Q: I was successfully treated for tuberculosis (TB) 11 years back. I have developed symptoms again now, in spite of following a healthy lifestyle. My husband's family (sister, grandmother, father) have suffered from TB (before we were married). Is it possible for a person with latent infection to spread TB through sex/kissing? Is it possible that I could have contracted TB again? I am HIV negative? I have never skipped or forgotten to take the medicine. I took the full course as prescribed by the doctor. Please advise.

A:

Productive cough, fever and weight loss are typical symptoms of pulmonary tuberculosis. Haemoptysis or chest pain, night sweats, fatigue or anorexia are the other systemic manifestations. The sputum may be scanty, or bloody and purulent, and as a result is usually associated with cavitatory lesions in the lung. Pulmonary tuberculosis may manifest in various forms including progressive pulmonary disease, involvement of pleura and reactivated pulmonary disease. Post primary (secondary) tuberculosis is caused either by reactivation of latent infection or by exogenous reinfection. Reactivation of primary lesion occurs more commonly in patients with decreased immunity such as patients receiving transplants, patients infected with human immuno deficiency virus (HIV), and in the elderly patients. Humans are the only source and reservoir for M. tuberculosis infection.

The infectiousness of the source is of primary importance, which determines the possibility of transmission of the disease. This depends on bacillary load of lesions and also on the morphology of the lesion. Lesions with cavities have 100 – 10,000 bacilli, therefore, cases with cavitatory lesions are potentially highly infectious. Cases treated with antitubercular therapy are less infectious than those who are not treated with any antitubercular drugs. The decrease in infectiousness is primarily due to reduction in the bacillary load in the lungs. Environment factors also contribute to transmission of infection. Overcrowding, poor housing, and inadequate ventilation predispose population to development of tuberculosis. Concentration of tubercle bacilli in the environment depends on the exposure to ultraviolet light and ventilation of the surroundings. The infection is transmitted from person to person by inhalation of airborne droplet nuclei. The droplet nucleus is small, measures 5 µm or less and may contain approximately 1 – 10 tubercle bacilli. Theoretically, although single tubercle bacillus may cause disease, upto 10 inhaled bacilli are essential for infection. These droplets by virtue of their small size remain suspended in the air for a very long period of time. Primary infection of lung occurs as a result of inhalation of the infectious aerosols. The risk of infection depends on the exposure to ultraviolet rays and ventilation; therefore, the risk of infection is high in small rooms and in rooms with poor ventilation. There are many risk factors for tuberculosis. HIV is one of the most important risk factors. Case rates for individuals who are infected with both HIV and M. tuberculosis exceed the infective risk of individuals with M. tuberculosis infection who are not infected with HIV. Other factors which increases the risk of tuberculosis are steroid therapy, cancer chemotherapy, malignancies and under nutrition. The later condition alters cell-mediated immunity therefore, is responsible for the increased frequency of tuberculosis in impoverished persons.

Tuberculosis: Will it spread if we kiss?

Tuberculosis may be transmitted during the act of kissing if the person kissing is an open case of tuberculosis excreting large numbers of mycobacteria in the sputum. Transmission through sex is a possibility, but is rare. You are advised to consult your Physician for rechecking your health status and reviewing your antitubercular regimen, because drug resistance in the mycobacteria is a notorious problem encountered frequently nowadays. Please get your blood screened for HIV antibodies by ELISA.