A new low-cost screening strategy could aid the detection and treatment of Chagas disease in poor countries, scientists report.

The research, published in PLoS Neglected Tropical Diseases last month (26 December), shows that data on the number of parasite-carrying insects from insecticide spraying campaigns can be used to identify clusters of high-risk children who should be tested.

Previous Chagas disease control programmes have focused on interrupting the transmission of the Trypanosoma cruzi parasite by controlling its vector — the blood-sucking triatomine bug — with measures such as insecticide spraying , rather than on active case detection and treatment.

These programmes have been highly successful, but early diagnosis is essential for effective treatment — the earlier a child is treated for the disease, the more likely they will be cured of it.

The scientists looked for antibodies against T. cruzi in the blood of 433 children aged 2–18 living in a poor neighbourhood in the southern Peruvian city of Arequipa.

They found that 5.3 per cent of the children had contracted the infection before their households received insecticide application. Additionally, those infected lived in tight clusters.

The team, led by Michael Levy of the US-based Fogarty International Center of the National Institutes of Health, then compared this information with data obtained during a vector control campaign.

Levy and colleagues concluded that data easily collected during an ongoing insecticide spraying campaign in Arequipa could be used to identify children at greatest risk of infection with T. cruzi.

He told SciDev.Net that, to put this new strategy into practice, Latin American governments can "train exterminators to gather information on bugs and other indicators of disease transmission while vector control professionals apply insecticide to houses". 

"The ecology of Chagas disease varies greatly from country to country, so local expertise will be key to tailor the targeted screening strategy to the different species of insects," Levy added.

Chagas disease affects an estimated 11 million people in Latin America according to the WHO, and kills more people than any other parasitic disease in this region.


Link to full paper in PLoS Neglected Tropical Diseases

Reference: PLoS Neglected Tropical Diseases doi 10.1371/journal.pntd.0000103 (2007)