Question

Discuss the medical and epidemiological features that you would expect to be associated with a novel Avian Influenza virus epidemic

Answer 1

Avian influenza virus occurs naturally in wild aquatic birds and can infect humans through domestic poultry. This virus is known as avian influenza type A viruses. It spreads to humans through very easily even the person inhales the air which has virus. Strains present in poultry are either non-pathogenic or mildly pathogenic in nature and may convert into pathogenic strain by genetic mutation. In 1997, occurance of infection in humans by H5 avian influenza virus leads to the consideration of avian species in epidomology of human influenza.

Novel Avian influenza virus (H7N9) was first reported in Shanghai in 2013 and readily spread to nearby cities in China. Outside China there was only one case in Taipei. By 2014, there were 440 human cases out of which 220 were from China. The patients age was ranging from 2 to 91 years with the median age of 61 years. Most of the patients were poultry workers. There is no evidence of person to person transmission of virus as no healthcare personnel or people in close contact were reported as affected. Scienctic study reported that patients with high severity were obese, smokers, compromised immunity or drug users.

Study has established that patients were at high risk of acute respiratory distress syndrome and respiratory failure. One of the reason for outbreak of this influenze is widespread (90%) use of H5N1 vaccine which has common subtype with H7.

Mutation in the receptor binding site of hemagglutinin gene has lead to increased affinity towards human salicylic receptors of the respiratory tract.