New Delhi: While the latest outbreak of swine flu in India is less worrisome than its predecessor in 2009-10, the government and international organizations say the H1N1 virus is now endemic to India and one expert warned that it could presage the creation of new, more virulent strains.
An endemic disease is one that is present in the community at all times, without the need for an external source to spread it; the virus is typically restricted to the local region—it could be a district or a country.
A virus being endemic may cause fewer fatalities, but this means the virus is widespread in India and could potentially combine with existing endemic strains and form newer, more lethal strains, said Sunil Lal, an expert on human influenza viruses.
“It’s endemic when at least half of a population (in a local community) carries the virus within them,” said Lal, who works at the International Centre for Genetic Engineering and Biotechnology in New Delhi.
“That means a greater chance of recombination and a new lethal strain emerging. Especially so, given India’s wide population and poor surveillance and monitoring facilities,” Lal said.
The outbreak has claimed 19 lives across the country in the past week alone. In the latest wave, 132 deaths and 708 cases of swine flu have been reported across the country with the maximum number of cases coming from Rajasthan—236 of swine flu and 65 deaths.
To be sure, however, the current wave is so far mild when compared with December 2009 and February 2010—the late-winter of the pandemic—that saw 2,898 confirmed cases and 373 deaths, according to information from the ministry of health and family welfare.
A senior official in the health ministry said endemicity wasn’t something to worry about yet. “It just means that the virus is widespread in the environment and that the local viruses couldn’t get the better of it this season. Don’t read anything more into it.” He didn’t want to be identified because he isn’t the appointed spokesperson for the ministry.
The current outbreak of swine flu in India is in keeping with the scenario sketched out by the World Health Organization (WHO) when it declared the H1N1 pandemic over in 2010.
WHO had at the time warned that in the post-pandemic years, localized outbreaks were expected as the virus “would take on the behaviour of seasonal influenza virus and continue to circulate for some years to come”.
In a statement, the health ministry noted that the pandemic stage of the H1N1 virus had ended in August 2010, but a large number of swine-flu cases would surface in the post-pandemic period and a significant level of virus transmission is expected.
A pandemic is an epidemic occurring worldwide. An epidemic is a sudden outbreak of disease that affects whole regions.
“In the post-pandemic period, our country had experienced outbreaks during the period between August and October 2010; May and July 2011; March and October 2012 and now in January-February 2013,” the health ministry said.
“Increase in number of cases of Influenza H1N1 are being reported at present from the states of Delhi, Gujarat, Haryana, Rajasthan and Punjab. Small pockets of population who remained unexposed to the pandemic and susceptible would be affected,” it said.
Experts say the epidemiology of the virus is much the same as that of viruses like HIV/AIDS, cholera and chikungunya.
“All these diseases started as waves in different countries, assumed pandemic proportions and went on to become endemic diseases in different countries,” said Manish Kakkar, an expert at the Public Health Foundation of India.
“In the case of H1N1, the virus has not changed much since 2009, which is good. We will have to keep collecting samples and studying it for genetic change and clinical manifestations over the coming years to see if there is any change. Largely, the case fatality of H1N1 virus infection remains same so we know it will behave in a certain way and can, therefore, address it more efficiently,” he said.