- US confirms second death (33 year old pregnant woman from Texas)
- 41 states have reported a total of 642 cases
- At least 35 hospitalizations have occurred in the US
- WHO reports 22 countries have reported cases (including Southern Hemisphere countries)
Swine Flu Update: May 4
- 226 confirmed cases in the US
- WHO considering moving to “Stage 6”
- 109 cases in the US in 10 states
- South Carolina newest state with confirmed cases
- 11 countries now have cases, up from 9 yesterday
- New cases in Switzerland, Netherlands
- WHO upgrades to stage 5
- 9 countries with confirmed cases
- New cases in Germany, England, and Austria
Q: If 36,000 Americans died during a recent year from seasonal flu, is that not about 100 per day? During the flu season, maybe twice that many, with half as many during the off season? How is swine flu special? I sort of understand that this could be different because it is a unique strain, but I think we need some perspective.
Keep up the good work.
Rich Wilson DO
- There are 91 cases reported in the US
- New cases have cropped up in Arizona, Indiana, Michigan, Massachusetts and Nevada
- First US swine flu death confirmed in Texas
- 5 hospitalizations (3 in CA, 2 in TX) have occurred.
- Worldwide seven countries (USA, Canada, Mexico, Spain, New Zealand, and Israel) have confirmed cases according to the WHO.
- The CDC’s antiviral guidance was updated and now does not include recommendations for dual therapy with an adamantane to cover seasonal influenza infection if oseltamivir is used.
- An Emergency Use Authorization was also issued allowing for the use of oseltamivir in those aged under one year.
Swine Flu Update: April 28
On April 21, 2009, the Centers for Disease Control and Prevention (CDC) issued an MMWR Dispatch describing 2 cases of swine influenza A (H1N1) infection that occurred in Southern California in April. While both patients recovered uneventfully, the isolated viruses harbor novel genetic characteristics not seen in swine flu isolates in the U.S. prior to this event. The other striking feature of these cases is that there was no known contact with swine, raising the question of efficient human-to-human transmission of this virus [1] Subsequent investigation has uncovered 40 additional cases in the United States—all of whom have recovered uneventfully—and reports of severe morbidity and mortality in Mexico. Several other countries including Canada, Scotland, and Spain are reporting confirmed cases.
Swine Flu in Humans
• Case fatality rates were 14% (likely reflecting case ascertainment bias).
• 61% of civilian cases reported swine exposure.
• Person-to-person transmission did occur.[4]
CDC reports the receipt of approximately 1 human swine flu case report every 1 to 2 years (swine flu has been a nationally reportable condition since 2007). Since 2005, 12 cases have been reported in the U.S., most with exposure to pigs.1 Most swine influenza infections do not have a presentation distinct from human influenza infections. Seroprevalence studies have shown 23% positivity in those with occupational exposure to pigs.[2]
The Basics
•Swine Flu is a reassortant type A influenza virus that originated from swine at some point in the past
•Unlike past infections with swine flu, the current outbreak strain efficiently spreads from person to person—secondary attack rates are approximately 20%
•The diagnosed cases in the US represent only the tip of the iceberg, it is likely to be circulating in your community
Symptoms
•All cases outside of Mexico reported to date have consisted of mild influenza-like illness with the exception of the prominence of nausea, vomiting, and diarrhea
•The US should be prepared to see severe cases with fulminant pneumonia given the experience in Mexico
•The incubation period is approximately one to seven days
•The infectiousness period begins 1 day prior to symptoms and continues for seven days after symptoms commence
•real-time RT-PCR
•viral culture
•positive for influenza A, but negative for H1 and H3 by influenza RT-PCR, or
•positive for influenza A by an influenza rapid test or an influenza immunofluorescence assay (IFA) plus meets criteria for a suspected case
A suspected case of swine influenza A (H1N1) virus infection is defined as a person with acute febrile respiratory illness with onset
•within 7 days of close contact with a person who is a confirmed case of swine influenza A (H1N1) virus infection, or
•within 7 days of travel to community either within the United States or internationally where there are one or more confirmed swine influenza A(H1N1) cases, or
•resides in a community where there are one or more confirmed swine influenza cases.
•The virus is susceptible to treatment with the neuraminidase inhibitors, oseltamivir and zanamivir; it is resistant to amantadine and rimantidine
•Standard treatment for seasonal flu should be employed (i.e. either zanamivir alone or oseltamivir in combination with an adamantane to cover the possibility of resistant seasonal flu)
•Antiviral guidelines are available at: http://www.cdc.gov/swineflu/recommendations.htm
•Full airborne protections are warranted (N-95 masks)
•Vaccination with seasonal influenza vaccine is not protective
Emergency physicians will continue to be one of the first lines of defense against this virus and the care and advice they will provide will be an essential component of what may be a marathon battle against this virus.
Center for Biosecurity of UPMC: www.upmc-biosecurity.org
8. Krause R. The swine flu episode and the fog of epidemics. Emerg Infect Dis 2006; 12:40-43. http://www.cdc.gov/ncidod/EID/vol12no01/05-1132.htm. Accessed April 23, 2009.