Swine Flu (H1N1)

The recent surge of cases of swine flu originated from Mexico where the mortality from it is in the 30% category. The first cases likely occurred in mid March 2009, but were only confirmed in a laboratory in California as H1N1 in early April 2009 when a returning visitor from Mexico turned ill.

According to this Lancet article this strain of swine flu is actually a hybrid of human/avian/pig influenza. This means there is no species barrier (the virus is adapted to humans, pigs and birds) and it can travel around the world easier. However, it seems much less deadly than the feared avian flu that never materialized. The good news is that because of preparations for the bird flu in the recent past countries around the world take this present swine flu seriously and use isolation methods that have proven to be effective in the past against SARS. The other good news is that the present swine flu strain H1N1 is sensitive to two antivirals, one of them Tamiflu. It is unlikely that there will be a vaccine available in the near future as it will take months to manufacture enough vaccine doses for millions or billions to be vaccinated.

Here are some swine flu related questions answered by an expert.

What can I do to protect myself?

· Wash your hands frequently and thoroughly, using soap and warm water, or use hand sanitizer
· Avoid close contact with those who are ill
· Keep your hands and fingers away from your eyes, nose, and mouth
· If you're ill, stay home
· Cover your nose and mouth with a tissue when you sneeze. Throw the tissue in the trash after you use it. When you cough, do so into your sleeve to avoid spreading the flu bug.
· If you experience severe flu-like symptoms, talk to a health professional.

Are all cases of human swine influenza severe?

No. The cases reported in Canada and the U.S. were milder than those reported in Mexico. To date, almost all of the individuals diagnosed with swine flu to date in Canada and the U.S. have recovered. The cases reported in Mexico have been more severe, involving mostly healthy young people who rapidly progressed from mild illness to severe respiratory distress, within an average of five days.

I have travelled to Mexico, California, or Texas recently, and I'm feeling sick, what should I do?

If you become sick with severe flu-like symptoms, especially respiratory symptoms like a fever and cough or difficulty breathing, stay home from work, call your doctor, and tell your health professional that you've recently travelled to those areas. If Tamiflu (=oseltamivir) or Relenza (=zanamivir) is taken in the first two days of the flu it will stop the flu from escalating (see Interim Guidance by CDC).

Here is a summary of flu symptoms as found in three common respiratory tract viral illnesses.

*How to Distinguish Between COLD, SEASONAL FLU and H1N1 Flu Symptoms*
*SYMPTOMS:*	*COLD:*	*SEASONAL FLU:*	*H1N1:*
Headache	*uncommon* with a cold	*fairly common* with seasonal flu	*very common* (in 80% of the cases)
Sudden onset	gradual onset over a few days	flushed face, dizziness, loss of appetite, vomiting & nausea develop over a few days. Diarrhea common. Symptoms last 4-7 days.	rapid onset , often within hours. High fever, diarrhea, aches and pains last 4-7 days.
Fever	rare with a cold	*common* with seasonal flu	in 80% of H1N1 cases a fever (temperature of 101°F or more) is *usually present*
Chills	*uncommon* with colds	mild to moderate chills present	*about 60%* will have chills
Sore throat	*common* with a cold	common with the seasonal flu	NOT commonly present with H1N1
Sneezing	common with a cold	*common* with seasonal flu	*uncommon* with H1N1
Stuffy nose	*common*; resolves within 1 week	*common* with the seasonal flu	this is uncommon with H1N1
Coughing	a productive cough is *common*	a dry, hacking cough is *common*	a dry cough (non-productive) is *common*
Chest discomfort	*mild to moderate*	*moderate; if severe, it could turn into pneumonia (see physician* right away)	*often severe* chest discomfort with H1N1
Aches	slight body aches and pains can occur	*moderate* body aches *common*	severe body aches and pains *common*
Tiredness	*mild* with a cold	*moderate*, patients complain of lack of energy	*moderate to severe* tiredness is *common*

Here are some useful links:

· The Public Health Agency of Canada
· The World Health Organization
· Centers for disease control and prevention
· Tips from the Government of Canada on how to fight the flu
· Travel notices and advisories

Infections Overview

Respiratory Infection

Disclaimer

This outline is only a teaching aid to patients and should stimulate you to ask the right questions when seeing your doctor. However, the responsibility of treatment stays in the hands of your doctor and you.

References

1. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 161.

2. TC Dixon et al. N Engl J Med 1999 Sep 9;341(11):815-826.

3. F Charatan BMJ 2000 Oct 21;321(7267):980.

4. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 43.

5. JR Zunt and CM Marra Neurol Clinics Vol.17, No.4,1999: 675-689.

6. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 162.

7. LE Chapman : Antivir Ther 1999; 4(4): 211-19.

8. HW Cho: Vaccine 1999 Jun 4; 17(20-21): 2569-2575.

9. DO Freedman et al. Med Clinics N. Amer. Vol.83, No 4 (July 1999): 865-883.

10. SP Fisher-Hoch et al. J Virol 2000 Aug; 74(15): 6777-6783.

13. PE Sax: Infect DisClinics of N America Vol.15, No 2 (June 2001): 433-455.

14. David Heymann, MD, Editor: Control of Communicable Diseases Manual, 18th Edition, 2004, American Public Health Association.

Last Modified: Nolv. 7, 2009