Influenza A H1N1 (Swine Flu)-LA COUNTY Clinician Guidance #2

Updated Investigation and Interim Recommendations Influenza A H1N1 (Swine Flu)

BACKGROUND

To date, human cases of swine influenza A (H1N1) virus infection have
been confirmed in the United States. Illness signs and symptoms have
consisted of influenza-like illness - fever and respiratory tract illness (cough, sore throat, runny nose), headache, muscle aches - and some cases have had vomiting and diarrhea. These cases had illness onset during late March to mid-April 2009. However, cases of severe respiratory disease, including fatal outcomes, have been reported in Mexico. The potential for exacerbation of underlying chronic medical conditions or invasive bacterial infection with swine influenza virus infection should be considered.

The swine influenza A (H1N1) virus that has infected humans in the U.S. and Mexico is a novel influenza A virus that has not previously been identified in North America. This virus is resistant to the antiviral medications amantadine and rimantadine, but is sensitive to oseltamivir and zanamivir. Investigations of these cases suggest that ongoing human-to-human swine influenza A (H1N1) virus is occurring.

University students may be more likely to have recently traveled to Mexico or another affected region therefore a heightened awareness of your students’ travel history is important. Additionally, parents of your students may be concerned regarding the health of their children, and we would suggest updating your parents if you have not done so already.

INTERIM RECOMMENDATIONS

Definition

Acute respiratory illness is defined as recent onset of at least two of the following: rhinorrhea or nasal congestion, sore throat, cough (with or without fever or feverishness).

Clinicians should consider swine influenza A (H1N1) virus infection in the differential diagnosis of patients with febrile (>100.0ºF)
respiratory disease and who 1) live in San Diego and Imperial Counties, California, or Guadalupe County, Texas, or traveled to these counties or 2) who traveled recently to Mexico or were in contact with persons who had febrile respiratory illness and were in the two U.S. counties or Mexico in the 7 days preceding their illness onset.