The infection was caused by the H5N1 subtype of the Influenza A virus and occurred in at least thirteen districts, including Birbhum, Nadia, Murshidabad, Burdwan, Hooghly, Cooch Behar, Malda, Bankura, Purulia, Howrah, West Midnapore, South 24 Parganas and South Dinajpur and several new inclusion are reported daily.
An ongoing or lingering pandemic may amount to a humanitarian crisis, especially where there are increasing levels of virulence, or rates of infection as in the case of AIDS, bird flu or Tuberculosis.
RT-PCR is commonly used in studying the genomes of viruses whose genomes are composed of RNA, such as Influenzavirus A and retroviruses like HIV.