A single intervention for cockroach control reduces cockroach exposure and asthma morbidity in children

Cockroaches are small, scurrying insects that we just don’t like to think about.  But as small as they are, they have a large impact on asthma and allergies.  In this month’s issue of JACI, Rabito and colleagues look at the effect of cockroach elimination on asthma outcomes (J Allergy Clin Immunol 2017; 140(2): 565-570).  They build on previous work showing that integrated pest management (IPM) reduces cockroach levels.  But because IPM is s costly and requires special expertise, it is generally not practical for low-income families.  Instead, the authors looked at the efficacy of insecticidal bait, which is much cheaper and can be done by almost anybody. 

They followed 102 children (between the ages of 5 and 17) who live in New Orleans. At the beginning of the study, field technicians laid traps for cockroaches.  Over the next 12 months, 53 of the children’s houses were visited six times to place the bait, and asthma was evaluated every 2 months by standardized questionnaires. The remaining 49 were in the control group, meaning that they did not get the insecticidal bait placed in their houses.

After 12 months, they found that cockroach levels were reduced in both groups, although the intervention had near complete elimination.  Compared to the control group, the group that had the baits place had 47 fewer days with symptoms over the year, and a 17% reduction in unscheduled Emergency room and unscheduled clinic visits.  Although benefit was mostly seen in children with cockroach allergy, the benefits were also seen in children without cockroach allergies, suggesting that irritation may also be a large part of why cockroach exposure drives asthma symptoms.

The investigators conclude by noting that because insecticidal bait is inexpensive and placement has a measurable impact on asthma outcomes, this could be a promising way to help reduce the burden of childhood asthma in other settings.  However, more studies are needed to replicate the findings on a larger scale.