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India witnessed the worst outbreak of the Swine flu, renamed the influenza A(H1N1) pdm09 virus by the World Health Organisation (WHO), in the pandemic years of 2009-10 when the disease affected close to 50,000 people and killed more than 2,700 across the country. (WHO Influenza update, 7th August 2017) (1)

India had 8,648 cases and 345 swine flu deaths till May 7 this year, compared to 1,786 cases and 265 deaths in 2016, reveals data from the ministry of health and family welfare. Tamil Nadu alone recorded 2,798 cases till May 7, which is more than the total tally of 2016. Maharashtra has the highest death toll, with 181 people succumbing to H1N1 complications till May 7. Flu peaks twice a year in India, in July and August and again from October to February. But cases are reported throughout the year. (2)

In a study done by M. S. Chadha, Parvaiz A. Koul, et al, analysis of Monthly trends and seasonality of circulating influenza viruses in India, 2009–2013.showed Peaks of influenza were observed during July-September coinciding with the monsoon in cities Delhi and Lucknow (north), Pune (west), Allaphuza (southwest), Nagpur (central), Kolkata (east) and Dibrugarh (northeast), whereas Chennai and Vellore (southeast) revealed peaks in October-November, coinciding with the monsoon months in these cities. In Srinagar (Northernmost city at 34°N latitude) influenza circulation peaked in January-March in winter months.In Delhi, 809 of 5571 specimens (14.5%) were positive for influenza viruses. Analysis of monthly data over a five year period showed influenza circulation primarily from June-October for most years, with discrete peaks in July-September during four of the study years. The predominant subtype was influenza A/H1N1pdm09 in 2009, and 2010; A/H3 in 2011 and 2013; and influenza B in 2012. [Dynamics of Influenza Seasonality at Sub-Regional Levels in India and Implications for Vaccination Timing] (3)

Swine flu virus: How it attacks the cell?

check this video

Swine flu: Symptoms

Influenza (also known as the flu) is a contagious respiratory illness caused by flu viruses. It can cause mild to severe illness, and at times can lead to death. The flu is different from a cold. The flu usually comes on suddenly. It’s important to note that not everyone with flu will have a fever People who have the flu often feel some or all of these symptoms:

  • Fever or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches, 
  • Headaches
  • Fatigue (tiredness)

Some people may have vomiting and diarrhoea, though this is more common in children than adults.

Flu complications:

Most people who get influenza will recover in a few days to less than two weeks, but some people will develop complications, such as:

  • Pneumonia
  • Bronchitis
  • Sinus and Ear infections
  • Worsening of chronic health problems like Asthma, COPD, Congestive heart failure. 

Who are at risk?

Anyone can get flu, and serious problems related to the flu can happen at any age, but some people are at high risk of developing serious flu-related complications:

  • Age >65 years
  • Pregnant women
  • Young children
  • Residents of nursing homes and other long-term care facilities.
  • People with chronic medical conditions[Asthma, COPD, ILD, Diabetes]
  • Neurological and neurodevelopmental conditions [including disorders of the brain, spinal cord, peripheral nerve, and muscle such as cerebral palsy, epilepsy (seizure disorders), stroke, intellectual disability (mental retardation), moderate to severe developmental delay, muscular dystrophy, or spinal cord injury].
  • Chronic lung disease (such as chronic obstructive pulmonary disease [COPD] and cystic fibrosis)
  • Heart diseases (such as congenital heart disease, congestive heart failure and coronary artery disease)
  • Blood disorders (such as sickle cell disease)
  • Endocrine disorders (such as Diabetes mellitus)
  • Kidney disorders
  • Liver disorders
  • Metabolic disorders (such as inherited metabolic disorders and mitochondrial disorders)
  • Weakened immune system due to disease or medication (such as people with HIV/AIDS, or cancer, or those on chronic steroids)
  • People younger than 19 years of age who are receiving long-term aspirin therapy
  • People with extreme obesity (body mass index [BMI] of 40 or more) 

What are the emergency warning signs of flu sickness?

In children:

  • Fast breathing or trouble breathing
  • Bluish skin colour
  • Not drinking enough fluids
  • Not waking up or not interacting
  • Being so irritable that the child does not want to be held
  • Flu-like symptoms improve but then return with fever and worse cough
  • Fever with a rash

In adults:

  • Difficulty breathing or shortness of breath
  • Pain or pressure in the chest or abdomen
  • Sudden dizziness
  • Confusion
  • Severe or persistent vomiting
  • Flu-like symptoms that improve but then return with fever and worse cough
  • In addition to the signs above, get medical help right away for any infant who has any of these signs:
  • Being unable to eat
  • Has trouble breathing
  • Has no tears when crying
  • Significantly fewer wet diapers than normal

What is the treatment?

Antiviral drugs: Oseltamivir (Tamiflu) 

[To know more about the drug, check the video]

Vaccine – the Advisory Committee on Immunization Practices (ACIP) recommends annual influenza vaccination for everyone 6 months and older with either the inactivated influenza vaccine (IIV) or the recombinant influenza vaccine (RIV). 

The nasal spray flu vaccine (live attenuated influenza vaccine or LAIV) should not be used during 2016-2017.There is no preference for one vaccine over another among the recommended, approved injectable influenza vaccines.

References:

1. World Health Organisation. Influenza transmission zones. influenza update 2017. Available online at http://www.who.int/influenza/surveillance_monitoring/updates/EN_GIP_Influenza_transmission_zones.pdf

2. HT News. Alarming rise in swine flu cases in India as 345 killed this year alone. Available online at http://www.hindustantimes.com/health/alarming-rise-in-swine-flu-cases-in-india-as-345-killed-this-year-alone/story-ykBIl6q7QT4ZJRZgNSRqaO.html

3. Mandeep S. Chadha, Varsha A. Potdar, Siddhartha Saha, Parvaiz A. Koul, Shobha Broor, Lalit Dar, Mamta Chawla-Sarkar, Dipankar Biswas, Palani Gunasekaran, Asha Mary Abraham, Sunanda Shrikhande, Amita Jain, Balakrishnan Anukumar, Renu B. Lal, Akhilesh C. Mishra. Dynamics of Influenza Seasonality at Sub-Regional Levels in India and Implications for Vaccination Timing. PLoS ONE 10(5): e0124122.  Available at: http://doi.org/10.1371/journal.pone.0124122. 

4. Center for disease control and prevention. Information on Swine Influenza/Variant Influenza Virus. Updated 2017. Available online at https://www.cdc.gov/flu/swineflu/index.htm