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Influenza

Flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. It can cause mild to severe illness, and at times can lead to death. The best way to prevent flu is by getting a flu vaccine each year.

Symptoms: Cough; Sneeze

or

Disease characteristics

It is an acute respiratory viral infection. The important clinical features are Sudden high fever, headache, muscle aches, fatigue Influenza is one of the most important diseases in emerging and re-emerging infectious diseases. Due to outbreaks around the world (pandemic) many times. Each time it occurred widely on almost every continent. causing sickness and death to millions of people

Cause

It is caused by three types of influenza viruses (types) A, B and C. Type A is the type that causes widespread outbreaks around the world. Type B viruses cause regional outbreaks, while type C is often infectious. with mild or subclinical symptoms and does not cause an outbreak

Type A viruses are divided into subtypes based on different viral proteins known as The hemagglutinin (H) and neuraminidase (N) subtypes of the A virus currently found to cause infections in humans are A(H1N1), A(H1N2), A(H3N2), A(H5N1) and A(H9N2) virus type B is not divided into subtypes.

Since influenza viruses have 7-8 separate genomes of RNA, the genome is often subject to genetic variation, known as genetic variation. Genome alteration also alters the antigens that are the products of the genes, that is, antigenic variation. which has 2 types:

Antigenic drift is a small change in antigens. Due to RNA point mutation, one or more amino acids are changed. But not enough to cause H or N to change. The antigenic drift caused a relatively small outbreak.

Antigenic shifts arise from a gene reassortant process, where two strains of influenza A viruses infect one cell. A genome from one virus strain is inserted into particles of another virus strain in the same cell. produce new types of virus particles where the antigen changes to the point that the H or N is changed to a new subtype, causing a pandemic in the past.

can now be found There are 15 different hemagglutinin (H) and nine neuraminidase (N) types of A virus, but only H1N1 and H3N2 are more common in humans. Due to the frequent changes in antigens, new influenza virus strains are produced in different places and at different time intervals. Therefore, there must be a nomenclature system to prevent confusion. A panel of experts has set the name of influenza in accordance with international principles around the world as follows. Virus type/City or country in which the virus was found/Place order found in that year/Year Isolated AD/subtypes of H and N such as A/Sydney/5/97(H3N2), A/Victoria/3/75/(H3N2).

Ecological studies indicate that mammalian influenza viruses originate from avian influenza virus, aquatic birds as reservoirs. in the intestines of wild duck animals without causing symptoms These animals excrete large amounts of the virus with their feces. A large number of teal chicks are produced each year around the world, and these chicks are exposed to the waterborne virus. When the baby teal grows up, it migrates and spreads kratom. spread the virus widely

A 1997 outbreak of avian influenza on Hong Kong Island, caused by the H5N1 virus, suggests the infection is spread from shorebirds to ducks through faecal contamination. It then spreads to chickens and settles in live bird markets. Coastal birds and ducks are free from disease because they are natural reservoirs. Chickens are highly infectious and die. People are infected through fecal oral contaminated chickens. The virus is transmitted through multiple races and is highly pathogenic in chickens and humans. A reassortment of viruses of different species occurs. It could easily lead to the addition of new subtypes that can infect humans. It has been studied that the use of duck feces in fish feeds leads to the transmission of avian influenza virus to pigs. The infection may be transmitted in feed and carcasses of birds fed to pigs.

Contact method

The influenza virus is transmitted through respiratory tract. It can get airborne contaminants when a patient coughs, sneezes, or speaks. In crowded areas such as schools and factories, transmission is highly contagious. In addition, transmission of infection may occur by touching the snot droplets. The patient’s saliva (droplet transmission) from hands that have come in contact with surfaces that have influenza virus. Then use your hand to touch the nose and mouth.

Incubation period

about 1-3 days

Contact distance

A patient can transmit the influenza virus one day before symptoms develop and continues to spread the virus 3-5 days after symptoms develop in adults. In children, it can be transmitted for more than 7 days. People who have been exposed to the influenza virus but have no symptoms can also spread it during that time.

Differential diagnosis

It is difficult to differentiate influenza from other pathogens based on clinical features alone. Other organisms that can cause flu-like symptoms include Mycoplasma pneumoniae, adenovirus, respiratory syncytial virus (RSV), rhinovirus, parainfluenza virus, and Legionella spp.

Laboratory tests to confirm the diagnosis

• Influenza virus is detected in sputum smeared or sucked from the nose or throat; or
• Influenza virus antigens were detected in epithelial cells from nasopharyngeal secretion by fluorescent antibody method or
• At least a 4-fold increase in serum immunity was detected in the acute and convalescent phases by standard haemaglutination inhibition (HI) or complement fixation (CF) or Enzyme-linked immunosorbent assay ( ELISA)

Signs and symptoms

Symptoms begin 1-4 days after infection. Patients will develop a sudden onset of fever (38 C in adults, often higher in children), headache, chills, muscle aches, extreme tiredness, and possibly a stuffy nose. Sore throat. Long-term illnesses may include coughing from post viral bronchitis. Symptoms are more severe and last longer than the common cold. Most people get well within one to two weeks, but there are some. severe cases Because there is a major complication is pneumonia, which can lead to death. Those at high risk of complications or death include:

• People aged 65 and over
• Children under 2 years
• Patients with chronic diseases such as lung disease, heart disease, kidney disease, diabetes, immunodeficiency
• Children who have been treated with aspirin for a long time.
• Stage 2 or 3 pregnant women in high flu season.

Treatment

Administration of amantadine hydrochloride or rimantidine hydrochloride within 48 hours for 3-5 days reduces symptoms and the number of A virus types in respiratory secretions. Dosage for children aged 1-9 years: 5 mg/kg/day in 2 divided doses; for patients 9 years of age and older: 100 mg twice a day (but if the patient is overweight less than 45 kg, use the same dose for children aged 1-9 years) for 2-5 days for patients 65 years of age or older or those with impaired liver and kidney function. need to reduce the dose.

In the later stages of antiretroviral therapy Drug resistance may be found followed by spreading the disease to others. In this case, antiretroviral therapy may be needed to group at high risk. If there are complications from bacteria Ria also needs to be given antibiotics. Antipyretics such as salicylates should be avoided to reduce the risk of Reye’s syndrome.