There has been an increase in the number of cases of pandemic influenza H1N1 reported from the states of Andhra Pradesh, Maharashtra, Rajasthan, Karnataka and Tamil Nadu during March-April 2012.
Small pockets of population, hitherto unexposed to the pandemic, will be affected during this period, said the Union health ministry in a press release issued through the Press Information Bureau (PIB) on Wednesday. However, the ministry maintained that the situation was well under control and was being constantly monitored.
"As reported in some sections of the press, the virus has not mutated to a more virulent form or changed its character," the ministry said.
The director of the National Institute of Virology, Pune, has clarified that circulating strain of H1N1 pandemic virus belongs to clade 6 and 7. These clades are circulating in many countries.
All are treatable with antiviral drug oseltamivir, popularly known as Tamiflu, stated the ministry.
A clade is a group consisting of a single common ancestor. "The currently available vaccine can be used, as antigenic differences are not significant. There is no mutation to suggest a change of virus to 'dangerous form'," stated the ministry.
An antigen is a substance that when introduced into the body stimulates the production of an antibody. Antigens include toxins, bacteria, foreign blood cells and the cells of transplanted organs.
The World Health Organisation while declaring the pandemic over in August 2010, had conveyed that the influenza H1N1 pandemic virus would take on the behaviour of seasonal influenza virus and continue to circulate for some years to come. Hence, in the post-pandemic period, localised outbreaks of varying magnitude with significant level of H1N1 transmission are expected.
"Subsequent to this declaration, our country had experienced major outbreaks during the period August to October 2010 and again from May 2011 to July 2011. Now, in March-April 2012, there is an increased number of cases of pandemic influenza A H1N1 reported from some states," the ministry said.
"In the first week of March almost 30% of referred samples were positive for H1N1 in Pune, this has now come down to approximately 10%," the ministry stated.
A large number of these cases will present a mild influenza-like illness and as such requires no testing or anti-viral drug treatment.
"However, it is important to get oneself examined at the nearest hospital in the initial part of the illness to detect moderate illness and other associated risk factors/diseases that require hospitalisation," the health ministry said.
The anti-viral drug oseltamivir is available free of cost through the state public health system. It is also available with retail chemists licensed to keep Schedule X drugs.
A central stockpile of about 8 million doses of oseltamivir is also maintained. As the virus is circulating within the country, there is no need to impose travel restrictions or screening at inter-state points of entry, railway stations etc, said the ministry.