Tuberculosis (TB) is an infection caused by a bacterium called mycobacterium tuberculosis.

It usually infects the lungs and is transmitted when an ill person coughs bacteria into the air, and a well person breathes in the bacteria.  It is difficult to transmit the bacteria, as it usually requires prolonged exposure (days to weeks) to contaminated air in an enclosed space.  About 90% of healthy people who are exposed to the bacteria do not become seriously ill; their immune system controls the bacteria for their lifetime.  About 5% of people who are exposed will develop active TB of the lungs within one year.   People with underlying severe illnesses (such as cancer or abnormal immune systems) are at increased risk of developing the disease.

If there is a possibility a person has been exposed to the TB bacterium then he or she should contact their physician who can perform a Mantoux skin test to determine if he or she has been exposed at some time in their life.  This test only indicates if a person has been exposed; it does not determine if the person has active TB disease.  If the skin test is positive (a raised area within 48 hours of the test) then a chest x-ray may be done to rule out active disease.  If the chest x-ray is normal, an antibiotic may still be recommended.  If the chest x-ray shows TB of the lungs, further tests and antibiotic therapy are indicated.

A person with TB is only contagious when coughing up the TB bacterium.  After two to three weeks on appropriate antibiotics, almost all people are no longer contagious.

Mantoux skin tests, also called PPD or TB skin tests, are routinely required by many employers and schools.   You were required to have one on entrance to the College.  This is a common test and again, only indicates exposure to TB.

Some people, mainly from Asia, India, Latin America, and some parts of Europe, have received a drug called BCG.  This drug was used to possibly control TB disease in areas where transmission occurs very frequently.  This drug will possibly give a person a positive Mantoux skin test. This response is highly variable and unreliable.  There is no good way to tell if a positive skin test is from BCG or from early infection with TB.

If you have further questions please do not hesitate to call the Student Health and Wellness Center at 925-631-4254 or ext. 4254.

Information about INH

The medicine you have received (called isoniazid or INH) had been prescribed to help protect you from developing active tuberculosis.  It will be most effective if you follow these instructions:

  1. Take the pills as the doctor has directed.


  1. Take the pills every day.  Do not take a double dose if you forget a day.  Keeping them by your toothbrush will help you remember.
  1. INH increases the body’s need for vitamin B-6.  You may be given this along with INH.


  1. Avoid drinking any alcohol!  Alcohol may cause inflammation of the liver when taken with this medication.

If you experience any distress after starting the medicine, contact the Student Health and Wellness Center.  Any medication may cause symptoms or side effects.  If you have the following, stop taking the pills and call the Health Center.

  1. Unexplained loss of appetite, nausea, vomiting, fatigue or weakness lasting more than three days


  1. Numbness and/or tingling of the hands or feet
  1. Dark urine, yellowing of the eyes, rash or fever


  1. Tenderness of the abdomen
  1. Weakness of the wrist or ankle


You will be contacted by a nurse from the Health Center monthly so we can assess your progress and answer any questions.

If you have questions, please call the Student Health and Wellness Center at 925-631-4254.