we might.

For example one fourth of cases present with diarrhea and another one fourth present with vomiting. The usual “flu” is an upper and lower respiratory presentation. The virus is continuing to rapidly evolve on a DNA basis and the presentation may evolve as well.

Children and teens seem to be most susceptible and older adults less vulnerable to the virus. The ages of between 10 and 18 years were most effected and only 5% were 50 or older. Symptoms included fever in 94%, cough in 92%, sore throat in 66%, diarrhea in 25%, and vomiting in 25%.

The young with disorders as asthma and eczema, as well as other disorders of immunodeficiency seem to be at more risk. All patients given Tamiflu recovered.