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Tuberculosis

Tuberculosis (TB) is making a resurgence, and the World Health Organisation has declared it a global emergency. Figures from the United States showed that during the 1960s the prevalence of TB was decreasing, during which compliance with drug regimes and reporting decreased. This allowed for the emergence of resistant TB strains, which have created renewed interest for tuberculosis control in many countries through increased publicity and funding for TB control programs.

Tuberculosis (TB) is a serious bacterial disease. The bacteria is airborne and can be coughed or sneezed into the air by an infected person. Most people who contract TB have had prolonged, close, exposure to an infected person. This means they have spent days or weeks – not just a few hours – sharing the same air space with an infected person (e.g. living in the same house). People who work or live in institutions such as nursing homes or correctional facilities are also at higher risk. Of those exposed to the bacteria, only 10% develop the disease as either infectious (lung) or non-infectious (non-lung) TB. With treatment the disease can be cured, but without treatment possible outcomes range from recovery to death.

Incidence of tuberculosis in Indonesia

The World Health Organization (WHO) has designated Indonesia a "high burden country" for tuberculosis. There are 22 high burden countries worldwide, and together they account for about 80 percent of the world’s tuberculosis infections. Expatriates or frequent travelers who spend significant amount of time in a high-burden country may benefit from TB screening. Some countries may recommend that infants and children have a BCG vaccination.

The annual risk of TB infection in Southeast Asia is 1-2.5%, representing an upward trend for the region. In Indonesia, there are roughly 500,000 new cases of TB annually and 175,000 attributable deaths. Tuberculosis is the second major killer of adults after cardiovascular disease and the deadliest pathogen out of all communicable diseases.

In global terms, there are one billion people infected with tuberculosis at any one time. Eight million new cases are reported annually with three million attributable deaths. However, despite these grim figures and without the influence of consistent treatment and immunisation, its incidence is not as high as it was in the 20th century. The problem now is that with inadequate and inconsistent treatment regimes, a pool of persistent sputum positive cases is being created.

Symptoms and Diagnosis of tuberculosis

Active TB causes a variety of symptoms that are sometimes vague, but often include cough, fever, night sweats, unintended weight loss and lethargy. Latent (inactive) TB causes no symptoms. Most strains of TB can be treated with antibiotics. Up to four different types of antibiotics may be used together to treat a patient. If left untreated, active TB can be life-threatening.

At the local level, diagnosis is best achieved through microscopic detection of bacillus in a sputum smear. Culturing bacillus is expensive and impractical as it takes 6 weeks for results, and x-rays can be misleading. Skin testing is recommended by the WHO, but it is not a test specific to human TB bacillus. Additionally, the size of the reaction is not always helpful, as strong reactions may occur in healthy people with repeated occupational exposure and people cured of TB.

It has been recognized that males in the 25 to 34-year old age group are the most common transmitters of the TB bacillus. An infectious case will typically infect up to ten other people in a year. In case-finding, the general rule is that anyone who has had a cough for more than 3 weeks should have a sputum smear. Crowded dark places are ideal areas for the spread of TB, as direct sunlight will kill the bacillus in a few minutes but it can live in dark and dusty areas up to 20 years.

Treatment of tuberculosis

No matter the treatment regime used, the following basic rules must be observed:

Any drug intake must be supervised.
Drug intake must continue until otherwise directed, which may be many months.
There needs to be an uninterrupted drug supply to prevent emergent drug resistance.

A number of drug-resistant forms of TB have emerged over the years. Multidrug-resistant TB (MDR-TB) occurs when the TB bacteria becomes resistant to both isoniazid and rifampicin. Extensively drug-resistant TB (XDR-TB) occurs when the TB bacteria becomes resistant to a fluoroquinolone (a class of antibiotics, e.g – ciprofloxacin, ofloxacin, sparfloxacin) and at least one of the three injectable drugs (capreomycin, kanamycin and amikacin), in addition to MDR-TB. Total drug-resistant TB (TDR-TB) occurs when the TB bacteria becomes resistant to all first line (isoniazid, rifampicin, ethambutol, pyrazinamide and streptomycin) and second-line anti-tuberculous drugs (ofloxacin, moxifloxacin, kanamycin, amikacin, capreomycin, para-aminosalicylic acid and ethionamide). Drug-resistant TB is acquired either through direct contact with an MDR/ XDR TB patient, or it develops when anti-tuberculous drugs are used inappropriately in a TB patient.

Prevention of tuberculosis

Travellers and expatriates may be able to reduce their chance of contracting TB by limiting the amount of time they spend in crowded places. Avoiding people who are coughing also minimizes risk. If you live in an area with higher rates of TB infection, consider screening local staff who live with you – especially if you have young children in your household.

The BCG vaccine has been used for many years and is usually given to infants in the first month of life. Studies have shown conflicting results, ranging from limited usefulness to 14 years of protection. However, it only provides protection against serious disease.

Countries such as Canada and the USA have prefered to concentrate their preventative efforts by monitoring the spread of the disease and treating these who test positive, rather than immunizing the whole population. They feel that a positive test fails to differentiate those who have been immunized from those who actually have the disease, and that the vaccine is ineffective and complicates diagnosis which takes many weeks to begin with.

European authorities believe that even the partial protection provided by the BCG vaccine is worth the increased diagnosis difficulty, and they also believe that repeated Tine testing will cause a false-positive reaction after a number of tests. This is caused by a response to the inoculation with reactive parts of the organism in the previous tests.

The BCG vaccine

Now used worldwide and originating from the first bacterium isolated (Bacillus Calmette-Guerin) isolated in Paris, France, this vaccine is freeze-dried and diluted before injection via the intradermal route over the deltoid muscle in the upper left arm. It should never be given subcutaneously as this can cause EXTENSIVE local reactions.

The result of a local lesion at the injection site is an indication that conversion to TB sensitivity has occurred. If correctly performed, this should result in close to 100% conversion. The lesion should be approximately 6-8 mm in diameter over a period of weeks and may be itchy or develop as a sore or shallow ulcer, but should start to heal in 6-8 weeks. The upper left arm should ALWAYS be used unless a sound medical reason is given, as this is the only site validated for efficiency and easily observation in future checkups.

Tuberculin testing

Three tuberculin tests are used In Indonesia:

A. Heaf test
This uses a multiple puncture 'gun' with rings of spikes to inject a purified protein derivative (PPD) from the tuberculin mycobacteria. It has fallen out of general use, as the same spike rings are used repeatedly with sterilization between patients and the AEA does not recommend it as a screening procedure.

B. Mantoux test
0.1 ml of PPD is injected intradermally into the forearm. The injection should raise a weal about 7 mm in diameter. The injection site is usually examined after 72 hours and the diameter of any induration (hardening) on light pressure is measured.

Results:
Negative: less than 5mm diameter
Weakly positive: 5-9mm diameter
Intermediately positive: 10-14mm diameter
Strongly positive: 15mm diameter or more with sores or spots

c. Tine test
Comparable to the Heaf test in that it involves inoculation of PPD from the tuberculin mycobacteria by means of similar spikes, but they are only used once.

Prevention of spreading infection from a single source

In order to limit the spread of infection in confined spaces and crowded areas such as offices, institutions and schools, the following minimum precautions should be observed in addition to medical and possibly radiological screening of personnel:

Sanitary and washing facilities in accommodation should be clean and cubicles available for individual ablutions and sleeping.
There should be a generous supply of clean towels. Soap and warm or hot water should be provided at all washing facilities, especially near kitchens and toilets.
Messroom accommodation with facilities for keeping food covered and washing hands should be available.
Paper towels are preferable to cloth napkins.
Living and sleeping areas should be constantly inspected for health concerns.
Especially in air-conditioned, moist, and confined environments, persons suffering from respiratory infections should not go to work when ill without consulting a doctor. Such environments are ideal for the spread of TB via aerosol droplet transmission.
A system should be in place for reporting the symptoms of throat and chest infections and medical surveillance of site staff.

Medical prevention of tuberculosis

Employees should undergo pre-employment medical assessments with chest x-rays and tuberculin testing especially in countries where TB is endemic. There should also be annual medical examinations conducted for all employees. Most doctors agree that resuming work after the earliest stage of treatment is justifiable, and the few differing opinions are concerned with the duration and conditions of a work cessation. In general, TB is no longer infectious after 2-4 weeks of treatment. However, multidrug-resistant forms are arising and treatment is not always applied appropriately or carried on for long enough. There may also be primary resistance to the drug(s) used and a lack of cooperation with the treatment regime.

For closed sites, it is recommended that patients be removed from the worksite for a minimum of 120 days, provided adequate treatment is available. In some countries, the regulations controlling this period are much more stringent.

IT IS CLEAR THAT THE DIAGNOSIS OF TB MUST BE CONFIRMED BY SPUTUM CULTURE AND DRUG SENSITIVITIES ESTABLISHED BEFORE A DECISION CAN BE MADE ABOUT THE RISK OF ALLOWING PERSONNEL TO RETURN TO WORK AFTER TREATMENT.

Some resistant strains may result in a delayed conversion to negative TB culture, requiring 18 to 24 months of treatment and possible surgical intervention in the case of certain stubborn strains.

For the worker, the period of rest may have to be extended in unfavorable circumstances such as a particularly serious attack of the illness, resistance to particular antibiotics, aggravating diseases, special ethnic or social circumstances, and particularly unfavorable or unhealthy conditions of work.

The above comments apply to a case where the patient is ill and therefore at risk of spreading the disease by droplet spread. TB discovered by chance, with no clinical symptoms, and resulting in two or three negative results from successive bacilloscopies is not likely to pose a risk to other workers. Absence from work over a long period is no longer necessary when major antibiotics can be used, providing a proper course of treatment is followed and clinical and radiological supervision is assured.

The decision to stop work for asymptomatic patients must still be taken whenever certain types of tuberculosis are found, the patient shows signs of bacillary dissemination, there is a progressive lesion discovered through x-rays, and clinical signs such as coughing, fever, weight loss, or pleurisy are present. In all such cases, antibiotic treatment should be continued for a total period of about a year, while a return to work may happen after 6-8 weeks of treatment, taking into account the bacteriological findings and results of follow-up.

Although correctly-treated pulmonary tuberculosis is usually cured without complications, there may be rare cases where temporary or permanent job redeployment or reclassification may be required. Examples include jobs that involve exposure to toxic substances that might amplify the toxicity of antibiotics or put the individual in contact with dangerous chemicals, as the antibiotics could impair visual or auditory acuity necessary for safe work practices.

Additional info on Tuberculosis from the US Center for Disease Control

We trust this information will assist you in making correct choices regarding your health and welfare. However, it is not intended to be a substitute for personalized advice from your medical adviser.

Our appreciation to International SOS, an AEA Company who has contributed this article in response to a growing health threat faced by expatriates in Indonesia.

If you have medical-related questions about living in Indonesia to ask of medical professionals, see Ask the Experts.