When someone has active TB disease, it is very important to find out if the disease has spread to other people. When public health workers look to see if the disease has spread, it is called a contact investigation.

A person with TB can spread the infection without even knowing it. If TB has spread to other people, they will need medicine so they don't get sick.

Information that you give to a public health worker during TB contact investigation is confidential. Your privacy will always be protected.

What happens in a TB contact investigation?

The public health worker will ask you when you started coughing or feeling sick. Try to think of all the people you have spent time with, including people living in your home, visitors, children, friends, coworkers, classmates, and babysitters. Think back several weeks or months to the time when you became sick or started to cough. Then the public health worker will determine who needs to be tested for TB.

What you tell your public health worker is private information. Your public health worker will not tell anyone else your name or information about you unless you say it is okay. This means that you can be honest with your public health worker.

Your public health worker may need to check the airflow in your home or other places you spend time. This helps decide who should have a TB test.

Your public health worker will arrange for people to get TB skin tests, but they will not tell them who has TB. The people who spent the most time with you will be tested first.

TB contact investigations take time. Your public health worker wants to make sure that everyone who needs a test can get one. Because of this, your public health worker may need to ask you the questions more than one time. They may ask you some different questions later. This is so that they can understand all of the information. Remember, what you tell your public health worker is private information.

How do people get TB?

Anyone can get TB. When someone who is sick with TB in their lungs coughs or sneezes, they can spray tiny TB germs into the air.

airborne spread of active TB.

If you spend time close to someone who is sick with TB in their lungs, you may breathe their TB germs into your lungs. This is how you get TB.

You cannot get TB from shaking hands or from clothes, food, dishes, or touching objects.

There is good medicine to treat LTBI and active TB disease.

What is the difference between latent TB infection and active TB disease?

When the TB germs get into the body, they usually go "to sleep." This is called "latent TB infection" or "LTBI." "Sleeping" TB germs do not hurt your body or make you sick. LTBI can last for many years. The Mantoux TB skin test can tell if there are TB germs in your body.

"Active TB disease" is when the TB germs "wake up" and start to grow and hurt your body. People with active TB disease can get very sick. TB symptoms include a cough that doesn't go away, losing weight, poor appetite, sweating at night, fever, and pain in your chest. If the TB is in their lungs, it can spread to other people.

About 10% of people with LTBI develop active TB disease. If you have other health problems, this risk may be higher.

If I have active TB disease, how can I protect my friends and family?

Four important things you should do are:

Take your TB medicines as directed. When you start taking your TB medicines, your doctor will do tests to see how well the medicine is working. When the medicine has killed enough TB germs you need to continue taking the medicine, but you can no longer spread TB.
Until you can no longer spread TB, always cover your mouth with a tissue when you cough.
Your public health worker will tell you what else you can do to avoid spreading TB germs to other people.
- You may need to stay away from public places, work, and school.
- You may need to keep visitors away from your home.
Help your public health worker with the TB contact investigation. Your public health worker wants to keep your family and friends healthy and safe from TB.

Someone I know has active TB disease of the lungs. What should I know?

If you have spent a lot of time with someone who has active TB disease, you may have breathed TB germs into your body. It is very important for you to be tested for TB.

Your public health department will arrange for you to get a free Mantoux test if you need one.

If your Mantoux test is "negative," (normal) you probably don't have TB germs in your body. To be sure about this, people may need to have another test several weeks later.

If your Mantoux test is "positive," you have TB germs in your body. You will need to see a doctor and have a chest x-ray to tell whether you have latent TB infection (LTBI) or active TB disease. If you have LTBI, it is very important that you take medicine to kill the TB germs.

Young children or people with HIV or certain health problems are more likely to develop active TB disease than other people. They may need to take medicine even if their Mantoux test is negative.

If you have symptoms of TB (cough that doesn't go away, losing weight, sweating at night, poor appetite, fever, chest pain), you should see a doctor even if your Mantoux test is negative.

What should I do if I have already had a positive Mantoux test?

If you have a written record that you have had a positive Mantoux test, you do not need another one. If you don't have a record, you need another test now. This will not hurt you.

What about BCG vaccine?

BCG does not always protect you from TB. BCG does not always cause a positive Mantoux skin test.

If you have had a BCG vaccine, it is safe for you to have a Mantoux skin test.