A study now reveals that exposing children early to pets and germs reduces their risk of developing asthma, later in life.
Earlier, studies have shown that reducing allergen exposure in homes help control the condition when it is already established in patients.
The new finding suggests that exposure to the allergens early on in life has a preventive effect on the condition.
According to the study, contact with felines, mice and cockroaches as early as when children are three-months-old lower chance of having asthma by the time children are seven years old.
Exposure to certain bacteria in house dust during infancy was also associated with a reduce risk.
The ongoing Urban Environment and Childhood Asthma Study, funded by NIH found higher concentrations of cockroach, mouse and cat allergens present in dust samples collected from children's homes during first three years of life were linked to a lower risk of asthma by age seven.
They found an association with dog allergen as well, but it was not statistically significant, according to the researchers.
However, further study showed that exposure to higher levels of all four allergens at age three months was associated with lower risk of developing asthma.
The research further discovered that certain bacteria in house dust, present in first year of life, may protect three-year-olds from wheezing.
The findings were published in the Journal of Allergy and Clinical Immunology.