TB Infection Contracted By Almost One In Six Child Contacts of Immigrants With Tuberculosis, Netherlands

Main Category: Tuberculosis
Also Included In: Pediatrics / Children's Health
Article Date: 01 Jul 2005 - 23:00 PDT

email to a friend   printer friendly   opinions  

While tuberculosis is relatively uncommon in Europe generally, it is increasingly widespread among migrants and other vulnerable groups. In the Netherlands, 16% of children in contact with immigrants who have pulmonary tuberculosis catch the disease, according to a study to be published in the July issue of European Respiratory Journal (ERJ). The authors call for better prevention.

While tuberculosis can affect the urinary tract, bones and brain (in which case it is referred to as extrapulmonary tuberculosis), it vastly prefers to attack the lungs. And the pulmonary form of tuberculosis is the most contagious one. When sufferers laugh, cough, sneeze or spit, they spread micro-droplets of mucus, containing Mycobacterium tuberculosis bacilli, into the surrounding air, and other people can get infected by inhaling these. Not all carriers will develop the disease, which remains latent in 90% of subjects. Where the infection is identified (for example by means of a tuberculin test), the patient can receive preventive treatment to prevent the full-blown condition developing.

Tuberculosis has declined markedly in western Europe. However, there is an alarming resurgence of the disease among migrants and vulnerable groups.

Since immigrants represent two-thirds of TB patients in western Europe and still have a high incidence of the condition a decade after their arrival, probably because of repeated infections within immigrant communities, a group of researchers in the Netherlands, led by Martien W. Borgdorff of the KNCV Tuberculosis Foundation (The Hague), set out to examine the degree of infection suffered by a particular group, namely children of immigrants, in regular contact with a TB patient.

How many were infected? What were their risk factors for infection? Was their infection active or latent?

The alarming figures published by the team in July's ERJ raises serious questions about the effectiveness of the TB screening and prevention measures currently in place.

Three times the risk for those born abroad

Borgdorff and his colleagues examined 359 children aged up to sixteen who had frequent contact (at least four times a week) with TB-infected immigrants.

Their results are a cause for some concern. They show that TB infection, both active and latent, is relatively widespread in children in contact with immigrants: while 16% of children in contact with a pulmonary tuberculosis sufferer were found to be infected, 2.5%, or nine children, had active disease. Their infections originated in a group of seven relatives and friends who were pulmonary TB patients and lived under the same roof.

When the researchers analysed the elements influencing child infection, they found that the only really significant risk factor was being born abroad.

"All infected child contacts of extrapulmonary TB sufferers were born abroad, and the mere fact of being born outside the Netherlands increases the risk of infection by 3.52", explains Suzanne Verver, the first author of the ERJ article.

The study also shows that children born in countries with a severe TB epidemic, such as those of sub-Saharan Africa, are clearly at greater risk: child contacts of Somalis with pulmonary tuberculosis are the worst affected, while children born in Asia have a smaller risk.

Major policy implications

The study thus underlines the importance of looking for secondary infection among the contacts of patients diagnosed with tuberculosis, particularly in immigrant communities.

"Not enough contacts are screened at present", emphasises Verver.

Moreover, children with latent tuberculosis need preventive treatment, which is not very expensive. Through extrapolation of the infection rates found in this study to all immigrants with pulmonary tuberculosis in the Netherlands, the authors are able to estimate that fewer than 80 children are newly infected each year, and this number, in their view, is small enough to make preventive treatment feasible.

http://www.cedos.int.ch

• Additional
• References
• Citations