W.U.S. HEALTH CENTRE
UNIVERSITY OF DELHI
DELHI – 110007
SWINE FLU (SWINE INFLUENZA)
Swine influenza is caused by influenza A subtypes H1N1 (most common), H1N2, H2N3, H3N1, H3N2, H7N9 that infect the respiratory tract. The virus infecting people this year is the one that infected the people last year. Gene sequencing of the H1N1 virus by premier labs has demonstrated that the virus has not mutated.
Incubation Period from exposure to first symptom is 1-4 days with average of 2 days. It is most contagious during the first 5 days of illness.
These symptoms develop 1-3 days after exposure to any strain of the influenza family of viruses that is endemic in pigs and continue for 7-14 days.
Swine flu is transmitted from person to person by inhalation or ingestion of droplets containing virus from people coughing or sneezing and not by eating cooked pork.
When to see a doctor :-
It is not necessary to see a doctor if one is healthy and develop mild flu symptoms and signs. Visit the doctor if one is having chronic disease like chronic obstructive pulmonary disease (COPD) or heart disease or pregnancy and develop moderate or severe flu symptoms.
Risk Factors :-
Swine farmers and Veterinarians have higher risk of swine flu. Smoking, not wearing gloves while working with sick animals increases the likely hood of hand to eye, hand to nose or hand to mouth transmission of virus.
If one has travelled to area where many people are affected by H1N1 virus, one may be exposed to the swine flu virus.
Diagnosis of confirmed swine flu require laboratory test of respiratory sample e.g. nasal swab, throat swab for particular antigens (surface proteins) in specialized laboratories. Doctors collect and send nasal swab/throat swab to the specialized laboratory for confirmation of swine flu virus.
Anti viral drugs make the illness milder and prevent serious complications.
Tablet Oseltamivir (Tamiflu/Fluvir) or Zanamivir (Relenza) within 48 hours after the onset of symptoms or after 48 hours in high risk patients. They should not be used indiscriminately because of the risk of viral resistance. They are also not recommended if the flu symptoms have been present for more than 48 hours. Pregnant females can be treated with the anti-viral drugs.
Majority of the people infected with the virus make a full recovery without anti-viral drugs.
Side effects of Vaccines :-
Flu shot vaccine (made from killed virus particals): - Soreness, redness, swelling at the injection site, muscle aches, nausea, low grade fever.
Nasal spray vaccine (made from live virus) : runny nose, wheezing, cough, vomiting, low grade fever.
Intradermal shot (trivalent vaccine) : redness, swelling.
The people who are allergic to eggs should not get vaccine unless tested and advised by the doctor.
Precautions while air travelling :-
Chief Medical Officer