Healthcare workers in the developing world have a significantly higher level of latent tuberculosis (TB) infections than the general population, according to a study published in PLoS Medicine.

This conclusion highlights the risk of TB transmission from patients to healthcare workers, with a subsequent impact on health services — a problem frequently neglected in countries that lack the resources to prevent it.

Researchers reviewed 51 published studies concerning healthcare workers and TB in several developing countries, including India, Malawi and Peru. The analysis shows that, on average, 54 per cent of healthcare workers have latent TB (where the bacterium responsible for the disease causes no symptoms but remains in the body).

They also found that the level of active disease among healthcare workers is higher than the general population, and that longer exposure was related to a higher prevalence of latent infection.

Many cases could be directly attributed to occupational exposure. Certain workplaces, such as in-patient TB facilities, laboratories and emergency facilities, carried a higher risk of infection. Some occupations, such as radiology technicians and nurses, were also more likely to be infected.

More than 90 per cent of the world's TB cases are found in hospitals in developing countries. Many of these facilities lack the resources to prevent TB transmission.

The authors call for simple measures, such as early diagnosis, segregation of infectious patients, and better training of healthcare workers, to be implemented.

They also say that further research into cheap and effective prevention measures in resource-limited settings is needed — particularly with the emergence of extensively drug-resistant TB.