H1N1 Virus / Swine Flu – Discuss

Swine flu (H1N1 influenza), these days, is one of the major public-health concerns that calls for attention among public in general and medicos and Para-medics in particular.

Swine flu is a respiratory disease caused by viruses (influenza) virus that infect the respiratory tract of pigs, resulting in nasal secretions, a barking cough, decreased appetite and listless behavior. Swine flu can last about one to two weeks in pigs that survive.

History of H1N1 Influenza in Humans
Investigators have detected that the outbreaks of swine flu in humans dates back to the 1918 Spanish influenza pandemic which infected one third of the world's population (an estimated 50 crore people) when the cause of human influenza and its links to bird flu (avian influenza) and swine influenza was not understood . The answers began to emerge in 1930s when related influenza viruses (now known as H1N1 viruses) were isolated from pigs and then humans.

Early in the spring of 2009, H1N1 flu virus was first detected in Mexico, causing some deaths among a "younger" population. It began increasing during the summer 2009 and rapidly spread to the U.S. and Europe and eventually worldwide. The WHO declared it first their criteria for an epidemic and then, in June 2009, the WHO declared this first flu pandemic in 41 years.

H1N1 in India
Currently in 2015, India has reported H1N1 influenza outbreak and virologists said the same California strain of 2009 was responsible for the disease here as well. According to data collated by the Union Health Ministry, as on March 20, the contagious disease has claimed the lives of 1,895 persons while the number of affected persons across various states stood at 31,974. Meanwhile, as per a ministry study, 34 per cent of the 723 swine flu deaths that were analyzed had occurred in the age group 30-40 years, followed closely by those in the 45-60bracket, who accounted for 32 per cent of the fatalities.

Fortunately, it has been reported that the H1N1 (swine flu) virus has not mutated and patients are still responding to Oseltamivir (Tamiflu), a joint study by the National Institute of Virology (NIV) and the National Centre for Disease and Control (NCDC).

Clinical Manifestation (symptoms)
H1N1 (Swine flu) manifests similarly to those of seasonal influenza (flu). The transmission is by droplet infection and fomites (non-living objects). The symptoms may appear after a period of 1-7 days after contracting H1N1 infection. However, it is transmitted from 1 day before to 7 days after the onset of symptoms. If illness persists for more that 7 days, chances of communicability may persist till resolution of illness. Children may spread virus for a longer period.
Patients present with the symptoms of acute respiratory illness, including at least two of the following, viz. Fever, Cough, Sore throat, Body aches, Headache, Chills and fatigue, Diarrhea and vomiting (possible). In children, signs of severe disease including breathlessness, fast breathing, cyanosis, dehydration, altered mental status, and extreme irritability. The most serious complication of the flu is pneumonia.

Investigations
Routine investigations required for evaluation and management of a patient with above mentioned symptoms may include hematological, biochemical, radiological and micro biological tests as necessary. Confirmation of Pandemic influenza A (H1N1) infection is through Real Time RT PCR or isolation of virus specific neutralizing antibodies.
For confirmation of diagnosis, clinical specimens such as nasopharyngeal swab, throat swab, nasal swab, wash or aspirate and tracheal aspirate (for incubated patients) are to be obtained.

Treatment
Some of the same antiviral drugs that are used to treat seasonal flu also work against H1N1 flu. Osteltamivir (Tami flu) and Zenamivir (Relenza) seem to work best. Paracetamol or ibuprophen is prescribed for fever, mylagia (muscle aches and pains) and headache. Patient is advised to drink plenty of fluids. Smokers should avoid smoking .Salicylate/ aspirin is strictly contra-indicated in any influenza due to its potential to cause Reye's syndrome.

Vaccine
The same flu vaccine that protects against seasonal flu offers protection against three strains of influenza and includes Swine Flu. You can get it as a shot or nasal spray. Either way, it "teaches" your immune system to attack the real virus. The vaccine takes two weeks to work and will last for about twelve months.
Vaccine (like intra-nasal NASOVAC-S) is contra-indicated in children and adolescents (2-17 years of age) receiving aspirin therapy, because of association of Reye's syndrome with aspirin and wild-type influenza infection. So it is advisable to take vaccines under strict supervision of a doctor.

Conclusion
H1N1 influenza (swine flu) is much similar to seasonal flu and can be controlled by taking prompt action when suspected. We should develop better hygienic practices like regular hand-washing, cough etiquettes (e.g. covering face while coughing or sneezing by using handkerchief). Also avoid unnecessary hospital visits, frequent intermingling at public places, etc. There is no need to get panic and don't start taking anti-influenza Oseltamivir unless prescribed by a doctor. Swine flu generally doesn't cause significant illness or death but the high-risk groups need extra care in preventing disease.

Safiyah Zuhra