Influenza is commonly called flu. It is acute viral infection of upper or lower respiratory tract with fever, chills, feeling of weakness and pain in muscles.
The virus originated from birds attacks human respiratory system; nose, throat and lungs.it may leads to serious health complications like pneumonia leading to death. In it, mortality rate is very high. About 4-5 million Cases are reported each year and about 6,50,000 deaths each year.
Causative agent: Influenza is Caused by influenza virus; orthomyxovirus. It is single stranded , 8-segmented RNA virus. The viruses are of three types; Type- A, Type- B and Type-C.
Type- A spreads rapidly and may cause serious global pandemics.
Type- B Can Cause local outbreaks.
Type- C can Cause mild respiratory illness.
Type- A influenza virus may be of different subtypes on the basis of protein present on the surface of virus. Two types of protein are found on the surface which are Hemagglutinin (H or HA) and Neuraminidase (N or NA). There are 18 types of HA and 11 types of NA. The subtypes of Type - A are H1N1, H5N1 and H5N2.
H helps Virus to enter inside host cell while N helps virus to release and spread from host Cell.
Mode of transmission:
It is air born disease and is mainly transmitted by droplet infection by inhaling droplets produced during coughing/ sneezing.
Infection may also be caused by touching a surface or object that has flu viruses on it and then touching own mouth, nose or eyes.
Incubation period:
It is about 1-4 days.
symptoms:
⇒ Mild fever
⇒ sudden onset of fever and body Chills.
⇒ Dry cough, sore throat and hoarsness.
⇒ Headache
⇒ Running nose / stuffy nose (nose block)
⇒ Red face, Red watery eyes
⇒ Pain in muscles
⇒ loss of appetite
* Cough with fever is sign of influenza.
Diagnosis:
By swab (Nasal fluid) test, viral culture, Antigene - Antibody test & PCR test.
preventive methods:
⇒ Do not move into crowdy area.
⇒ use mask.
⇒ Avoid close Contact with infected people.
⇒ patient should be treated in Isolation.
⇒ Do not use Utensils of patient.
⇒ wash hands properly.
⇒ Avoid touching eyes, nose, mouth.
⇒ vaccination by influenza vaccine (shots).
⇒ Adopt healthy habits to help protect against flu.
Treatment: The symptoms of flu often improve with good rest and taking plenty of fluids for about one week.
The antiviral drugs like oseltamivir (Tamiflu) , Zanamivir (Relenza) , peramivir(Rapivab) etc are used.
These drugs inhibit activity of neuraminidase and prevent viral replication.