​Infectious Diseases and Microbiology - Influenza ( Influenza Virus)

​Infectious Diseases and Microbiology - Influenza ( Influenza Virus) 
Influenza A, B, and C viruses are the culprits that cause influenza. Influenza A is a contagious illness that can infect horses, birds, pigs, and people. Only humans can contract influenza B, which has a milder pandemic phenotype. Rarely, influenza C leads to subclinical illness. Respiratory droplets transmit influenza. Influenza A and B can cause antigenic drift, which involves minor changes in H or N antigens due to point mutations, or antigenic shift, which results in a major change in H or N antigens or both as a result of RNA gene segments being reassigned between the two influenza viruses. These two methods can cause antigenic variation of the influenza virus envelope proteins, hemagglutinin (H) or neuraminidase (N). In 2009, a fresh H1N1 influenza pandemic struck the world. The elderly were mainly immune to H1N1, but young people and pregnant women were particularly vulnerable.


The symptoms of influenza can appear suddenly and include fever, chills, headache, myalgia, prostration, and fever. Rhinitis and a dry cough are the next symptoms to appear. Usually taking 2-4 weeks, recovery is sluggish and accompanied by lethargy, coughing, and exhaustion. 

Influenza complications might include primary viral pneumonia (uncommon) and secondary bacterial pneumonia (common). Those with chronic heart or lung diseases as well as the elderly are at risk of problems.

Cell death occurs when the influenza virus attacks respiratory epithelial cells. Recovery from infection is linked to interferon, secretory IgA specific to the virus, and cytotoxic T-cell responses.

Viral antigen can be found in clinical specimens using immunocytochemistry or enzyme immunoassay.
In cell culture, the diagnosis virus can be isolated and identified.

Amantadine and rimantadine are antiviral medications used to treat influenza A; oseltamivir and zanamivir, which are neuraminidase inhibitors, are used to treat influenza B. The best way to avoid influenza and its complications is to have an annual vaccination against strains of influenza A and B. There is a live, attenuated influenza A vaccination available for children and adults in good health.