Infants who share their homes with dogs during their first year of life may experience fewer common illnesses such as fever and ear infections, according to new research. The study suggests that microbes originating from dogs may play a significant role in bolstering babies' immune systems.
Researchers collected dust samples from homes with dogs and analyzed them in conjunction with health records for approximately 368 infants. The findings indicate that eight specific microbes found in the dust, derived from dogs, were associated with a baby's ability to avoid ear infections or fevers, and reduce the need for antibiotics. For instance, the bacterium Collinsella, commonly found in the digestive tracts of canines and felines, was linked to an increase in healthy weeks for infants and a decrease in antibiotic use. Previous research has also suggested that Collinsella can promote gut microbiome diversity in infants, potentially lowering the risk of allergies and asthma.
Another microbe, Pasteurella, which resides in the mouths and airways of dogs and cats, showed a strong association with reducing the duration of fever in infants, according to the study.
The study's author and pediatrician, Jenni Mäki, stated that while dog ownership already contributes to a healthier home microbiome, future research might explore ways to intentionally modify home microbiota to promote health. The benefits of a healthier first year of life extend into later childhood and adulthood. Prior research indicates that children who experience more frequent illnesses in their first three years are more than twice as likely to become ill later in childhood and require antibiotics. Early-life illnesses have also been linked to increased risks of asthma, allergies, heart disease, diabetes, and certain mental health disorders.
"Respiratory tract infections in early childhood are a significant risk factor for asthma," said chief researcher Anne Karvonen. "When some of children’s respiratory tract infections can be prevented with dog-associated microbes, this may also reduce the child’s risk of developing asthma later in life."
These findings align with the "hygiene hypothesis," which posits that an overly sterile environment can hinder the development of a robust immune system in early life. Conversely, increased exposure to diverse microbes, often facilitated by pets, may lead to a stronger immune response. Beyond microbial exposure, pets are known to offer other advantages, including reducing anxiety and stress, encouraging physical activity, enhancing self-esteem, and fostering emotional and social development in children. Toddlers with dogs have been observed to have fewer behavioral and social problems compared to their peers without dogs.