3.What is the way of classification of infectious diseases according to the way of infectioning?

Direct contact  An easy way to catch most infectious diseases is by coming in contact with a person or animal who has one. Three ways infectious diseases can be spread through direct contact are:

• Person to person. The most common way for infectious diseases to spread is through the direct transfer of bacteria, viruses or other germs from one person to another. This can occur when an individual with the bacterium or virus touches, coughs on or kisses someone who isn't infected.

• Animal to person. Pets can carry many germs. Being bitten or scratched by an infected animal can make you sick

• Mother to unborn child. A pregnant woman may pass germs that cause infectious diseases to her unborn baby through the placenta milk delivery waters.

Indirect contact  Disease-causing organisms also can be passed by indirect contact. Many germs can linger on an inanimate object, such as a tabletop, doorknob or faucet handle.

Insect bites  Some germs rely on insect carriers — such as mosquitoes, fleas, lice or ticks — to move from host to host.

Food contamination  Another way disease-causing germs can infect you is through contaminated food and water.

4.What is immunity?What types of immunity do you know?Describe the types.

Immunity is a state in which the body is protected from infectious disease.

There are three categories of immune protection, all of which help protect the body from infectious diseases. Immunity can be innate or acquired, active or passive and natural or artificial.

Acquired immunity obtained either from the development of antibodies in response to exposure to an antigen, as from vaccination or an attack of an infectious disease, or from the transmission of antibodies, as from mother to fetus through the placenta.

Acquired immunity can be active or passive. Active immunity results from the development of antibodies in response to an antigen, as from exposure to an infectious disease or through vaccination.  Passive immunity  develops when a ready-made antibodies in serum are administered to a person or transfer from child to mother through foremilk or by intrauterine method

Innate immunity that occurs naturally as a result of a person's genetic constitution or physiology and does not arise from a previous infection or vaccination. 

Natural immunity include transfer from child to mother and after person suffered this disease

Artificial immunity arise when a person is given an alredy made antibodies in a serum or through the vaccination

5.What is influenza, its cause, way of transmission, symptoms, treatment and complication?

The flu is a higly contagious respiratory illness caused by influenza viruses(A, B, C). The flu is spread in droplets released by coughing and sneezing(air-droplets way). It usually spreads from person to person.The flu usually starts suddenly and may include these symptoms:

• Fever or chills

• Cough

• Sore throat

• Runny nose

• Muscle or body aches

• Headaches

• Fatigue (tiredness)

• Some people may have vomiting and diarrhea, though this is more common in children than adults

There are influenza antiviral drugs that can be used to treat flu illness and influenza vaccination as the first and most important step in preventing flu. Drink enough fluids so that you do not become dehydrated. Rest until the flu is fully resolved, especially if the illness has been severe

Some of the complications caused by flu include pneumonia, dehydration, and worsening of chronic medical conditions, such as heart or lung disease, asthma or diabetes. Children may get sinus problems and ear infections