TB hee-bee-gee-bees: Tuberculosis causes and concerns

Dear Alice...

My boyfriend just got a positive TB test. I wonder if his dog could be the cause of this. He lives alone in his apartment, so the cleanliness is often worrying. And does this mean we cannot do intimate stuff, i.e., kissing anymore? Does walking in the park and frequently breathing in morning air help at all?

Thank you, Alice...

Dear Reader,​

So… unlike silent (but pungent) flatulence, you may not be able to blame this one on the dog. When it comes to how tuberculosis (TB) is spread, the most common way is from one person to another. Tuberculosis, a bacterial infection of the lungs that can be fatal in serious cases, spreads through the TB bacteria that become airborne when an infected person coughs, speaks, sings, etc. People nearby could breathe in the bacteria in the air and become infected. Research suggests that transmission of TB from dogs to humans is highly unlikely because of a number of reasons, though there are some precautions you may take to prevent this unlikely event (more on this later). And, while a walk in the fresh air might be good for your overall well-being, it's recommended that your boyfriend follow whatever treatment plan prescribed by the health care provider. Now, more on TB and what a positive test means!

While a positive TB test result may sound alarming, it doesn’t necessarily mean that your boyfriend has TB. The result could mean that your boyfriend was exposed to TB through a vaccine that is typically used in countries outside of the United States (where TB is more common). When there’s suspicion of TB, a health care provider typically performs further tests to confirm and determine whether it’s in the latent (you have no symptoms and aren't contagious) or active (you have symptoms and are contagious) stage. If a diagnosis has been made, antibiotics may be prescribed for about six months. Most people can take the recommended antibiotics without experiencing major side effects, but it's recommended that they inform their health care provider if the following symptoms appear:

  • Yellowish skin
  • Loss of appetite
  • Stomach cramps
  • Unexplained fever
  • Dark urine
  • Vomiting or nausea

Adapted from Mayo Clinic.

In order to make sure that all the bacteria have been killed, it’s recommended to keep up the daily regimen and complete the entire antibiotic treatment. If the course of antibiotics are not completed, TB bacteria could survive in the body and pose a threat of developing active TB later in life.

If latent TB develops, its onset may be tricky to notice. Those with latent TB infection have no symptoms, do not feel sick, cannot spread TB to others, but could develop active TB later in life if they're not treated. Since those with latent TB infections cannot transmit TB, there is no harm in kissing them (where, in contrast, people with active TB can spread the disease to others). Symptoms of active TB disease include a persistent cough, fever, weight loss, night sweats, lethargy, and a loss of appetite, as well as a bloody cough in people with advanced active TB. It may be helpful to know that active TB is much less common than the latent, but speaking with a health care provider and following an appropriate course of treatment is nonetheless highly recommended. Regardless of whether it's latent or active TB, you might feel more comfortable getting a TB skin test yourself; it’s possible that you were exposed to the same original source of TB. To learn more about tuberculosis, the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) are great resources.

As for your boyfriend's dog, no need to turn on this furry friend just yet. Many species (e.g., elephants, birds, etc.) could transmit tuberculosis across species, but the case of a dog spreading TB to its human companion is highly unlikely — though not impossible. Humans could share different strains of TB bacteria with animal companions when there’s a lot of close contact with the bodily fluids of infected animal. Folks who may especially want to watch out for this cross-species spread are those who are generally at higher risk for the disease, including the elderly, children younger than five years old, and people with a weakened immune system. Conversely, people with active TB could spread the disease to dogs and other pets if the furry (or not-so-furry) friend has access to human trash that contains infected sputum (saliva and mucus), shares food, sleeps in the same space, and likes to lick the infected person’s face. Since pets also need a regular check-up to stay in tip-top shape, it may not be a bad idea to encourage your boyfriend to set up a visit with a veterinarian for a canine check-up. You might also consider checking out the CDC's Healthy Pets Healthy People resource to get more tips on supporting the health of furry (and not so furry) pets and their human companion(s).

Finally, your boyfriend's apartment is likely not the cause of this infection either. It might be worthwhile, however, to emphasize clean housekeeping in promoting health and relationships. All in all, you can take a deep breath, know that the dog is likely fine, and encourage your boyfriend to follow the instructions of the health care provider. Though this likely isn’t a serious illness situation, keep up the healthy habit of taking precaution and seeking information.

Last updated Dec 23, 2016
Originally published Jul 12, 2002

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