In the first 12 days of August, Maharashtra reported nearly 900 new cases of swine flu with 23 deaths related to the infection. That’s a nearly 162 percent increase over the total swine flu cases and toll, 552 and 20 respectively, that the state had reported from the start of the year through July 31.
With the massive rise in cases this month, the state has so far reported a total of 1,449 cases and 43 deaths, with Pune, Kolhapur and Nashik recording the highest number of fatalities.
What is swine flu or H1N1?
Influenza viruses belong to the Orthomyxoviridae family Of the four genera described, the influenza A virus infects humans most frequently. The virus has proteins called hemagglutinin (H) i neuraminidase (N), which help it infect cells in the human respiratory and gastrointestinal tract. There are at least 18 H subtypes and 11 N subtypes, and combinations of these are used to indicate strain type. Swine flu, named as a reassortment of human, swine and bird flu viruses, is a type of influenza A virus. It has the H1 and N1 subtypes of these proteins and is therefore called H1N1. It was responsible for a pandemic in 2009, and since then, H1N1, H3N2 and some strains of influenza B have been the predominant strains circulating around the world.
Why is the state seeing such a high increase in cases this year?
The virus is known to peak during the monsoon. This year’s increase could be a combination of three factors: First, this is the first monsoon since 2020 without blockages. Second, COVID-19 may have made people more aware and accessing health care sooner. Third, there is widespread acceptance of obtaining nasopharyngeal swabs and better access to diagnostic test kits, leading to increased testing. However, it is possible that this is a real increase, and what we are witnessing is an exceptional year.
It has been seen that in alternate years, the state/Mumbai reports a large number of swine flu cases. What are the epidemiological reasons behind it?
Reassortment of viral proteins on the surface of the influenza virus can occur every few years. This can render existing immunity from past infections ineffective as the virus evades antibodies formed as a result of exposure to previous strains. These “antigenic drifts” can cause variability from year to year. Once every decade or so, larger changes in the virus (“antigenic shift”) can have the potential to cause a major spike. Therefore, the creation of a new strain can have the same effects that the ancestral strain had on a native population.
How are the symptoms of COVID-19 different from swine flu? How can a person differentiate the symptoms?
The symptoms are similar and can be difficult to distinguish. Fever, nasal congestion, headache, sore throat, muscle aches and pains, cough are manifestations of both infections. Diarrhea can also be seen in both. Secondary bacterial infections are possibly more common in influenza than we have seen in COVID-19 over the past two years. In the absence of documented close contact with someone who has the flu, it is impossible to distinguish between the flu and COVID-19 based on symptoms. Testing is the only way to confirm infection.
What are the precautionary measures people should take?
Similar to COVID-19, the flu tends to cause the most severe illness among immunocompromised people. These would include the elderly, those with immunosuppressive conditions or on immune-suppressing medications, pregnant women and those with co-morbidities. These people should especially avoid crowded spaces, closed and poorly ventilated areas and wear masks, especially indoors. The annual flu shot is protective, and those who haven’t gotten it this year should get it after checking with their doctor. Frequent hand disinfection and isolation when sick are useful exercises to protect yourself and close contacts. Oseltamivir, when started early, can potentially reduce disease duration and transmissibility, and would be recommended, especially for high-risk individuals.
What kind of patients need hospitalization?
Most people who have a serious illness tend to be immunocompromised. Influenza can often make individuals vulnerable to secondary bacterial infections after the initial viremic phase, and antibiotics are needed if there are indicators of a secondary infection. Viral respiratory infections are known to worsen underlying chronic diseases, and people with respiratory diseases such as COPD, asthma and underlying heart disease are particularly vulnerable.