<prompt> Influenza virus has -5 segments of SS RNA8 Segments of ds DNA8 segments of ssDNA8 segments of ssRNA  <response>: Ans. is d i.e., 8 segments of ssRNA INFLUENZA VIRUS Belong to ohomyxoviridae --. Envelope, RNA virus Contain single stranded RNA which is segmented --4. 8 pieces There are three viral subtypes Type A Causes all pandemics and most of the epidemics Type B Can cause epidemics Type C -- Causes endemic infection Three types of influenza viruses are circulating in world --A H I N 1, A H3 N2 and B A new type has been recognized -A H5 NI Source of infection -- case or subclinical case Mode of transmission -- Droplet infection by respiratory route Incubation period___ _ 18-72 hours Clinical manifestations -Most infections are subclinical - Fever, headache and myalgia - Respiratory -- coughing - There is no viremia Complications - Pneumonia -- M.C. by str. pneumoniae - Worsening of COPD - Encephalitis - Reyes Syndrome with type B virus - GB. Syndrome - G I Symptoms gastric flu --i type B virus Laboratory diagnosis -most commonly, the diagnosis is established by the use of rapid viral tests that detect viral nucleoprotein or neuraminidase - Best specimen is nasopharyngeal secretion. 