Do Pets Harbor Pathogens Related to Childhood Asthma?

November 6, 2018
Amanda Carrozza

Amanda Carrozza is a freelance writer and editor in New Jersey.

As part of a larger study, investigators analyzed the presence of common respiratory pathogens in children who did and did not live with companion animals.

How does the presence of animals in the home impact children diagnosed with asthma? The answer to this question was presented at IDWeek 2018 in San Francisco, California.

A group of investigators from various schools at John Hopkins University in Maryland as well as from Dell Medical School at the University of Texas tested the hypothesis that companion animals might harbor respiratory pathogens that exacerbate asthma among inner-city children. Their work was part of a larger study evaluating microbial contributions from animals to children with asthma.


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The sample population for the study included 100 children aged 5 to 17 (36 girls, 64 boys) with confirmed asthma, some of whom had regular contact with a pet in their home. At a home visit, each child was swabbed for the respiratory pathogens Staphylococcus aureus, Moraxella catarrhalis, Streptococcus pneumoniae, and Haemophilus.

In addition, 61 study animals (29 dogs, 29 cats, 3 others) were sampled at the nares, mouth, or perineum, depending on access and temperament. Initial analysis found that male children were more likely to have a pet in the home that was not a cat or dog (e.g., a reptile), and dogs had more contact with the participants than cats did.


Of the 95 children with asthma that were evaluated, carriage of respiratory pathogens was as follows:

  • S aureus, 36.8%
  • M catarrhalis, 8.4%
  • Group A strep, 7.4%
  • S pneumoniae, 1%

In the animals sampled, 11.7% (1 dog and 6 cats, with 5 of the cats living in the same household) carried M catarrhalis and 1.7% were carriers of S pneumoniae. In the home where the dog carried M catarrhalis, the child was also a carrier.

Most notably, the investigators found that detection of M catarrhalis was 8 times more likely in children with dogs. M catarrhalis is a leading cause of acute otitis media in children, acute exacerbations of chronic obstructive pulmonary disease, and acute bacterial rhinosinusitis.


Ultimately, the investigators concluded that pets may harbor respiratory pathogens, including M catarrhalis. However, they noted that future studies are required to better determine the direction of transmission and whether pets can serve as a vehicle or reservoir of the pathogens correlated to respiratory disease in children.