Pest Allergen Exposure Linked to URIs in Children With Asthma

In children with asthma sensitized to allergens, indoor exposures to pests like mice and cockroaches were associated with occurrence of upper respiratory infections (URIs), according to a longitudinal study reported at the recent American Academy of Allergy, Asthma & Immunology (AAAAI) annual meeting.

In this exclusive MedPage Today video, investigator Darlene Bhavnani, PhD, MPH, of Dell Medical School at the University of Texas at Austin, shares key findings from the study.

Following is a transcript of her remarks:

Most of us have seen the data that shows that there are really stark disparities in asthma exacerbations by race and ethnicity. So we know that Black and Mexican American children end up in the emergency department at somewhere between two and four times the rate of white children. So these asthma disparities are very, very well documented right now. But what is not well documented are what underlies these disparities.

One thing that we do know is that many of these asthma exacerbations are actually triggered by upper respiratory viral infections. But no one’s actually looking at whether upper respiratory viral infections underpin these disparities in asthma.

And so our group has taken it upon ourselves to really dig into this question. And in our previous analysis that we just published, we actually show that there are racial and ethnic disparities in children with asthma in the report of an upper respiratory viral infection.

So what we found was that Black and Mexican American children are twice as likely to report having one of these infections. So it’s possible that with the disparities that we see in upper respiratory infection, they might underlie the disparities that we see in asthma exacerbations. So the next question really is, well, what causes these differences in who’s getting infected? And so the work that I presented at AAAAI was really about that, was really about trying to get at the contextual factors that underpin who gets infected.

And what we do know is that Black children are more exposed to pests in the home and at school. They’re more exposed to allergens from these pests, and they’re more likely to be sensitized to these pest allergens.

So one of the other things that we know is that there’s a lot of emerging evidence to show that exposure to allergens actually affects host viral defense mechanisms. And so this really begs the question of whether somebody who’s exposed to allergens in the home may be more or less likely to become susceptible to infection.

I do want to mention that the data that we used were collected in a previous clinical trial run by my mentor, Dr. Elizabeth Matsui. And so it’s important to know that that’s how these data were collected. And they were collected from a population that was mostly Black children who were publicly insured. So this is important when we consider the generalizability of our findings.

But what we found was that exposure to certain allergens in the home was positively associated with having an upper respiratory infection with both upper and lower respiratory symptoms. So these positive associations are suggestive of the fact that someone might be more susceptible to infection and to having symptoms with their infections if exposed to certain allergens.

And the allergens that we found in particular that had positive associations were cockroach and mouse allergen, and not necessarily cat and dog allergen. So those were the four that we looked at. And interestingly, we found that amongst sensitized children, the effects were a little bit different.

So I think that these findings need to be replicated in a larger study, which is well powered to be able to look at this question. And I think it’s really important as well when we’re addressing disparities — in particular in infection or asthma exacerbations — that we include multi-ethnic and multi-racial populations.

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