Tuberculosis

Tuberculosis is a quite common epidemic disease, especially in China. ALthough these years we did a lot to control it, it is still sever, we still have a long way to go. So let's have a look at what tuberculosis is.

Tuberculosis is caused by a bacteria names "mycobacterium tuberculosis", of course it is not the only cause of TB, but definitely the most common one around the world.

Tuberculosis

TB spreads mostly through the air. We know a sick person usually cough a lot, and then the other one near him might breathe it in and he may get TB by this way. But sharing food and drink or touching objects touched by a patient are not likely to be ways of spreading TB.

So how can we figure out if someone has TB?  We can tell it from two aspects:

1.Symptoms: including constitutional symptoms and lower respiratory tract symptoms. The  former one refers to fever,chill,night sweats,weight loss and so on. The latter includs cough, even hemoptysis, chest pain, dyspnea, ect.

2.Duration: it means how long the symptoms mentioned above are going for. Usually it lasts more than 3 weeks.

Tuberculosis

Now let's take a look at how tuberculosis infects us.

An individual breathes in mycobacterium tuberculosis, and then the bacteria goes down the person's airway and land in the lung. The host's immune system kicks in with that. Macrophages in the lung are the first "army" to greet these bacili, they take up the bacteria and then come together forming "granuloma". Once that granuloma becomes large enough to see, we call it"Ghon focus". If the local infection isn't controlled, the bacili might travel along the lymph-vessel to the hilar lymph nodes. Ghon focus, lymphangitis plus tuberculosis of the hilar lymph nodes is referred to as a " Ghon complex". All these mentioned above refers to primary infection, that means a person infects mycobacterium tuberculosis for the first time, this occurs among children usually. In most cases, the bacteria remains in where it is as a latent state and remains latent without causing any problems. But about 5 percent of the infected people, their primary infection is progressive and cause problems. The bacteria may even disseminate widely, not only in the lung, but also other organs, like liver, brain, ect.

Tuberculosis

If someone in latent state infects the bacteria again and the bacteria reactivates, we call it "secondary infection". This might happen in any stage of one's life, but mostly occurs among adults. The reactivation is actually influenced by many factors, including the decrease of the host's immune system, patients who have diabetes, patients who are malnourished and so on. These factors will increase the risk of getting secondary infection.

These are some ways can protect you from getting TB infection the picture below.

Tuberculosis