You may have TB and not know it

MANILA, Philippines -  Yes, you may have tuberculosis, but may not know that you have it. Latent TB, also known as LTBI or latent tuberculosis infection, is where the tuberculosis bacteria in the body is not active (it is latent)  so the person is not sick with the tuberculosis disease. It is not infectious and can remain dormant for many years without causing any symptoms.

“It can stay in your body most of your life and you do not know it,” says Camilo C. Roa, a full professor at the Department of Physiology of the University of the Philippines (UP) College of Medicine and clinical professor and attending physician at the Department of Medicine of the Philippine General Hospital (PGH). The thing is, “without treatment, about five to 10 percent of persons infected with latent TB will develop the TB disease at some point in their lives,” Dr. Roa explains. “About half of those people will develop TB within the first two years of infection.”

A person can get the disease by breathing infected air during close contact with an infected person who spreads it when coughing, sneezing, or even just singing. Because we all breathe, everyone is susceptible.  “It is an airborne infection,” Dr. Roa explains. “You get it by inhaling, and not by drinking from a glass or using the utensils used by an infected person.” Unfortunately, myths such as this and a certain stigma continue to be attached to the disease. There is still the reluctance to recognize or admit that one might have it.

“About one third of the world population is believed to be afflicted with latent TB,” Dr. Roa points out.

When the immune system is weak, the TB can become active. This is especially true among children below five years old. Other risk factors include diabetes, kidney disease, HIV, drug use, and smoking. Persons who underwent organ transplant operations are at high risk, as well as certain occupations such as health care workers. The risk of transmission is high in settings where people congregate such as schools, hospitals, dialysis units, nursing homes, and even jails and prisons.  

Here are the statistics: There are two billion infected worldwide, one person dies of the disease every 25 seconds. Asia accounts for 59 percent of the TB cases. The Philippines ranks second only to Cambodia and higher than India in terms of TB prevalence.  And we’re seventh in the region with the highest number of new TB cases.

 â€œTuberculosis is a global public health concern,” says visiting TB expert Dr. L. Masae Kawamura who was invited by United Laboratories (UNILAB) to hold a symposium on latent TB to raise awareness about it. “Early screening and subsequent prevention is a way to break the chain of TB transmission,” Dr. Kawamura stresses. She advocates a proactive approach by putting the focus on diagnosing TB before it becomes symptomatic or contagious, as opposed to the current practice of putting the focus on diagnosing patients who are already sick or found with TB inadvertently or by chance when tested for some other purpose.  TB cases should be actively sought in high-risk persons and targeted groups.

“It is not enough to just treat the person with TB, we must look for contacts such as other family and house members,” says Dr. Roa, an active clinician whose advocacies in tuberculosis control, asthma, chronic obstructive lung diseases, and lung infections garnered  for him the Civil Service Commission’s Gawad Lingkod Bayan award.

The TB Skin Test (TST) is one of the more common diagnostic tools for TB infection, but it has certain infirmities and problems with standardization. With advances in science and molecular technology, new and better tests have been developed, such as the Interferon Gamma Release Assays or IGRAS, a blood test for TB infection which is more specific than the skin test, Dr. Kawamura explains.

On the debate about treating LTBI, Dr. Kawamura cites a study by Dick Menzies (Indian J Med Res. 2011 March, “Recent developments in treatment of latent tuberculosis infection”) comparing LTBI and hypertension.  “Both are asymptomatic. Both have serious complications such as death and major disability. TB has the added bonus of transmission. Treatment for both takes time, with potential serious side effects, and requires close monitoring and followup. The difference is that hypertension treatment is expensive yet universally recommended, while LTBI treatment is cheap and the duration of treatment is shorter, about six to nine months.” And yet the debate about the treatment is only for LTBI, Dr. Kawamura rues.

TB is not only curable but preventable, too, says Dr. Kawamura. We can prevent TB in those with latent infection by targeted screening of high-risk groups. We can reduce transmission and reduce morbidity and mortality from TB through early diagnosis and treatment.

Should healthy individuals consider getting tested for LTBI?  If she ruled the world, as Dr. Kawamura would say, there should be no question about it.