Although many people may be allergic to certain animals, a study of pet ownership has found that a particular kind of pet may actually decrease your risk of allergic reactions.
The study shows that if you own a dog, the dust in your house can be good for you. It may reduce your immune response to allergens and triggers of asthma by influencing the beneficial bacteria that grow in your digestive tract.
These same researchers have also found that babies living in houses with dogs are at lower risk of developing allergies.
A contributing factor: The house dust in a home with a dog includes a wider (and more helpful) diversity of bacteria than the microorganisms in a home without a dog.
In lab tests, the scientists found that the bacterium Lactobacillus johnsonii seems to reduce the risk for infections with respiratory syncytial virus and for allergic reactions to cockroach allergens. Those are two important risk factors contributing to childhood asthma.